Department of Orthopedic Surgery, Chung-Ang University College of Medicine, Chung-Ang University Hospital, 102 Heukseok-ro, Dongjak-gu, Seoul, 06973, South Korea.
Orthopedic Department, Centre Hospitalier de Versailles, Le Chesnay, France.
Arch Orthop Trauma Surg. 2019 Sep;139(9):1293-1305. doi: 10.1007/s00402-019-03231-6. Epub 2019 Jul 12.
To evaluate the incidence and risk factors of postoperative hyperextension after mobile-bearing total knee arthroplasty (TKA) and its clinical outcomes.
This retrospective case-control study included 387 knees of primary TKA patients after a 5-year follow-up. The clinical outcomes and radiographs including posterior condylar offset (PCO), femur and tibial slope angle and its discrepancy were evaluated. The patients were divided into two groups (group 1: non-hyperextension, group 2: hyperextension). An extension greater than 5° measured using a goniometer at the final follow-up was defined as hyperextension. Logistic and linear regression analyses were performed.
Overall, 43 knees (11.1%) with hyperextension were observed at the last follow-up. There was no significant difference between groups in terms of the clinical outcomes although the functional scores were worse in group 2. There was no significant difference in the postoperative radiologic evaluation except for a change in PCO (group 1 vs. group 2; - 0.2 mm ± 3.8 vs. - 2.4 mm ± 3.0, p = 0.003), distal femoral resection slope angle (- 9.1° ± 2.1 vs. - 12.1° ± 1.7, p < 0.000) and discrepancy of the slope angle (0.3° ± 4.5 vs. - 3.6° ± 3.9, p < 0.000). The change in PCO [odds ratio (OR) 0.86, p = 0.012], discrepancy of the slope angle (OR 0.8136, p = 0.000) and the preoperative mechanical femorotibial angle (OR 1.09, p = 0.003) were associated with hyperextension.
Mobile-bearing TKA with hyperextension over 5° showed worse functional outcomes at the mid-term follow-up, even though no serious complications were observed. Care should be taken to maintain the posterior condylar offset and to match the resection angles in femur and tibia due to the risk of hyperextension and worse functional outcomes.
IV.
评估活动平台型全膝关节置换术后过伸的发生率和风险因素及其临床结果。
本回顾性病例对照研究纳入了 387 例初次接受 TKA 患者的膝关节，随访时间为 5 年。评估了临床结果和影像学检查，包括后髁偏心距（PCO）、股骨和胫骨倾斜角及其差值。患者被分为两组（组 1：无过伸，组 2：过伸）。在最后随访时使用量角器测量的超过 5°的伸展被定义为过伸。进行了逻辑和线性回归分析。
总的来说，在最后一次随访时，43 个膝关节（11.1%）出现过伸。尽管组 2 的功能评分较差，但两组在临床结果方面没有显著差异。术后影像学评估没有显著差异，除了 PCO 的变化（组 1 与组 2 相比；-0.2mm±3.8 与-2.4mm±3.0，p=0.003）、股骨远端切除斜率角（-9.1°±2.1 与-12.1°±1.7，p<0.000）和斜率角差值（0.3°±4.5 与-3.6°±3.9，p<0.000）。PCO 的变化[比值比（OR）0.86，p=0.012]、斜率角差值（OR 0.8136，p=0.000）和术前机械性股胫角（OR 1.09，p=0.003）与过伸有关。
过伸超过 5°的活动平台型 TKA 中期随访时功能结果较差，尽管未观察到严重并发症。由于过伸和功能结果较差的风险，应注意保持后髁偏心距和匹配股骨和胫骨的切除角度。
IV。
