CORR Insights^®: Rotator Cuff Fatty Infiltration and Atrophy Are Associated With Functional Outcomes in Anatomic Shoulder Arthroplasty

Excerpt

For more than 20 years, orthopaedic surgeons have improved fixation of the humeral and glenoid components, with an emphasis on restoring the anatomy of the glenohumeral joint. Although most studies have demonstrated success as determined by clinical outcome and radiographic measurements at short- and medium-term followup, researchers likely have neglected a biologic component. In the current study, Lapner and colleagues examined the influence of muscle atrophy and fatty infiltration in the outcomes of shoulder replacement. The authors utilized CT scanning before and after surgery to evaluate both lesser tuberosity healing and muscle changes in the rotator cuff. As part of their subgroup analysis, they evaluated how rotator cuff muscles change through the first year following shoulder replacement. Rather surprisingly, they found that although muscle atrophy did not change, fatty infiltration improved one year after shoulder replacement. This is an important finding, as it suggests that fatty infiltration is reversible in an intact rotator cuff repair state. This data is markedly different from rotator cuff repair data, where fatty infiltration is an important predictor of clinical outcome and appears in most situations to be irreversible [2, 3]. Therefore, this is one of few studies that show fatty infiltration to be a reversible process [1], and so gives hope that shoulder replacement and rotator cuff repair will have better outcomes once orthopaedic surgeons come to an improved understanding of rotator cuff muscle physiology. …