Vajapey Sravya P, Alvarez Paul M, Chonko Douglas
Department of Orthopaedics, The Ohio State University Wexner Medical Center, 241 W. 11th Avenue, Suite 6081, Columbus, OH, 43210, USA.
Arthroplasty. 2021 Jun 2;3(1):16. doi: 10.1186/s42836-021-00073-9.
We present two cases of unicompartmental knee arthroplasty (UKA) bearing failure in this report-one case of bearing dislocation and one case of bearing fracture. The causes of failure in both cases are evaluated in depth and recommendations are provided regarding intraoperative technique to reduce risk of bearing failure in mobile bearing UKAs.
In the first case, intraoperative evidence of metallosis and chronic pain preceding the traumatic event may indicate that the patient had attenuation of her collateral ligaments that precipitated the instability event. In the second case, the relatively atraumatic nature of the bearing fracture-dislocation and intraoperative evidence of extensive poly wear suggest that the bearing fracture was likely due to a 3-mm bearing selection in the initial surgery.
This case report shows that late bearing in mobile bearing unicompartmental knee arthroplasty can often be a multifactorial event and treatment must address all the risk factors that led to bearing dislocation. Bearing fracture is a very rare complication associated with mobile bearing UKA and patients with thin polyethylene inserts are at risk for bearing fracture even in the absence of poly wear.
在本报告中，我们介绍了两例单髁膝关节置换术（UKA）的假体失败案例——一例假体脱位和一例假体骨折。深入评估了两例失败的原因，并就减少活动平台UKA假体失败风险的术中技术提出了建议。
在第一例中，创伤事件发生前术中出现金属沉着病和慢性疼痛的证据可能表明，患者的侧副韧带已经松弛，从而引发了不稳定事件。在第二例中，假体骨折-脱位相对无创伤的性质以及术中广泛聚乙烯磨损的证据表明，假体骨折可能是由于初次手术中选择了3毫米厚的假体。
本病例报告表明，活动平台单髁膝关节置换术中晚期假体失败通常是多因素导致的，治疗必须解决所有导致假体脱位的风险因素。假体骨折是与活动平台UKA相关的一种非常罕见的并发症，即使没有聚乙烯磨损，使用薄聚乙烯衬垫的患者也有假体骨折的风险。
