BRUSSELS (EGMN) – When younger patients receive a total hip replacement, they are more likely to eventually need revision surgery, compared with older patients, according to findings from a 12-year follow-up study of more than 58,000 Medicare patients.

The finding makes sense and comes as no surprise, but the documentation of a link between younger age and increased revision rates has important implications for prosthesis design.

“As total hip replacement indications extend to increasingly younger populations, [the patients’] mortality risk will diminish, and a vast majority will remain at risk for revision for decades,” Dr. Jeffrey N. Katz said at the annual World Congress on Osteoarthritis.

“Research evaluating technical innovations to increase prosthesis longevity should recognize the competing risk of mortality. In a 75- or 80-year old, revision is a rather infrequent event; their implant will likely outsurvive them. The older a patient is, the more likely the patient is to die with their original prosthesis intact,” said Dr. Katz of the department of medicine at Harvard Medical School, Boston, and director of the orthopedic and arthritis center for outcomes research at Brigham and Women’s Hospital in that city.

“If a prosthesis manufacturer wants to increase the longevity of a prosthesis, the patients to target are those younger than 65. For patients who gets through the perioperative period, the real issue is biomaterials: How likely are the biomaterials to wear out over time?” he noted.

Currently, about 280,000 total hip replacements are performed in the United States annually (more than 90% because of osteoarthritis), along with 40,000 revision hip surgeries each year. Revisions alone cost more than $1 billion annually.

Dr. Katz and his associates studied the 58,521 Medicare beneficiaries who underwent a total hip replacement during July 1995–June 1996. Two-thirds were women, and 60% were aged 65-75 years, with the remaining patients older than 75 years. The researchers had complete follow-up records for all patients for the subsequent 12 years, through 2008. They presumed that all patients in this group with subsequent hip surgery had revisions, although it’s also possible that the second surgery involved the contralateral hip.

During follow-up, 60% of the patients who were older than 75 years at the time of surgery died; during the 12-year follow-up, the survivors had a revision rate of 9%. Among patients aged 65-75 years at the time of their initial hip surgery, 30% died during follow-up, with the survivors having a 13% revision rate. In both age groups, men had a higher revision rate than did women.

“Younger patients are more active and heavier,” Dr. Katz explained in an interview at the congress, which was organized by the Osteoarthritis Research Society International. “Younger patients probably wear their [prosthetic] joints out faster, and – given the same amount of wear – they are offered [revision] surgery more frequently and they accept surgery more frequently.

“We don’t have data for 45- to 65-year-olds, but by extension, their mortality is unlikely over the following 20 years, while a revision is likely. The younger age group has a very real risk of facing a revision in their lifetime. If a manufacturer could improve the longevity of their prosthesis, it would potentially save them an operation,” Dr. Katz said.

Dr. Katz said that he had no disclosures.

Copyright (c) 2010 Elsevier Global Medical News. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

布鲁塞尔(EGMN)——根据一项包含58,000多例患者的12年随访研究结果，与更年老的患者相比，接受全髋关节置换术的相对低龄患者在他们有生之年更可能需要再接受髋关节翻修术。年龄与髋关节翻修率之间的这种关联对今后假体的设计来说应是一个重要的提示。

 

哈佛大学医学院及Brigham整形外科和关节炎中心主任Katz医生在一年一度的世界骨关节炎大会(World Congress on Osteoarthritis)上说，“随着全髋置换术的指证扩展至越来越多的低龄人群，患者的总体死亡风险将下降，主要的风险将是几十年后的髋关节翻修”。

 

该研究的对象为58,521例1995年7月～1996年6月接受全髋关节置换术的医保患者，其中2/3为女性，60%为65~75岁，余者的年龄大于75岁。研究者们在随后的12年对所有入组患者进行了密切的随访及记录，直至2008年。他们假定所有患者随后进行的髋部手术都是翻修术，虽然二次手术有可能是在对侧髋部进行。随访期间，首次髋关节置换术时年龄大于75岁的患者有60%死亡，生存者有9%接受了髋翻修术。首次置换术时年龄65~75岁的患者有30%死亡，生存者有13%接受了髋翻修术。两组中，男性接受翻修术的比例均高于女性。

 

若假体制造商能够延长假体的使用寿命，那么对这些患者来说将是一个福音。对延长假体使用年限的技术创新进行评价时，应意识到它与死亡之间存在竞争风险。对于75~80岁的患者来说，需要进行翻修术的几率很低。患者的年龄越老，其最初置入的假体伴随他走过余生的可能性就越大。若一家假体制造商想研究如何延长假体的使用寿命，那么研究的受试者应选择小于65岁的患者。对于已经安全度过围手术期的患者而言，真正的问题是生物材料，即生物材料是如何随着时间的流逝而损耗的。

 

Katz医生声明研究没有利益冲突。

 

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