Derman Peter B, Fabricant Peter D, David Guy
Department of Orthopaedics, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021. E-mail address for P.B. Derman:
Health Care Management Department, The Wharton School, University of Pennsylvania, 3641 Locust Walk, Philadelphia, PA 19104.
J Bone Joint Surg Am. 2014 Jun 4;96(11):922-928. doi: 10.2106/JBJS.L.01731.
The volume of primary joint replacements performed in the United States increased rapidly over the past twenty years, but the growth rate of total knee arthroplasties exceeded that of total hip arthroplasties. The aim of this study was to identify the key contributing factors behind this differential growth rate.
We compiled longitudinal data on total hip arthroplasty and total knee arthroplasty volume, length of hospital stay, and in-hospital mortality from the Nationwide Inpatient Sample; we calculated reimbursement using information available in the Federal Register and Centers for Medicare & Medicaid Services databases; we determined trends in body mass index from Behavioral Risk Factor Surveillance System findings; and we estimated the size of the surgical workforce based on membership data from the American Academy of Orthopaedic Surgeons. These sources each contained at least ten years of data, ending in 2009. Data sources were analyzed and were compared to identify supply-side and demand-side factors contributing to the more rapid growth observed in total knee arthroplasty.
Of the factors examined, body mass index played the most substantial role in increasing demand for total knee arthroplasty above that of total hip arthroplasty, with younger individuals affected to a greater degree. More rapid growth in utilization of total knee arthroplasty over total hip arthroplasty in individuals with a body mass index of ≥25 kg/m was responsible for 95% of the differential increase in total knee arthroplasty over total hip arthroplasty volumes. Hospital and physician reimbursement, length of stay, and in-hospital mortality did not improve more for total knee arthroplasty than total hip arthroplasty. The surgical community responded to additional demand primarily by increasing per-physician output.
Growth in total knee arthroplasty volume has far outpaced that of total hip arthroplasty among those with a body mass index of ≥25 kg/m but not for those with a body mass index of <25 kg/m. The magnitude of this effect will continue to expand if the proportion of Americans with a body mass index of ≥25 kg/m continues to increase. Changes in hospital and physician reimbursement, length of stay, and in-hospital mortality did not contribute to this differential growth rate.
在过去二十年中，美国进行的初次关节置换手术量迅速增加，但全膝关节置换术的增长率超过了全髋关节置换术。本研究的目的是确定这种差异增长率背后的关键促成因素。
我们从全国住院患者样本中收集了全髋关节置换术和全膝关节置换术的手术量、住院时间和住院死亡率的纵向数据；我们使用联邦公报和医疗保险与医疗补助服务中心数据库中的可用信息计算报销金额；我们根据行为风险因素监测系统的结果确定体重指数的趋势；我们根据美国骨科医师学会的会员数据估计外科手术人员的规模。这些数据源各自包含至少十年的数据，截至2009年。对数据源进行分析并相互比较，以确定导致全膝关节置换术观察到的更快增长的供应方和需求方因素。
在所研究的因素中，体重指数在增加全膝关节置换术需求高于全髋关节置换术需求方面发挥了最重要的作用，年轻个体受影响程度更大。体重指数≥25 kg/m²的个体中，全膝关节置换术的使用量比全髋关节置换术增长更快，这占全膝关节置换术比全髋关节置换术手术量差异增加的95%。全膝关节置换术在医院和医生报销、住院时间和住院死亡率方面的改善并不比全髋关节置换术更多。外科界主要通过提高每位医生的手术量来应对额外需求。
在体重指数≥25 kg/m²的人群中，全膝关节置换术的手术量增长远远超过全髋关节置换术，但在体重指数<25 kg/m²的人群中并非如此。如果体重指数≥25 kg/m²的美国人比例继续增加，这种影响的程度将继续扩大。医院和医生报销、住院时间和住院死亡率的变化并未导致这种差异增长率。
