Abstract
Latissimus dorsi anterior to major transfers have been advocated in the setting of loss of external rotation and elevation in conjunction with reverse shoulder replacement. Reverse shoulder replacement is a prosthesis specifically designed for shoulders with poor rotator cuff function. In the vast majority of cases, some teres minor function at the minimum is maintained in shoulders destined for a reverse shoulder replacement. However, in certain circumstances there is complete loss of any external rotation, and a muscle transfer can be performed in order to restore some external rotation function. A reverse shoulder replacement in the absence of any rotator cuff function goes into obligate internal rotation with elevation. A minimum of external rotation strength is necessary in order to maintain the arm in normal rotation. The first tip is patient selection. Physical examination of active external rotation, external rotation strength and forward elevation should be just performed. A latissimus transfer is indicated in patients who cannot maintain their arm in neutral to at least a few degrees of external rotation. A lag sign is another physical examination finding which can indicate complete loss of rotator cuff function. The latissimus dorsi transfer is performed by first identifying and releasing the latissimus from its insertion on the anterior humerus. The arthroplasty is performed. The passage for the latissimus muscle is developed carefully and being mindful of the axillary nerve in particular. The latissimus is directed inferior to the nerve and around the medial and posterior aspect of the proximal humerus. Different ways of securing the transfer to the humerus have been described including bone tunnels and anchors. Often it is easier to place the anchors and/or the bone tunnels prior to inserting the humeral prosthesis. The latissimus is secured in the new position, enabling it to participate in external rotation. The value of this is difficult to clearly establish. Most studies are evidence level IV and there are no good comparative studies in a controlled patient population. This is a good option for shoulders with no active external rotation, but they may increase overall complication rate. Complications include dislocation, infection, and transient nerve palsy.
