[Therapy of extension deficits of the knee joint by arthroscopic arthrolysis and dorsal capsulotomy].

Loss of full knee extension is a typical complication of knee ligament surgery and is difficult to treat. We present a technique that is indicated especially in longstanding extension deficits and that combines arthroscopic arthrolysis and posterior capsulotomy. The intra-articular pathology is first treated by arthroscopic debridement and arthrolysis. Then a posteromedial arthrotomy is performed with the knee flexed 90 degrees. the posterior adhesions are divided under direct vision and finally the posterior capsule is detached completely from the distal femur. Twenty-one of 24 patients treated with arthroscopic arthrolysis and posterior capsulotomy from 1989 to 1993 were reviewed with a mean follow-up of 18 months (6-38). The mean extension deficit preoperatively was 17 degrees (10-30 degrees); symptoms persisted from 6 months to 7 years. The gain in extension by this procedure averaged 15 degrees; no patient had more than 5 degrees of extension deficit at follow-up. The knee function improved significantly (Lysholm score preoperatively 62, postoperatively 88, Tegner scale preoperatively 2.2, postoperatively 4.0). We conclude that posterior capsulotomy is a safe and efficient additional procedure to arthroscopic arthrolysis and is indicated in cases with chronic extension deficit after ligament surgery.