Stroobant Lenka, Marvellie Amber, Windels Jani, Vermue Hannes, Arnout Nele, Van Onsem Stefaan, Victor Jan
Department Orthopaedic Surgery, University Hospital Ghent, Ghent, Belgium.
Ghent University, Ghent, Belgium.
Knee Surg Sports Traumatol Arthrosc. 2025 Sep 12. doi: 10.1002/ksa.70065.
Instability is a rising cause of revision total knee arthroplasty (rTKA), creating significant challenges for patients, surgeons and the healthcare system. This systematic review and meta-analysis aimed to evaluate the outcomes of conservative management, isolated polyethylene exchange (PE), and rTKA as treatments for post-TKA instability. The primary outcome was patient-reported outcome measures (PROMs), with secondary outcomes including reoperation rates, revision rates, and implant survival (Aim 1). Additionally, the study examined the effect of instability type on PROMs (Aim 2) and the impact of prosthesis constraint on PROMs (Aim 3).
A systematic search of studies published from 2000 to July 2024 was conducted. (1) Studies analysing the outcome of conservative treatment, isolated PE exchange or revision surgery for instability were included, reporting on PROMs, reoperations, revisions, and/or survival free from revision. PROMs included the Knee Society Score, both clinical (KSCS) and functional (KSFS). Revision was defined as the removal and replacing of the femoral and/or tibial component. A meta-analysis was only performed for revision surgery as treatment. (2) Instability was classified into flexion and extension instability. (3) Prosthetic constraints analysed included posterior stabilised (PS), condylar constrained knee (CCK), and rotating hinged knee (RHK).
A total of 27 articles, involving 4269 knees, were included in the analysis: two studies on conservative management, 12 on isolated PE exchange, and 19 on revision surgeries. (1) Conservative treatment, primary physiotherapy, yielded inconsistent results. Isolated PE exchange showed poor outcomes, with recurrent instability and subsequent revision occurring in 6.5%-18.5% of cases. However, in carefully selected patients, outcomes comparable to rTKA were observed. Revision surgery showed a mean improvement of 32 points (95% confidence interval [CI], 20.5-43.5; p < 0.001) for KSKS and 24.3 points (95% CI, 17.2-31.4; p < 0.001) for KSFS. During follow-up, 5.3% (46/864) of the patients underwent a rerevision, with 41.3% attributed to instability. (2) Extension instability showed a trend toward better KSKS (p = 0.04) and KSFS scores (p = 0.03) than flexion instability, and (3) no evidence of superiority was found between different types of constraint in this study.
When guided by appropriate clinical indications, conservative management, isolated PE exchange, and revision surgery can yield favourable outcomes in the treatment of post-TKA instability. Instability remains the leading cause of rerevision, highlighting the need for higher prosthetic constraints when flexion-extension gap balancing cannot be achieved.
Level IV, systematic review.
关节不稳是全膝关节置换翻修术（rTKA）日益常见的原因，给患者、外科医生和医疗系统带来了重大挑战。本系统评价和荟萃分析旨在评估保守治疗、单纯聚乙烯垫片置换（PE）和rTKA治疗全膝关节置换术后不稳的疗效。主要结局为患者报告结局指标（PROMs），次要结局包括再次手术率、翻修率和植入物生存率（目标1）。此外，该研究还考察了不稳类型对PROMs的影响（目标2）以及假体限制对PROMs的影响（目标3）。
对2000年至2024年7月发表的研究进行系统检索。（1）纳入分析保守治疗、单纯PE置换或翻修手术治疗关节不稳的研究，报告PROMs、再次手术、翻修和/或无翻修生存率。PROMs包括膝关节协会评分，包括临床（KSCS）和功能（KSFS）评分。翻修定义为取出并更换股骨和/或胫骨组件。仅对作为治疗手段的翻修手术进行荟萃分析。（2）关节不稳分为屈曲不稳和伸直不稳。（3）分析的假体限制类型包括后稳定型（PS）、髁限制型膝关节（CCK）和旋转铰链膝关节（RHK）。
共纳入27篇文章，涉及4269个膝关节：2篇关于保守治疗的研究，12篇关于单纯PE置换的研究，19篇关于翻修手术的研究。（1）保守治疗，即主要进行物理治疗，结果不一致。单纯PE置换显示效果不佳，6.5%-18.5%的病例出现复发性不稳及随后的翻修。然而，在精心挑选的患者中，观察到与rTKA相当的结果。翻修手术显示KSKS平均改善32分（95%置信区间[CI]，20.5-43.5；p＜0.001），KSFS平均改善24.3分（95%CI，17.2-31.4；p＜0.001）。随访期间，5.3%（46/864）的患者接受了再次翻修，其中41.3%归因于关节不稳。（2）伸直不稳的KSKS（p = 0.04）和KSFS评分（p = 0.03）有优于屈曲不稳的趋势，（3）本研究未发现不同类型限制之间存在优越性的证据。
在适当的临床指征指导下，保守治疗、单纯PE置换和翻修手术在治疗全膝关节置换术后不稳方面可取得良好效果。关节不稳仍然是再次翻修的主要原因，这凸显了当屈伸间隙平衡无法实现时，需要更高的假体限制。
IV级，系统评价。
