To the Editor:
The article by Waters and Bae reports their updated experience in the management of internal rotation contractures secondary to brachial plexus birth palsy. In it, they demonstrate improved glenohumeral relationships with open capsulorrhaphy. These new results contrast with those in their earlier publication in which they observed no significant improvement in glenohumeral deformity when no capsular release was performed (1).
There are several issues addressed by the authors that are inconsistent with our own experience including the suggestion that "extra-articular" procedures do not lead to significant glenohumeral remodeling. Before developing an arthroscopic approach, all the children under our care were treated with an open subscapularis slide (effectively detaching the subscapularis from its medial attachment on the ventral surface of the scapula). We reported the pre-operative arthrographic findings of 25 such cases in JBJS in 1998. 72% of the patients had significant glenohumeral deformity (2). Follow-up MRI of these children often showed extensive remodeling of the glenohumeral joint so long as external rotation was achieved at surgery and maintained at follow up (Figures 1A and 1B).
Figure 1A: arthrogram of two year old with pseudoglenoid on arthrography prior to subscapularis slide (extra-articular release, no muscle transfers). Humeral head (HH), glenoid (GL), pseudoglenoid (PsGL) and acromion (Ac). Reproduced from Pearl, M. L. and B. W. Edgerton (1998). "Glenoid deformity secondary to brachial plexus birth palsy." J Bone Joint Surg Am 80(5): 659-67, Figure 5A.
Figure 1B: Same child 3.5 years post-op showing round humeral head (HH) well centered on concave glenoid (GL).
We abandoned this surgical approach because 20% of the time we were unable to achieve an effective release without attention to the anterior capsule. Consequently, these data were never submitted for publication. For surgeons who still favor extra-articular procedures, however, it merits recognition that glenohumeral remodeling may occur so long as the contracture is effectively dealt with and the child is young enough. The surgical variable of "extra- or intra-articular" is only relevant to the extent that it does or does not allow for adequate release of the contracture.
A related concern is how the multitude of procedures presently in use for these children affects internal rotation. The authors report improvements in Hand to Spine of the Mallet scale from an average grade of 1 pre-operatively to grade 2 post-operatively and explain these improved results on the basis of their specific surgical technique. If we understand correctly how the authors are using this score, a Mallet score of 1 means that the children were not able to put their hands behind their back before surgery (on average) and the Mallet score of 2 means that they were able to do so (to the level of S1) postoperatively. The author's surgical approach apparently results in a similar amount of internal rotation as we reported for the arthroscopic approach, taken directly from our publication "The ability to reach up the back was… restricted at the time of follow-up, with the children only able to reach between the sacrum and L5 on the average" (3). The apparent discrepancy is that this is reported as an improvement in the present article but was experienced as a reduction of motion in the arthroscopic series.
These children have profound internal rotation contractures pre-operatively, sometimes availing them an extraordinary range in this direction. While some children begin with poor internal rotation, many of them can easily reach up their backs, Mallet 3 or 4 before surgery. After surgery, arthroscopic release or any other that we have tried, their weakened and diminished internal rotation leaves them on average with the ability to just put their hand on the small of their back (Mallet 2) but not always (Mallet 1). Furthermore, is it reasonable to expect a procedure that weakens the internal rotators will "improve" internal rotation, even in an otherwise normal shoulder let alone one that has paralyzed muscles and an irregular shape?
It is entirely probable that different surgical techniques are better suited to some children with varying ages, severity of contracture, and deformity, than others. It is also possible that the authors' surgical approach does not diminish internal rotation to the same extent as the arthroscopic release or other methods of treating the contracture. As presented in their current report, however, we do not see sufficient information to make this determination nor the means to differentiate patients that are perhaps better suited to one technique or another.
The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families received 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, division, center, clinical practice, or other charitable or nonprofit organization with which the authors, or a member of their immediate families, are affiliated or associated.
References
1. Waters, P. M. and D. S. Bae (2005). Effect of tendon transfers and extra-articular soft-tissue balancing on glenohumeral development in brachial plexus birth palsy. J Bone Joint Surg Am 87-A(2): 320-5.
2. Pearl, M. L. and B. W. Edgerton (1998). Glenoid deformity secondary to brachial plexus birth palsy. J Bone Joint Surg Am 80(5): 659-67.
3. Pearl, M. L., B. W. Edgerton, et al. (2006). Arthroscopic release and latissimus dorsi transfer for shoulder internal rotation contractures and glenohumeral deformity secondary to brachial plexus birth palsy. J Bone Joint Surg Am 88(3): 564-74.
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