Non-fracture stem vs fracture stem of reverse total shoulder arthroplasty in complex proximal humeral fracture of asian elderly.

PURPOSE: Fracture stem of the reverse total shoulder arthroplasty (RTSA) was designed for better tuberosity bone healing for the proximal bone defect of complex proximal humeral fractures (PHF). Our purpose was to compare the clinical and radiological outcomes of patients using fracture stem vs non-fracture (conventional) stem of RTSA in complex PHF of elderly patients.

METHODS: Between 2008 March and 2017 June, 48 patients who had undergone an RTSA with non-fracture or fracture stem for complex PHF with a minimum 18 months of follow-up were evaluated. Finally, total 45 patients with a mean age of 80 ± 7 years (65-92 years) were enrolled because three patients were excluded due to age related mortality. We divided them into two groups: 25 patients using non-fracture stem (non-fracture stem group) in the early period of this study, and consecutive 20 patients using fracture stem (fracture stem group) in the later period. Between two groups, we compared clinical and radiologic outcomes such as tuberosity failure, heterotopic ossification (HO), dislocation, acromion fracture, notching, loosening and periprosthetic fracture.

RESULTS: In all patients, clinical outcomes were improved significantly and tuberosity failure was found in 62% (28/45). Between two groups, there were no statistically significant differences on clinical outcomes and radiologic outcomes except UCLA score. As complications, two humeral stem revision was performed due to tuberosity failure related HO and stem loosening with subsequent periprosthetic fracture in non-fracture stem group.

CONCLUSIONS: Compared to non-fracture stem, fracture stem usage of RTSA in complex PHF of elderly patients has no significant different impact on clinical and radiological outcomes. However, tuberosity failure related secondary HO of non-fracture stem might be responsible for stem loosening and periprosthetic fracture in the RTSA for complex PHF of elderly patients.

LEVEL OF EVIDENCE: Level IV, case series study.