Anserina bursitis. A treatable cause of knee pain in patients with degenerative arthritis.

The anserina bursa is located on the medial surface of the tibia deep to the tendons of the sartorius, gracilis, and semimembranosus muscles and superficial to the insertion of the tibial collateral ligament. Knee pain, a palpable swelling of the bursa, and tenderness over the medial anterior aspect of the tibia just below the knee are the hallmarks of anserina bursitis. In a three-year period, 24 patients with anserina bursitis were seen in a rheumatology clinic. All but one were women, 18 were obese, and only four were under 50 years old. Knee x-ray studies showed degenerative arthritis in 20 of the 24 patients. In ten, varus knee deformities were present, while three had valgus deformities. Ultrasound or local steroid injections gave dramatic relief in all but one patient.