Risk factors for revision surgery after humeral head replacement: 1,431 shoulders over 3 decades.

HYPOTHESIS: To assess the long-term risk of revision surgery and its predictors after humeral head replacement (HHR).
METHODS: We used prospectively collected data from the Mayo Clinic Total Joint Registry and other institutional electronic databases. Revision-free survival for HHR at 5, 10, and 20 years was calculated by use of Kaplan-Meier survival analysis. We used univariate and multivariate-adjusted Cox regression analyses to examine the association of age, gender, body mass index (BMI), comorbidity assessed by Deyo-Charlson index, American Society of Anesthesiologists class, implant fixation (cemented vs uncemented), and underlying diagnosis with the risk of revision surgery. Hazard ratios with 95% confidence intervals (CIs) and P values are presented.
RESULTS: During the study period (1976-2008), 1,359 patients underwent 1,431 shoulder HHRs. The mean age was 63 years, 63% of patients were female, the mean BMI was 28 kg/m(2), and 60% of implants were cemented. During the follow-up, 114 HHRs were revised. At 5, 10, and 20 years, the shoulder implant survival rate was 93.6% (95% CI, 92.1%-95%), 90% (95% CI, 88%-92%), and 85% (95% CI, 81.8%-88.4%), respectively. In multivariate-adjusted analyses, older age was associated with a lower hazard of revision, with a hazard ratio of 0.97 (95% CI, 0.96-0.99; P < .001), and higher BMI was associated with a higher hazard ratio of 1.04 (95% CI, 1.01-1.08; P = .02).
CONCLUSIONS: Long-term survival of HHR at 20 years was excellent. Obesity and younger age are risk factors for a higher revision rate after HHR. Further studies should investigate the biologic rationale for these important associations. Surgeons can discuss these differences in revision risk with patients, especially young obese patients. Published by Mosby, Inc.