Review Question - QID 217090

This patient has recurrent shoulder instability and chronic deficiency of the subscapularis tendon, which given his age, would be best managed with a tendon transfer (latissimus dorsi or pectoralis major).

Chronic rotator cuff tears are not uncommon but represent difficult problems for surgeons to manage. In this case, the patient's age further complicates the decision-making process, as he is 29 and has an irreparable subscapularis tear that is likely secondary to failure of the tendon to heal after his open bankart repair. The amount of retraction and atrophy seen in the images are indicators of the tendon's irreparable nature. Reverse total shoulder arthroplasty (RTSA) would not be the initial treatment of choice for this patient given his age and need for subsequent revisions. Tendon transfers represent an option for helping to recreate anterior shoulder instability and establish an appropriate muscular vector of pull, albeit not "normal," compared to the native subscapularis. Historically, the pectoralis major was transferred to the lesser tuberosity with relatively good results, but recently latissimus dorsi transfers have become more well-publicized, also with reasonable results. Along these lines, there is some biomechanical evidence that latissimus transfers may better recreate the line of pull of the native subscapularis, allowing for improved internal rotation.

Elhassan et al. studied patients with pectoralis transfer for irreparable cuff tears in multiple settings, including those with instability, failed total shoulder arthroplasty, and those with patients with instability and rotator cuff tears rather than patients who were having surgery after arthroplasty failure. Their conclusion was that in patients who had a failed subscapularis repair after arthroplasty, pectoralis major transfer is not recommended, although it may be beneficial in cases of instability.

Resch et al. describe their technique for pectoralis major transfer for the treatment of irreparable subscapularis tears. They found that both pain and function improved in the elderly population (average age 65) who had pectoralis transfer for subscapularis deficiency. This was not compared to reverse total shoulder arthroplasty with regards to outcome or function but in the authors' eyes represents another potential treatment option for these patients.

Luo et al. performed a systematic review of the outcomes of latissimus and pectoralis major transfers when used to treat irreparable subscapularis tears. They found that both groups showed improvement postoperatively, but the latissimus transfer group had better outcome scores and flexion/abduction. There were no differences in the groups between complications or failure rates, which allowed them to come to the conclusion that latissimus transfers were preferred based on improved clinical outcomes.

Kontaxis et al. performed a biomechanical analysis of latissimus, pectoralis minor, and pectoralis major transfers for irreparable subscapularis tears. They noted that the internal rotation moment arm of the latissimus transfer more closely replicated the native subscapularis than either of the pectoralis transfers. They concluded that the latissimus transfer was a reasonable option and maybe a better choice to replicate subscapularis function rather than the pectoralis.

Figure A shows a belly press test, weakness of which indicates functional subscapularis deficiency. Figure B is an axial MRI image showing that the subscapularis is retracted away from its insertion. Figure C demonstrates a sagittal MRI image showing significant atrophy of the subscapularis muscle.

Incorrect Answers:
Answer 1: Physical therapy would not be an appropriate next step given this patient's recurrent instability and known chronic, irreparable subscapularis tear.
Answer 2: A latarjet may provide some stability based simply on its sling effect but would not recreate the stability or strength accounted for by the subscapularis. Additionally, the latarjet procedure is used primarily in cases of bony anterior glenoid deficiency.
Answer 3: The Magnuson-Stack procedure is a lateral advancement of the subscapularis which is no longer commonly used. As this subscapularis tear is chronic and retracted this would not be an appropriate option.
Answer 5: RTSA would not be the most appropriate initial option for this patient given his age.