These authors point out that the reported rates of subscapularis (SC) failure after arthroplasty vary considerably, due in large part to the silent nature of its clinical presentation in many cases. In one series, ultrasound evidence of complete SC failure after anatomic total shoulder arthroplasty (TSA) was found in 13% of patients at a minimum follow-up of 8 months, but the majority of patients did not show any clinical signs of failure.
They point out that symptomatic subscapularis failure after TSA is difficult to treat. The point out that treatment options for symptomatic SC failure include nonoperative treatment, soft-tissue repair, tendon transfer, or revision to reverse total shoulder arthroplasty (RSA). Traditionally, soft-tissue repair has been performed when there is adequate and good-quality tissue to substantiate the potential for healing. Augmentation with a graft or tendon transfer is an option if tissue quality is poor or the native SC is not repairable. It has been shown, however, that pectoralis
major tendon transfer for irreparable SC failure after TSA carries a high risk of failure, particularly if there is anterior subluxation of the humeral head. SC repairs without augmentation also carry a significant risk of failure.RSA has shown acceptable survivability and low complication rates in the setting of TSA revision, however not specifically to address SC failure.
They reviewed their one year outcomes of patients undergoing reoperation for SC failure after TSA. Of the 25 patients, 15 had had lesser tuberosity osteotomies, 5 had had peels, and 2 had had tenotomies. 9 had injuries. The average time to revision surgery was 7 months. Patients underwent either revision SC repair (N=17) or revision to reverse shoulder arthroplasty (N=8).
Patients who initially underwent SC repair were significantly younger than patients who underwent revision to reverse shoulder arthroplasty (mean age, 59.3 years vs. 70.3 years; P .004), had a better comorbidity profile (mean Charlson Comorbidity Index, 2.2
vs. 3.6; P .04), and had a more acute presentation (mean time between injury and surgery, 9.1 weeks vs. 28.5 weeks; P ..03). Patients who underwent SC repair also had a significantly higher reoperation rate (52.9% vs. 0.0%, P ..01).
At final follow-up, functional outcomes scores and patient satisfaction rates were not significantly different between treatment groups.
Comment: Subscapularis failure is easier to prevent than to treat.
First of all the subscapularis needs to be released to avoid undue tension after surgery.
