Orthopaedic Department, Charité University Hospital Berlin, Charitéplatz 1, 10117, Berlin, Germany.
Arch Orthop Trauma Surg. 2010 Dec;130(12):1487-91. doi: 10.1007/s00402-010-1064-9. Epub 2010 Feb 18.
Varus malalignment after total knee replacement is mentioned to be a major risk factor for postoperative pain and functional impairments. This wide spread opinion is based on the historical data derived from implantations performed in the late 1970s and early 1980s. We tested the hypothesis whether significant varus malalignment leads to minor functional results and early loosening using modern implants and operating techniques.
Two hundred and eighteen knee joints (184 patients) having been replaced with a PFC Sigma or Natural Knee II with a minimum follow-up of 5 years were included in this case control study. From the 30 most varus malaligned knees (30 patients) 25 patients were available for clinical and radiographical examination (group A) and were compared with a control group without significant varus malalignment that was matched for sex, age and implant (group B). The Knee Society Score (KSS), the WOMAC and the SF36 were determined.
No implant showed radiological signs of loosening or had been revised. The deviation from the mechanical axis was 6.3° [3.9°-10.7° varus] in group A and 0° [2.6° valgus to 2.1° varus] in group B (P < 0.001). The KSS was 158 [99-199] points in group A and 142 [78-198] points in group B (n.s.). The WOMAC did not reveal any significant differences between the groups either (group A 22 ± 27 points, group B 21 ± 21 points). Likewise in the SF36, neither in the sum nor in the individual scores was a significant difference found between groups A (56 ± 24 [8-90] points) and B (56 ± 18 [26-86] points).
The present data do not support the assumption that there is a correlation between varus malalignment and a bad medium-term radiological and clinical outcome after total knee arthroplasty. This questions the indication for revision of painful and varus malaligned prostheses, since an improvement of the clinical outcome is not to be expected.
全膝关节置换术后的内翻畸形被认为是术后疼痛和功能障碍的主要危险因素。这种普遍的观点是基于 20 世纪 70 年代末和 80 年代初植入物的历史数据得出的。我们使用现代植入物和手术技术来验证这样一个假设，即显著的内翻畸形是否会导致轻微的功能结果和早期松动。
本病例对照研究纳入了 218 例膝关节（184 例患者），这些膝关节均使用 PFC Sigma 或 Natural Knee II 进行置换，随访时间至少为 5 年。从 30 例最内翻畸形的膝关节（30 例患者）中，有 25 例患者可进行临床和影像学检查（A 组），并与无明显内翻畸形且性别、年龄和植入物匹配的对照组（B 组）进行比较。采用膝关节协会评分（KSS）、WOMAC 和 SF36 进行评估。
没有任何植入物显示松动的影像学迹象或需要翻修。A 组的机械轴偏离为 6.3°[3.9°-10.7°内翻]，B 组为 0°[2.6°外翻至 2.1°内翻]（P<0.001）。A 组 KSS 为 158[99-199]分，B 组为 142[78-198]分（无统计学差异）。WOMAC 评分两组间也无明显差异（A 组 22±27 分，B 组 21±21 分）。同样，SF36 总分和各分项评分在 A 组（56±24[8-90]分）和 B 组（56±18[26-86]分）之间也无统计学差异。
本研究数据不支持这样一种假设，即全膝关节置换术后的内翻畸形与中期放射学和临床结果不良之间存在相关性。这质疑了对疼痛和内翻畸形假体进行翻修的指征，因为预计临床结果不会得到改善。
