Purpose: Although hamstring retraction is a frequent complication of spastic hypertoniq, very few series have been reported in adults. The purpose of this study was to evaluate results of therapeutic modalities proposed: distal hamstring tenotomy and use of an external fixator in case of permanent knee flexion.

Material and methods: This retrospective series included 37 cerebral palsy patients, 59 with permanent knee flexion. Mean flexion was 69° (20–130°). Mean motion was 61° (10–100°). Deformation of the supra and infra joints was present in 82%. There were 22 patients with bilateral permanent knee flexion. Simple tenotomy of the sartorius, the semitendinous and the gracilis with lengthenings of the semimembranous and biceps. Disinsertion of the gastrocnemius and section of posterior aponeurosis were associated as needed. Postoperative immobilization was achieved with a Zimmer cast in case of moderate flexion and with an external femorotibial fixator in case of major deformation. Postoperative rehabilitation exercises performed several times daily were initiated in all patients.

Results: At mean follow-up of 641 days, residual flexion was 6° (0–40°) and mean joint motion was 111°. All knees were stable. Three dehiscent wounds required surgical repair. The function objective, established pre-operatively, was achieved or exceeded.

Discussion: When postoperative immobilization is necessary, external fixation limits cutaneous risks and facilitates rehabilitation. It appears to be better than successive cases. Unlike other authors, we did not find section of the posterior cruciate ligament to be necessary.

Conclusion: Distal hamstring tenotomy associated with postoperative immobilization with an external fixator is a reliable and effective technique for the treatment of permanent knee flexion in cerebral palsy adults.