National Institute for Health and Welfare, Centre for Health and Social Economics CHESS, Finland.
Acta Orthop. 2013 Feb;84(1):25-31. doi: 10.3109/17453674.2013.771299. Epub 2013 Jan 31.
Little is known about the effect of the learning curve for different types of total hip arthroplasties (THAs). We investigated the prostheses survival of THAs just after the implementation of a model new to the hospital, and compared these results with the results of THAs done when more than 100 implantations had been undertaken. In addition, we investigated whether differences exist between different types of femoral stems and acetabular cups at the early implementation phase.
We used comprehensive registry data from all units (n = 76) that performed THAs for primary osteoarthritis in Finland between 1998 and 2007. Complete data including follow-up data to December 31, 2010 or until death were available for 33,819 patients (39,125 THAs). The stems and cups used were given order numbers in each hospital and classified into 5 groups: operations with order number (a) 1-15, (b) 16-30, (c) 31-50, (d) 51-100, and (e) > 100. We used Cox's proportional hazards modeling for calculation of the adjusted hazard ratios for the risk of revision during the 3 years following the implementation of a new THA endoprosthesis type in the groups.
Introduction of new endoprosthesis types was common, as more than 1 in 7 patients received a type that had been previously used in 15 or less operations. For the first 15 operations after a stem or cup type was introduced, there was an elevated risk of revision (hazard ratio (HR) = 1.3, 95% CI: 1.1-1.5). There were differences in the risk of early revision between stem and cup types at implementation.
The first 15 operations with a new stem or cup model had an increased risk of early revision surgery. Stems and cups differed in their early revision risk, particularly at the implementation phase. Thus, the risk of early revision at the implementation phase should be considered when a new type of THA is brought into use.
对于不同类型全髋关节置换术（THA）的学习曲线的影响，我们知之甚少。我们调查了医院新实施的一种模型的 THA 假体生存率，并将这些结果与超过 100 例植入物的 THA 结果进行比较。此外，我们还研究了在早期实施阶段不同类型股骨柄和髋臼杯之间是否存在差异。
我们使用了芬兰 1998 年至 2007 年间所有单位（n=76）进行的原发性骨关节炎初次 THA 的综合登记数据。对于 33819 名患者（39125 例 THA），完整的数据（包括截至 2010 年 12 月 31 日或直至死亡的随访数据）均可用。每个医院的柄和杯都有编号，并分为 5 组：手术编号为（a）1-15、（b）16-30、（c）31-50、（d）51-100 和（e）>100。我们使用 Cox 比例风险模型计算了在新 THA 假体类型实施后的 3 年内，各分组中修订风险的调整风险比。
引入新型假体类型很常见，超过 1/7 的患者接受了之前使用不到 15 次的类型。在引入一种新的柄或杯类型后的前 15 次手术中，翻修风险升高（风险比（HR）=1.3，95%CI：1.1-1.5）。在引入阶段，柄和杯类型的早期翻修风险存在差异。
新柄或杯模型的前 15 次手术有增加早期翻修手术的风险。在早期实施阶段，柄和杯的早期翻修风险存在差异，特别是在实施阶段。因此，在引入新型 THA 时，应考虑实施阶段的早期翻修风险。
