**6. Rationale, indications, and contraindications for superior capsule reconstruction (SCR)**

The main reason to consider superior capsule reconstruction (SCR) is as an alternative to reverse shoulder arthroplasty or tendon transfers in patients with irreparable superior rotator cuff tears, with or without early cuff tear arthropathy. In this procedure a graft tissue is attached to the superior glenoid and the greater tuberosity, thereby spanning the superior aspect of the glenohumeral joint (**Figure 6**). The biomechanical rationale behind this surgery is debated. One proposed rationale is a tenodesis effect between the glenoid and the humeral head, which helps regain the stabilizing effect to the glenohumeral articulation normally conferred by the superior capsule and the rotator cuff [2]. This has been called the "reverse trampoline" effect. The other proposed mechanism is that the inserted graft acts a spacer between the humeral head and the underside of the acromion, essentially keeping the head depressed by

 **Figure 6.** Schematic drawing, showing a shoulder with a normal superior rotator cuff (A), a large and irreparable defect of the superior cuff (B), and after a SCR (C and D).

way occupying the space above it. Biomechanical cadaveric studies by Mihata and colleagues have shown that SCR does restore superior translation to physiologic conditions [33]; and also that increased thickness of the graft improves stability [34]. These studies lend credence to both theories regarding biomechanical function of SCR; indeed both factors may be at play.

Indications for this surgery currently include physiologically young (absolute age has not been determined) and relatively active patients with symptomatic irreparable superior rotator cuff, with intact anterior-posterior force couples, and no or minimal glenohumeral arthritic wear. Young patients with moderate cartilage wear and symptoms primarily related to cuff function may be considered for SCR, in lieu of RTSA, but guarded expectation are warranted with more severe arthritic wear. SCR may also be an attractive option for previous failed cuff repair, in a setting of poor tissue quality, fatty infiltration, and other factors that may result in tear irreparability.

Absolute contraindications include infection, neuropathic disease of the shoulder, and neurologic disorders significantly affecting function of the deltoid muscle. Relative contraindications include advanced arthritis, tears of the anterior/posterior rotator cuff, as well as unwillingness or inability to comply with postoperative immobilization and rehabilitation protocol.
