Does severe osteoarthritis in knees with varus deformity alter the adductor ratio?

Abstract

Objective: In our retrospective study, we aimed to investigate the differences between the adductor ratio(AR) in knees with and without osteoarthritis, and its validity in determining the articular level.Methods: Data from 80 knees of 80 patients were retrospectively evaluated. Anteroposterior weightbearing knee radiographs of the patients with and without osteoarthritis (40 knees in each group)were obtained. The adductor ratio was determined using the following formula: ATJL/FW (adductortubercle-joint line distance/femoral width). All radiographs were evaluated at the baseline and at onemonth intervals afterwards. Intraobserver reliability of the two measurements was assessed usinginterclass correlations (ICC). Pearson's correlation test was used to evaluate the correlation between theATJL and the FW. The differences between the adductor ratios of the two groups were evaluated by theindependent samples two-tailed t-test.Results: Most of the ICC values were well above 0.95, indicating a very high intraobserver reliability. Theadductor ratio was signiŞcantly greater in Group 2 in comparison to Group 1 (Mean AR in Group 2:0.522± 0.031 and Mean AR in Group 1: 0.502 ± 0.032; p ¼ 0.005). There was a signiŞcant correlationbetween the ATJL and FW in the groups when assessed both separately and combined.Conclusion: In conclusion, we can assert that if the AR is used to determine the articular level in revisionarthroplasty cases, it may be sensible to measure the FW intraoperatively rather than measuring it onprimary or contralateral radiographs of arthritic patients.Level of evidence: Level III, Diagnostic study.