Prognostic factors influencing the outcome of rotator cuff repair: a systematic review

Purpose: To identify prognostic factors significantly associated with rotator cuff repair outcome and define the strength of these associations. Methods: Search was performed using electronic databases. Studies reporting prognostic factors affecting rotator cuff repair outcome were included. Primary outcomes were: structural integrity, Disabilities of the Arm, Shoulder and Hand score, American Shoulder and Elbow Surgeons score, and Constant score. Each other outcome was considered as secondary outcome. Descriptive statistics was used. When possible, meta-analyses were performed. Methodological quality was assessed using the Quality In Prognosis Studies Tool. A best evidence synthesis was performed using the Grading of Recommendations Assessment, Development and Evaluation framework adapted to prognostic studies. Results: Sixty-four studies were included. Methodological quality was high only for twelve studies. The overall quality of evidence was low to very low. Meta-analyses were possible only for seven studies. Older age and larger tears size were found to affect retear risk. Results were controversial for fatty infiltration, acromioclavicular joint or biceps procedures, acromiohumeral distance, delamination of tendon edges, musculotendinous junction position, number of tendons involved, and tendon length, quality and retraction. Baseline scores and workers compensation claim predicted functional outcomes. Subjective outcome was also affected by patient's expectations. Conclusions: Despite the large number of outcomes and prognostic factors evaluated by a relative small number of studies, almost not prognostic in design, it was not possible to reach any definitive conclusion regarding the most relevant predictors of outcome of rotator cuff repair. Moreover, the low methodological quality of the included studies and, subsequently, the low quality of evidence, seriously affected the strength of recommendation of the present review. Based on data available, retear risk is mainly affected by older age and larger tears size. Baseline scores and work compensation claim are the most significant predictors for functional outcomes. Level of evidence: Systematic review of level I-IV prognostic studies, Level IV.