Tuberosity healing in reverse shoulder arthroplasty in traumatology: Use of an offset modular system with bone graft.

Introduction: Reverse shoulder arthroplasty (RSA) has become a common treatment in displaced proximal humeral fracture (PHF) in elderly patients due to inconstant results with osteosynthesis or hemiarthroplasty. RSA allows a good anterior elevation but rotational results are more random and depend on tuberosity healing.

Hypothesis: Use of an offset modular system (OMS) on the prothesis improve tuberosity healing and functional results.

Material And Methods: This retrospective cohort analysed radiological and clinical outcomes at least one year after the use of RSA Humelock II Reversed (Fx Solutions) after a displaced PHF Neer 3 or 4 in patients over 70 years. The first criterion was tuberosity healing with or without the use of the OMS device on radiographs. The second criterion was a clinical analysis of active range of motion (ROM), anterior elevation (AAE), external and internal rotations (ER, IR), Constant, DASH, SSV, VAS scores according to tuberosity healing. We also analysed radiological and clinical complications.

Results: We analysed from November 2013 to May 2018 thirty-four RSA. Mean age was 78±5,7 years, mean follow up was 18±7,2 months and the mean tuberosity healing rate was 79%. Mean ROM were: 117±24 (AAE), 18̊±18 (ER) and L2 (IR). On the first analysis, healing tuberosity with cage was present on 24 (92%) patients versus 3 (37,5%) without (p<0,005). The second analysis showed a non-significant improvement on ER, IR, Constant, DASH and SSV. Complications found were three removal of prothesis after infection, one axillary nerve lesion, one ulnar paraesthesia and one humeral loosening.

Conclusion: The use of the OMS cage allows a better consolidation of tuberosities in a significant way but no significant clinical effects was highlighted due to a small patient number in the study.

Level Of Evidence: level III, retrospective cohort.