Snapping Knee Syndrome of the Medial Hamstrings.

Abstract

Snapping of the medial hamstrings is a rare condition, with few cases reported throughout the literature. The snapping sensation reportedly occurs when a hamstring tendon passes over the medial tibial condyle, a muscle belly, or another tendon. The semitendinosus tendon is frequently involved, but concomitant involvement of the semitendinosus and gracilis tendons has also been described. Although the exact etiology remains unclear, authors have theorized that the condition results from a congenital malformation or degradation of the accessory tendinous expansions of the semitendinosus. Whereas most cases resolve with conservative treatments, select cases require surgical intervention. Both the distal surgical release and tendon harvest have proved viable surgical procedures, achieving symptom alleviation with minimal patient morbidity. In this article, a case of medial snapping hamstring tendons involving both the semitendinosus and gracilis tendons is reviewed. A 17-year-old African American girl presented with extreme pain and snapping on the posteromedial aspect of her knee was appreciated. Radiographs were ordered and showed no acute fracture, no acute dislocation, normal medial joint space, normal lateral joint space, and normal patellofemoral space. Conservative and surgical options were reviewed, and the patient elected to undergo harvest of the tendons. Four weeks postoperatively, the patient reported complete resolution of symptoms. To date, there has been no recurrence of symptoms. The authors hope to increase awareness of this condition and add to the existing body of literature.