胫骨假体的不同后倾角度对内侧间室单髁置换术后膝关节功能的影响

目的: 研究分析胫骨假体在矢状面上的位置对牛津(Oxford)单髁置换术后膝关节功能的影响。方法: 回顾性分析2016年1月1日至2020年5月31于北京大学第一医院骨科行膝关节内侧间室单髁置换术的患者。依据术后胫骨假体后倾角度(posterior tibial slope,PTS), 将患者分为PTS标准组(PTS≥3°且PTS<8°)及PTS异常组(PTS<3°或PTS≥8°)。患者随访至少12个月,比较两组病例术后膝关节协会临床评分(Knee Society Clinical Score,KSS-C)、膝关节协会功能评分(Knee Society Functional Score,KSS-F)及膝关节活动范围,并评估手术前后PTS变化值与术后KSS-C评分、KSS-F评分及膝关节活动范围的相关性。结果: 共纳入72例患者(82膝),其中PTS标准组51例患者(58膝)、PTS异常组21例患者(24膝),所有患者均完成随访,中位随访时间23.6个月。两组病例的一般资料(性别、年龄、体重指数)、术前膝关节活动范围、术前KSS-C评分及KSS-F评分差异无统计学意义(P>0.01)。术后12个月随访时,所有病例在膝关节活动范围、KSS-C评分及KSS-F评分上均较术前显著改善(P<0.01)。两组病例在术后KSS-C评分上差异有统计学意义[PTS标准组(88.76±2.79)vs. PTS异常组(84.42±3.35),P<0.01],但在术后KSS-F评分、膝关节活动范围上差异无统计学意义(P>0.01)。另外,手术前后PTS的变化值与术后KSS-C评分(r=-0.034,95%CI:-0.247 ~ 0.186,P=0.759)、KSS-F评分(r=-0.014,95%CI:-0.238 ~ 0.198,P=0.901)及膝关节活动范围(r=0.045,95%CI:-0.214 ~ 0.302,P=0.686)无相关性。结论: 膝关节单髁置换术中采用3°~<8°的PTS可以使患者获得更好的术后功能,术中应避免胫骨假体PTS的过度增大或减小。

Effect of posterior tibial slope on the short-term outcome in mobile-bearing unicompartmental knee arthroplasty

Objective: To evaluate the relationship between postoperative knee function and the sagittal position of tibial component in unicompartmental knee arthroplasty (UKA). Methods: We retrospectively enrolled the patients who underwent UKA from January 2016 to May 2020. They were assigned into 2 groups according to postoperative posterior tibial slope (PTS): the normal PTS group (PTS≥3° and PTS<8°) and the abnormal PTS group (PTS<3° or ≥8°). The patients were followed up for at least 12 months. The postoperative Knee Society Clinical Score (KSS-C), Knee Society Functional Score (KSS-F) and knee range of motion (ROM) were compared between the two groups. Results: A total of 72 patients (82 knees) were included with 51 patients (58 knees) in PTS normal group and 21 patients (24 knees) in PTS abnormal group. All the patients were followed up with median of 23.6 months. There was no significant difference in the general data [gender, age, body mass index (BMI)], pre-operative knee range of motion, preoperative KSS-C score and KSS-F score (P > 0.01). The KSS-C score, KSS-F score, and knee range of motion significantly improved after surgery (P<0.01) for all the patients. The postoperative KSS-C score in normal PTS group (88.76±2.79) was significantly higher than the KSS-C score in abnormal PTS group (84.42±3.35, P<0.01), but no significant difference between the 2 groups was observed in postoperative KSS-F score and knee range of motion (P > 0.01). In addition, there was no correlation between the change of PTS and postoperative KSS-C score (r=-0.034, 95%CI: -0.247 to 0.186, P = 0.759), KSS-F score (r = -0.014, 95%CI: -0.238 to 0.198, P = 0.901) and knee range of motion (r= 0.045, 95%CI: -0.214 to 0.302, P = 0.686). Conclusion: The posterior tibial slope between 3° and <8° can be recommended to improve knee joint function in mobile UKA, and excessive or insufficient PTS should be avoided.