Long-term survival of resurfacing humeral hemiarthroplasty

Introduction The indication for shoulder resurfacing arthroplasty is controversial, and survival of these implants is somewhat inconsistent. This study aimed to evaluate the long-term survivorship of resurfacing humeral head implants (RHHIs) and determine risk factors for complications and revisions. Materials and methods This retrospective cohort study consisted of 275 cases and two types of RHHIs. The survival rate was evaluated using the Kaplan-Meier method and Cox regression for risk factor analysis. Demographic factors were studied, and the change in the humerus centre of rotation (COR) was measured. Results The mean follow-up time was 8.7 years (SD 2.7 months, range 2.8-15.9 years). The mean age of the patients was 67.6 years (SD 9.6, range 33.5-84.9). Ten-year cumulative RHHI survival was 94.1%. The cumulative estimate without any complication was 98.9% at 5 years, 80.0% at 10 years and at 15 years it was 61.5%. The most common complication was persistent pain in 13.8% of the RHHIs. The risk factors for complications and revisions were implant type, preoperative conditions and change of COR > 5 mm. Conclusions RRHIs showed excellent long-term survival, but many complications were found. The most common complication was persistent pain, which seemed to be caused by a change of COR and was more related to one type of implant.