Commentary on
"Position of Immobilization After Dislocation of the Glenohumeral Joint. A Study with Use of Magnetic Resonance Imaging"
By Eiji Itoi, MD et al.

Commentary by Christian Gerber, MD*,
Department of Orthopaedics, University of Zurich, Zurich, Switzerland

Recurrence of instability is the most frequent complication of traumatic anterior dislocation of the glenohumeral joint in the young patient. Currently, arthroscopic labral repair is advocated by some to reduce the rate of recurrence of dislocations, but as indicated in the article by Itoi et al., surgical treatment for every patient who sustains a primary dislocation of the glenohumeral joint would result in every other patient possibly undergoing an unnecessary operation.

The lesions that lead to recurrence are not well understood, let alone identifiable with current imaging techniques. Empirically determined nonoperative treatment involves some form of immobilization with the arm in a stable position for an arbitrary period of time. These nonoperative methods probably do not reduce the rate of recurrence when compared with that for the natural history of the condition. Methods of preventing the detachment of the anteroinferior labrum through better immobilization techniques have been documented. I had the privilege to discuss these techniques with Dr. Itoi during his travelling fellowship in Europe in 1994, and I find the results of his current study very interesting.

The authors studied six fresh traumatic anterior shoulder dislocations and thirteen recurrent dislocations. MRI studies were made at a mean of four days after the initial dislocations and twenty-nine days after the most recent dislocation for the recurrent cases. The imaging methodology was different in the two groups: no contrast medium was used in the acute cases, while 10 mL of contrast fluid was used in each recurrent case, irrespective of patient size. Although a blinded evaluation is not possible because the observer obviously sees whether the arm is in internal or in external rotation, the results are convincing and very similar in both the acute and recurrent groups. The study confirmed that the standard immobilization technique with the arm in a sling (in internal rotation) prevents the reduction of the capsulolabral structures to the anterior glenoid neck . Furthermore, the study showed for the first time, to my knowledge, that external rotation with the arm at the side improved the position of the detached capsulolabral structures in essentially all of the study cases.

Because of the consistency of these findings, I believe that even the group of acute shoulder dislocations, which is really the group of interest, is large enough to support the conclusion that the external rotation technique has a higher chance of leading to anatomical healing than do conventional immobilization techniques. The early results suggesting reduction of the rate of recurrence with use of simple arthroscopic lavage (see references 11 and 18 of the article) have not stood the test of time. The study by Itoi et al. did not evaluate whether the capsulolabral structures are also displaced if there is no fluid in the joint, but it is to be inferred that after lavage the arms of the patients were immobilized in internal rotation, so that the results of lavage were probably compromised by a suboptimal immobilization technique.

The authors have employed sound methodology to conduct a very interesting and important study with applications that may reduce the rate of recurrence following traumatic anterior shoulder dislocation. They have already proposed the next step—namely, a prospective study to verify the clinical benefit of their excellent observations.

*The author did not receive grants or outside funding in support of his research or preparation of this manuscript. He 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. Arciero RA, Wheeler JH, Ryan JB, McBride JT. Arthroscopic Bankart repair versus nonoperative treatment for acute, initial anterior shoulder dislocations. Am J Sports Med. 1994;22:589-94.
2. Les instabilites de l`epaule. In: Duparc J, editor. Cahiers d'enseignement de la SOFCOT. No. 33. Paris: Expansion Scientifique Francaise; 1988. p 51-74.
3. Hovelius L, Augustini BG, Fredin H, Johansson O, Norlin R, Thorling J. Primary anterior dislocation of the shoulder in young patients. A ten-year prospective study. J Bone Joint Surg Am. 1996;78:1677-84.