Pes Anserinus Bursitis

Between the hamstring and shin bone is the pes anserine bursa, a sac dedicated to providing smooth movement of the three hamstring tendons and the MCL (medial collateral ligament). These tendons are the biceps femoris, semitendinosus and semimembranosus; together they form a pattern on the tibia like a goose foot. This is the pes anserinus, and the pain arising from pes anserinus bursitis is sometimes known as goose foot pain.

Symptoms

The pain is typically felt approximately 2 or 3 inches beneath the anterior (front) of the knee joint. This is the location of the pes anserinus. But the pain can also spread to the middle of the shin bone (tibia), particularly if additional parts of the leg or lower body have become injured, e.g. the meniscus cartilage. Pain is worsened during any strenuous leg activity, when weight or resistance acts against the pes anserinus tendons, and also while performing the everyday motions involved in climbing stairs.

Causes

The main cause of pes anserinus bursitis is hamstring overuse. This is especially prevalent with athletes participating in endurance sports, such as running, bicycling and occasionally swimming. Because such activities require great stamina and fitness, overtraining can be damaging to an athlete. Stepping up a training program too quickly, such as extending the length of your distance running, can lead to excessive hamstring strain and injury to the pes anserinus. Other overuse factors include inadequate warm ups, continuing to train on weakened muscles, and exercising on hills or uneven surfaces.

People with tight hamstrings or a pre-existing condition like knee osteoarthritis are more likely to sustain the injury. Biomechanical errors such as flat feet or 'knock knees' (genu valgum) can also increase the risk. Another cause is direct trauma below the knee joint, releasing too much synovial fluid into the pes anserine bursa and leading to inflammation and pain.

Diagnosis

The doctor will examine the injury, looking for the specific cause of the knee pain and attempting to rule out any complications or associated damage. The possibility of a fracture or arthritis can be eliminated by taking an x-ray. In case of infection, an extraction of bursa fluid might be needed. Another common physical exam tests for hamstring tightness by assessing how far the knee can be straightened while the hip is bent.

Treatment

Surgery is very rarely needed for an overuse injury like pes anserinus bursitis. Instead the recovery process will focus on reducing pressure on the damaged area, firstly by abstaining from the activity that caused the injury and any others that could exacerbate the condition. Stairs and other activities requiring stressful hamstring use should be avoided until you are free of pain. Rest is also important, though staying in bed is not usually helpful as this leads to muscle inflexibility. Take any prescribed anti-inflammatory medications early on in the recovery phase. Icing the injured area can also relieve symptoms.

Gradual hamstring stretching is encouraged. Suitable stretching a few times per day for 1 minute can help with healing as long as you do not stretch so far as to cause pain. Also strengthen the quadriceps with closed kinetic chain exercises. A full return to activity is expected when the symptoms are gone.