ULTRASOUND EVALUATION OF THE SUBSCAPULARIS TENDON AFTER TOTAL SHOULDER ARTHROPLASTY

Abstract

Healing of the subscapularis, documented by ultrasound, following total shoulder arthroplasty was examined in thirty shoulders. All had marked improvement in pain, SST, and ASES scores. Four subscapularis tears were identified but only one patient had a positive abdominal compression test, 7/26 patients had a positive compression test despite an intact cuff, and 4/7 patients had a significant internal rotation contracture. The abdominal compression test was not accurate in detecting sub-scapularis tears. There was a significant false positive rate, which may be related to a lack of internal rotation. Overall, the outcome was excellent and not related to the status of the subscapularis.

Very little information is available on healing of the subscapularis after shoulder arthroplasty. The purpose of this study was to document the subscapularis healing rate and relate it to post-operative function and the abdominal compression test.

Thirty consecutive shoulders (twenty-three patients) s/p total shoulder replacement had standardized pre- and post-operative examinations including quantitative strength assessment and specific subscapularis testing. Ultrasound (validated for postop accuracy) was performed to document tendon healing.

All thirty shoulders had marked improvements in pain, SST, and ASES scores. Four subscapularis tears were identified but only one patient had a positive abdominal compression test. Seven out of twenty-six patients had a positive compression test despite an intact cuff. Four of seven patients had a significant internal rotation contracture. Neither the status of the subscapularis nor a positive compression test appeared to affect outcome.

Although specific subscapularis tests are often positive, only a small percentage of subscapularis tendons appear to retear after shoulder arthroplasty. The abdominal compression test is not accurate in detecting subscapularis tears post arthroplasty. There is a significant false positive rate, which may be related to a lack of internal rotation. However, overall outcome of shoulder arthroplasty was excellent and did not appear to be dependant on the status of the subscapularis.