Does bony increased-offset reverse shoulder arthroplasty decrease scapular notching?
Journal of Shoulder and Elbow Surgery
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© 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Background: The purpose of this cohort study was to compare scapular notching rates, range of motion, and functional outcomes between patients who underwent a standard Grammont-style reverse shoulder arthroplasty (RSA) and patients who underwent bony increased-offset reverse shoulder arthroplasty (BIO-RSA) at a minimum of 2years' follow-up. We hypothesized that the BIO-RSA cohort would have lower notching rates and improved rotational range of motion; however, validated outcome scores between cohorts would be no different. Methods: A comparative cohort study was designed after a sample size calculation. A total of 40 patients were studied with 20 in each cohort (RSA vs BIO-RSA). All patients underwent an interview and physical examination. Outcomes included range of motion; shoulder strength; Disabilities of the Arm, Shoulder and Hand (DASH) score; American Shoulder and Elbow Surgeons score; Simple Shoulder Test score; Constant score; and Global Rating of Change scale score. Radiographs were obtained for all patients and examined for scapular notching. Results: When we compared demographic characteristics between the standard RSA and BIO-RSA cohorts, including age, sex, and follow-up duration, there were no significant differences between groups (. P>.05). In addition, there were no significant differences between cohorts when we compared forward elevation (. P=.418); external rotation (. P=.999); internal rotation (. P=.071); strength (. P>.376); Disabilities of the Arm, Shoulder and Hand score (. P=.229); American Shoulder and Elbow Surgeons score (. P=.579); Simple Shoulder Test score (. P=.522); Constant score (. P=.917); or Global Rating of Change scale score (. P=.167). The frequency of scapular notching, however, was significantly higher (. P=.022) in the RSA cohort than in the BIO-RSA cohort: 75% versus 40%. Conclusions: Although the scapular notching rate was significantly higher in the standard RSA group, no other outcome measures were statistically different, including range of motion, strength, and validated outcome scores.