Tendon transfers for rotator cuff insufficiency

OVERVIEW

Chapter synopsis

Rotator cuff insufficiency resulting from large, chronic rotator cuff tears (RCT) can lead to shoulder pain, weakness, and loss of range of motion (ROM). Tendon transfers are a potential treatment option for irreparable posterior-superior rotator cuff insufficiency. The two most commonly transferred tendons for this pathology are the latissimus dorsi and the lower trapezius. Although the latissimus dorsi tendon transfer (LDT) has a longer track record and does not require the use of allograft augmentation, proponents of the lower trapezius tendon transfer (LTT) argue in favor of its more anatomic line of pull and simpler postoperative rehabilitation. Outcomes of both techniques are promising, and the decision to use either is ultimately the surgeon’s preference.

Important points

Patient selection is paramount.
Indications: LDT and LTT should be performed for isolated irreparable posterosuperior RCT with no instability, intact deltoid, and intact or repairable subscapularis musculature.

Clinical/surgical pearls

LDT
- Arthroscopic identification and preparation of the plane between the deltoid and teres minor facilitates axillary identification of the correct window for graft passage.
- The release of the proper axillary LD muscle is important for tension-free LDT tendon reinsertion at the anterior part of the greater tuberosity
LTT
- Access to the medial scapular margin and scapular spine is crucial for graft identification and harvest.
- Removing the fat pad in the harvest area helps to better visualize the lower trapezius tendon.
- Releasing adhesions of the LTT ensures smooth graft sliding.
- Opening the infraspinatus fascia and using a large clamp helps to create a broad tunnel from the infraspinatus fossa to the subacromial space in which the graft can slide smoothly.
- Marking the dorsal surface of the graft and using different suture colors for each margin helps with graft orientation to avoid twisting during passage.

Clinical/surgical pitfalls

LDT
- A small, tight shuttling tunnel can cause the latissimus dorsi tendon and muscle to tubularize and restrict the graft from sliding freely.
- Twisting of the graft or tangling of the sutures typically happens if the sutures are not separated through different portals before the anchors are inserted.
LTT
- A skin incision set too far laterally and superiorly is a common error.
- A small and tight path between the infraspinatus fossa and the subacromial space can restrict the graft from sliding smoothly.

Video available

: Latissimus dorsi transfer

Introduction

Rotator cuff insufficiency resulting from large, chronic rotator cuff tears (RCT) can lead to the loss of the shoulder force couple that allows for normal shoulder mechanics. This can lead to shoulder pain, weakness, and decreased motion. Tendon transfers are a potential treatment option for posterior-superior rotator cuff insufficiency. The two most commonly transferred tendons for this pathology are the latissimus dorsi and the lower trapezius.

The seminal description of latissimus dorsi tendon transfer (LDT) for chronic posterosuperior RCT was put forth by Gerber in 1988. In this procedure, the insertion of the latissimus dorsi is transferred from the floor of the intertubercular groove to the superolateral humerus to provide humeral head depression and external rotation (ER). This effectively balances the force couple about the humeral head, allowing more effective function of the deltoid, and/or restoring shoulder function. As the intended action of the transferred tendon is opposite that of its native function (adduction, internal rotation, and extension of the humerus), the transfer is out of phase. Given the size and/or excursion of the latissimus dorsi, the tendon is generally able to reach the superolateral humerus without the addition of an interposed graft.

The lower trapezius tendon transfer (LTT) was originally described to treat patients with brachial plexus palsy who suffer from lack of ER. ^, These patients typically have a non-functional deltoid muscle, and the treatment with a latissimus dorsi transfer can result in posterior subluxation of the glenohumeral joint. By detaching the lower trapezius from the scapula spine and tenodesing it to the intact infraspinatus tendon ER can be restored without subluxation of the joint. Elhassan et al. extended the indication of this procedure to patients with irreparable posterosuperior cuff tears and reported short-term results comparable to those of patients undergoing a latissimus dorsi transfer.

An advantage of the LTT is that the lower trapezius muscle contracts during ER of the shoulder, thus enabling easier rehabilitation and recruitment compared to the LDT, which is active during internal rotation.

Long term results are available for the LDT, but not for the LTT. Short-term results of LTT are comparable to those of LDT.

Preoperative considerations

History

Patients with irreparable RCT typically present with chronic shoulder pain (>6 months) and weakness. Shoulder pain, which is usually worse at night and interferes with sleep, is often the primary symptom, while weakness is often a secondary complaint that must be actively elicited by the shoulder specialist. When prompted, patients may report inability to perform daily activities of living requiring overhead motion and ER, such as washing/brushing their hair or putting their clothes on. They often require assistance from their non-dominant hand to support their affected extremity while performing tasks such as holding a wine bottle for pouring.

Physical examination

During inspection, a prominent scapular spine can indicate atrophy of the infra- and supraspinatus muscles, which is pathognomonic of an irreparable RCT.

Range of motion (ROM) examination typically reveals an ER lag, which is a discrepancy between active and passive ER in both adduction, and abduction greater than 20 degrees. Patients can also demonstrate a “horn-blower” sign, or inability to externally rotate the shoulder in abduction, indicating a teres minor involvement. However, not all patients with irreparable RCT exhibit deficits with ROM. Often patients may present with surprisingly good to normal motion. In fact, patients who have a flexion of more than 60 degrees despite massive RCT show significantly better treatment results after LTT. Nevertheless, despite exhibiting good motion, patients tested with the Jobe and Whipple test or with resisted ER can reveal profound weakness attributable to their rotator cuff insufficiency.

Imaging

Standard anterior-posterior and axillary radiographs of the affected shoulder are performed to rule out advanced arthrosis or cuff tear arthropathy with acetabularization of the acromion (Hamada III or higher), both of which would be contraindications for the procedure. Although the diagnosis of RCT can be made clinically, magnetic resonance imaging (MRI) can help assess tissue reparability. For this purpose, the fatty infiltration of the rotator cuff muscles in the non-fat saturated oblique-sagittal T1 sequences is assessed according to Goutallier’ s classification. Fatty infiltration of stage III and IV is associated with high failure rates of rotator cuff repair and a cuff tear with these characteristics can therefore be considered functionally irreparable. The retraction and length of the tendon stump should also be assessed since advanced retraction to the level of the glenoid or medial to it could also indicate lower repair potential.

Indications and contraindications

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