The Effect of Total Knee Arthroplasty on Hindfoot Alignment in Patients with Severe Genu Varum and Genu Valgum

Abstract

Background: The maintenance of deformity in the ankle and hindfoot after correction of knee deformity following knee<br />arthroplasty may cause abnormal tension in the knee and patient dissatisfaction. The aim of this study was to determine<br />the effect of knee arthroplasty on the hindfoot alignment in patients with severe genu varum and valgum.<br />Methods: A total of 84 patients with primary osteoarthritis, were enrolled in the study. The knee deformity was measured<br />using a long leg film before surgery. The long axial radiographic view of hindfoot was taken in the standing position for<br />all patients, before and six months after surgery. Comparisons were made on changes in the hindfoot angles measured<br />before and after surgery.<br />Results: A total of 84 patients with mean age of 62.28 ± 7.77 years, 77 (92%) and seven patients (eight percent)<br />had knee varus and valgus deformity, respectively. In the knee varus group, the mean preoperative hindfoot angle<br />was + 5.32 ± 6.12 ° (valgus) which was changed to - 0.25 ± 4.91 ° (varus) in the postoperative phase. In the knee<br />valgus group, the mean pre and postoperative hindfoot angles were - 7.71 ± 7.06° (varus) and - 2.14 ± 5.92 ° (varus),<br />respectively. The mean preoperative hindfoot angle in severe and very severe varus knee groups were + 5.45 ± 3.30<br />and + 5.28 ± 6.86 °, respectively. These angles were changed to + 0.21± 5.17 and -1.60 ± 3.89° six months after<br />surgery, respectively. The mean preoperative hindfoot angle in severe and very severe valgus knee deformity groups<br />were - 7.00 ± 4.69 and -8.66 ± 10.69 °, respectively. These angles were changed to - 2.00 ± 5.71 and - 2.33 ± 7.50<br />°after surgery, respectively. There was no significant difference between patients with severe and very severe deformity<br />in terms of pre and post-operative hindfoot angle.<br />Conclusion: The hindfoot alignment is significantly corrected after knee arthroplasty. The severity of knee deformity<br />does not correlate with the severity of the hindfoot deformity before and after surgery.<br />Level of evidence: I