Ultrasound-determined healing rates with subscapularis tenotomy versus peel after anatomic shoulder arthroplasty

BACKGROUND

Several techniques have been described for mobilizing the subscapularis tendon in anatomic total shoulder arthroplasty (TSA). The purpose of this study was to compare subscapularis tendon healing rates, as determined by ultrasound, in patients following anatomic TSA with either a subscapularis tenotomy or subscapularis peel.

METHODS

This study was a secondary analysis of patients from a previous randomized controlled trial in which patients underwent anatomic TSA and were randomized to either a tenotomy or peel approach. The primary outcome was postoperative tendon healing rates determined on ultrasound at >12 months after surgery. Secondary outcomes included postoperative tendon thickness measured on ultrasound; elbow position (neutral alignment in the belly-press position vs. posterior); internal rotation function measured with the third and fourth questions of the American Shoulder and Elbow Surgeons questionnaire; and Western Ontario Osteoarthritis of the Shoulder index. Radiographs were analyzed in patients with torn tendons.

RESULTS

One hundred patients were randomized to a tenotomy (n = 47) or peel (n = 53) approach. Postoperative ultrasound results were available in 88 patients. Tendon healing rates were 95% for tenotomy vs. 75% for peel (P = .011). The mean postoperative tendon thickness was 4 mm (standard deviation, 1.0 mm) and 4 mm (standard deviation, 1 mm) in the tenotomy and peel groups, respectively (P = .37). Internal rotation function was not associated with healing status (P = .77 and P = .22 for questions 3 and 4, respectively, of the American Shoulder and Elbow Surgeons questionnaire), nor was elbow position (P = .2) in the belly-press position.

DISCUSSION

We observed that subscapularis tenotomy had a higher healing rate than peel as determined by ultrasound in TSA patients. There was no statistically significant difference in postoperative tendon thickness in intact tendons as measured on ultrasound when comparing subscapularis mobilization techniques, nor was there any association between healing status and internal rotation function or elbow position.

Biomechanical comparison of subscapularis peel and lesser tuberosity osteotomy for double-row subscapularis repair technique in a cadaveric arthroplasty model

INTRODUCTION

Management of the subscapularis during shoulder arthroplasty is controversial. The purpose of this study was to compare the biomechanical performance of subscapularis peel (SP) and lesser tuberosity osteotomy (LTO) in a cadaveric model.

METHODS

The subscapularis and proximal humerus were dissected from all soft tissues in 21 fresh-frozen human cadaveric shoulders and randomized to undergo SP, LTO, or standard subscapularis tenotomy (ST, control). For SP and LTO, six #5 sutures were passed through eyelets in the implant (on lateral border and through drill holes in bicipital groove [2] and under trunion [4]). Double-row repair was performed using two lateral row transosseous sutures and four medial row sutures through the tendon (SP) or osseotendinous junction (LTO). Biomechanical properties and mode of failure were tested.

RESULTS

There were no significant differences in elongation amplitude, cyclic elongation, or maximum load to failure between the three groups (P > 0.05). Mean stiffness was significantly higher in LTO (P = 0.009 vs. SP and ST). In the ST group, 7/7 specimens failed at the tendon-suture interface. For SP, 4/7 failed at the tendon-suture interface, one at the suture-bone interface, one fractured around the implant stem, and one at the knots. For LTO, 3/7 failed at the tendon-suture interface, two at the suture-bone interface and two fractured around the implant stem.

CONCLUSIONS

In this cadaveric model, subscapularis repair via ST, SP, and LTO techniques was biomechanically equivalent. Additional studies are needed to confirm these findings and determine the influence of biologic healing on healing rates and clinical outcomes.

LEVEL OF EVIDENCE

N/a, biomechanical laboratory study.