Is the Subscapularis Function Preserved after the Latarjet Procedure? A Quantitative Analysis Using Positron Emission Tomography.

Abstract

Backgroud: In the Latarjet procedure, the subscapularis is divided at the superior two-thirds junction. It has been believed that this subscapularis split approach resulted in better internal rotation strength rather than an L-shaped subscapularis tenotomy. However, there are few studies demonstrating the preserved function of the subscapularis after the Latarjet procedure. The aim of the present study was to clarify the subscapularis activity using positron emission tomography (PET) in patients after the Latarjet procedure.

Methods: Six men who had undergone the Latarjet procedure were enrolled. The internal rotation exercise with elastic bands was performed with the arm at 0° and 90° of abduction. After the exercises, the patients had an intravenous injection of fluorine 18 fluorodeoxyglucose (¹⁸F FDG). Each PET image was fused to the corresponding computed tomography image to calculate the standardized uptake value (SUV). The internal rotation muscle strength was measured by a dynamometer.

Results: At 0° of abduction, the subscapularis SUVs of the involved side were significantly lower than those of the uninvolved side (p = 0.010), although there was no significant difference at 90° of abduction. The SUVs of the involved subscapularis were significantly lower at 0° of abduction than at 90° (p = 0.034). The internal rotation strength of the involved side was 81.1% ± 12.1% of the uninvolved side at 0° of abduction.

Conclusions: After the Latarjet procedure with the subscapularis split approach, subscapularis activity was well preserved at 90° of abduction. However, internal rotation strength was reduced by 19%.