Shoulder arthroplasty volume standards: the more the better?

Introduction: The wide use of hip and knee arthroplasty has led to implementation of volume standards for hospitals and surgeons. For shoulder arthroplasty, the effect of volume on outcome has been researched, but no volume standard exists. This review assessed literature reporting on shoulder arthroplasty volumes and its relation to patient-reported and functional outcomes to define an annual volume threshold. Materials and methods: MEDLINE and EMBASE were searched for articles published until February 2018 reporting on the outcome of primary shoulder arthroplasty in relation to surgeon or hospital volume. The primary outcome was predefined as any patient-reported outcome. The secondary outcome measures were length of stay, costs, rates of mortality, complications, readmissions, and revisions. A meta-analysis was performed for outcomes reported by two or more studies. Results: Eight retrospective studies were included and did not consistently show any associations of volume with in-hospital complications, revision, discharge to home or cost. Volume was consistently associated with length of stay (shorter length of stay for higher volume) and in-hospital complications (fewer in-hospital complications for higher volume). It was not consistently associated with mortality. Functional outcomes were not reported. Conclusions: There is insufficient evidence to support the concept that only the number of shoulder arthroplasties annually performed (either per hospital or per surgeon) results in better patient-reported and functional outcomes. Currently, published volume thresholds are only based on short-term parameters such as length and cost of hospital stay.