Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota.
J Bone Joint Surg Am. 2019 Jul 17;101(14):1320-1330. doi: 10.2106/JBJS.18.01217.
Stiffness is a common reason for suboptimal clinical outcomes after primary total knee arthroplasty (pTKA). There is a lack of consensus regarding its definition, which is often conflated with its histopathologic subcategory-i.e., arthrofibrosis. There is value in refining the definition of acquired idiopathic stiffness in an effort to select for patients with arthrofibrosis. We conducted a systematic review and meta-analysis to establish a consensus definition of acquired idiopathic stiffness, determine its prevalence after pTKA, and identify potential risk factors for its development.
MEDLINE, Embase, Cochrane Controlled Register of Trials (CENTRAL), and Scopus databases were searched from 2002 to 2017. Studies that included patients with stiffness after pTKA were screened with strict inclusion and exclusion criteria to isolate the subset of patients with acquired idiopathic stiffness unrelated to known extrinsic or surgical causes. Three authors independently assessed study eligibility and risk of bias and collected data. Outcomes of interest were then analyzed according to age, sex, and body mass index (BMI).
In the 35 included studies (48,873 pTKAs), the mean patient age was 66 years. In 63% of the studies, stiffness was defined as a range of motion of <90° or a flexion contracture of >5° at 6 to 12 weeks postoperatively. The prevalence of acquired idiopathic stiffness after pTKA was 4%, and this did not differ according to age (4%, I = 95%, among patients <65 years old and 5%, I = 96%, among those ≥65 years old; p = 0.238). The prevalence of acquired idiopathic stiffness was significantly lower in males (1%, I = 85%) than females (3%, I = 95%) (p < 0.0001) as well as in patients with a BMI of <30 kg/m (2%, I = 94%) compared with those with a BMI of ≥30 kg/m (5%, I = 97%) (p = 0.027).
Contemporary literature supports the following definition for acquired idiopathic stiffness: a range of motion of <90° persisting for >12 weeks after pTKA in patients in the absence of complicating factors including preexisting stiffness. The mean prevalence of acquired idiopathic stiffness after pTKA was 4%; females and obese patients were at increased risk.
Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
僵硬是初次全膝关节置换术（pTKA）后临床效果不佳的常见原因。目前对于僵硬的定义尚未达成共识，其通常与组织病理学亚分类（即关节纤维化）相混淆。精确定义获得性特发性僵硬，并筛选出关节纤维化患者具有重要意义。本研究进行了一项系统评价和荟萃分析，旨在建立获得性特发性僵硬的共识定义，确定其在 pTKA 后的发生率，并确定其发生的潜在危险因素。
从 2002 年至 2017 年，检索了 MEDLINE、Embase、Cochrane 对照试验注册库（CENTRAL）和 Scopus 数据库。通过严格的纳入和排除标准筛选出 pTKA 后发生僵硬的患者研究，并将其与已知的外在或手术原因引起的僵硬患者相分离。三位作者独立评估研究的纳入标准和偏倚风险，并收集数据。然后根据年龄、性别和体重指数（BMI）分析感兴趣的结局。
在 35 项纳入的研究（48873 例 pTKA）中，患者的平均年龄为 66 岁。在 63%的研究中，僵硬被定义为术后 6-12 周时的活动度<90°或屈曲挛缩>5°。pTKA 后获得性特发性僵硬的发生率为 4%，且该发生率与年龄无关（<65 岁患者发生率为 4%，I = 95%；≥65 岁患者发生率为 5%，I = 96%；p = 0.238）。男性（1%，I = 85%）获得性特发性僵硬的发生率明显低于女性（3%，I = 95%）（p < 0.0001），BMI<30 kg/m（2%，I = 94%）的患者发生率也明显低于 BMI≥30 kg/m（5%，I = 97%）的患者（p = 0.027）。
目前的文献支持将获得性特发性僵硬定义为：pTKA 后 12 周以上，且无包括术前僵硬在内的其他并发症的情况下，患者的活动度<90°。pTKA 后获得性特发性僵硬的平均发生率为 4%；女性和肥胖患者的风险增加。
治疗学四级。有关证据等级的完整描述，请参见作者须知。
