The pes anserinus is the tendon insertion of three thigh muscles (sartorius, gracilis, and semiendinosus) into the upper portion of the tibia, just below the knee to the inner side of the front of the leg. Where the tendon attaches to bone, there is a bursa sac between the bone and the tendon. The bursa functions like a water balloon to reduce friction and wear of the tendon against the bone. With this syndrome there is inflammation and pain of the bursa (bursitis), tendon (tendinitis), or both.
Initial treatment consists of medication and ice to relieve the pain, stretching and strengthening exercises (particularly the hamstring muscles), and modification of the activity that initially caused the problem to occur. These all can be carried out at home, although referral to a physical therapist or athletic trainer for further evaluation and treatment may be helpful. An orthotic (arch support) for those with flat feet may be prescribed to reduce stress to the tendon. A knee sleeve or bandage can be worn and may help keep the tendon and bursa warm during activity as well as reduce some of the symptoms. An injection of cortisone into the bursa may be recommended. Surgery to remove the inflamed bursa is usually only considered after at least six months of conservative treatment or when the condition reoccurs many times and the bursa is very large.