[Corrective osteotomy in the treatment of degenerative changes in the knee joint]

Angular deformity of the knee can be corrected by high tibial osteotomy or distal femoral osteotomy. In this research we have analysed effects of corrective osteotomy in knees with varus or valgus deformity. In this research we present a long-term evaluation of 67 patients older than 40 with angular deformity of the knee in which high tibial osteotomy and distal femoral osteotomy were performed at the Department of Orthopaedic Surgery, School of Medicine, University of Zagreb, in the period 1982-1992. Operation was performed bilaterally in 14 patients. There were 66 knees with varus deformity and 15 with valgus deformity out of a total of 81 knees. The most patients with valgus deformity were corrected by supracondylar osteotomy and the most with varus deformity by osteotomy of proximal tibia. The average preoperative duration of symptoms was 6.1 years. The average age was 57.5 at the moment of operation. The mean follow-up was 7 years (range 3-13 years). We assessed the degree of arthrosis according to Ahlböck in five-grade scale. The mean arthrosis was 2.0 preoperatively, 2.2 postoperatively and 2.6 at the last follow-up examination. Although the patients with valgus deformity had smaller degree of arthrosis preoperatively than patients with varus deformity, arthrosis developed equally in both groups despite the fact that the operation was performed. We measured joint tilt according to Shoja and Insall. The patients with varus deformity had joint tilt 7 degrees before operation, -4.3 degrees after operation and -2.4 degrees at the last control. The patients with varus deformity had femurotibial angle of 185 degrees preoperatively, 173 degrees postoperatively, and 175 degrees at the last follow-up examination. The average revarisation of 2 degrees occurred despite overcorrection. The patients with valgus deformity had femurotibial angle of 164 degrees preoperatively, of 178 degrees postoperatively and of 180 degrees at the last follow-up examination. Revarisation progressed 2 degrees on average after varisation osteotomy was performed in the knees with valgus deformity. There was no statistically significant correlation between pain and femurotibial angle and pain and degree of arthrosis preoperatively, postoperatively and at the last follow-up examination. The patients were assessed according to the system developed at the Hospital for Special Surgery (HSS). The mean preoperative HSS score was 2.91 (2.82 varus and 3.33 valgus deformity), and postoperative 4.47 (4.42 varus and 4.47 valgus). The mean score at the last follow-up evaluation was 4.05 (varus 4.03 and valgus 4.13). The patients assessed the improvement themselves and it was 1 to 14 (6.1) years. Although the indications for aloarthroplasty of the knee are more frequent nowadays, the authors recommend not to forget corrective osteotomy in the treatment of angular deformity of the knee with osteoarthritis.