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Comparison of Postoperative Alignment Using Fixed vs Individual Valgus Correction Angle in Primary Total Knee Arthroplasty With Lateral Bowing Femur.

Research paper by Xiaojun X Shi, Hai H Li, Zongke Z Zhou, Bin B Shen, Jing J Yang, Fuxing F Pei

Indexed on: 21 Jan '16Published on: 21 Jan '16Published in: Journal of Arthroplasty



Abstract

Lateral bowing of the femur, commonly observed among Asian populations, may cause malalignment after primary total knee arthroplasty (TKA). Therefore, in this study, a fixed valgus correction angle (VCA) technique for TKA was compared with individual VCA to determine which surgical technique leads to better limb and component alignment.Patients with primary TKAs with lateral bowing femurs (n = 133) were randomized to 2 groups: individual VCA (group A) and fixed VCA (group B). Full-length standing hip-knee-ankle radiographs were used to measure the VCA and limb alignment. The postoperative mechanical axis, femoral component, and tibial component alignment were measured and compared between the 2 groups.The mean postoperative mechanical axis and femoral component alignment were 178.1° and 88.3°, respectively, in group A, compared with 175.9° and 86.4°, respectively, in group B (P < .05). There were 52 (77.6%) knees with ±3° mechanical axis deviation from the neutral axis in group A, compared with 19 (28.8%) in group B (P < .001). There were 56 (83.6%) knees with femoral component alignment deviation within ±3° in group A, compared with 26 (39.4%) in group B (P < .001).The individual VCA achieves a better radiographic limb and femoral component alignment than fixed VCA in our study patients. Preoperative hip-knee-ankle radiographs are imperative for distinguishing a bowing femur and performing accurate planning of the distal femoral resection.