Francois Elvis L, Abdel Matthew P, Sousa Paul L, Chapman Danielle M, Miller Mike J, Dalury David F, Berry Daniel J
Orthopedics. 2019 Mar 1;42(2):90-94. doi: 10.3928/01477447-20190225-04.
In the setting of total knee arthroplasty, patella baja has been associated with decreased range of motion and increased risk of certain extensor mechanism complications. The goal of this study was to determine whether obese patients had an increased prevalence of patella baja before and/or after primary total knee arthroplasty. A multicenter retrospective review of 5089 unilateral total knee arthroplasties performed between 1998 and 2012 for osteoarthritis was conducted. Only total knee arthroplasties with cemented modular, metal-backed constructs and patellar resurfacing were included. An a priori power analysis determined that 500 patients (stratified into 5 World Health Organization body mass index groups, matched by age and sex) were needed to detect a significant Insall-Salvati ratio difference of 0.07. Patella baja was defined as an Insall-Salvati ratio of less than 0.8. Preoperative and postoperative Insall-Salvati ratios were compared between groups and analyzed using linear regression and analysis of variance. Preoperatively, there was a higher prevalence of patella baja in the higher body mass index groups (>25 kg/m) compared with normal weight patients (10% vs 6%; P=.02). Postoperatively, there was no difference in the prevalence of patella baja between the 2 groups (5% vs 5%; P=.91). On comparison of postoperative Insall-Salvati ratio with preoperative Insall-Salvati ratio, the higher body mass index groups had a greater change in Insall-Salvati ratio (Δ 0.10 vs Δ 0.07; P=.01). This is the first study to report an increased prevalence of patella baja in obese patients and to show that the prevalence normalizes to that of a control group after total knee arthroplasty. Obese patients undergoing primary total knee arthroplasty had a higher rate of preoperative patella baja. [Orthopedics. 2019; 42(2):90-94.].
在全膝关节置换术中，低位髌骨与活动范围减小以及某些伸肌机制并发症风险增加有关。本研究的目的是确定肥胖患者在初次全膝关节置换术前和/或术后低位髌骨的患病率是否增加。对1998年至2012年间因骨关节炎进行的5089例单侧全膝关节置换术进行了多中心回顾性研究。仅纳入采用骨水泥固定模块化金属背衬假体并进行髌骨表面置换的全膝关节置换术。一项预先的功效分析确定，需要500例患者（按世界卫生组织的5个体重指数组分层，年龄和性别匹配）才能检测到Insall-Salvati比率有0.07的显著差异。低位髌骨定义为Insall-Salvati比率小于0.8。比较各亚组术前和术后的Insall-Salvati比率，并采用线性回归和方差分析进行分析。术前，与正常体重患者相比，较高体重指数组（>25kg/m²）的低位髌骨患病率更高（10%对6%；P=0.02）。术后，两组间低位髌骨的患病率无差异（5%对5%；P=0.91）。比较术后Insall-Salvati比率与术前Insall-Salvati比率，较高体重指数组的Insall-Salvati比率变化更大（Δ0.10对Δ0.07；P=0.01）。这是第一项报告肥胖患者低位髌骨患病率增加，并表明全膝关节置换术后患病率恢复至对照组水平的研究。接受初次全膝关节置换术的肥胖患者术前低位髌骨的发生率较高。[《骨科》2019年；42(2):90-94。]
