Department of Orthopedic Surgery, Joint Surgery Center, Takatsuki General Hospital, Takatsuki, Osaka, Japan; Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
Department of Orthopedic Surgery, Joint Surgery Center, Takatsuki General Hospital, Takatsuki, Osaka, Japan.
J Arthroplasty. 2019 Nov;34(11):2606-2613. doi: 10.1016/j.arth.2019.05.054. Epub 2019 Jun 6.
Bearing dislocation is a serious complication of unicompartmental knee arthroplasty (UKA) with the Oxford knee prosthesis equipped with a mobile bearing. We aimed to clarify the extent of intraoperative movement of the mobile bearing and its relationship with the positioning of prosthesis components in patients undergoing Oxford UKA.
This retrospective study included 50 patients (50 knees) who underwent Oxford UKA for anteromedial osteoarthritis or osteonecrosis of the knee. Intraoperative bearing movement was assessed at various angles of knee flexion (0°, 30°, 60°, 90°, and 120°). We stratified patients according to the extent of bearing movement posteriorly during intraoperative knee flexion, with or without contacting the lateral wall of the tibial component (with contact, 20 knees; without contact, 30 knees). Postoperative radiographic evaluations were conducted at 1 week postoperatively to assess the positional parameters of the tibial and femoral components (varus/valgus alignment, rotation, mediolateral position). Clinical evaluations were conducted at 1 year postoperatively (maximum flexion angle, Oxford Knee Score).
Abnormal intraoperative movement of the mobile bearing resulting in contact with the lateral wall of the tibial component was associated with a significantly more medial position and external rotation of the tibial component, as well as poorer improvement in knee flexion angle at 1 year postoperatively.
In Oxford UKA recipients, the bearing may impinge on the lateral wall of the tibial component during flexion above 60° if the tibial component is placed too medially or exhibits pronounced external rotation, which may limit knee function improvement postoperatively.
在配备活动衬垫的牛津膝关节假体的单髁膝关节置换术中，关节脱位是一种严重的并发症。我们旨在明确活动衬垫在术中的移动程度及其与行牛津膝关节单髁置换术患者假体组件定位的关系。
本回顾性研究纳入了 50 例（50 膝）因膝关节前内侧骨关节炎或股骨头坏死而行牛津膝关节单髁置换术的患者。在膝关节不同屈曲角度（0°、30°、60°、90°和 120°）下评估术中的衬垫移动情况。我们根据术中膝关节屈曲时衬垫向后移动的程度将患者分层，有无接触胫骨组件的外侧壁（接触，20 膝；无接触，30 膝）。术后 1 周行影像学评估，以评估胫骨和股骨组件的位置参数（内翻/外翻对线、旋转、内外侧位置）。术后 1 年进行临床评估（最大屈曲角度、牛津膝关节评分）。
活动衬垫在术中发生异常移动并与胫骨组件的外侧壁接触与胫骨组件的位置更偏内侧和明显外旋有关，并且术后 1 年膝关节屈曲角度的改善较差。
在牛津膝关节单髁置换术中，如果胫骨组件放置过于偏内侧或出现明显外旋，在屈曲超过 60°时，衬垫可能会与胫骨组件的外侧壁碰撞，这可能会限制术后膝关节功能的改善。
