[Comparative analysis of three models of reverse shoulder prosthesis based on the new angles of distalization and lateralization].

PURPOSE

Compare functional and radiological outcomes of three different designs of reverse shoulder arthroplasty according to distalization and lateralization shoulder angle, in heterogenic diagnostics (fracture, cuff arthropathy, fracture sequela and osteoarthritis).

MATERIAL AND METHODS

Prospective cohort of 33 patients of reverse shoulder arthroplasty (RSA) between December 2014 and July 2017 with a minimum one year of follow-up. We defined three groups, G: 10 patients with Grammont (155o, Medialized Glena), B: 9 patients with Bio-RSA (155º, lateralized bone glena) and A: 14 patients with Arrow (135o, lateralized metallic glena). We analyze demographic, clinical, functional and radiological outcomes (lateralization shoulder angle (LSA) and distalization shoulder angle (DSA)). For the statistical analysis, ANOVA, T-tests and linear regression tests were used, with a statistical significance of 5%.

RESULTS

The LSA was significantly higher in group A (98o A, 79o G, 80o B) (p < 0.05). In DSA, group B was significantly higher than A (52o B, 39o A) (p < 0.05) and not significant to G (48o G) (p = 0.06). There was no correlation of LSA and DSA with external rotation (p = 0.51) and active elevation (p = 0.41), respectively. There was no significant clinical (anterior elevation, external rotation, internal rotation) and functional outcomes (adjusted Constant score and subjective shoulder evaluation) differences between the different RSA models (p > 0.05).

CONCLUSIONS

The LSA was higher in the Arrow and the DSA was higher in Bio-RSA. We did not find Clinical - Radiological correlation in this heterogeneous series of patients.