Arthroscopic Rotator Cuff Repair With Allograft Augmentation (AKA Superior Capsular Reconstruction)
The following information is attributed to Kholinne and Jeon and published in the Annals of Translation Medicine, an open access journal. You may read the publication at the following link: https://atm.amegroups.com/article/view/61644/html
- The boxes below are specifically for our patients and will provide answers to frequently asked questions and postoperative wound care instructions.
Irreparable rotator cuff tears (IRCTs) are difficult to treat for it is mostly associated with massive tear size. The increase in rotator cuff tear size and patient age are reported to be associated with the poor outcome and higher failure rate following surgical repair (1). The massive IRCTs are reported to have 79% retear rate following primary surgical repair. Over the past few years, the biological augmentation of rotator cuff repairs using patch graft (8) with or without scaffolds has increased in utilization. Reverse shoulder arthroplasty is a treatment option for IRCTs but there are concerns regarding its longevity, especially in the young population (11). Thus, joint-preserving surgery such as SCR (12) has been advocated for the younger population with IRCTs.
Arthroscopic SCR (ASCR) is probably the most popular topic in shoulder surgery nowadays. This enthusiasm for SCR indicates the difficulty of the problem it is intended to address: an IRCT in the patient that is poorly suited for an alternative procedure. SCR has been first introduced in 2013 by Mihata et al. (23). Theoretically, it works by providing a superior static restraint to the superior migration of the humeral head. The premise of the procedure is to optimize the rotator cuff force couples, thus improving joint kinematics (24). SCR represents a valuable additional tool for the shoulder surgeon and not a universal solution for every challenging rotator cuff tear. Many questions still exist regarding the best indications, surgical technique, the long-term outcome, the complications, and the risk of the procedure. This study reviews the current evidence of SCR in an attempt to provide a state-of-the-art knowledge.
The Biomechanics of Superior Capsule of the Shoulder
The rotator cuff tendon provides a dynamic stability to the glenohumeral joint, which restraints the superior migration of the humeral head when the deltoid muscle is activated. The muscles at the coronal plane (the deltoid and the supraspinatus muscle) and the transverse plane (the infraspinatus, the teres minor, and the subscapularis muscle) work synergistically to provide a balanced force couple. Disruption to the balanced force couple caused by a large rotator cuff tear or MIRCT will result in the proximal migration of the humeral head (25). In addition, this will decrease the efficiency of the biomechanics of the glenohumeral joint because it requires more force to abduct and elevate the arm. When it continuously occurs, this will lead to the deterioration of the shoulder joint function that leads to fixed humeral head migration, further extension of the tear, and eventually the end stage, that is, rotator cuff arthropathy. Superior capsule reconstruction is performed to restore shoulder joint stability, hence allowing normal joint kinematics and functional outcome (29-32).
Surgical Indications
Medium-term or long-term follow-up studies on the outcome of this relatively new procedure are limited. Most published studies that reported its outcomes are with either without control group or technically driven, which makes it difficult to recognize which patients benefit more from SCR. Thus, the indication for SCR remains indefinite as to which patients are best indicated for this procedure.
Preoperative assessment
History and physical exam
The initial workup for SCR candidate patients is similar with any surgical procedure to treat rotator cuff tears. A thorough physical examination for all patients should be performed on both shoulders to assess the status of muscle atrophy. The presence of pseudoparalysis, which is an inability to actively raise the arm above 90° with a full painless passive motion, should be recorded (37). It is important to note why a patient is having pseudoparalysis, because this is multifactorial, including weakness, severe superior humeral head migration, and significant pain. The cause of pseudoparalysis, together with imaging and intraoperative findings, may have an impact on surgical decision making (38).
Because a concomitant subscapularis repair may be needed at the time of SCR, it is also important to assess the status of subscapularis muscle strength. The repairability of the subscapularis tendon in the presence of a tear is also found to be a prognostic factor of SCR because an irreparable subscapularis tear will have less postoperative muscle strength than those with intact or repairable subscapularis (39,40).
Imaging assessment
Preoperative imaging assessment using standard shoulder plain radiographs will provide information regarding the presence of arthritic changes of the shoulder joint, the degree of proximal humeral migration, and the acromiohumeral distance (Figure 1). The acromiohumeral distance is best evaluated on an X-ray taken with the beam tilted 20° caudally in anteroposterior projection (41). Magnetic resonance imaging (MRI) may provide information regarding the involved tendons, tear size, and fatty infiltration according to Goutallier’s index (36,42).
Summary
The management of patients with IRCTs still remains challenging despite the effort to treat with SCR. The mainstay of the challenge is imminent when patients are thought to be too young for the prosthetic joint replacement. Reports of studies after SCR are increasing, which mostly described encouraging results. However, with respect to functional restoration of the shoulder joint as the endpoint of the procedure, we hope to see long-term outcomes of this procedure