Influence of prosthetic lateralization on tuberosity healing in reverse shoulder arthroplasty for proximal humerus fractures.

INTRODUCTION

To evaluate the effect of prosthetic lateralization on tuberosity healing following reverse shoulder arthroplasty (RSA) for proximal humerus fractures (PHFs) in older adults.

MATERIAL AND

METHODS

This single-center retrospective study included patients aged >65years with displaced Neer 3- or 4-part PHFs treated with RSA within four weeks of injury. Patients were allocated according to the global lateralization of the prosthesis: Very Highly Lateralized (VHL; 21.4mm, Arrow®, n=53) and Lateralized (L; 14.7mm, Unique®, n=20). Tuberosity healing was assessed radiographically and classified as anatomic, non-anatomic, or failed consolidation. Statistical analysis was performed using Student's t-test or Mann-Whitney U test for continuous variables, and Chi-square or Fisher's exact test for categorical variables.

RESULTS

The final cohort consisted of 73 patients (62 women, 11 men) with a mean age of 76.2±6.9years. Overall tuberosity healing occurred in 60 patients (82.2%), while 13 (17.8%) demonstrated failed consolidation. The L group showed a significantly higher overall healing rate (100%) compared with the VHL group (75.5%; P=.020). Anatomic healing was achieved in 55% of the L group and 28% of the VHL group (P=.020). All failures occurred exclusively in the VHL cohort (24.5%). The overall complication rate was 6.8%, with no significant differences between groups.

CONCLUSION

Very high prosthetic lateralization (>20mm) is associated with reduced rates of anatomic tuberosity healing and a higher incidence of failed consolidation, likely due to increased mechanical tension that compromises osteointegration in osteoporotic bone.