Arthrofibrosis continues to be a difficult complication in articular surgery on the knee. We present our experience in 21 cases of arthroscopic lysis as an alternative to mobilization under anesthesia. The technique begins with the liberation of the adhesions of the suprapatellar pouch, continues down both gutters, and ends with a cleaning of the notch where necessary. When a restriction of patellar mobility persists, we make a retinacular release. The results obtained are very satisfactory, with an average increase in the arc of mobility of 68 degrees. The average gain in mobility at 6 months is significantly greater than that achieved in the immediate postoperative period. Longer follow-up showed no improvement in range of motion after 6 months.