Chinese Journal of Tissue Engineering Research ›› 2017, Vol. 21 ›› Issue (11): 1658-1663.doi: 10.3969/j.issn.2095-4344.2017.11.004

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Does a fixed distal femur resection angle influence radiographic alignment in total knee arthroplasty?  

Ma Lu-yao1, Guo Wan-shou1, 2, Ma Jin-hui1, Yue De-bo2   

  1. 1China-Japan Friendship School of Clinical Medicine, Peking University, Beijing 100029, China; 2Department of Joint Surgery, China-Japan Friendship Hospital, Beijing 100029, China
  • Revised:2017-01-09 Online:2017-04-18 Published:2017-05-06
  • Contact: Guo Wan-shou, Chief physician, Professor, Doctoral supervisor, China-Japan Friendship School of Clinical Medicine, Peking University, Beijing 100029, China; Department of Joint Surgery, China-Japan Friendship Hospital, Beijing 100029, China
  • About author:Ma Lu-yao, Studying for doctorate, China-Japan Friendship School of Clinical Medicine, Peking University, Beijing 100029, China

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Abstract:

BACKGROUND: The distal femur resection in total knee arthroplasty is commonly made using a fixed angle relative to an intramedullary rod. Does a fixed distal femur resection angle influence radiographic alignment in primary total knee arthroplasty?

OBJECTIVE: To research the femoral mechanical-anatomical angle in Chinese and how it affects the femoral component angle and postoperative mechanical alignment for total knee arthroplasty.
METHODS: Totally 109 cases (148 knees) underwent primary total knee arthroplasty. One surgeon used a fixed resection angle of 5° (group A; n=56 cases, 76 knees). The second surgeon adjusted the resection angle according to preoperative coronal alignment, using 5° for neutral/mild varus, 6° for more severe varus, 4° for mild valgus and 3° for severe valgus knees (group B; n=53 cases, 72 knees). Preoperative hip-knee-ankle angle, femoral mechanical-anatomical angle, postoperative hip-knee-ankle angle, femoral component angle and tibial component angle were measured from standing hip-knee-ankle angle radiographs. For postoperative hip-knee-ankle angle, 177°-183° were considered as neutral mechanical axis. For femoral and tibial component angles, the target results were 88°-92°.
RESULTS AND CONCLUSION: (1) There was no statistically significant difference between groups in postoperative hip-knee-ankle angle (group A: (178.78±3.57)°, group B: (178.23±2.78)°; P=0.302) and good rate of hip-knee-ankle angle (group A: 62%, group B: 65%). (2) The mean femoral mechanical-anatomical angle was (6.70±1.34)° preoperatively. There was no significant difference in the good rate of hip-knee-ankle angle (hip-knee-ankle angle < 7°: 69%; hip-knee-ankle angle ≥7°: 55%; P=0.108) postoperatively. There was a statistically significant difference about good rate of femoral component angle between different femoral mechanical-anatomical angle angles (femoral mechanical-anatomical angle < 7°: 76%; femoral mechanical-anatomical angle ≥7°: 39%; P < 0.01). (3) There was a statistically significant correlation between preoperative femoral mechanical-anatomical angle and postoperative hip-knee-ankle angle (r=−0.42, P < 0.01) and postoperative femoral component angle (r=−0.58, P < 0.01). (4) The mean femoral mechanical-anatomical angle was larger than foreign values. When the resection angle less than femoral mechanical-anatomical angle, the femoral component may tend to be varus which could affect the lower extremity mechanical alignment. For the larger femoral mechanical-anatomical angle, we advise to adjust the resection angle according to measured value preoperatively.
 
中国组织工程研究杂志出版内容重点：人工关节；骨植入物；脊柱；骨折；内固定；数字化骨科；组织工程

Key words: Arthroplasty, Replacement, Knee, Osteotomy, Tissue Engineering

CLC Number: