Common causes of pain in the back of the knee:

Pain behind or in the back of the knee is relatively common. The pain behind your knee can be sharp and severe; or mild and dull. In some of you, the pain in the back of the knee started after a sports injury. For others, the pain behind the knee began after bending down or even occurred at rest.

Pain in the back of the knee can occur with or without swelling or a feeling of fullness. Most causes of pain in the back of your knee are straightforward, and others might need urgent attention. In this post, we will review some of the most common causes of pain in this region of your knee.

What’s behind your knee? A brief anatomy lesson.

The back of the knee is a complicated area. There are several critical structures back there. From a functional perspective, we have many muscles, such as the hamstring and calf muscles. The hamstrings start at the pelvis, cross the back of the knee, and attach to your tibia or shin bone. The calf muscles start on the back of your thigh bone or femur, cross the knee and form the achilles tendon, which attaches to your heel.

From the Medical Media Group.

Behind our knee, we have critical structures such as the popliteal artery and the nerves to the leg. The nerves are the peroneal nerve and the tibial nerve. The peroneal nerve is a troublemaker sometimes. It doesn’t cause pain in the back of your knee but can cause pain elsewhere. We discuss the peroneal nerve elsewhere on this page.

Most people think their knee joint is in the front. But the back of our knee goes further back than we think. The attachment of both the medial and lateral meniscus is in the back of the knee. These meniscus attachment points are called roots. Root tears can be a cause of severe knee pain which may start in the back of your knee. We cover root tears of the meniscus in this post.

There is cartilage on the bones in the back of the knee. Osteoarthritis can start back there, so the first sign of osteoarthritis could be pain in the back of your knee.

Many of these structures in the back of the knee are capable of causing pain. Because of the complicated anatomy, a proper examination, Xrays, and perhaps an MRI will be useful in determining which structure could be the cause of your pain. Once the cause of the pain is determined, the best possible treatment can be recommended.

Below we are going to cover some of the more common causes of pain behind your knee.

First, we will list the potential causes of pain behind your knee, then we follow through with a more detailed discussion of each potential cause of pain.

  • Swelling due to a Bakers cyst: A Bakers cyst is a common cause of swelling and pain behind your knee.
  • Root tears of the meniscus
  • Hamstring injury: usually occur higher in the thigh.
  • Tears of the posterior horn of the medial meniscus
  • Deep vein thrombosis — or a blood clot in the back of your leg
  • Overuse syndromes in runners and athletes.- usually causing a grinding or snapping in the back of the knee.
  • Osteoarthritis: probably the most common cause of pain. Often due to swelling and inflammation.
  • Nerve pain- the pain of sciatica can radiate to behind your knee

DVT: Deep vein thrombosis can cause pain in the back of your knee and calf

Deep vein thrombosis or DVT can cause pain in the back of your knee… but the pain is not often isolated to the back of the knee. There is usually calf pain, calf swelling and perhaps thigh pain too. A DVT is not a common cause of pain and swelling, but I list it first because it can be a worrisome cause of pain.

Usually, the pain from a DVT will also occur in the back of your calf or your inner thigh. While not impossible, the pain can be isolated to just the back of your knee. Most people with a DVT will also have swelling in their calf or leg. In people who are obese, swelling of the leg is not uncommon so swelling alone does not mean you have a DVT.

People who are at risk for a DVT include people who are obese, have cancer, chronic diseases, and those of you who recently traveled and sat still for hours/days while recovering from illness, injury, or surgery. We do not know the exact incidence of people walking around with a DVT. People who recently had surgery are at an increased risk for a DVT. If your calf is tender and swollen and the back of your knee hurts, you need to see your doctor urgently or go to an emergency room.

Meniscus tears and pain behind your knee

Root tears of the meniscus are prevalent. The “root” of a meniscus is where the meniscus attaches to the shin bone or tibia. Much like a tree roots into the ground, the meniscus has a firm, deep attachment to your bones as well.

Sadly, over the years, these attachment points or roots can weaken. A common story is that you bent down or knelt and felt a pop in the back of the knee. Later that day or two days later, your knee is swollen, and the pain is very severe. The root of the meniscus tore in this situation because it had degenerated from decades of activity.

The pain from root tears often subsides over the next few weeks to months. By the time you see a doctor, and they order an MRI, the pain is often starting to improve. This post below goes into far more detail about root tears as the cause of pain in the back of your knee.

The meniscus is a shock absorber. When the root of the meniscus tears, the meniscus no longer works as a shock absorber. Therefore, following a root tear, you may develop stress fractures or stress reactions. That is why the pain worsens a few days after you felt the pop.

This post goes into detail about how root tears cause these stress fractures and how they can be treated. This is usually a situation where you have very severe pain and require crutches for support. As I have talked about elsewhere, root tears will often cause a significant stress reaction or a stress fracture. When root tears lead to a stress reaction, the pain will often move from behind the knee to the inner side.



On some occasions, we need to consider surgery to repair these root tears… but this is not usually necessary.

Pain behind the knee in runners

Overuse syndromes are prevalent in runners. Most runners are going to experience an overuse injury during their running careers. The most common cause of pain behind the knee in runners is due to a hamstring strain. Hamstring strains that occur around the knee tend not to be as painful or as chronic as those that occur up higher in the buttock region.

Runners should consider shortening their stride and increasing their cadence, as well as avoiding hills for a few weeks. In most cases, this approach should enable a painful hamstring to settle down.

A less common cause of pain in the back of the knee in a runner is bursitis that occurs where a few tendons cross over and therefore rub against each other. The pain is usually associated with a grinding or snapping sensation as you squat down. The grinding sensation is due to the hamstring tendons being irritated from rubbing against each other.

Some believe the location of this friction might be due to one of your calf muscles rubbing along one of the hamstring muscles in the back of the knee. This has also occurred in some patients after a hamstring ACL reconstruction. Surgical treatment is rarely necessary for this situation.

In runners, the pain in the back of the knee will usually subside with a change in their running style (shorter stride, higher cadence) and workout schedule. Physical therapy may be useful, as well.

Bakers cyst and pain in the back of the knee

A Bakers cyst is a fluid-filled pocket in the back of the knee. Bakers cysts are a common cause of painful swelling. If the cysts are small, they do not create much discomfort.

A Bakers cyst can grow larger. If a cyst becomes large, it can put pressure on the muscles, blood vessels, and nerves behind the knee and can cause discomfort. Most people with a Bakers Cyst will also have osteoarthritis.

In most instances, treatments to diminish the swelling associated with arthritis will help reduce the pain and swelling from the cyst. In the majority of cases, these cysts are not dangerous. An ultrasound can usually tell if you have a simple cyst versus something more complex that warrants further evaluation with an MRI. If the Bakers cysts are huge, then one treatment alternative is to have the fluid drained. While that will result in relief of pain, the fluid might come back again.

Read more about a Bakers cyst.

Osteoarthritis and pain in the back of the knee

Osteoarthritis is a widespread cause of pain behind your knee. Some of you might also note that you have a loss of motion and can not fully bend the knee. The pain from arthritis can be due to inflammation of the structures behind the knee. That irritates the lining or inside of the knee joint and makes the joint stiff and painful.

If osteoarthritis is causing pain in the back of the knee you might note that the pain can refer up the back of the thigh, or down into the calf. Many of you with arthritic knee pain will benefit from wearing a compression sleeve or brace. You will also find that gentle stretching, an ice pack, or a warm compress can help calm arthritic pain.

If the pain does not improve over a few days, consider seeing your doctor to look into why the back of your knee hurts.

Hamstring Injuries

Hamstring injuries are a prevalent injury in sports. Hamstring injuries usually occur higher and in the back of the thigh up near the pelvis. We discuss hamstring injuries and some of the difficulties in managing them here and here. It is possible to injure the hamstring near the back of your knee too.

Usually, the pain from a distal hamstring injury is about 4-6 inches above your knee. The pain from a lower hamstring injury will be most severe immediately after the injury and start to improve within a few weeks. It is important to begin stretching the hamstrings as soon as you tolerate it to prevent stiffness.

Nerve Pain

Nerve pain can be present in the back of the knee. Nerve pain generally radiates to the back of the knee from higher up the leg or buttock area. The nerves are rarely a cause of pain that is isolated to the back of the knee and doesn’t radiate anywhere else.

Pain in the back of the knee is common but can be non-specific. There are many reasons why the back of your knee might be bothering you. I hope you find this short guide useful in determining the possible causes of your pain.

Disclaimer: this information is for your education and should not be considered medical advice regarding diagnosis or treatment recommendations. Some links on this page may be affiliate links. Read the full disclaimer.

Pain at the back of the knee is known as posterior knee pain. Here we explain the common causes of both sudden onset and chronic (overuse) pain behind the knee. Acute posterior knee pain is sudden onset and includes sprains and strains. Gradual onset, or chronic knee pain develops over time and is often caused by overuse.

Quick links:

If you are not sure what is causing your knee pain, try our sports injury symptom checker.

Acute pain behind the knee

The most common causes of sudden onset pain behind the knee:

Hamstring tendon strain

A hamstring tendon strain is a tear of one of the hamstring tendons. This is usually the biceps femoris hamstring muscle, at the point of insertion at the back of your knee. It is more common in sprinters or sports involving kicking. Symptoms include:

  • A sudden sharp pain in the back of your knee.
  • You may have swelling, tenderness or heat at the site of injury.
  • It is important to get an accurate diagnosis and rule out a complete rupture or an avulsion strain.

Read more on biceps femoris tendon rupture.

Biceps femoris tendon avulsion

An avulsion strain occurs when a tendon tears pulling a small piece of bone with it. Like a Biceps femoris tendon strain, this occurs through sprinting or kicking activities. If you suspect you have an avulsion injury, seek professional advice. An X-ray is needed to confirm the diagnosis. Symptoms of an avulsion strain:

  • A sudden severe pain at the back of your knee (similar to that of a hamstring tendon strain).
  • Sudden swelling and tenderness at a point on the back of your knee.

Read more on biceps femoris tendon avulsion

Posterolateral corner injury

The Posterolateral corner of the knee consists of a number of structures. It is a less common cause of pain at the back and outside of the knee. Symptoms can include any of the following:

  • Pain and swelling at the back, and outside of your knee.
  • Tenderness on the outside of your knee when pressing in.
  • Knee joint instability.

Read more on Posterolateral corner injury

Chronic pain behind the knee

Pain at the back of the knee may occur gradually. You are unlikely to be able to pinpoint the exact time your injury occurred. These injuries often start out as a ‘niggle’ which you will attempt to ignore. Eventually they become progressively worse.

Chronic knee injuries can be more difficult to treat so do not ignore the early signs!

Baker’s Cyst

A Baker’s Cyst or Popliteal cyst is a swelling that protrudes out the back of the knee. It is often about the size of a golf ball but can vary over time. Symptoms consist of:

  • You will feel sensation of pressure in the back of your knee.
  • You will have difficulty bending the knee.

Read more on Baker’s Cyst.

Gastrocnemius tendinopathy

Gastrocnemius tendinopathy (or tendinitis) is inflammation (or more likely degeneration) of the calf muscle tendon at the back of the knee. This is an overuse injury which is more common in runners and sprinters. Symptoms include:

  • Gradual onset pain behind the knee, often localized to a specific point.
  • Your knee will feel tender when pressing it at the back of your knee.
  • Going up on tip toes with your legs straight may be painful.

Read more on Gastrocnemius tendinopathy.

Biceps femoris tendinopathy

Biceps femoris tendinopathy or biceps femoris tendonitis is inflammation (or more likely degeneration) of the hamstring tendon where it inserts at the back of your knee. Symptoms include:

  • Tenderness and swelling at a specific point at the back of your knee.
  • Pain is likely to have developed over time.
  • You may have stiffness in the morning, or after sitting for long periods.

Read more on Biceps femoris tendinopathy.

Popliteus strain/tendinopathy

The Popliteus is a small muscle located at the back of the knee. The muscle, or tendon can be torn, especially from twisting activities, or injuried through overuse. Symptoms may include:

  • Acute (sudden onset), or gradual onset pain behind the knee.
  • The back of your knee will feel tender when pressing in.
  • Trying to bend your knee against resistance, whilst your tibia (shin) bone is turned outwards is a specific test used to help diagnose a Popliteus injury.

Read more on Popliteus strain/tendinopathy.

Referred knee pain

Posterior knee pain can be caused by injuries or dysfunction in the lower back and hips. Symptoms may include:

  • Sciatic pain which radiates down into the back of your leg, knee and/or lower leg.
  • The slump test is to identity sciatic type referred pain referred pain.

Knee joint swelling

Swelling within the knee joint is a symptom rather than a specific injury. Swelling alone can be enough to cause pain and tightness behind the knee. A full knee assessment should be done to identify the root cause of any effusion (swelling). Previous injuries can often be the cause of chronic knee swelling and development of a Baker’s Cyst.

Immediate first aid for knee injuries

All acute knee injuries should be treated using the P.R.I.C.E. principles (protection, rest, ice, compression & elevation). You should apply the PRICE principles for at least the first 2 – 3 days.

  • Protect knee from further damage. Rest to allow healing to take place
  • Apply ice or cold therapy to reduce pain, swelling, and inflammation.
  • If you have swelling then then apply compression and elevate your knee to allow tissue fluids to drain away.

Read more on first aid for knee injuries.

When should I see a doctor?

The majority of knee injuries, especially minor ones, can be treated at home. However, if you have any of the following symptoms you should seek medical assistance.

  • Severe pain in or around the knee, especially during walking.
  • Severe swelling (oedema) in the knee.
  • An audible “pop” or “crack” in the knee joint that is painful.
  • A “giving way” feeling in the knee during walking or going up/downstairs.
  • A feeling when the knee “locks” whilst bending or straightening it.
  • Altered sensation in the foot – such as a feeling of “pins and needles” (paresthesia) or a “loss of feeling” (anesthesia) in the lower leg.
  • Inability to complete your normal daily activities after the initial 72 hours.

Read more on when to see a doctor about your knee injury.

References & further reading

  • Fritschy D, Fasel J, Imbert J-C et al. The popliteal cyst. Knee Surg Sports Traumatol Arthrosc 2006;14:623–8.

This article has been written with reference to the bibliography.

Baker’s Cyst: A Common Type of Knee Pain

One condition that can cause knee pain is called Baker’s cyst, named for Dr. William Morrant Baker, the 19th-century physician who described it.

Baker’s cyst (also called popliteal cyst) is a fluid-filled swelling that appears at the back of the knee when the fluid sac that lubricates the knee (called a bursa) bulges out of the joint. Though a Baker’s cyst is usually small, in extreme cases the cyst can grow to the size of a baseball size.

In adults, Baker’s cyst typically results from an underlying problem in the knee. In active people, this may be a tear in the cartilage that is supposed to keep the bursa within the knee joint. In older people, deterioration of the knee joint from osteoarthritis may be the underlying problem. In either case, inflammation in the joint produces excess synovial fluid in the bursa, which increases the pressure in the sac, distends it, and forces it out of the joint.

“Anywhere from 10 to 25 percent of people with any kind of knee problem at all — arthritis, injury, or trauma — will wind up getting Baker’s cyst. It’s usually a secondary complaint,” explains Robert Gotlin, DO, director of orthopedic and sports rehabilitation at Beth Israel Medical Center in New York City.

In children, Baker’s cyst also can occur when a normal bursa forms an abnormal connection to the knee joint.

A small Baker’s cyst is generally painless, but as a cyst grows larger it can cause stiffness and pain behind the knee. Patients often complain of a feeling of tightness behind the knee when it is flexed past 90 degrees or a pulling sensation when the knee is straightened. If the cyst ruptures, it can be quite painful and produce a bruised area on the back of the knee and the calf.

Diagnosing Baker’s Cyst

Diagnosing Baker’s cyst usually is not difficult, especially if the patient is known to have another knee problem. The first thing a physician or orthopedist will do is look for the characteristic swelling at the back of the knee. If the cyst is not obvious, the physician may compare the affected knee to the unaffected knee to discern the swelling.

If the cyst has bruising associated with it, as with a rupture, the examining doctor will take pains to make sure that it is a ruptured cyst and not a deep venous thrombosis (blood clot), which can be dangerous and requires immediate medical intervention.

Sometimes the physician will use a technique called transillumination, in which the examination room is darkened and a bright halogen light is shone through the cyst to tell if it is a solid mass or fluid-filled.

If the suspected cyst exhibits any unusual signs, like rapid growth or severe pain, or if it is accompanied by fever, the physicians may order an X-ray or magnetic resonance imaging (MRI) to see if the mass might be a tumor. An X-ray can identify undiagnosed arthritis, while an MRI can visualize the cyst or undiagnosed meniscal injury.

Treating Baker’s Cyst

There are several options in the treatment of Baker’s cyst.

  • Watch and wait. Baker’s cyst is often not treated specifically, though the underlying condition — such as arthritis or meniscal tear — may require treatment. If no treatment is planned for the underlying condition, the physician may recommend that the patient wear an elastic knee bandage and monitor the cyst to see if it gets larger. A Baker’s cyst usually goes away on its own, but it can take months or even years.
  • Treatment to reduce inflammation. If the cyst causes discomfort, the physician may recommend anti-inflammatory medications or cortisone injections in the knee to reduce inflammation.
  • Aspiration or surgery. If the cyst causes pain or inhibits freedom of movement, the physician may recommend that it be drained of fluid (aspirated), but this does not address the underlying problem and the cyst will often return. If the cyst becomes so large that it threatens to compress blood vessels supplying the lower leg, the physician may recommend it be surgically removed. Surgery to remove a Baker’s cyst is rarely resorted to because there is the risk of damaging blood vessels and nerves that pass through the back of the knee.

Preventing Baker’s Cyst

While there is no specific prevention for Baker’s cyst, people with knee problems can reduce their risk by taking care not to overstress their knee joint or by treating the underlying joint problem. More generally, an anti-inflammatory or low-salt diet can help reduce inflammation that contributes to the condition.

“If you are prone to the cyst, you need to curtail certain exercises,” says Gotlin. “The cyst is at the attachment of the hamstring muscles, and those muscles flex the knee, so you need to be cautious about overdoing exercise using the hamstring muscles.”

Burning Knee Pain

How to Help Ease Burning Knee Pain

Relief of burning knee will vary depending on the cause of the knee injury. After your doctor determines the cause of the burning sensation in your knee, then he will suggest a form of treatment. Here are some common ways to help manage burning knee pain:

For burning knee pain caused by recent trauma to the knee, such as an injury during sports, the RICE method (rest, ice, compression, elevation) should be applied as first aid. Knee strain and sprains may recover on their own over time, but a more severe injury such as a ligament tear or cartilage tear (meniscus tear) may require surgery.

For burning knee pain caused by recent trauma to the knee, such as an injury during sports or from falling, the RICE method (rest, ice, compression, elevation) should be applied as first aid. Knee strain, sprains, and bone bruises may recover on their own over time, but a more severe injury such as a ligament tear or cartilage tear (meniscus tear) may require surgery. Consider wearing a mild support knee brace as you wait to see a doctor.

For overuse injuries causing a burning sensation in the knee, rest is usually suggested. You may have tracking issues with your patellar and a patellar stabilizing knee brace might help. If the area is inflamed then over the counter medications such as ibuprofen and aspirin will help reduce the inflammation.

For burning knee pain due to arthritis, mild exercise or physical therapy may be the ideal solution. Your physician may also suggest wearing a knee brace for arthritis since they help transition stress from the unhealthy areas of the knee to the healthier, stronger areas – minimizing the burning sensation.

If you feel burning in your knees at night, at rest, or while sitting, you may have a more serious knee injury. Follow the RICE method to help alleviate the pain. Consider wearing a knee sleeve throughout your daily activities to compress the area and help give added support to your knee and the muscles surrounding the area.

There may be other forms of treatments that may be used to treat burning sensations in the knee. It can vary greatly depending on if you have a burning sensation behind the knee, a kneecap burning sensation, burning on the sides of knee, or burning knee pain all over. Again, be sure to check with your physician before pursuing any form of treatment for your burning knee pain.

Many people wonder if they can keep running, participating in their sporting activities, or job when they are feeling burning pain in their knees. This is up to the discretion of your physician. However, if you do choose to continue your activity prior to consulting a doctor, consider wearing a knee brace with moderate support for added stability.

Pain/weird sensation BEHIND right knee

>I haven’t seen a doctor because I’m working super crazy hours
>but, weirdly the pain is no longer constant and is almost
>gone. I’ll wait a bit and see if it returns and then I’ll
>act. It just freaked me out because it felt like something
>had snapped loose.
>A needle in her knee? Holy cow!
I am the last person who should give you advice. I have a mild, intermittent pain in the front of my knee and am in denial that I should slow doen on intensity until it blows over. I am too scared to go see a doc to get it properly diagnosed because I dont want to hear “Stop working out.”
So I am doing my own set of precautions, avoiding some exercises that I feel are bad, icing, wearing a knee guard and hoping!
I already know very well that the knee is a very complex structure and that issues are easier to treat early. When they become acute, recovery is tougher and less likely to be complete. A physio once told me the knee is a “good” body part. It usually gives mild warning of an upcoming serious over-use issue well in advance. Treated early, the knee makes good recovery so the person can continue athletic activity for years to come. However moset people ignore the knee because early warnings are not debilitating.
I resolved to go see a PT or doc from sports medicine (less likely to make blanket “dont exercise” prescriptions). Yet to get around to it.
Good luck.
~* Vrinda *~

What causes pain behind the knee?

It may be important to work closely with a doctor to diagnose pain in the back of the knee, as some causes require long-term treatment to heal completely.

Possible causes for pain in the back of the knee include:

Leg cramps

Share on PinterestLeg cramps commonly cause pain behind the knee.

Cramps are when muscles become too tight. This tightness may be because the muscle is doing too much work without being stretched. If it is stretched and still cramps, the muscle may simply be overused.

Overuse syndrome can affect different areas of the knee. A person might feel a cramp in the thigh or calf near the knee.

The sensation resembles a sudden, painful spasm of the muscle. The pain may last seconds or minutes and can range from uncomfortable to severe.

Other possible reasons for leg cramp include:

  • dehydration
  • infection such as tetanus
  • liver disease
  • excess toxins in the blood
  • nerve problems

Women who are pregnant may also experience leg cramps as a normal side effect of pregnancy.

Some people who often experience leg cramps may find relief through regularly stretching their calves. Also, they can try shortening their stride to put less strain on the knee and surrounding muscles.

Baker’s cyst

A Baker’s cyst is a pocket of fluid that builds up in the back of the knee, leading to pain and swelling.

Baker’s cysts may not be noticed at first, as small cysts do not typically cause pain. However, as the cyst grows, it may shift the surrounding muscles or put pressure on tendons and nerves, causing pain.

Baker’s cysts may grow to about the size of a table tennis ball. People with Baker’s cysts often feel pressure in the back of the knee, which may cause a tingling sensation if the cyst is hitting a nerve.

In most cases, Baker’s cysts are not a cause for concern, but treatment can relieve the symptoms.


Osteoarthritis is a condition that wears down the cartilage of the joints over time. This condition can easily cause pain in the back of the knee.

People with osteoarthritis in the knee may display other symptoms, such as loss of motion or difficulty bending the knee. Inflammation in the joint may make it stiff and painful. This discomfort may also be felt anywhere around the knee.

Other forms of arthritis that could be causing the pain include autoimmune diseases, such as lupus and rheumatoid arthritis.

Runner’s knee

Share on PinterestRunner’s knee is when the cartilage in the knee joint wears down.

Runner’s knee is the wearing down of the cartilage in the knee joint. When the cartilage is gone, the bones of the knee rub together. Typically, this causes a dull, aching pain behind the knee.

Other symptoms of runner’s knee include:

  • the knee giving out or buckling randomly
  • weakness in the knee and leg
  • restricted movement in the leg and knee
  • crackling or grinding feeling when the knee bends

Hamstring injury

A hamstring injury is a tear or strain in one or more of the muscles in the back of the thigh.

These muscles include:

  • the biceps femoris
  • semitendinosus
  • semimembranosus

A hamstring strain happens if the muscle is pulled too far. It may tear completely from being pulled too much and can take months to heal fully.

Hamstring injuries may be more common in athletes who run fast and in bursts, such as those who play basketball, tennis, or football.

Meniscus tears

The meniscus is a piece of cartilage on either side of the knee. Twisting motions while squatting or bending the leg may tear this cartilage. Many people hear a pop when they tear their meniscus.

The pain from a meniscus tear may not show up at first but worsen over the next couple of days.

Meniscus tears often cause other symptoms, including:

  • loss of knee motion
  • weakness and fatigue in the knee and leg
  • swelling around the knee
  • the knee giving out or locking up when used

Surgery may be required if a meniscus tear is severe and does not heal on its own.

ACL injuries

The anterior cruciate ligament or ACL is a band of tissue that runs through the front of the knee joint, connecting the bones and helping to keep the knee joint stable.

ACL strains often happen from sudden stops or changes in direction. Similarly to meniscus tears, a strain in the ACL may cause a popping sound, followed by pain and swelling.

A torn ACL is a well-known, serious injury, often side-lining an athlete for a long time. Torn ACLs usually require reconstructive surgery.

PCL injuries

Share on PinterestPCL injuries may occur because of a traumatic injury. Surgery and rest are usually recommended treatments.

The posterior cruciate ligament or PCL plays a similar role to the ACL, though it is less likely to be injured than the ACL.

PCL injuries may happen during traumatic events, such as falling directly on to the knee from a height or being in a car accident. With enough force, the ligament may tear completely.

PCL injuries cause symptoms including:

  • knee pain
  • stiffness in the knee if bending
  • trouble walking
  • swelling in the knee

Completely resting the knee may help a PCL strain to heal. A severe PCL injury may require surgery.

Deep vein thrombosis (DVT)

A thrombosis is a blood clot, and a DVT occurs when a clot happens in the veins deep within the leg.

Many people who have a DVT feel more pain when they stand up. Nevertheless, they may feel pain in their leg and knee at most times.

Other symptoms of DVT may include:

  • skin that is red or warm to the touch
  • swelling in the area
  • fatigue in the affected leg
  • prominently visible surface veins

Risk factors for DVT can include being overweight, being older, and smoking. People who lead sedentary lifestyles may also experience DVT.

DVT needs medication and care, as it can become more serious if the clot breaks loose into the bloodstream.


16th October 2018 By Mr. Sam Rajaratnam FRCS (Tr. & Ortho)

Because your knees bear the body’s weight and are subject to movement in a number of planes they can be quite vulnerable to trauma and to conditions resulting from trauma and wear and tear.

There are a number of different types of condition which can cause pain to the back of the knee. These include strains or tears to the muscle or tendons, damage to the ligaments, damage to the cartilage within the knee joint, excess fluid in the knee or blood vessel problems.

The information given below will give you an indication of the problem you may be having, but is not intended that you diagnose yourself. Also this guide is intended for pain behind the knee itself; if your pain is part of general joint pain there will be other reasons for this and you should consult a doctor.


The shallow depression formed at the back of the knee is called the popliteal fossa; it is formed at the junction of the femur and tibia. There is a muscle here on the floor of the popliteal fossa which is the deepest muscle of the knee joint. It works on the femur to rotate it on the tibia when walking. Through the popliteal depression a bundle of muscles (the semimembranosus, semitendinosus and biceps femoris) run from the pelvis to the knee and attach to the tibia and fibula respectively by tendons. These three muscles are collectively called the hamstring muscles, and function to extend the leg and bend the knee.

At the back of the lower leg the calf muscles are composed of the gastrocnemius and soleus muscles which flex the leg at the knee and flex the ankle via the achilles tendon.

Pain behind the knee when walking or running

The cause of pain at the back of the leg behind the knee could be hamstring tendonitis. This is caused by the tendons of the hamstring becoming inflamed, often due to overuse of the hamstring muscles, but the pain will subside after rest and first aid centred on the ‘RICE’ method (Rest, Ice to reduce the swelling, apply a Compression bandage and Elevate the knee).

If you notice a sudden sharp pain in the back of the thigh when undergoing vigorous exercise this may be due to a pull, partial tear or tear of the hamstring, and is due to overloading the muscle. This type of injury is most often treated by a doctor. A similar pain in the calf may be due to gastrocnemius tendonitis.

A tenderness behind the knee, felt when rotating the leg inwards in the act of walking could denote an injury to the popliteus muscle. A cold pack applied for 10 minutes every hour for the first day after injury can alleviate the symptoms.

All the muscles at the back of the leg can be subject to cramp. This is a common condition and occurs when a muscle goes into spasm. The symptoms are a tightening of the muscle accompanied by pain. Amongst other causes, it could be due to dehydration, muscle fatigue or a restriction of the blood supply to the affected muscles. Cramp is not serious and can be relieved by relaxing, massaging and stretching the affected muscle.


Ligaments are strong, flexible, fibrous and elastic connective tissue which connect one bone to another, provide stability and support joints. They do not connect muscles to joints, that is done by the tendons.

The ligaments of the knee comprise the medial and lateral collateral ligaments, on the inside and outside of the knee respectively, which give sideways stability to the knee joint, and the anterior and posterior cruciate ligament at the front and back of the knee. There is also a patellar tendon, which is really a ligament, which attaches the bottom of the patella to the top of the tibia.

A sudden severe pain or ‘popping’ sound accompanied by swelling and a feeling of looseness of the joint and instability

This may be due to damage to one of the knee ligaments, and is commonly seen as a result of sports injuries concerned with a sudden impact, twisting or over stretching. If the ligament is torn or twisted it is a sprain (equivalent to a strain in a muscle or tendon). If you suspect a damaged ligament you should comply with the ‘RICE’ procedure, but not immobilise the joint as there is a risk of stiffness and possible muscle atrophy. The injury should be clinically assessed, and may need surgery.

Pain behind the knee when bending it or pain and stiffness below the kneecap

Although not behind the knee, the patellar tendon can be overloaded and torn by repetitive actions such as jumping, running or kicking. This is called patellar tendonitis, and can get progressively worse as the the torn tendon swells and becomes weaker. Again the RICE formula should be applied, and your doctor should be consulted.

Pain, swelling and a bony lump below the kneecap, typically in children or adolescents

The patellar tendon can also be a factor in both Osgood-Schlatter’s Disease and Sinding-Larsen-Johansson Syndrome, where it become inflamed at its attachments to bones during growth spurts together with inflammation of the growth plates. This typically occurs in children or adolescents and often heals of its own accord, but your doctor may prescribe physiotherapy, knee protection or other measures.


In the knee joint the ends of the femur and tibia are enclosed within a synovial joint. This synovial joint has a synovial capsule enclosing both the articular cartilage on the end of your femur and tibia, and the synovium. The synovium contains loose connective tissue, blood vessels, lymphatic vessels and cells which produce synovial fluid to lubricate the joint.

A swelling at the back of the knee and calf causing pain, and a feeling of tightness when straightening the leg

This may be due to a Baker’s Cyst, which is an accumulation of synovial fluid in the popliteal fossa. The synovial fluid is over-produced, due often to a trauma to the knee or in conditions such as arthritis. The cyst may clear up on its own, but if not it is advisable to visit the doctor.
Swelling in the knee joint due to extra synovial fluid being produced also occurs due to accidental damage to the knee or when osteoarthritis is present.


There are two triangular, or wedge shaped, pieces of cartilage in the synovial joint which are called menisci. One lies on the inside, or medial side, of the knee, and one on the outside or lateral side. They act as shock absorbers between the femur and tibia, the end surfaces of which also have a cartilage covering called articular cartilage. At the front of the synovial joint is the patella which is an oval bone protecting the front of the joint and lined internally with cartilage.

A popping sensation behind the knee or pain and stiffness at the side of the knee

May be the result of a torn meniscus, particularly the posterior horn of the meniscus. This can often occur due to an impact or twisting sports injury, and is more likely as one gets older and the meniscus becomes worn. Pain might not be evident until some time after the injury occurred. RICE may temporarily alleviate the symptoms, but the tear will often require a surgical procedure.

Discomfort, aching and tightness in the knee, grating and pain behind the kneecap when bending the knee or when it is exercised after a period of rest

May be due to chondromalacia patella. In this condition the cartilage on the underside of the patella softens and deteriorates. Some people are able to ignore the condition, but it will not improve and will probably need surgery. Sometimes an unstable flap of surface cartilage may cause this pain, and may be curable with simple keyhole surgery and a chondroplasty.

Pain and stiffness. A grinding sound when the knee is bent. Perhaps swelling of the knee and a feeling of instability

These are often the symptoms of arthritis. Although there are many different forms of arthritis, osteoarthritis is the most common. It is more likely to affect women than men, and, if it occurs, it is more prevalent after middle age. It is caused by erosion of the articular cartilage within the synovial joint, so that the bone of the femur and tibia come into contact and rub against each other causing pain and inflammation. Osteoarthritis is often due to normal wear and tear over a period of time, although injury, repetitive activity, obesity and genetics can also be factors. There is no cure for osteoarthritis, and, although various methods can temporarily mollify the symptoms, surgery is the only permanent solution to eliminate pain and increase mobility.


The popliteal artery and its accompanying vein are major blood vessels at the back of the knee. The artery branches off from the large femoral artery which runs down from the top of the leg, and divides into several other significant blood vessels around the distal end of the femur and proximal ends of the tibia and fibula. The popliteal vein follows the path of the artery and carries blood back to the heart.

Aching, cramp, tiredness or numbness at the back of the knee and calf

Is most likely due to Popliteal Artery Entrapment Syndrome, where the artery becomes compressed due to pressure on it from the muscles and tendons around the knee. The blood supply to the artery is reduced or cut off. This can occur due to overuse or because of athletic activity, particularly if the calf muscles and muscles around the artery become over-developed due to exercise. Normally the artery will simply recover, but if the problem is persistent medical help should be sought.

Pain, tenderness, warm or red skin or a swelling behind the knee

May be the indication of a blood clot in the popliteal vein. This is also called a thrombosis, and the block would restrict the circulation of blood in your leg. More importantly a clot could form an aneurysm, which is an abnormal bulging in the vein walls, and could lead to a pulmonary embolism. If you suspect you have a blood clot it is imperative that you see a doctor as soon as possible. Your body can eventually break up small clots, but you may be sent for a CT scan to investigate the blood clot and given a prescription for blood-thinning medication.


If you are at all worried about any symptoms you experience, and certainly if you suspect a blood clot, you should consult your doctor. In addition any knee pain, swelling or reduced mobility that lasts for more than 48 hours needs a doctor’s opinion.

Pain Behind the Knee / In Back of Knee

Back of Knee Anatomy

The knee is one of the largest and most complex joints in the human body. If you think about it, your knee supports almost all of your body weight, which is a big job in itself. Not to mention, the added work your knee puts in when you decide to walk, run, jump or skip. It’s no mystery why knee injuries are so common.

If you understand how your knee works and the parts within it, you will be able to easier identify the cause of your knee pain. The knee is made up of bones, ligaments, tendons, and muscles.

Ligaments join the knee bones and provide stability to the knee.

There are four major ligaments in the knee:

  1. Anterior cruciate ligament
  2. Posterior cruciate ligament
  3. Medial and lateral collateral ligaments
  4. Patellar ligament

Tendons connect the knee bones to the leg muscles that move the knee joint.

There are two major tendons in the knee:

  1. Quadriceps tendon: connects the quadriceps muscles to the kneecap
  2. Patellar tendon: connects the keep cap to the shin bone

Take this short quiz to identify the cause of your knee pain:

12 Common Causes of Pain Behind Your Knee

  1. Pain Behind Your Knee from Popliteal Cysts or Baker’s Cyst

    This is a fluid-filled cyst that creates a bulge on the back of your knee or the area specifically called the popliteal fossa. This occurs when a problem with your join causes your knee to produce too much fluid. Any type of condition that causes joint swelling can lead to a popliteal cyst.

    Symptoms of a popliteal cyst:

    • Swelling behind knee and leg
    • Knee pain
    • Stiffness and inability to flex knee

    Causes of a popliteal cyst:

    • Inflammation of knee joint
    • Arthritis
    • A knee injury or cartilage tear
  2. Back of Knee Pain from Hamstring Tenonitis

    There are soft tissues that connect all of your back thigh muscles to the pelvis, knee and lower legs. Hamstring Tendonitis occurs when that tendon, or soft tissue, becomes damaged or inflamed due to strain or force being placed on the tendon. The RICE method (rest, ice, compress, elevate) can be a good way to treat this. In order to compress your hamstring, a thigh compression will do the trick.

    Symptoms of hamstring tendonitis:

    • Pain in back of knee or leg
    • Swelling
    • Muscle weakness

    Causes of hamstring tendonitis:

    • Overuse
    • Excessive speed changing while running
    • Insufficient warm-up
    • Poor core strength
  3. Popliteus Muscle Injury

    The popliteus is a small muscle located at the back of your knee. This muscle is used for unlocking your knees when walking. In order to treat this injury, it may be helpful to apply a cold pack for 10 minutes every hour in the first 24 hours of your injury.

    Symptoms of a popliteus muscle injury:

    • Tenderness when pressing back of your knee
    • Pain when your leg is rotated inward

    Causes of a popliteus muscle injury:

    • Overuse
    • Sudden twisting
    • Falling or collision
  4. Pain Behind Your Knee from a Blood Clot

    The popliteal vein is one of the major blood vessels in the lower body and runs up the back of the knee. If a blood clot (also called a thrombosis) occurs, it can block the vein and restrict circulation in your leg.

    Symptoms of a blood clot:

    • Pain, swelling and tenderness in back of knee
    • Skin may feel warm to the touch
    • Calf cramping

    Causes of a blood clot:

    • Smoking
    • Drug use
    • A major injury
    • Chronic inflammation, which injures the inner lining of the vein
    • Obesity
  5. Knee Pain from Nerve Damage or Artery Compression

    Popliteal Artery Entrapment Syndrome (PAES) is a condition where the artery becomes compressed and blood flow is restricted to the lower leg, damaging the artery. The muscle and tendons near the knee are positioned so they compress the popliteal artery. In most cases, this condition will treat itself. If symptoms don’t improve, medication and physical therapy may be needed.

    Symptoms of nerve damage or artery compression:

    • Aching pain, numbness, or tiredness
    • Cramping calf
    • Symptoms will go away in 3-5 minutes

    Causes of nerve damage or artery compression:

    • Overuse
    • Running or kicking activity
    • At higher risk if you are a male athlete under age 30
  6. Posterior Horn Meniscus Tear

    The meniscus is a thin, fibrous cartilage that is in between the joints in your body. This is an extremely important part of your knee since it distributes the weight in your knee muscles. The most common location for a meniscus tear is in the posterior (back side) or your knee.

    Symptoms of a posterior meniscus tear:

    • Pain
    • Swelling and stiffness, increasing gradually after injury
    • Instability
    • Difficulty straightening knee

    Causes of a posterior meniscus tear:

    • Trauma
    • Sports injury
    • Worn out meniscus
  7. Arthritis in the Back of Your Knee

    There are three different types of arthritis that can occur in the back of your knee: osteoarthritis, rheumatoid arthritis, and post-traumatic arthritis. The most common type is osteoarthritis, which is most likely to occur after middle age.

    Symptoms of arthritis in the back of your knee:

    • Inflammation in the morning or after activity
    • Red skin
    • Skin warm to the touch
    • Muscles weaken
    • Sticking or locking of joint
    • Poor range of motion
    • Cracking or popping sounds

    Causes of arthritis in the back of your knee:

    • Joint cartilage wears away
    • Inflammation
    • Another knee injury
  8. Knee Ligament Sprain

    There are four different ligaments within your knee: ACL, PCL, LCL, MCL. A strain is caused by ligaments stretching or tearing. To treat this injury, the RICE method (rest, ice, compress, elevate) is recommended. A functional knee brace for ligament tears can also help to speed up the healing process.

    Symptoms of a knee ligament sprain:

    • Pain, sudden and severe
    • A loud pop during the injury
    • Swelling within the first 24 hours after the injury
    • Looseness in the joint
    • Inability to bear weight on the joint

    Causes of a knee ligament sprain:

    • Trauma
    • Sports injury
    • Stretching or tearing of the ligament
  9. Gastrocnemius Tendonitis (calf strain)

    A calf strain occurs when the muscle fibers of your calf muscle tears. The severity of the injury will determine how much you will be able to exercise and your range of mobility. In the first 48 hours of this injury, it’s important to rest and ice the muscle. A knee support can also help the injury by supporting and warming the tendon during activity.

    Symptoms of a calf strain:

    • Sharp pain
    • Swelling
    • Bruising of the calf

    Causes of a calf strain:

    • Sudden, pushing movement
    • Excessive overstretching of the calf muscle
    • Tight muscle
  10. Pain Below Your Kneecap from Osgood Schlatter Disease

    Osgood Schlatter Disease typically occurs in children and adolescents who are experiencing growth spurts during puberty. It can cause a painful, bony bump below the kneecap. This disease typically heals on its own, but a patellar strap for children can help to relieve pain and tension.

    Symptoms of Osgood Schlatter Disease:

    • Knee pain
    • Swelling just below the kneecap
    • Pain worsens during activity
    • Bony bump below the kneecap

    Causes of Osgood Schlatter Disease:

    • The thigh muscle pulls on the tendon that connects the kneecap to the growth plate at the top part of the shinbone
    • Activities like soccer, basketball, volleyball
  11. Pain Below Your Kneecap from Patellar Tendonitis (a.k.a Runner’s Knee or Jumper’s Knee)

    When a large amount of strain is placed on the patellar tendon, it is very likely that you will develop tendonitis. The patella tendon is the most common place to develop knee tendonitis. A patellar tendon strap can help to take force away from the tendon, relieving pain.

    Symptoms of Patellar Tendonitis:

    • Pain just below the kneecap with activity
    • Pain with any pressure through the tendon
    • Aching and stiffness after activity
    • Stiffness in the morning
    • Dull pain
    • Thickening of the tendon

    Causes of Patellar Tendonitis:

    • Overuse
    • Repeated stress on the tendon
  12. Chondromalacia Patellae

    Chondromalacia Patellae is the most common cause of chronic knee pain. This occurs when the cartilage on the undersurface of the kneecap deteriorates and softens. A patellar centering brace can help to relieve pain and heal the injury.

    Symptoms of Chondromalacia Patellae:

    • Discomfort of the inner, front of your knee
    • Aggravated by activity or prolonged periods of sitting
    • Tightness or fullness of knee area

    Causes of Chondromalacia Patellae:

    • Poor alignment due to a congenital condition
    • Weak hamstrings and quadriceps
    • Muscle imbalance between adductors and abductors
    • Repeated stress on knee joints

Symptom Checker: Find Out What is Wrong with Your Knee

If you have pain behind your knee after sitting:

It is likely you are experiencing a symptom of Chondromalacia Patellae. This is the most common cause of chronic knee pain. Chondromalacia Patellae is caused by your patella being pulled to the outer side of your femur, rather than in a straight line. This will cause discomfort when you stand up from sitting in a chair for a long period of time. In order to prevent this at work, taking microbreaks will help to keep your body loose. You may also feel discomfort after physical activity or a tightness or fullness in the knee area.

If it hurts when you try to straighten your knee:

You may have a popliteal cyst (also known as Baker’s Cyst). This is a bulge in the back pit of your knee, called the popliteal fossa, that is filled with fluid and causes tightness behind your knee. The pain may increase when you while participating in physical activity. You may also feel swelling, pain and stiffness or tightness behind your knee.

If you feel pain behind your knee when bending or squatting:

You may be feeling a symptom of Patellar Tendonitis (also known as Runner’s Knee or Jumper’s Knee). This is caused by repetitive activity like kicking, jumping or running. The repetitive exercise puts a lot of strain on the tendon resulting in tiny tears and inflammation along the patellar tendon. Other symptoms include pain just below the kneecap, pain with any pressure to the knee, aching and stiffness after activity, knee stiffness in the morning and thickening of the patellar tendon.

If the back of your knee hurts while running or walking:

This could be a symptom of hamstring tendonitis. The hamstring tendon connects the hamstring muscle to the outer aspect of the knee. This is caused by overuse in running or jumping or insufficient warm-up exercises. If you are an individual who has just started working out or increased your level of fitness, you are at risk for this injury. Pain can be felt when putting strain on the muscle or tendon.

If you have leg pain in the back of your knee or calf:

This is most likely a symptom of gastrocnemius tendonitis (or a calf strain). The gastrocnemius muscle, which is the muscle that makes up your calf, controls the bending of your knees and the pointing of your toes. A sport that requires you to accelerate quickly can strain or tear the calf muscle. Other symptoms include swelling and bruising of the calf or trouble standing tiptoe.

If the back of your knee feels tight or stiff:

You may have Osgood Schlatter’s Disease. This is an inflammation of the area just below your knee where the tendon of the kneecap attaches to the shinbone. It occurs during growth spurts or times when bones, muscles, and tendons are changing rapidly. Other symptoms include knee pain and tenderness or swelling.

If the back of your knee feels swollen or sore:

This could be a symptom of a blood clot behind your knee. The popliteal vein runs through the back of your knee, close to the skin. At first, the pain just may feel like a cramp in the lower leg. If you notice swelling, it is important to get medical help immediately.

If you feel a sharp or shooting pain behind your kneecap:

It could be a symptom of nerve damage surrounding your knee. Your knee may also feel weak, numb or achy. To be more specific, femoral nerve dysfunction is a common condition that causes these symptoms. This is the loss of movement or sensation in parts of the leg due to damage to the nerve.

If you feel pressure or throbbing behind your kneecap:

It is possible that this is a symptom of arthritis in your knee. You may also be feeling swelling, tenderness, poor range of motion, and buckling or locking. Although there are many types of arthritis, the most common form of arthritis found in the knee is osteoarthritis. Other common forms include rheumatoid arthritis and post-traumatic arthritis, which occurs after an injury to the knee.

If you feel a popping or cracking sensation behind your kneecap:

If this sensation occurs during a knee injury – you most likely tore your meniscus. The meniscus is a piece of cartilage in your knee that cushions and stabilizes the joint. This type of tear is very common in contact sports like football and non-contact sports that require jumping and cutting like volleyball. Other symptoms include pain in the knee, swelling, difficulty bending your knee, pain behind your knee when straightening your leg, or a tendency for your knee to lock or get stuck.

7 Signs Your Knee Injury Is Serious

Any athlete’s worst fear—professional or amateur—is injuring themselves to a point that prevents them from continuing to work out. But, the reality is, exercise injuries are far more common than we think.

According to the Centers for Disease Control and Prevention (CDC), hundreds of thousands of exercise injuries occur each year. Among these, knee injuries are the most common.

However, experts agree that the best thing to do if you fall victim to a knee injury is to seek help (or use an effective topical cream like this one) and to know the signs that signal something serious.

Knee Injuries

You’re on a run and trip over a crack on the sidewalk, or you’re playing tennis and your knee turns at an unnatural angle while the rest of your leg stays in place. If you play any sport, particularly contact or collision sports, you’re no stranger to knee injuries.

You’re also in good company because according to a study published by the Society for Academic Emergency Medicine, the knee is the most commonly injured joint among athletes.

Knee injuries are caused by trauma or damage to the underlying structure of the knee, which could include ligaments, tendons, cartilage, or bursa (a fluid-filled sac that protects the joint from friction). Together, these tissues surround the bone and allow the knee to move with ease. Because the knee is such a complex series of mechanisms, a lot can happen to it.

The most common knee injuries include the following:

  • Anterior cruciate ligament (ACL) damage is usually the result of sudden changes in direction, jumps, abrupt stops, and high-speed impact.
  • A torn meniscus usually happens after a sudden twist in the leg.
  • Knee bursitis, a condition in which the bursa becomes inflamed, is often a result of constant kneeling.
  • Patellar tendinitis happens when the tendons that connect the front of the thigh to the shin become inflamed. The impact of running and jumping tends to cause this injury.
  • Fractures, i.e., broken bones, are often the result of a fall or a car accident.

After you’ve sustained a knee injury, it’s natural to feel concerned. How do you know if you should walk off your injury or rush to the doctor’s office for an examination? Will a few days of rest be enough for your knee to heal naturally, or do you need to start evaluating options for knee surgery?

Here are seven reasons that should prompt an immediate visit to your doctor’s office.

You’re experiencing swelling.

One of the most obvious signs that a knee injury has occurred is excessive swelling that you can see or feel. This CBD pain freeze cream has helped thousands of people feel relief from their nagging pain. It’s the most effective on the market.

Swelling is most indicative of a serious cartilage or ligament injury to the knee, according to Taylor Brown, M.D., an orthopedic surgeon at Houston Methodist in Texas.

The amount of swelling that is considered “serious” is subjective. A small amount of swelling may not be cause for concern. If you notice a subtle difference between the sizes of your knees, you probably don’t need to sound the alarm just yet. It’s only extreme swelling you need to worry about.

When we talk about extreme swelling, what we mean is when one knee is significantly larger than the other. According to Dr. David Geier, a doctor specializing in orthopedic surgery, significant swelling “could be a sign of a torn ACL or a patella dislocation with a little piece of bone knocked off, and it should be checked out.”

If your knee doesn’t immediately appear swollen and you’re unsure, “feel the injured and normal knee at the same time, with a hand on each knee to compare the two,” he says. “A swollen knee will feel like a large, warm, fluid-filled balloon.”

If you experience any of the above, he recommends a highly reviewed topical cream or the RICE principle. Rest with crutches and activity reduction, ice for 20 to 30 minutes several times a day.

Compression with a soft knee sleeve brace (like this top seller) will help, and elevating your knee above the level of the heart. Over-the-counter pain medication can also provide relief until the swelling goes down.

Aaptiv has workouts specifically to help work around your knee injury. Learn more about Aaptiv here.

If your swelling is minor, you might be tempted to reach for the ice and Advil, but research suggests that some amount of swelling could be good for you. A Cleveland Clinic study confirmed that swelling is caused by a rush of cells called macrophages to the affected area.

Macrophages help repair your injury by ingesting damaged cells. This process results in swelling as fluid rushes into the holes in the tissue left by the macrophages, and this is key to muscle regeneration. Pain and swelling are an adaptive body response. While we often view them as an inconvenience, they are natural signals that we need to slow down.

When an injury causes swelling, the pain and stiffness prevent the athlete from using the injured part of their body. This is where the first part of PRICE – protection – comes into play. By protecting your knee from further injury, you have a better chance of minimizing the damage.

In addition to the severity of the swelling, the speed with which the swelling occurs could indicate a serious injury. If the knee immediately blows up and becomes the size of a grapefruit, then you’ve probably sustained a severe injury.

If you’re unsure or you have swelling that doesn’t subside after 72 hours, please consult with your doctor.

You notice an obvious deformity.

If you notice your knee jutting outward in a way it never has before, take note. A dislocated or fractured patella (kneecap) can cause injuries like this, explains Brian Schwabe, C.S.C.S., board-certified sports physical therapist based in Los Angeles.

While some deformities occur over time, when the deformity is a result of an injury, it could be the result of a fracture or chronic wear on the knee joint. If you are already experiencing any kind of misalignment in your lower extremities, then you could be more prone to this type of injury.

If you notice a bone deformity after an injury, he recommends seeking the assistance of an orthopedic doctor immediately. The doctor will likely take x-rays as well as perform a visual diagnosis to determine if you need surgery.

You felt or heard a “pop”.

Sometimes, a “popping” sound after a movement can indicate something is out of place.

“Oftentimes this type of sound upon injury is indicative of a ligamentous injury,” says Schwabe. Not all ligamentous injuries are full tears, though, and not all require surgery.

However, if you also experience excessive swelling and instability, get it checked out by an M.D. “If you only have a mild sprain then you will be able to rehab it with physical therapy,” he says.

The pop is what you hear as a result of a ligament tear, a meniscus tear, strained tendons, or a dislocated kneecap. Usually what happens is you’ll simultaneously hear and feel the pop.

If you’re not familiar with the meniscus, it’s the cartilage in the knee that functions as a shock absorber. Each knee has two menisci, and they’re shaped like horseshoes. The medial meniscus is on the inside of the knee, and the lateral meniscus is on the outside.

The popping sensation can be difficult to explain, but you’ll certainly know it when it happens to you. Though the sound originates in the knee, you’ll hear it as though it was directly in your ear. It’s as if the sensation travels up your body, and when it gets to your brain, it becomes audible.

Depending on the severity of the tear, your age, and your overall health, you may able to heal on your own. You could start by using a brace and keeping your knee elevated and protected until you can get in to see a sports medicine doctor. However, a pop will almost always bring you down to the ground, and it’s not recommended that you put any weight on it until you can stabilize it.

If the pain is severe, you’ll want to visit a doctor as soon as possible. Surgery is often the recommended course of action, but physical therapy and other non-invasive remedies may be prescribed as alternatives.

You experience greater than normal movement.

If you feel like your range of motion in the knee is higher than usual, something might be out of place or injured. This is known as joint instability.

You may feel like your knee will buckle or fold with walking, twisting, or weight-bearing.

“The sensation of the knee giving away may occur with simple daily activities or upon return to sport following what was thought to be a minor injury,” explains Dr. Brown.

“Additional episodes of joint instability may worsen the condition of a knee after an injury.” Tears of the ACL or MCL and patellar (kneecap) dislocations could also create joint instability, he says.

Hundreds of thousands of exercise injuries occur each year. Among these, knee injuries are the most common.

The best plan of action is to make an appointment with an orthopedic surgeon.

Wear a compression-sleeve-type brace or a knee brace with hinges in the interim, says Dr. Brown.

This may provide some comfort or level of support. Use crutches if you feel like you could fall and suffer additional injury because of knee joint instability.

Another type of hypermobility can occur when the kneecap moves out of place. This condition is called a patella dislocation. It’s usually painful when it happens, and it might be sore the next day. If it pops back in by itself, the injury might not be serious. The true test is whether you feel confident that you can resume regular activity later that day or the next day.

According to Dr. Geier, if the knee resituates itself naturally or if you can put it back in place with little effort, then you may be able to “see how it goes” and avoid a visit to the doctor.

However, if it’s difficult to get the knee back in place or you need assistance to do so, then you’re bound feel pain and most likely swelling as well. If this is the case, Dr. Geier recommends consulting with a doctor. If anything, he says, you’ll get peace of mind.

When the kneecap dislocation is accompanied by swelling, this could indicate that a piece of cartilage or bone got knocked out of place. If the knee feels “loose” when you resume activity, a visit to the doctor may be in order. Your doctor may take x-rays, recommend an MRI, or suggest a visit to a physical therapist.

Knee instability is often caused by weak surrounding muscles. Working on balance and isolation exercises can significantly strengthen the knee and prevent injury. Aaptiv has hundreds of workouts on the app that can build a strong base for your core and lower body. Sign up for Aaptiv today and get a free trial.

You can’t put weight on it.

If it’s immensely painful to stand or put any weight on your injured knee, there’s definitely something serious going on.

“Inability to bear weight after a knee injury could be caused by a fracture, bone contusion, cartilage injury or ligament tear,” explains Dr. Brown. “Initial treatment includes using crutches or a steerable scooter to take pressure off the injured limb and minimize additional damage to the knee.”

If this sounds like you, listen to what your body is trying to tell you. Dr. Brown warns that the old adage of “no pain, no gain” doesn’t apply in this situation.

He advises seeking orthopedic evaluation as soon as possible—even that same day if you can.

After a minor injury like a twist or fall, you might not be able to put weight on your leg immediately. That’s not necessarily a cause for alarm, but if you don’t feel like you’ve recovered within a few minutes, this could indicate something more serious.

It’s similar to when you injure a wrist or ankle. If you fall on your wrist or twist your ankle, you may experience searing pain for a moment or two. When the injury isn’t severe, you’re able to shake it off and resume your life after a few minutes at the most. However, if you’ve experienced a sprain, the pain doesn’t subside. Instead, it gets worse.

Think of a knee injury in the same way. You may experience agony for a moment, but pay attention to how long it takes to go away. If it doesn’t go away within minutes and you’re not able to put any weight on the knee without feeling excruciating pain, then you might need a doctor to help you consider treatment options.

Also, watch out for numbness after the injury. This could be a result of a pinched or damaged nerve and blood vessels. William Blahd Jr., M.D., reports that this symptom could indicate an ACL or MCL tear, a kneecap dislocation, a fractured kneecap, or loose bone.

You can’t straighten your knee or leg.

If you have trouble straightening your leg or it hurts to do so, you probably have a serious knee injury.

To test this, start in a seated position and try to lift your lower leg using your own leg muscles. “You may still be able to bear weight and walk slowly and carefully without assistance, but will probably require assistance to lift your lower leg and fully extend your injured knee,” says Dr. Brown.

“Patella fractures, quadriceps tendon tears, and patellar tendon tears all tend to be associated with an inability to straighten the leg.”

Use a knee immobilizer to hold the knee in a straight position and help with pain relief. This also makes it easier to move about until your appointment with an orthopedic surgeon, he adds.

Another test is to lie down and try to straighten your leg. The goal is to get your knee to lie flat. This might be difficult or impossible to do due to the pain, but what you should watch out for is a total inability to straighten your knee.

Some of the problems that could cause a locked knee include meniscus tears or a torn ACL. The key is to determine whether you can’t straighten your knee due to sheer pain or physical blockage. If you feel blocked, then we recommend getting in touch with a doctor sooner rather than later.

On the flip side, you might have trouble bending your knee. If your knee feels stuck in any way, and the feeling doesn’t go away within a few hours, you could be experiencing something more severe.

Your knee keeps buckling.

When you got hurt, did it feel like your knee gave way underneath you? We’re not talking about a temporary sensation of weakness or some wobbliness, but more like your shin and thigh bone weren’t connecting or staying in place. A buckling knee could signal an ACL tear or a cruciate ligament injury.

It could start with a small pop or crack, or you could feel it after a strenuous exercise session or a soccer game.

Either way, your knee feels unstable or weak. Your knee may give out momentarily, which is scary because you might not trust yourself to walk safely when this happens. According to Dr. Howard Luks, an orthopedic surgeon, this could indicate a tear in the patella or the quadriceps tendon.

These tendons are on the front of your knees and offer a lot of support to keep you upright. If they’re not in top form, you’re bound to feel weak in the knees (cue the terrible SWV song from the ‘90s), and you might not be able to walk at all. If this is the case, you could need surgery.

On the other hand, the weakness could be temporary, caused by wear and tear, improper footwear, or a strain. If you’re a weekend warrior or you’re over the age of 30 (sorry!), you might experience this symptom on a regular basis.

However, if the weakness is recurring and happens every time you exercise, it’s possible you have a time bomb that’s waiting to happen. When in doubt, seek advice from a physician.

This could also signal a torn ACL or a large meniscus tear. These two common injuries are both serious and could cause this symptom to occur, says Aideen Turner, physical therapist and CEO of Virtual Physical Therapists.

“If your knee buckles under you when you are walking, then it usually indicates instability,” she says.

“A lot of people have ACL tears, but if the knee still has functional stability, then surgery is not necessarily needed. But the buckling indicates damage to the cartilage, which means surgery should be performed.”

No matter what you’re going through, remember that a setback is a setup for a comeback. Whether your knee heals on its own, you need some rehab, or you have to resort to surgery, the key is to keep your entire body strong to ensure that your knees have the support and structure they need to keep you moving.

Don’t let your knee stop you from working out. Join Aaptiv today and get classes for meditation, stretching and more.

To help prevent knee injuries in the first place, we recommend taking the following precautions:

  1. Warm up before exercising. You can try one of our stretching routines on the Aaptiv app.
  2. Use proper gear designed for your chosen activity. Many sports have shoes designed specifically for playing them, and we recommend using those specialized shoes.
  3. Keep the muscles surrounding your knees strong.
  4. Use the correct exercise techniques. Subscribers to the Aaptiv app get the benefit of having virtual trainers guide them through workouts, ensuring that they’re doing the exercises safely.

There’s no magic formula for preventing knee injuries, but taking some precautions before you step out onto the field or the court and knowing the signs of serious injury can help protect your joints.

Pain Behind the Knee

Written By: Chloe Wilson, BSc(Hons) Physiotherapy
Reviewed by: KPE Medical Review Board

Pain behind the knee is a common problem.

Not only can it affect your ability to walk and carry out your usual activities, back of knee pain can also really affect your sleep.

Posterior knee pain may develop gradually over time, or suddenly with an injury.

There may be a general ache, leg movements may be restricted by swelling or there may be a sharp pain at the back of the knee.

Common Causes of Back Of Knee Pain

Here we look at the most common causes of pain behind the knee and then go on to look at each one in depth with loads of great advice on how to ease your back of knee pain.

Bakers Cyst

Swelling develops in the popliteal bursa at the back of the knee. Bakers Cyst is the most common cause of pain behind the knee.

Causes: Excess fluid in the knee e.g. from an injury or arthritis

Symptoms: swelling behind knee, tightness and back of knee pain when bending the leg, walking and kneeling

Full Article: Bakers Cyst Knee

Knee Sprain

Overstretching of one or more knee ligaments, which can result in a full or partial thickness tear

Causes: Sudden twisting movements or a large force through the knee

Symptoms: Knee instability, back of knee pain, swelling, bruising, decreased knee movement

Full Article: Knee Ligament Sprains

Posterior Cartilage Tear

A tear in the cartilage aka meniscus at the back of the knee

Causes: Sudden twisting, a force through the knee or gradual wear and tear

Symptoms: Swelling, locking and pain behind the knee with knee extension, walking, running, squatting & going up stairs

Full Article: Meniscus Tears

Calf Strain/Tear

Overstretching, partial or complete tear of one of the two calf muscles

Causes: Suddenly changing speed or direction when running, or repetitive running or jumping

Symptoms: Pain in back of knee or calf, bruising, swelling & difficulty walking. Worse when running or on tiptoes

Full Article: Calf Strains

Knee Arthritis

Erosion of the knee bones and cartilage, bone spur formation, loss of joint space. Most common in the over 50’s

Causes: Aging, obesity, previous knee injury or surgery, genes, gender

Symptoms: Knee stiffness, pain, clicking, grinding, reduced leg movements. Worse with prolonged rest, activity, cold weather

Full Article: Knee Arthritis

Hyperextended Knee

An injury where the knee bends back too far damaging the structures at the back of the knee

Causes: Sporting injury where knee is pushed backwards e.g. awkward tackle or skiing

Symptoms: Sharp or aching pain behind the knee, swelling, bruising and instability. Worse standing, walking, going down stairs

Full Article: Hyperextended Knee

Deep Vein Thrombosis (DVT)

A DVT is a blood clot in one of the deep leg veins. If it breaks off it can lead to a heart attack or stroke

Causes: prolonged inactivity, certain medical conditions, pregnancy, obesity, genetics

Symptoms: Pain behind the knee or in the calf, swelling, redness, warmth, usually only on one leg

Self-Test: Pull your toes up towards you (your foot doing the work, not your hands) – an increase the pain behind the knee/calf indicates possible DVT

Safety Warning: A DVT is a potentially life-threatening condition. If you are showing symptoms of a DVT seek immediate medical attention

Overstretching the hamstring muscles on the back of the thigh beyond their elastic limit so they tear

Causes: Sudden, fast movements e.g. sprinting, lunging & jumping

Symptoms: aching behind knee/thigh, sharp pain behind the knee. Worse when bending knee or with sudden acceleration or deceleration

Common Pain Behind The Knee Questions

Here, you can find answers to the questions we are most commonly asked regarding symptoms associated with back of knee pain.

What Causes Pain Behind The Kneecap?

Pain behind the kneecap is usually caused by a problem with the cartilage that lines the back of the kneecap. It may be Runners Knee, where a problem with how the kneecap glides causes friction and pain behind the kneecap.

In teenagers, pain behind the kneecap is often caused by Chondromalacia Patella, a condition where there is thinning of the cartilage on the back of the kneecap.

What Causes Tightness Behind The Knee?

Tightness behind the knee is often caused by tightness in the hamstring or calf muscles. The hamstring muscles run down the back of the thigh attaching behind the knee, and one of the calf muscles, gastrocnemius, arises from the back of the knee and travels down to the heel.

Tightness in these muscles is a common problem, particularly in men, and makes the back of the knee feel very tight. Simple knee stretches are the best way to treat the tightness and relieve back of knee pain.

What Causes Swelling Behind The Knee?

Swelling behind the knee is most commonly caused by a Baker’s Cyst. Excess fluid in the knee joint, usually from an injury or knee arthritis, leaks out of the back of the joint.

This fluid fills the semimembranosus bursa and causing swelling behind the knee. It often feels like there is a squashy orange behind the knee which can be really painful.

What Causes Sharp Pain Behind The Knee?

If you are a runner, then sharp back of knee pain often indicates a problem with the hamstring tendons, such as tendonitis. If you do a lot of cycling, then a sharp pain behind your knee is usually caused by a problem in one of the calf muscles, gastrocnemius.

If you have recently twisted your knee or had a fall, then a meniscus tear is probably causing the sharp pain.

What Causes Pain Behind The Knee When Bending?

The most common cause of pain behind the knee when bending is a Bakers Cyst. This is when there is inflammation of the semimembranosus bursa, a small sac filled with fluid that sits at the back of the knee.

If the bursa gets inflamed, then any time you bend your knee, the bursa gets squashed, causing posterior knee pain.

What Causes Pain Behind The Knee When Straightening The Leg?

The most common cause of knee pain when you straighten the leg is a meniscus tear, particularly if you’ve been sitting down or squatting for a while.

As the knee straightens out from a bent position, the torn, inflamed portion of cartilage gets squashed in the joint, causing back of knee pain.

What Causes Pain Behind The Knee After Sitting?

Pain behind the knee after sitting for prolonged periods is often caused by arthritis. When we sit still, the fluid that lubricates the knee joint dries out slightly so when we then stand up, there is less cushioning.

The wear and tear associated with arthritis mean you can end up with the knee bones rubbing together, causing knee pain. Once you are up and moving about, the joint produces more synovial fluid so, after a few minutes of moving around, the back of knee pain eases off.

What Can Help Back Of Knee Pain?

So what’s the best back of knee pain treatment? The best treatment for pain behind the knee will depend on what’s causing the pain. Generally, the first step is to reduce any swelling, then work on exercises to improve the strength and stability of the knee to reduce the force that goes through the knee joint.

Just because there is back of knee pain, it doesn’t necessarily mean the problem is there. Pain can refer to different places so a problem around the front of the knee can produce a feeling of posterior knee pain.

Remember, the best way to accurately diagnose the cause of your pain behind the knee is to see your doctor.

  1. Knee Pain Guide
  2. Diagnosis
  3. Pain Behind Knee

Page Last Updated: 2019/11/20
Next Review Due: 2021/11/20

Knee Pain Bending
March 18, 2019

Knee Pain Diagnosis
March 11, 2019

Knee Strengthening
May 2, 2019

Posterior Knee Pain by S. English & D. Perret. Journal of Current Reviews in Musculoskeletal Medicine, Oct 2010
Pain Behind Knee? Injury vs. Disease-Related Causes from University Health News, March 2018

Bakers Cyst – NHS UK June 2018

Meniscus Tears – OrthoInfo. American Academy of Orthopedic Surgeons

Baker’s Cyst

What is a Baker’s cyst?

A Baker’s cyst is also known as a popliteal cyst or synovial cyst. It is a soft, fluid-filled lump that forms on the back of the knee. The lump is sometimes mistaken for a blood clot. A Baker’s cyst usually develops because of damage to the knee. When the structures in or around the joint are damaged, the knee produces more fluid.

What are the symptoms of a Baker’s cyst?

Sometimes there is only slight pain to signal a Baker’s cyst. There can still be pain in the knee from the initial damage that caused the Baker’s cyst. You may notice a soft lump that sticks out from the back of the knee. Any strain can cause this lump or the knee to swell in size.

It is possible for the Baker’s cyst to go away. The cyst can reduce in size on its own or burst under the skin. When the cyst bursts under the skin, the fluid is absorbed back into the body. It is often best to treat the source of the knee problem to get rid of the Baker’s cyst.

What causes a Baker’s cyst?

A Baker’s cyst is the result of damage that causes swelling in the knee. Examples of damage include:

  • Arthritis (osteoarthritis or rheumatoid)
  • Direct damage to the knee(meniscus tear, ligament tear)
  • Inflammation
  • Gout

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Posterior Knee Pain

This article or area is currently under construction and may only be partially complete. Please come back soon to see the finished work!

Original Editor ­ – Joyce De Gelas Top Contributors – Vidya Acharya, Kim Jackson, Joyce De Gelas, Oyemi Sillo and Stan Dieleman

Description/ definition

Posterior knee pain is a common patient complaint. Knee pain is more common in the anterior, medial, and lateral aspect of the knee than in the posterior aspect of the knee. The differential diagnoses for posterior knee pain include pathology to the bones, musculotendinous structures, ligaments, and/or to the bursas. Less common are neurologic and vascular injuries. Also tumours, such as a begin tumour that contains both bone and cartilage and usually occurs near the end of a long bone (osteochondroma) or bony tumours. Tenderness of palpation over the tendons or muscles in the back of the knee can indicate muscle or tendon injury. Pain or swelling in the popliteal area suggests an effusion or cyst. A precise understanding of knee anatomy, the physical examination and of the differential diagnosis is needed to accurately evaluate and treat posterior knee pain.

Clinically Relevant Anatomy

The anatomy of the knee is important when evaluating posterior knee pain. There is a complicated network of muscles, ligaments, and other soft tissues around the knee that contributes to the structure and support of the joint. These include both passive and active stabilizers. Examples of passive stabilizers include the medial collateral ligament (MCL), lateral collateral ligament (LCL), anterior cruciate ligament (ACL), and posterior cruciate ligament (PCL), while examples of active stabilizers consist of the hamstrings, extensor mechanisms, and the popliteus muscle. Gastrocnemius and the hamstring complex are two sets of muscles important in posterior knee anatomy. The hamstring muscle group consists of the medially located semimembranosus and semitendinosus and the laterally located biceps femoris. It is also important to note the anatomy of the popliteal fossa when evaluating posterior knee pain. The popliteal fossa is also composed of nerves (posterior femoral cutaneous, common peroneal and tibial), vascular structures (small saphenous vein, popliteal artery and popliteal vein), bursae, lymph nodes, and fat. The bursae of the knee are synovial-lined sacs that decrease the friction of moving structures. Pain and swelling of the bursa are caused by inflammation, external pressure, or overuse.

The semimembranosus tendon is a part of the posteromedial joint capsule, which is important in controlling anteromedial rotatory instability. (Together with the pes anserinus tendons it gives medial and posteromedial reinforcement.) There is a U-shaped bursa that surrounds the distal SM tendon, separating it from the medial tibial plateau, medial (tibial) collateral ligament (MCL), and semitendinosus tendon (surrounding structures).


There is a large variety of potential causes of posterior knee pain.

Tendinopathy and muscle complex injuries

Tendon injuries are associated with repetitive mechanical stresses that cause degenerative lesions. Hamstrings, gastrocnemius, and popliteus tendon typically cause posterior knee pain.

The hamstrings are frequently injured in sports that require sprinting. Semimembranosus tendinopathy usually presents as an aching pain localized to the posteromedial knee with tenderness on palpation inferior to the joint. Some of the possible risk factors for hamstring injury include body mechanics, flexibility, balance, hamstring strength, improper warm-up, fatigue, specific activities, running techniques, and psychosocial factors.

The gastrocnemius muscle’s superficial location and action across the knee and ankle make it susceptible to injury. Pain in the gastrocnemius occurs during knee flexion with resistance and during calf raises.

The popliteus muscle can also be a significant source of posterior knee pain. Both the muscular and tendinous aspects of the popliteus can be injured. Injuries to the popliteus may promote injuries to other structures in the postero-lateral complex and to ligaments of the knee. The mechanism of injury is thought to occur from direct stretch or when overused to maintain posterolateral stability. Guha et al. suggested that a stable knee with posterolateral pain and hemarthrosis on exam indicates a rupture of the popliteus tendon.

2. Nerve injury

Injury to the common peroneal nerve is seen with posterolateral knee injury.

3. Ligamentous injury

Posterolateral complex injuries can be seen along with ligamentous injury (PCL) leading to cause pain.

4. Meniscal injury

A medial meniscal tear can cause a catching sensation in the knee and rarely presents as posterior knee pain. A tear in the posterior part of the meniscus can also cause pain behind the knee, particularly when straightening the knee, epecially after sitting or squatting for a while, as the torn part of the meniscus can get caught in the joint.

5. Bone injury

Bone pain can rarely cause posterior knee pain.

Bone pathologies include degenerative bone disease, tibial stress fractures, and bone tumors. Bone tumors are a rare cause of pain that can be difficult to diagnose. Besides bony tumors of the knee, some other tumors can also cause knee pain. These tumors include osteochondromas, osteosarcomas, chondroblastomas, endochondromas, synovial chondromatosis, and pigmented villonodular synovitis. Recently, an angiomyomatous hamartoma has been described as causing posterior knee pain. This angiomyomatous hamartoma was in a single popliteal lymph node that caused posterior knee pain.

6. Knee cysts and bursal injury

Injury to bursae is usually the result repetitive motions and will elicit pain and tenderness. Cystic lesions of the knee can be caused from a diverse group of entities from benign etiologies to complications of arthritis, infection, and malignancy. The classic cystic lesion causing posterior knee pain is the Baker’s (or popliteal) cyst. A Baker’s cyst is caused either by a herniation of the synovial membrane through the posterior capsule or by an escape of fluid through an anatomic bursa next to semimembranosus or gastrocnemius. Fluid seeps in to the popliteal bursa, located at the back of the knee causing it to swell. It often feels like a squashy orange. A Bakers Cyst typically causes pain behind the knee when bending the knee as the bursa gets squashed.

7. Other neurological and vascular injuries

These include popliteal artery entrapment syndrome, aneurysms, and deep venous thrombosis (DVT).

There is minimal literature available on neurological causes of posterior knee pain as there are few case reports, randomized control trials, or meta-analyses that discuss the neurological causes of posterior knee pain. However, referred pain has been implicated as a cause of posterior knee pain. The patellofemoral joint and lumbar spine may both refer pain to the posterior knee. Pain can also be caused by entrapment of nerves in the popliteal fossa.

Clinical presentation/Characteristics

Semimembranosus tendinopathy (SMT)
This is an uncommon cause of chronic posteromedial knee pain that more often occurs with older patients. It may be underdiagnosed or inadequately treated because of a lack of understanding of the condition. But timely diagnosis can lead to effective treatments.
Although tendinopathy may occur in any of the hamstrings tendons, the semimembranosus tendon is the most commonly affected. It may occur as a primary phenomenon in endurance athletes or as a secondary, overuse, compensatory condition from a primary knee abnormality, such as patellofemoral disorders.
SMT usually presents as an aching pain localized to the posteromedial knee with tenderness on palpation inferior to the joint. The pain is severe in its acute form, but symptoms increase with activities that involve significant hamstring activation: running, cycling, walking down stairs, climbing, or sudden deep knee flexion.
• Hamstring Strain (HSS)
Characteristics of the hamstring strain.
Main symptoms are, a sudden sharp pain during sports activities, it can also be described as a tearing impression, and tightness, weakness and impaired range of motion.

Diagnostic Procedures

Management / interventions

Medical therapy management
– Injection(s) of 3 mL of 2% lidocaine and 10 mg triamcinolone at the insertion site can be effective in relieving the symptoms.
– Surgery to reroute and reattach the tendon is rarely needed but may be effective.

Physical therapy management

– ¬SMT (Evidence level: 5)
In more than 90% of the cases, this condition will heal without further intervention.

1. Initial conservative treatment includes relative rest, ice, pain-relieving modalities, a short course of NSAIDs, and physical therapy that includes hamstring strengthening and stretching exercises.

2. SMT may benefit from proper shoe fit to prevent overpronation or a medial heel lift in patients with genu valgum. Proper shoe fits are stable running shoes and shoes with motion control technology, they provide extra support preventing your ankle from rolling inwards extremely. Wearing these shoes is even more important when you are overweight. The main stability features are the medial post, the engineered heel and the plastic shank under the arch. (Evidence level:5)

E.g. : Nike Zoom Structure Triax 15

Hamstring strain – RICE-method: rest, ice, compression and elevation to speed the recovery. After the acute stages, heat can be used such as hot packs, whirlpool or heating before the stretching exercises. All the activities should be followed by ice-treatment to decrease inflammation and discomfort.

-The first phase (level of evidence:5): the athlete begins pain-free submaximal isometric strengthening at multiple angles.

-Exercise: The athlete completes a set of isometric contractions at 30°, 60°, and 90° of knee flexion by placing the injured limb on top of the contralateral limb and contracting the strained hamstring. The hamstring should not be stretched into a painful range at this time but available hip and knee ROM should be maintained. Motion is also good for aligning fibres and increasing the strength of the lateral adhesion of fibres, which protects the injured fibres from stump separation. The goals of this stage are to normalize gait and to obtain knee flexion strength at greater than 50% of uninjured length upon manual muscle testing at 90 degrees of knee flexion.

-Isometric knee flexion in the seated position. Note that this would be performed at multiple angles.

– The second phase (level of evidence:5): The athlete progressively regains strength throughout the ROM and improves neuromuscular control of the hips and pelvis in preparation for sports specific movements. End range lengthening should be avoided if painful in this stage.

Exercises: Eccentric training can be achieved using an isokinetic dynamometer if available and performing exercises such as straight leg deadlift, single leg windmills and the Nordic hamstring exercise.

(Eccentric) Single leg windmills

The patient stands with the uninjured leg on a chair or fixed surface and reaches down in a diagonal plane while keeping stance leg straight and maintaining lumbar lordosis.
It can be performed without (early) weights and progressed by using hand-held weights or kettlebells, as shown.

Nordic hamstring exercise

Having the clinician holds the patient’s feet, while in tall kneeling, performs the Nordic hamstring exercise. The patient slowly falls forward while maintaining neutral hip posture until he or she can’t control descent any longer and then pushes back into starting position with upper extremities.

You can do the Nordic hamstrings exercise with elastic assistance, which means that you can replace the helper/clinician into elastic assistance attached to the wall.”

At the completion of this phase, the athlete should have full strength upon manual muscle testing (5/5) or be within 20% of the uninjured leg in the zero to 90° range when measured with a hand-held or isokinetic dynamometer in order to progress to the next phase. The athlete should also be able to jog both forward and backward without pain at a moderate speed at this point.

– The third phase (Evidence level:5): Focus is on functional movements and eccentric strengthening in the lengthened state. Plyometric and sports specific training may be initiated as well as advanced balance exercise. Alternative lengthened state eccentric training may also be achieved without a dynamometer by keeping the involved thigh on the subject’s chest while resisting an outside force with an elastic resistance like a thera-Band, cable column, or manual resistance.

Lengthened state eccentric training on the Biodex.

Using a setup, the Biodex may be modified so that the patient is in hip flexion and then passively extends and flexes the knee into the end range of motion. The patient resists the passive motion as the knee is extended.

Lengthened state eccentric training on cable column.

This exercise may be performed by having the patient lay supine pulling knee snugly into chest while hooked up to cable column or elastic resistance. The patient then uses his or her arms to pull the knee into flexion and then slowly eccentrically resists the cable or elastic band as it pulls the knee into extension. At the completion of this stage, the athlete should have full strength throughout the range of motion and should be able to confidently perform all sport-related tasks without limitation.

Differential Diagnosis

Posterior knee pain can be caused by a number of conditions:

  • Semimembranosus tendinopathy
  • Biceps femoris tendinopathy
  • Hamstrings strain
  • Calf strain
  • M. popliteus strain
  • M. popliteus tendinitis
  • Posterior cruciate ligament injury
  • PLC: Posterolateral corner/ posterior complex
  • Knee Bursitis
  • Common peroneal nerve injury
  • Baker Bursitis
  • popliteal artery entrapment syndrome, aneurysms
  • Deep venous thrombosis (DVT)

Posterior knee pain can also be referred pain, such as from ☃☃intra-articular hip pathology, lumbar facet arthropathy, sacroiliac joint dysfunction, and sacral radiculopathy. Or it can be caused by peripheral neurological injury and entrapment of nerves in the popliteal fossa.

Pain back of knee

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