Shoulder surgeons need to be aware of the critical size of the glenoid or humeral osseous defects seen in patients with anterior shoulder instability, since the considerable size of osseous defect is reported to cause postoperative instability. Biomechanical studies have identified the size of the osseous defect which affects stability. Since engagement always occurs between a Hill-Sachs lesion and the glenoid rim, when considering the critical size of the Hill-Sachs lesion, we have to simultaneously consider the size of the glenoid osseous defect. With the newly developed concept of the glenoid track, we are able to evaluate whether a large Hill-Sachs lesion is an "on-track" or "off-track" lesion, and to consider both osseous defects together. In case of an off-track Hill-Sachs lesion, if the glenoid defect is less than 25%, no treatment is required. In this case, the Latarjet procedure or arthroscopic remplissage procedure can be a treatment option. However, if the glenoid defect is more than 25%, treatment such as bone grafting is required. This will convert an off-track lesion to an on-track lesion. After the bone graft or Latarjet procedure, if the Hill-Sachs lesion persists as off-track, then further treatment is necessitated. In case with an on-track Hill-Sachs lesion and a less than 25% glenoid defect, arthroscopic Bankart repair alone is enough.
Biomechanical Phenomena ; *Glenoid Cavity/injuries/pathology/physiopathology ; Humans ; *Humeral Head/injuries/pathology/physiopathology ; Shoulder Dislocation/physiopathology ; *Shoulder Joint/injuries/pathology/physiopathology

Background: 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 ( 18 F 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%.

Background: 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 ( 18 F 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%.

Background: 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 ( 18 F 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%.

Background: 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 ( 18 F 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%.