To reduce revisions following primary total hip replacement for osteoarthritis, efforts should be targeted at revisions that occur within 18 months after the index procedure and at younger patients who are more likely to survive long enough to require revision, according to the results of a 12-year study of Medicare beneficiaries.
“About 1% of survivors undergo revision each year,” Jeffrey N. Katz, MD, MSc, professor of medicine and orthopedic surgery at Harvard Medical School, told Orthopedics Today. “Males and younger patients are at higher risk. For patients, 75 years old or older at the time of [total hip replacement] THR, the risk of death over the subsequent 12 years is 10-fold greater than the risk of revision of the implant.”
To study the risk of revision after elective THR for osteoarthritis in Medicare patients and the impact of sociodemographic factors, and hospital and surgeon volume on this risk, Katz and colleagues used Medicare claims to conduct a 12-year follow-up of 51,347 patients treated between July 1995 and June 1996.
The primary end-point for the study included revision THR as indicated by hospital discharge codes according to the International Classification of Diseases, Ninth Revision.
Researchers found that the 18-month risk of revision THR for patients who were still alive was approximately 2% per year and then 1% per year for the remainder of the follow-up period. The absolute risk of death during the 12-year follow-up period was 59%, exceeding the risk of revision THR, which was 5.7%, in patients older than 75 years at the time of primary THR, according to study results. In patients aged 65 years to 75 years at the time of the index surgery, the absolute risk of death was 29% vs. 9.4% for the risk of revision THR.
Jeffrey N. Katz
“In the elderly, lifetime risk of revision is low,” Katz told Orthopedics Today. “Development of implants to reduce revision risk are appropriate in younger patients, but existing technology provides adequate implant longevity for older patients whose risk of death is much greater than the risk of revision.”
Multivariate Cox proportional hazard models showed the relative risk of revision was higher in men than in women and in patients aged 65 years to 75 years at the time of primary THR compared with those older than 75 years. Study results also showed a higher risk of revision in patients of surgeons who performed fewer than six THRs annually in the Medicare population vs. surgeons who performed more than 12 per year.
The researchers observed important implications for patient decision-making, quality improvement and research among patients older than 75 years who undergo primary THR. With a higher risk of patient death for replacement than revision, researchers believe that “older patients should place revision risk in perspective as they discuss the advantages and drawbacks of total hip replacement with their physician.”
Katz and colleagues also stressed the importance of optimizing short-term outcomes of THR in the elderly since these patients are more likely to die than to have a revision. To assess and optimize the outcomes of younger patients, the researchers recommend long-term survival data on implants obtained by longitudinal joint replacement registries. Further investigations should also be directed at the consistent differences in failure rates seen between younger and older patients, and between men and women, and whether shorter follow-up periods could be used to assess differences in implant performance rather than longer periods of observation.
“Further study of the predictors of revision in younger patients would provide a more quantitative assessment of these trade-offs and should be a research priority,” the researchers wrote. “These observations also impact the optimal frequency with which to monitor patients with radiographs following surgery. Finally, our findings suggest that the development of innovative technologies to improve implant longevity should target younger populations with advanced arthritis, who have a longer anticipated time span in which the implants might fail and require revision arthroplasty.” – by Casey Murphy
Katz JN. J Bone Joint Surg Am
For more information:
Jeffrey N. Katz, MD, MSc, can be reached at Brigham and Women’s Hospital, 75 Francis St., OBC – 4-016, Boston, MA, 02115; email: firstname.lastname@example.org.
Disclosure: One or more of the authors received payments or services from a third party in support of an aspect of this work. In addition, one or more of the authors has had a financial relationship with an entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in the work.