Subscapularis integrity and patient-reported outcomes after total shoulder arthroplasty: does time to mobilization matter?

Abstract

BackgroundMaintaining subscapularis integrity may be a significant variable in optimizing patient outcomes following total shoulder arthroplasty. Multiple factors have been reported in orthopedic literature as a contributor to subscapularis failure. Most surgeons follow a protocol that calls for some period of immobilization. However, time of mobilization and rehabilitation is still a point of discussion, as no consensus currently exists. Our study aimed to compare postoperative outcomes of patients who followed a traditional immobilization protocol to those who underwent rapid mobilization. MethodsA single-blinded, randomized controlled clinical trial was conducted between December 2015 and May 2018. Patients were prospectively enrolled and randomized using a 1:1 random allocation into 2 groups: prolonged immobilization for 4 weeks or rapid mobilization at 1 week. All cases were performed by a single, fellowship-trained shoulder and elbow surgeon with standard pre- and intra-operative protocols. Metallic markers were used to mark the musculotendinous junction of the subscapularis tendon. Postoperatively, patients were notified of their randomization assignment and provided detailed instructions on when to begin mobilization. Patient-reported outcome measures, physical examination, and radiologic assessments were evaluated preoperatively and at 6 weeks, 3 months, 6 months, 12 months, and 32 months postoperatively. Our primary outcome was clinical and radiographic subscapularis failure. ResultsForty-three patients consented with 40 procedures randomized to the 2 cohorts. Among these 40 procedures, there were up to 235 follow-up visits over 32 months. Of the 40 procedures, 2 (5.0%) were complicated with a postoperative tear, both associated with a weak belly test and radiographically confirmed with medialization of the surrogate markers on plain radiographs. No statistically significant difference was seen between the prolonged immobilization and rapid mobilization groups for American Shoulder and Elbow Surgeons shoulder score, Constant Shoulder Score, Visual Analog Scale Score, Simple Shoulder Test Score, and Short-Form Surveys at any follow-up point (all P > .05). On evaluating active forward flexion and external rotation, no statistically significant difference was also appreciated between the 2 groups at any time point (all P > .05). DiscussionOur randomized control trial compared currently accepted protocols to immobilize for 4 weeks following total shoulder arthroplasty using a peel to early mobilization at 1 week and found no statistical and clinical difference in outcomes. However, further study is necessary before a consensus recommendation can be made.