Department of Orthopedic Surgery and Joint Surgery Centre, Takatsuki General Hospital, 1-3-13, Kosobe-cho, Takatsuki, Osaka, 569-1192, Japan.
Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
Knee Surg Sports Traumatol Arthrosc. 2022 Sep;30(9):3236-3243. doi: 10.1007/s00167-021-06729-y. Epub 2021 Sep 13.
Lateral compartment osteoarthritis progression (LOP) is a major complication after Oxford mobile-bearing unicompartmental knee arthroplasty (OUKA). This study aimed to identify the association between tibiofemoral subluxation (TFS) and LOP after OUKA. Patients whose TFS was uncorrectable according to preoperative stress radiographs were hypothesised to develop residual TFS even after surgery, and thought to be more likely to develop LOP.
The study included 201 patients who underwent medial OUKA. Fifteen patients showed increases in LOP of at least two Kellgren-Lawrence grades after surgery [progression (P) group], while the others had no progression (N group, n = 186). TFS was measured on preoperative full leg weight-bearing radiographs, valgus stress radiographs and postoperative plain radiographs. Valgus stress radiographs were obtained using a firm manual valgus force with the knee flexed at 20°. Leg alignment, Oxford knee score (OKS), and revision rates were assessed.
The P group had significantly higher TFS values on preoperative valgus stress (6.8° ± 2.2° vs. 4.5° ± 2.0°; P < 0.001) and postoperative radiographs (6.6° ± 2.3° vs. 4.6° ± 2.9°; P < 0.001) than the N group. Patients with postoperative residual TFS and postoperative valgus alignment were more likely to have LOP, but 9 of the 15 LOP patients did not show postoperative valgus alignment. The P group had significantly poorer postoperative OKS (33.0 ± 10.2 vs. 37.4 ± 6.5, P = 0.017) and a higher rate of revision (6/15 vs 6/186; odds ratio = 19.16; 95% CI = 4.98-76.05, P < 0.001).
OA progression in the lateral compartment after medial OUKA might be associated with postoperative residual TFS, but does not always coexist with postoperative valgus alignment. Preoperative assessment of TFS with valgus stress could be a potential predictor of postoperative residual TFS and LOP.
Level III.
外侧间室骨关节炎进展（LOP）是牛津活动衬垫单髁膝关节置换术（OUKA）后的主要并发症。本研究旨在确定胫骨股骨半脱位（TFS）与 OUKA 后 LOP 之间的关系。根据术前应力位 X 线片，假设 TFS 无法矫正的患者即使在手术后仍会出现残余 TFS，并且更有可能出现 LOP。
本研究纳入了 201 例接受内侧 OUKA 的患者。术后 LOP 至少增加两个 Kellgren-Lawrence 分级的 15 例患者[进展（P）组]，而其他患者无进展（N 组，n=186）。术前采用全腿负重位 X 线片、外翻应力位 X 线片和术后平片测量 TFS。外翻应力位 X 线片采用膝关节屈曲 20°时的牢固手动外翻力获得。评估下肢对线、牛津膝关节评分（OKS）和翻修率。
P 组术前外翻位应力位 X 线片（6.8°±2.2°比 4.5°±2.0°；P<0.001）和术后 X 线片（6.6°±2.3°比 4.6°±2.9°；P<0.001）的 TFS 值明显高于 N 组。术后残余 TFS 和术后外翻对线的患者更有可能出现 LOP，但 15 例 LOP 患者中有 9 例未出现术后外翻对线。P 组术后 OKS 明显较差（33.0±10.2 比 37.4±6.5，P=0.017），翻修率较高（6/15 比 6/186；比值比=19.16；95%可信区间=4.98-76.05，P<0.001）。
内侧 OUKA 后外侧间室 OA 进展可能与术后残余 TFS 有关，但并不总是与术后外翻对线共存。术前外翻位应力评估 TFS 可能是术后残余 TFS 和 LOP 的潜在预测指标。
III 级。
