ANTERIOR LAXITY AND MEDIAL ARTHRITIS IN V ARUS KNEES - RESULTS OF THERECONSTRUCTION OF THE ANTERIOR CRUCIATE LIGAMENT ASSOCIATED WITH A HIGH TIBIAL OSTEOTOMY

Fifty-one knees were reviewed out of 53 which had been operated on (be tween 1981 and 1991) for instability due to a long-standing rupture of the anterior cruciate ligament (A.C.L.), associated with medial arthr itis related to a varus deformity. They had undergone a reconstruction of the cruciate ligament using the patellar tendon (5 cases had recei ved an artificial ligament) and a high tibial osteotomy. In 80 per cen t of cases this was an opening osteotomy with interposition of a heter ologous bone graft, and in 39 cases it was a closing osteotomy. The av erage age was 37 +/- 6 years. The oldest patient was 58 years old. 80 per cent of cases were men and 88 per cent of the patients practised s port on a regular basis at the time of the accident, The average delay before surgery was 9,5 years. Almost all the patients has already und ergone a medial meniscectomy and there were deep cartilaginous lesions and the bone was exposed in 50 per cent of cases. 28 knees were reexa mined after a follow-up of over 4 years. Based on the ARPEGE score the results on pain and stability were good. Return to sport has been pos sible for 43 per cent of patients. Pivot shift, which was constant bef ore surgery (grade 2 or 3), disappeared in 20 cases and was estimated at grade 1 in 8 cases (of which 6 had suffered a rupture of the graft) . For the 20 cases in which the reconstruction of the A.C.L. had held, the average anterior radiological subluxation was 4.3 +/- 3.2 mm (fro m 2 to 14 mm) and the average gain after surgery was 6.7 +/- 3.7 mm (f rom 2.5 to 18 mm). The femoro-tibial angle went from an average of 6-d egrees of varus to 3-degrees of valgus. The opening osteotomy was more precise for correction in the frontal plane. A large valgus (over 3-d egrees) was not desirable and a hypercorrection was occasionally diffi cult to accept by relatively young patients who are likely to take up sport again. The osteotomy often involuntarily modified the normal pos terior tibial plateau slope (especially closing osteotomy). A backward s increase of the tibial plateau slope is a factor which increases the anterior subluxation of the femur on the tibia. This is confirmed bef ore and after surgery. It seems preferable to decrease the tibial slop e during the osteotomy in order to protect the A.C.L. reconstruction. Reconstruction of the A.C.L. with the patellar tendon, associated with a high tibial valgus osteotomy, means that patients less than sixty w ith severe medial arthritis can recover good stability.