Commentary & Perspective

Commentary & Perspective on
"Outcome of Pectoralis Major Transfer for the Treatment of Irreparable Subscapularis Tears"
by Bernhard Jost, MD, et al.

Commentary & Perspective by
Robin R. Richards, MD, FRCSC*,
University of Toronto and Sunnybrook and Women's College Health Sciences Centre, Toronto, Ontario, Canada

Jost et al. discuss an uncommon but problematic disorder of the rotator cuff. The authors have already contributed in an important and abiding way to the diagnosis of this rotator cuff disorder by providing the readership with clinically useful information regarding the diagnosis of this uncommon condition. It is estimated that approximately 8% of full-thickness rotator cuff tears involve the subscapularis tendon¹. We are indeed fortunate that the authors have been able to assemble twenty-eight patients (thirty shoulders) who underwent treatment for this uncommon condition. Many surgeons, including this commentator, have confronted the uncomfortable and frustrating intraoperative problem of attempting to repair a subscapularis tear that cannot be adequately mobilized. This situation is all the more frustrating since the operating surgeon must have considerable ability as a diagnostician even to identify this disabling condition. The technique described in the manuscript provides a practical and evidently functional solution to the challenge presented by irreparable subscapularis tears.

The methodology employed by the authors in their study was rigorous. That series was consecutive, all of the patients were reviewed in a standardized fashion, and all shoulders underwent follow-up study for a minimum of two years. Furthermore, all patients were investigated with magnetic resonance imaging with arthrography preoperatively, and the subscapularis muscle was assessed.

The authors described how they attempted to mobilize the subscapularis tendon intraoperatively and how they divided their patients into three subgroups: those with an isolated subscapularis tear only, those with a massive reparable supraspinatus tear, and those with a massive irreparable supraspinatus tear. The follow-up method was that of Constant and Murley, which is a widely accepted follow-up measure that includes a strength assessment. Radiographs were available at the time of follow-up for all of the shoulders, and magnetic resonance images were available for twenty-nine shoulders. Postoperatively, most of the patients were satisfied with the result and there were significant improvements in the scores for pain, activities of daily living, functional use of the arm, mobility (except external rotation, was had decreased significantly), and abduction strength.

The authors noted that eighteen of the shoulders (60%) were still mildly painful following reconstruction, which is consistent with this commentator's experience. The lift-off test remained positive in twenty-three of thirty shoulders. None of the patients had symptoms of instability postoperatively, although the humeral head was slightly subluxed in five shoulders. There was a weak correlation between the Constant score and preoperative fatty muscle degeneration of the supraspinatus (p = 0.012) and the infraspinatus (p = 0.0367).

Six complications occurred, with four of them specific to the transferred pectoralis major tendon: two avulsions of the transferred pectoralis major tendon, one axillary vein thrombosis, and one mechanical conflict of the coracoid process that required a corrective osteotomy of the coracoid.

In the Discussion, the authors noted that shoulder function was not restored to normal, although flexion improved from a mean of 119° to a mean of 132°. Patients estimated the value of the operatively treated shoulder to be only 55% of the value of the normal shoulder. The relatively high rate of satisfaction is explained by the very poor preoperative condition and the substantial improvement that occurred as a result of surgery. The authors noted that their transfer is routed over the conjoint tendon (as opposed to a previously described technique to route the tendon under the conjoint tendon^2-4), which decreases the technical difficulty of the procedure and may reduce the risk of musculocutaneous nerve palsy. This commentator would agree with this assertion. Due to residual pain at the site of the transfer insertion, the authors have recently changed their technique to one of transosseous suture fixation, which may or may not obviate this phenomenon.

Jost et al. should be complimented for their innovative operative technique and the thoroughness of their study. In particular, the follow-up data are forthright and detailed and include a comprehensive imaging analysis. The authors have provided the readership with a practical method of dealing with irreparable tears of the subscapularis tendon and an honest appraisal of the results that can be expected following surgery. I am deeply appreciative for the opportunity to comment on this excellent manuscript.

*The author did not receive grants or outside funding in support of research or preparation of this manuscript. The author did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the author is affiliated or associated.

References

1. Frankle M, Cofield R. Rotator cuff tears involving the subscapularis tendon. Techniques and results of repair. Read at the Fifth International Conference on Shoulder Surgery; 1992 July 12-15; Paris, France.
2. Resch H, Povacz P, Ritter E, Matschi W. Transfer of the pectoralis major muscle for the treatment of irreparable rupture of the subscapularis tendon. J Bone Joint Surg Am. 2000;82:372-82.
3. Wirth MA, Rockwood CA Jr. Operative treatment of irreparable rupture of the subscapularis. J Bone Joint Surg Am. 1997;79:722-31.
4. Warner JJ. Management of massive irreparable rotator cuff tears: the role of tendon transfer. Instr Course Lect. 2001;50:63-71.