Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
J Arthroplasty. 2018 Oct;33(10):3181-3185. doi: 10.1016/j.arth.2018.06.001. Epub 2018 Jun 9.
Postoperative neutral alignment may be an important factor for longevity of total knee arthroplasty (TKA). In knees with severe varus deformity, greater soft tissue release and bone resection were required to achieve neutral alignment. We investigated the relationship between the severity of preoperative varus deformity and longevity of neutral-aligned TKAs.
Of the 723 knees in patients who underwent primary TKA for varus-type osteoarthritis between November 1998 and June 2009, 496 knees aligned neutrally (the postoperative mechanical hip-knee-ankle [HKA] axis angle ranged between -3° and 3°) and followed up for at least 5 years were included in the study. The mean follow-up period was 9.28 years. Patients were divided into 4 groups based on their preoperative HKAs: mild (0° < HKA ≤ 5°, n = 79), moderate (5° < HKA ≤ 10°, n = 204), severe (10° < HKA ≤ 15°, n = 149), and very severe (HKA > 15°, n = 64) groups. Failure was defined as need for revisional TKA for mechanical reason. Survival was analyzed by Kaplan-Meier method and log-rank test.
The overall failure rate was 2.02% (10 of 496 prostheses). The cumulative survival rates of neutral-aligned TKAs at 10 years were 97.4% (95% confidence interval [CI], 93.9%-100%), 99.0% (95% CI, 97.6%-100%), 97.8% (95% CI, 95.4%-100%), and 96.9% (95% CI, 92.6%-100%) in mild, moderate, severe, and very severe varus groups, respectively. There were no significant differences between group survival rates (P = .395).
The severity of preoperative varus deformity did not affect survival rates of neutral-aligned TKAs over 10 years.
术后中立对线可能是全膝关节置换术（TKA）长期效果的一个重要因素。在严重内翻畸形的膝关节中，需要进行更大程度的软组织松解和骨切除，以实现中立对线。我们研究了术前内翻畸形的严重程度与中立对线 TKA 长期效果之间的关系。
1998 年 11 月至 2009 年 6 月期间，对患有内翻型骨关节炎的患者行初次 TKA，共纳入 723 例膝关节，其中 496 例膝关节获得了中立对线（术后机械髋-膝-踝[HKA]轴角度在-3°到 3°之间），并至少随访 5 年，平均随访时间为 9.28 年。根据术前 HKA 值，患者分为 4 组：轻度（0°<HKA≤5°，n=79）、中度（5°<HKA≤10°，n=204）、重度（10°<HKA≤15°，n=149）和极重度（HKA>15°，n=64）。以机械原因为由需要行翻修 TKA 定义为失败。通过 Kaplan-Meier 方法和对数秩检验进行生存分析。
总的失败率为 2.02%（496 例假体中有 10 例）。10 年时，中立对线 TKA 的累积生存率分别为 97.4%（95%可信区间[CI]，93.9%-100%）、99.0%（95%CI，97.6%-100%）、97.8%（95%CI，95.4%-100%）和 96.9%（95%CI，92.6%-100%），在轻度、中度、重度和极重度内翻畸形组中。组间生存率无显著差异（P=0.395）。
术前内翻畸形的严重程度并不影响 10 年以上中立对线 TKA 的生存率。
