Spontaneous disruption of the bilateral knee extensor mechanism: a report of two cases.

Spontaneous disruption of the knee extensor mechanism is associated with systemic diseases, steroid usage, and repeated microtrauma. Early repair or reconstruction is imperative for optimal outcome. We report 2 cases of spontaneous disruption of the bilateral knee extensor mechanism. The first patient had connective tissue disease and long-term steroid use. She had acute-on-chronic spontaneous bilateral patellar tendon rupture. She underwent reconstruction with an allograft and defunctioning wire. The second patient had end-stage renal failure with tertiary hyperparathyroidism and was on haemodialysis. He had a right patellar tendon rupture and a left quadriceps tendon rupture. He underwent primary repair of both tendons. Postoperatively, both patients followed a strict physiotherapy regimen and achieved good functional outcome.