John W. Sperling, MD, MBA, is Professor of Orthopedic Surgery at the Mayo Clinic. Dr. Sperling’s principal clinical and research interest is primary and revision shoulder arthroplasty.
Along with a dramatic growth in primary shoulder arthroplasty worldwide, there has been a corresponding increase in revision procedures. This section covers some techniques learned over time to improve outcomes of this technically challenging procedure.
A deltopectoral approach is preferred due to the extensile nature. The easiest manner to find the deltopectoral interval is below the clavicle, and it is typically 1 cm medial to the coracoid. In cases without a deltopectoral interval one can look for the different fiber orientations of the deltoid and pectoralis. The cephalic vein is typically retracted medially. The coracoid is a very useful “lighthouse” in the shoulder. The dissection takes place on the lateral side of the coracoid and conjoint group. As one moves distally, a retractor is placed between the conjoint group and remaining subscapularis.
There may be abundant scar between the deltoid and remaining superior and posterior rotator cuff. The easiest way to find this plane is with internal rotation of the arm and first developing the subacromial space, and then moving distally. Placing the arm on a Mayo stand can decrease tension on the deltoid and help with developing this tissue plane. It is essential to release all of the scar in the subacromial space to ensure proper exposure as well as maximize patient motion. After incising superior scar in the subacromial space, one then moves distally. The axillary nerve is palpated on the undersurface of the deltoid, and the deltoid is then mobilized distally to the deltoid insertion. A Browne retractor is then used on the humerus.
In cases where the rotator cuff is intact, one incises the rotator interval and takes the subscapularis down through tendon or off bone. A large inferior capsule release is performed, and this is extended posteriorly along the metaphysis of the humerus. The arm is placed in adduction and external rotation on a Mayo stand. The extent of the inferior capsular release is dictated by the stiffness of the shoulder. The stiffer the shoulder, the greater the inferior capsular release that is required. This will facilitate access to the humeral component as well as enable glenoid exposure. The posterior capsular release is stopped short of the teres minor. In revision cases with significant scarring, I also prefer to release some of the pectoralis major. Releases on the glenoid side are performed after completion of humeral exposure.
Humeral component removal
Over time, we have developed a routine process for humeral component removal. A router bit is initially used circumferentially around the proximal humerus at the interface of the humeral component and the bone or humeral component and cement ( Fig. 66.1 ). A square tip impactor is then used from below with a mallet to remove the humeral component. When the humeral component does not have a collar, one can make a collar with a helicoidal bur ( Fig. 66.2 ). In a recent report from our institution, this has resulted in humeral component removal greater than 97% of the time without requiring a humeral window or split. There is also good evidence that one can use short stems in revision to reverse arthroplasty, as well as a cement within cement technique, rather than bypassing the old pedestal with a long stem. This can greatly facilitate the current and future revision surgery.