Watts Chad D, Wagner Eric R, Houdek Matthew T, Lewallen David G, Mabry Tad M
Department of Orthopedic Surgery, Mayo Clinic, 200 First Street S.W., Rochester, MN, 55905, USA.
Clin Orthop Relat Res. 2015 Aug;473(8):2621-7. doi: 10.1007/s11999-015-4283-0. Epub 2015 Apr 7.
Patients with obesity are known to have a higher risk of complications after primary TKA; however, there is a paucity of data regarding the effects of obesity with revision TKAs.
QUESTIONS/PURPOSES: We asked the following questions : (1) Are patients with morbid obesity (BMI≥40 kg/m2) at greater risk for repeat revision, reoperation, or periprosthetic joint infection (PJI) compared with patients without obesity (BMI<30 kg/m2) after an index revision TKA performed for aseptic reasons? (2) Do patients who are not obese achieve higher Knee Society pain and function scores after revision TKA for aseptic reasons?
We used a retrospective cohort study with 1:1 matching for sex, age (±3 years) and date of surgery (±1 year) to compare patients with morbid obesity with patients without obesity with respect to repeat revision, reoperation, and PJI. Using our institution's total joint registry, we identified 1291 index both-component (femoral and tibial) aseptic revision TKAs performed during a 15-year period (1992-2007). Of these, 120 revisions were in patients with morbid obesity (BMI≥40 kg/m2) and 624 were in patients with a BMI less than 30 kg/m2. We then considered only patients with a minimum 5-year followup, which was available for 77% of patients with morbid obesity and 76% of patients with a BMI less than 30 kg/m2 (p=0.84). All patients with morbid obesity who met criteria were included (morbid obesity group: n=93; average followup, 7.9 years) and compared with a matched cohort of patients with a BMI less than 30 kg/m2 (nonmorbid obesity group: n=93; average followup, 7.3 years). Medical records were reviewed to gather details regarding complications and clinical outcomes.
Overall, patients with morbid obesity had an increased risk of repeat revision (hazard ratio [HR], 3.8; 95% CI, 1.2-16.5; p<0.02), reoperation (HR, 2.9; 95% CI, 1.3-7.4; p<0.02), and PJI (HR, 6.4; 95% CI, 1.2-119.7; p<0.03). Implant survival rates were 96% (95% CI, 92%-100%) and 100% at 5 years, and 81% (95% CI, 70%-92%) and 93% (95% CI, 86%-100%) at 10 years for the patients with morbid obesity and those without morbid obesity, respectively (p=0.02). At 10 years, The Knee Society pain (90 [95% CI, 88-92] vs 76 [95% CI, 71-81]; p<0.01) and function (61 [95% CI, 53-69] vs 57 [95% CI, 42-52]; p<0.01) scores were higher in patients with a BMI less than 30 kg/m2 compared with patients with morbid obesity.
Morbid obesity is associated with increased rates of rerevision, reoperation, and PJI after aseptic revision TKA. As the time-sensitive nature of revision surgery may not always allow for patient or comorbidity optimization, these results emphasize the need for improving our care of patients with morbid obesity earlier on during the osteoarthritic process. Additional studies are needed to risk stratify patients in the morbidly obese population to better guide patient selection and effective optimization.
Level III, therapeutic study.
已知肥胖患者在初次全膝关节置换术（TKA）后出现并发症的风险更高；然而，关于肥胖对翻修TKA影响的数据却很匮乏。
问题/目的：我们提出了以下问题：（1）与非肥胖患者（BMI<30kg/m2）相比，病态肥胖患者（BMI≥40kg/m2）在因无菌性原因进行初次翻修TKA后，再次翻修、再次手术或假体周围关节感染（PJI）的风险是否更高？（2）非肥胖患者在因无菌性原因进行翻修TKA后，膝关节协会疼痛和功能评分是否更高？
我们采用回顾性队列研究，按照性别、年龄（±3岁）和手术日期（±1年）进行1:1匹配，比较病态肥胖患者与非肥胖患者在再次翻修、再次手术和PJI方面的情况。利用我们机构的全关节登记系统，我们确定了15年期间（1992 - 2007年）进行的1291例初次双组件（股骨和胫骨）无菌性翻修TKA。其中，120例翻修手术的患者为病态肥胖（BMI≥40kg/m2），624例患者的BMI小于30kg/m2。然后，我们仅考虑随访至少5年的患者，病态肥胖患者中有77%、BMI小于30kg/m2的患者中有76%可获得至少5年的随访（p = 0.84）。所有符合标准的病态肥胖患者均被纳入（病态肥胖组：n = 93；平均随访7.9年），并与BMI小于30kg/m2的匹配队列患者（非病态肥胖组：n = 93；平均随访7.3年）进行比较。查阅病历以收集有关并发症和临床结果的详细信息。
总体而言，病态肥胖患者再次翻修（风险比[HR]，3.8；95%可信区间[CI]，1.2 - 16.5；p<0.02）、再次手术（HR，2.9；95%CI，1.3 - 7.4；p<0.02）和PJI（HR，6.4；95%CI，1.2 - 119.7；p<0.03）的风险增加。5年时，病态肥胖患者和非病态肥胖患者的植入物生存率分别为96%（95%CI，92% - 100%）和100%，10年时分别为81%（95%CI，70% - 92%）和93%（95%CI，86% - 100%）（p = 0.02）。10年时，BMI小于30kg/m2的患者膝关节协会疼痛评分（90[95%CI，88 - 92]对76[95%CI，71 - 81]；p<0.01）和功能评分（61[95%CI，53 - 69]对57[95%CI，42 - 52]；p<0.01）高于病态肥胖患者。
病态肥胖与无菌性翻修TKA后再次翻修、再次手术和PJI的发生率增加有关。由于翻修手术对时间的敏感性可能并不总是允许对患者或合并症进行优化，这些结果强调了在骨关节炎病程早期改善对病态肥胖患者护理的必要性。需要进一步研究对病态肥胖人群进行风险分层，以更好地指导患者选择和有效优化。
III级，治疗性研究。
