The Relation Between Clinical Results and Correction Angle in Proximal Tibial Osteotomy

ABSTRACT

PURPOSE: To determine the relation between clinical results and correction angle in proximal tibial osteotomy through the retrospective study. MATERIALS AND METHODS: Seventy-two valgus osteotomies of the tibia were performed in forty-nine patients from 1985 to 1992; average follow-up period was 7 year 11 months(range, 5 to 12 years). We classi- fied the patients into three groups according to the tibiofemoral angle measured at the last follow-up. Group I includes patients with less than valgus 6 degrees of tibiofemoral angle, Group II with from valgus 7 degrees to 9 degrees and Group III with more than valgus 10 degrees. RESULTS: The Insalls Hospital for Special Surgery knee score was gradually decreased in time as 95 at postoperative 2 years, 92 at 5 years and 82 at the last follow-up. The average preoperative tibiofemoral angle was varus 3.4 degrees and the average postoperative tibiofemoral angle was corrected as valgus 8.0 degrees, 7.9 degrees at two years, valgus 7.0 degrees at five years and valgus 5.4 degrees at the last follow-up. The group I, 40 cases(mean 9 year 7 month follow-up), showed postoperative valgus 6.4(3-15) degrees and val- gus 2.6 degrees at the last follow-up. Loss of correction was 3.8 degrees and knee score was 76 at the last fol- low-up. The group II, 21 cases(8 year 1 month), showed postoperative valgus 9.0(7-11) degrees and 7.6 degrees at the last follow-up. Loss of correction was 1.4 degrees and knee score was 83.5 at the last follow- up. The group III, 11 cases(7 year 7 month) showed postoperative valgus 11.4(10-15) degrees and 10.9 degrees at the last follow-up. Loss of correction was 0.5 degrees and knee score was 97 at the last follow-up. The group III showed better maintenance of postoperative correction angle and clinical results than the other gf OUpS. CONCLUSION: Deductively, it is essential to correct tibiofemoral angle more than 7, especially ranged from 10 to 15 degrees for the best long-term clinical results.