BSR2013：髋关节表面重建术后生存期更长

　　英国伯明翰——在英国风湿病学会(BSR)2013年会上，牛津大学国立卫生研究院(NIHR)骨骼肌肉生物医学研究中心的Adrian Kendal博士报告称，一项基于人群的大规模研究表明，与全髋关节置换术(THR)相比，金属对金属髋关节表面重建术(MoMR)治疗骨关节炎可提高患者的10年生存率。

Dr. Adrian Kendal

　　研究者基于英国医院情景统计数据库和国家统计局数据库，收集了1999年4月~2012年3月在英格兰和威尔士的国民健康服务(NHS)所属医院接受择期初次髋关节置换术治疗骨关节炎的所有成年患者(年龄＞18岁)的死亡记录。

　　在针对年龄、性别、合并症、农村、社会剥夺等因素进行倾向评分匹配之后，在总共91,633例手术中有12,580例为MoMR，37,740例为骨水泥THR，41,312例为非骨水泥THR。MoMR组的累计死亡率为2.8%，而骨水泥THR组为7.3%[危险比(HR)，0.51]。MoMR组和非骨水泥THR组的10年死亡率分别为2.6%和3.2%(HR，0.64)。

　　此外，与骨水泥THR相比，MoMR每多预防1例死亡所需治疗的人数为29人；与非骨水泥THR相比，所需治疗的人数为88人。

　　Kendal博士说：“由于我们针对已知混杂因素进行了校正，所以研究结果的鲁棒性较高。与接受骨水泥或非骨水泥THR的患者相比，接受MoMR的患者可能获得了一些长期生存优势。”

　　有与会者指出，选择接受MoMR的患者可能年龄更小、活动水平更高，因此坚持锻炼的可能性更大。Kendal博士承认的确可能存在一些影响生存率的其他因素。在推测导致上述生存率差异的原因时，Kendal博士说：“我个人认为不仅是使用骨水泥的问题，因为这不能解释非骨水泥THR组与MoMR组之间的差异。”他补充道，无论是否使用骨水泥，THR期间股骨的准备方式可能很重要。已知的血栓形成风险也可能会影响生存率。此外，这与医疗不平等可能也有关系，因为表面重建术不如THR那么常用，这可能是因为缺乏专业的医疗机构或专业的治疗团队。

　　英国东英格兰大学的风湿病学专家Alex MacGregor博士对上述研究结果做出了评论。他指出，去年也发表过关于该主题的类似数据(BMJ 2012;344:e3319)并且引发了一些争议，因为作者存在一些倾向于髋关节表面重建术的利益冲突。作为英国国家关节登记库指导委员会的成员，MacGregor博士参与了后续对该论文结果的重新分析，他表示重新分析的结果将在今年晚些时候公布。

　　MacGregor博士说：“我对这项研究的疑问之一是，为什么要采用10年死亡率作为终点？如果表面重建术可以挽救更多的生命，那么应该能早一点观察到其生存优势，比如术后90天。”

　　Kendal博士回答道，他们也曾试图解决这个问题，但可能需要开展设计合理的随机对照试验。“就这项研究而言，我们没有任何利益冲突。其实我们一开始可能希望得到相反的结果；我们原本以为表面重建组的死亡率会更高，但结果并非如此，所以我相信上述数据支持那篇BMJ文章的结果。”

与髋关节相关的拓展阅读：

• OARSI：推荐膝、髋关节炎机能指标
• JCEM：中山大学陈裕明等发现高脂饮食增加髋关节骨折的发生
• BMJ Open：血钴浓度高或可预示髋关节置换失败
• AAOS 2013：≤55岁全髋关节置换术（THA）患者翻修失败率更高 更多信息请点击：有关髋关节更多资讯

Osteoarthritis patients survive longer after hip resurfacing than replacement
Contrary to expectations, metal-on-metal hip resurfacing for osteoarthritis was associated with higher patient survival at 10 years than was total hip arthroplasty in a large, population-based study.
Cumulative mortality rates were 2.8% for hip resurfacing versus 7.3% for cemented total hip replacement (THR; hazard ratio, 0.51). Ten-year mortality rates comparing hip resurfacing to uncemented THR were 2.6% and 3.2%, respectively (HR, 0.64).
Furthermore, the number needed to treat with hip resurfacing to prevent 1 excess death was 29 when compared to cemented THR, and it was 88 when compared to uncemented THR.
"Patients who received a metal-on-metal resurfacing [MoMR] procedure seem to have a long-term survival advantage compared to patients receiving cemented or an uncemented THR," said Dr. Adrian Kendal of the National Institute for Health Research (NIHR) Musculoskeletal Biomedical Research Unit at the University of Oxford, England.
"Our findings were robust after adjustment for known confounders," Dr. Kendal said at the British Society for Rheumatology annual conference. Propensity matching was used in the trial, which took age, gender, comorbidity, rurality, and social deprivation into account.
For the study, data from the English Hospital Episode Statistics database were obtained and linked to Office for National Statistics mortality records for all adults (over age 18) undergoing elective primary hip replacement for osteoarthritis in National Health Service hospitals in England and Wales between April 1999 and March 2012.
After propensity score matching, there were 91,633 procedures performed, of which 12,580 were MoMR, 37,740 were cemented THR, and 41,312 were uncemented THR.
In response to a comment that perhaps people opting for MoMR were more likely to be younger, more active, and hence more likely to exercise, Dr. Kendal conceded that other factors might exist that could have affected survival.
Speculating about why there might be such a difference in survival, he said: "I personally don’t think it’s just the use of cement, because that doesn’t explain the group that received an uncemented total hip replacement."
He added that the way the femur is prepared during THR might be important, regardless of whether or not cement is used. The known risk of thrombotic consequences also could affect survival. In addition, health care inequality might be important, as resurfacing procedures are less common than THR, perhaps because of the lack of specialized centers or dedicated teams. {nextpage}
Commenting on the findings after their presentation, consultant rheumatologist Dr. Alex MacGregor, of the University of East Anglia, Norwich, England, noted that similar data were published on this topic last year (BMJ 2012;344:e3319), but the results had proved somewhat controversial as the authors had a conflict of interest in favor of hip resurfacing.
Dr. MacGregor, who is a member of the National Joint Registry Steering Committee, has been involved in a subsequent reanalysis of the paper’s findings and said that the results will be made public later in the year.
"One of my concerns [with this study] is the use of the 10-year mortality endpoint. If these resurfacing procedures are saving lives, then you would expect to see a survival benefit sooner, say at 90 days," Dr. MacGregor said.
Dr. Kendal responded that they tried to account for this, but the answer will need to come from a properly organized, randomized controlled trial.
"We don’t have a conflict of interest here. If anything, we were perhaps looking for the opposite effect; we were expecting to see an increased mortality rate in the resurfacing group," Dr. Kendal said. "That was not the case as it turned out, so I am reasonably confident that our data support the findings of that BMJ article."
Dr. Kendal and Dr. MacGregor reported no conflicts of interest.