Instability after reverse shoulder arthroplasty: a systematic review of interventions and clinical outcomes.

BACKGROUND

Instability or dislocation is the major cause of revision after reverse shoulder arthroplasty (rTSA). There is controversy regarding the optimal treatment for rTSA dislocation. The aim of this study is to analyze the success of the various treatment options, as reported in the literature, for achieving stability following rTSA dislocation.

METHODS

A systematic review using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was performed. PubMed, Embase, and the Cochrane Library were queried to identify all studies reporting on outcomes following treatment of rTSA dislocation. Data extracted included patient demographics, follow-up, interventions, revision technique, complications, and subjective and objective outcomes. Study quality was evaluated using the Methodological Index for Non-Randomized Studies scoring system.

RESULTS

The analysis included 12 studies (mean Methodological Index for Non-Randomized Studies score, 10.8) with a total of 206 rTSA dislocations (61% male, average age 68 years). The overall rate of instability was 2.2%. Closed reduction (50% of cases) successfully avoided revision surgery in 29% of cases. First revision was followed by a second revision procedure in 24% of cases. After first and second revisions, 78% and 52% of rTSAs remained stable, respectively. The most common strategy to address rTSA dislocation was to alter the humeral spacer (47% of revisions) which was successful in 60% of cases. Complete revisions and revising the humeral spacer with the glenosphere were both successful in 82% of cases. Ultimately, 78% had a stable rTSA implant, 11% an unstable rTSA, 6% resection arthroplasty, and 5% a hemiarthroplasty in-situ.

CONCLUSION

Strategies to address rTSA dislocation have not been clearly established. Closed reduction has some but limited success. Revision surgery for rTSA dislocation can be challenging and multiple interventions may be required to achieve stability. Revision strategies that increase humeral length and glenohumeral offset have the highest success.