Purpose: We report a retrospective series of 28 patients with trauma-induced dislocation of the knee. The purpose of our study was to evaluated long-term outcome after orthopaedic as well as surgical management of these injured knees and to propose a therapeutic attitude best adapted to the initial situation.
Material and methods: The series included 28 patients, including one who had a bilateral dislocation. There were four women and 24 men, mean age 35.3 years at the time of the accident (17–69). Mean follow-up was 10.8 years. Nineteen knees were treated orthopaedically after reduction, surgery was used for ten patients. Five patients underwent an initial operation (during the first week following the accident), five had a secondary operation one to eight years after the accident. Mobility and laxity were assessed clinically. The Lysholm-Tegner and the Meyers scores were used to assess function. Radiological results were assessed with the Ahlback classification and the IKDC score to judge potential progression to single-or triple compartment osteoarthritis.
Results: Clinically, mean amplitude was 105° flexion and −2° extension. Four knees were stiff with flexion = 80°. There was a persistent anterior drawer sign for all knees except four. Medial laxity (valgus) was often important (83% of the patients). Functionally, the mean Lysholm score was 80.5 (17–100). The mean pre and post-trauma Tegner score was 5.1/3. The Meyes classification showed 15 good and excellent results and eight fair and six poor results. Radiographically, more than half the patients had no sign of degenerative joint disease and only four knees has signs of true three-compartment osteoarthritis according to the Ahlback classification. Separate analysis of patients treated orthopaedically and surgically showed that good results with orthopaedic treatment concerned patients with an anterior or posterior dislocation with predominantly anterior laxity. The fair and poor results concerned six of the eight patients with initially multidimensional laxity, particularly postero-lateral laxity that persisted at last follow-up. Surgical treatment gave good results mainly when given early (four very good results out of five knees).
Discussion: Recent work has demonstrated very satisfactory results for femorotibal stability after ligament reconstruction, usually with allografts. Our good functional results, comparable with earlier series, and the encouraging radiographic results have led us to chose orthopaedic treatment for selected patients (correct preservation of the posterolateral plane, particularly in case of dislocation with hyperextension corresponding to grade II in the Schenck classification), and on the contrary, to prefer early surgical treatment for the posterolateral plane.
Conclusion: Management of injury to knee ligaments after femorotibial dislocations should be guided by a precise examination of the initial laxities conducted under general anaesthesia. If the posteriolateral plane is satisfactory, orthopaedic treatment followed by active rehabilitation can provide good functional and radiographic results.
