The difference in leg lengths following total knee replacement for patients with severe osteoarthritic deformity

PURPOSE: Increased height after total knee replacement surgery (TKR) may offer patients higher satisfaction as well as the quality of life. Therefore, in this paper, we aim to document the changes in leg length after TKR in patients with severe bilateral deformities. METHODS: The data of 61 patients were collected from the Egyptian Community Arthroplasty Register; of them, 21 patients had unilateral TKR while 40 had bilateral simultaneous TKR. The patterns of changes in height of 101 osteoarthritic knees were followed up for 1 year after having TKR. All patients had standing leg X-rays, before and after surgery, to document the length of the femur and tibia before and after TKR. Correlations were assessed using the two-sample t-test. RESULTS: The sample was mostly females (56/61, 91.8%). The distribution of the operated side was nearly equal (right knee was 47/101, 46.5%). The overall average leg length difference was 5.4 (SD = 2.3); for the unilateral group, the average was 4.6 (SD = 2.6); and for the bilateral group, the average was 5.6 (SD = 2.3), p = 0.119. We found that leg length may differ according to the varus deformity angle (p < 0.001) as well as fixed flexion deformity (p < 0.001). CONCLUSIONS: Leg length increased significantly 1 year after TKR. However, there is not enough evidence to suggest that the bilateral group had a greater height increase when compared to the unilateral group. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00264-023-05948-x.