Gibbons John P, Zeng Nina, Bayan Ali, Walker Matthew L, Farrington Bill, Young Simon W
Department of Orthopaedic Surgery, North Shore Hospital, Auckland, New Zealand.
Department of Surgery, University of Auckland, Auckland, New Zealand.
Clin Orthop Relat Res. 2025 Jan 1;483(1):140-149. doi: 10.1097/CORR.0000000000003193. Epub 2024 Aug 14.
There is continuing debate about the ideal philosophy for component alignment in TKA. However, there are limited long-term functional and radiographic data on randomized comparisons of kinematic alignment versus mechanical alignment.
QUESTIONS/PURPOSES: We present the 10-year follow-up findings of a single-center, multisurgeon randomized controlled trial (RCT) comparing these two alignment philosophies in terms of the following questions: (1) Is there a difference in PROM scores? (2) Is there a difference in survivorship free from revision or reoperation for any cause? (3) Is there a difference in survivorship free from radiographic loosening?
Ninety-nine patients undergoing primary TKA for osteoarthritis were randomized to either the mechanical alignment (n = 50) or kinematic alignment (n = 49) group. Eligibility for the study was patients undergoing unilateral TKA for osteoarthritis who were suitable for a cruciate-retaining TKA and could undergo MRI. Patients who had previous osteotomy, coronal alignment > 15° from neutral, a fixed flexion deformity > 15°, or instability whereby constrained components were being considered were excluded. Computer navigation was used in the mechanical alignment group, and patient-specific cutting blocks were used in the kinematic alignment group. At 10 years, 86% (43) of the patients in the mechanical alignment group and 80% (39) in the kinematic alignment group were available for follow-up performed as a per-protocol analysis. The PROMs that we assessed included the Knee Society Score, Oxford Knee Score, WOMAC, Forgotten Joint Score, and EuroQol 5-Dimension score. Kaplan-Meier analysis was used to assess survivorship free from reoperation (any reason) and revision (change or addition of any component). A single blinded observer assessed radiographs for signs of aseptic loosening (as defined by the presence of progressive radiolucent lines in two or more zones), which was reported as survivorship free from loosening.
At 10 years, there was no difference in any PROM score measured between the groups. Ten-year survivorship free from revision (components removed or added) likewise did not differ between the groups (96% [95% CI 91% to 99%] for the mechanical alignment group and 91% [95% CI 83% to 99%] for the kinematic alignment group; p = 0.38). There were two revisions in the mechanical alignment group (periprosthetic fracture, deep infection) and four in the kinematic alignment group (two secondary patella resurfacings, two deep infections). There was no statistically significant difference in reoperations for any cause between the two groups. There was no difference with regard to survivorship free from loosening on radiographic review (χ 2 = 1.3; p = 0.52) (progressive radiolucent lines seen at 10 years were 0% for mechanical alignment and 3% for kinematic alignment).
Like the 2-year and 5-year outcomes previously reported, 10-year follow-up for this RCT demonstrated no functional or radiographic difference in outcomes between mechanical alignment and kinematic alignment TKA. Anticipated functional benefits of kinematic alignment were not demonstrated, and revision-free survivorship at 10 years did not differ between the two groups. Given the unknown long-term impact of kinematic alignment with regard to implant position (especially tibial component varus), we must conclude that mechanical alignment remains the reference standard for TKA. We could not demonstrate any advantage to kinematic alignment at 10-year follow-up.
Level I, therapeutic study.
关于全膝关节置换术（TKA）中假体对线的理想理念一直存在争议。然而，关于运动学对线与机械学对线随机比较的长期功能和影像学数据有限。
问题/目的：我们展示了一项单中心、多外科医生随机对照试验（RCT）的10年随访结果，该试验从以下几个方面比较了这两种对线理念：（1）患者报告结局量表（PROM）评分是否存在差异？（2）因任何原因无需翻修或再次手术的假体生存率是否存在差异？（3）无影像学松动的假体生存率是否存在差异？
99例因骨关节炎接受初次TKA的患者被随机分为机械学对线组（n = 50）或运动学对线组（n = 49）。本研究的纳入标准为因骨关节炎接受单侧TKA、适合保留交叉韧带的TKA且能接受磁共振成像（MRI）检查的患者。排除既往有截骨术、冠状面与中立位对线大于15°、固定屈曲畸形大于15°或存在不稳定（考虑使用限制性假体）的患者。机械学对线组使用计算机导航，运动学对线组使用患者特异性截骨模块。10年时，机械学对线组86%（43例）的患者和运动学对线组80%（39例）的患者可进行符合方案分析的随访。我们评估的PROM包括膝关节协会评分、牛津膝关节评分、西安大略和麦克马斯特大学骨关节炎指数（WOMAC）、遗忘关节评分和欧洲五维健康量表评分。采用Kaplan-Meier分析评估无再次手术（任何原因）和翻修（任何部件更换或添加）的假体生存率。由一名单盲观察者评估X线片有无无菌性松动迹象（定义为两个或更多区域出现进行性透亮线），并报告无松动的假体生存率。
10年时，两组间测量的任何PROM评分均无差异。两组间10年无翻修（部件移除或添加）的假体生存率同样无差异（机械学对线组为96% [95%可信区间91%至99%]，运动学对线组为91% [95%可信区间83%至99%]；p = 0.38）。机械学对线组有2例翻修（假体周围骨折、深部感染），运动学对线组有4例翻修（2例二次髌骨表面置换、2例深部感染）。两组间因任何原因再次手术的情况无统计学显著差异。影像学检查无松动的假体生存率无差异（χ² = 1.3；p = 0.52）（10年时机械学对线组出现进行性透亮线的比例为0%，运动学对线组为3%）。
如同先前报告的2年和5年结果一样，该RCT的10年随访表明，机械学对线TKA和运动学对线TKA在功能或影像学结局方面无差异。运动学对线预期的功能益处未得到证实，两组间10年无翻修的假体生存率无差异。鉴于运动学对线对假体位置（尤其是胫骨部件内翻）的长期影响尚不清楚，我们必须得出结论，机械学对线仍是TKA的参考标准。在10年随访中，我们未能证明运动学对线有任何优势。
I级，治疗性研究。
