International Orthopaedics (SICOT) (2015) 39:55–60 DOI 10.1007/s00264-014-2484-x
ORIGINAL PAPER
Femoral rotation influences dynamic alignment of the lower extremity in total knee arthroplasty Zhongyuan Zhao & Weiguang Wang & Shijun Wang & Limin Jiang & Shudong Zhang & Yuchi Zhao
Received: 25 June 2014 / Accepted: 26 July 2014 / Published online: 10 August 2014 # SICOT aisbl 2014
Abstract Purpose Besides the long-leg standing X-ray film focusing on static standing mechanical alignment of the lower extremity, dynamic alignment from full extension to 90° flexion after total knee arthroplasty (TKA) is rarely mentioned. Computerassisted surgical technology enables surgeons to measure and assess knee behaviour during surgery. This study was designed to analyse the influences of femoral rotation on dynamic alignment of the lower extremity in TKA. Methods Seventy-six consecutive patients with end-stage knee osteoarthritis were enrolled. External rotation osteotomy of the distal femur during TKA was completed according to the pre-operative external rotation angle (ERA), intraoperative transepicondylar axis (TEA) and anteroposterior (AP) line. Passive dynamic alignment of the lower extremity during knee flexion was recorded. The variation trend of hip– knee–ankle (HKA) alignment and the influences of femoral external rotation osteotomy were analysed. Results Postoperative deviation of HKA alignment from 0° to 90° flexion was associated with the rotational alignment of the femoral component (r=−0.769, p 1° internal to the mean). In the external group, HKA alignment tended to be in varus when the knee flexed to 90° (r2 =0.992, p=0.0003, Fig. 5). In the internal group, HKA alignment tended to be in valgus when the knee flexed to 90° (r2 =0.964, p=0.008). In the neutral group, HKA alignment fluctuated around 0° (r2 =0.101, p=0.601).
Mean rotational alignment of the femoral component was −0.934°, with standard deviation (SD) of 2.167°. Postoperative deviation of HKA alignment from 0° to 90° of knee flexion was associated with rotational alignment of the femoral component (r=−0.769, p
ORIGINAL PAPER
Femoral rotation influences dynamic alignment of the lower extremity in total knee arthroplasty Zhongyuan Zhao & Weiguang Wang & Shijun Wang & Limin Jiang & Shudong Zhang & Yuchi Zhao
Received: 25 June 2014 / Accepted: 26 July 2014 / Published online: 10 August 2014 # SICOT aisbl 2014
Abstract Purpose Besides the long-leg standing X-ray film focusing on static standing mechanical alignment of the lower extremity, dynamic alignment from full extension to 90° flexion after total knee arthroplasty (TKA) is rarely mentioned. Computerassisted surgical technology enables surgeons to measure and assess knee behaviour during surgery. This study was designed to analyse the influences of femoral rotation on dynamic alignment of the lower extremity in TKA. Methods Seventy-six consecutive patients with end-stage knee osteoarthritis were enrolled. External rotation osteotomy of the distal femur during TKA was completed according to the pre-operative external rotation angle (ERA), intraoperative transepicondylar axis (TEA) and anteroposterior (AP) line. Passive dynamic alignment of the lower extremity during knee flexion was recorded. The variation trend of hip– knee–ankle (HKA) alignment and the influences of femoral external rotation osteotomy were analysed. Results Postoperative deviation of HKA alignment from 0° to 90° flexion was associated with the rotational alignment of the femoral component (r=−0.769, p 1° internal to the mean). In the external group, HKA alignment tended to be in varus when the knee flexed to 90° (r2 =0.992, p=0.0003, Fig. 5). In the internal group, HKA alignment tended to be in valgus when the knee flexed to 90° (r2 =0.964, p=0.008). In the neutral group, HKA alignment fluctuated around 0° (r2 =0.101, p=0.601).
Mean rotational alignment of the femoral component was −0.934°, with standard deviation (SD) of 2.167°. Postoperative deviation of HKA alignment from 0° to 90° of knee flexion was associated with rotational alignment of the femoral component (r=−0.769, p
