Loose fit versus press fit stems and risk for surgical reintervention following radial head arthroplasty: A US-based cohort study of 1575 patients.

ABSTRACT

INTRODUCTION: Radial head arthroplasty (RHA) is performed with increasing frequency for reconstruction of comminuted radial head fractures. Implants can be categorized by stem design, either loose fit or press fit. Currently, the RHA literature does not suggest one implant type is superior to another based on revision and reoperation rates, although most RHA outcome studies have small numbers of patients with few events to detect a difference. This study evaluated the association between stem design and risk of revision and reoperation after RHA. METHODS: 1575 patients aged ≥18 years who underwent primary RHA within a US-based healthcare system were identified (2009-2021). Revision following the index RHA was the primary outcome of interest; ipsilateral reoperation was a secondary outcome. Multivariable Cox proportional hazard regression was used to evaluate the risk of outcomes by loose versus press fit with the adjustment for race/ethnicity, ASA classification, region, surgeon RHA volume, and simultaneous ipsilateral extremity procedures. RESULTS: Of the 1575 RHA, 681 (43.2%) received a loose fit stem. The cumulative revision probability was 2.6% for loose fit and 3.5% for press fit. In adjusted analysis, we did not observe a difference in risk of revision (HR=0.78, 95% CI=0.41-1.46) or reoperation (HR=0.73, 95% CI=0.43-1.25). Additionally, there were no observed differences in risk of revision (HR=0.62, 95% CI=0.28-1.38) or reoperation (HR=0.90, 95% CI=0.48-1.71) in the patient subgroup who underwent additional procedures in the same extremity at the time of RHA. CONCLUSION: In this large multi-center cohort of 1575 primary RHA, we did not observe a difference in risk of revision or reoperation following RHA based upon stem design. The choice between using an implant with a loose or press fit stem may be based more on surgeon familiarity, implant availability and cost, and ease of use.