Ultrasound assessment after a subscapularis-sparing approach to total shoulder arthroplasty

Abstract

Background: Although anatomic total shoulder arthroplasty (ATSA) has favorable outcomes, nearly all techniques involve subscapularis tendon release for shoulder joint access. Such takedown of the subscapularis may be associated with decreased function, instability, and pain. Subscapularis-sparing approaches have the theoretical benefits of improved function, decreased failure of the tendon reattachment site, and early range of motion and rehabilitation. The primary purpose of this study was to use ultrasound to assess the postoperative integrity of the subscapularis tendon and surrounding soft tissues after ATSA with a subscapularis-sparing technique through an extensile anterosuperior skin incision. Our hypothesis was that this subscapularis-sparing approach would have low rates of subscapularis disruption.

Methods: A consecutive cohort of patients who underwent subscapularis-sparing ATSA between 2014 and 2017 were included. Ultrasound was used to evaluate the rotator cuff tendons and deltoid postoperatively, and these were classified as intact, disrupted, or unable to be adequately visualized. Clinical outcome scores, range of motion, and strength measurements were also collected at 1-3 years postoperatively.

Results: Thirty-seven subscapularis tendons and 40 supraspinatus and infraspinatus muscles were adequately visualized and included for analysis. Of the subscapularis muscles, 32 (86%) were intact; 38 of the visualized supraspinatus muscles (95%) and 39 of the infraspinatus muscles (98%) were intact. No dehiscence or loss of integrity of the deltoid was noted. Clinical comparison between patients with disrupted subscapularis muscles and patients without such disruption demonstrated no difference in clinical outcome scores and postoperative range of motion but showed less strength in forward flexion, abduction, and external rotation.

Conclusions: The rate of subscapularis disruption using a subscapularis-sparing approach for ATSA was low (14%), but the potential for tendon disruption was not eradicated. Favorable clinical outcomes support this surgical approach as a potential technique for ATSA.

Keywords: Shoulder arthroplasty; approach; patient-reported outcomes; rotator interval; subscapularis sparing; ultrasound.