Clinical, Radiographic, and Ultrasonographic Comparison of Subscapularis Tenotomy and Lesser Tuberosity Osteotomy for Total Shoulder Arthroplasty

BACKGROUND: Recently, a lesser tuberosity osteotomy has been promoted as an alternative to tenotomy for release of the subscapularis during shoulder arthroplasty. To our knowledge, no direct comparison of the clinical results of the two techniques has been presented. METHODS: Thirty-five shoulders in thirty-four consecutive patients with osteoarthritis who had a primary total shoulder arthroplasty, performed with use of a standard subscapularis tenotomy (Group 1) or lesser tuberosity osteotomy (Group 2) to release the subscapularis, were evaluated retrospectively at an average of thirty-three months. Group 1 consisted of fifteen shoulders in fourteen patients (seven in males and eight in females, with an average age of sixty-seven years). Group 2 consisted of twenty shoulders in twenty patients (fourteen males and six females, with an average age of sixty-nine years). Assessment included a physical examination, clinical outcome questionnaires, conventional radiography, ultrasound examination of the subscapularis, and measurement of internal rotation strength. RESULTS: The postoperative total Penn Shoulder Scores improved significantly from the preoperative levels in both groups (mean and standard deviation, 29 +/- 15 points to 81 +/- 20 points p < 0.00001 in Group 1 and 29 +/- 16 points to 92 +/- 11 points p < 0.00001 in Group 2). However, the postoperative mean total Penn Shoulder Score was higher in Group 2 (92 +/- 11 points) than in Group 1 (81 +/- 20 points) (p = 0.04). At one year, an abnormal subscapularis on ultrasound was associated with a lower mean Penn Shoulder Score in Group 1 (73 +/- 19 points compared with 92 +/- 3 points; p = 0.01). However, at a minimum two-year follow-up, this difference was not significant (mean, 74 +/- 24 points and 86 +/- 15 points, respectively; p = 0.25). There were more abnormal subscapularis tendons in Group 1 (six attenuated tendons and one full-thickness tear) than in Group 2 (two attenuated tendons). Internal rotation strength did not differ between the groups when controlled for sex (mean, 117 +/- 8 N and 127 +/- 21 N for males in Group 1 and Group 2, respectively p = 0.22 and 77 +/- 27 N and 101 +/- 26 N, respectively, for females p = 0.1). CONCLUSIONS: Both techniques resulted in improved clinical outcome scores. The lesser tuberosity osteotomy resulted in higher clinical outcome scores, a lower rate of subscapularis tendon tears, and universal healing of the osteotomy. This technique offers a means by which the rate of postoperative subscapularis tears may be reduced in patients undergoing total shoulder arthroplasty.