Background: Relative to dislocations, glenohumeral subluxation events have received little attention in the literature, despite a high incidence in young athletes. The pathoanatomy of first-time, traumatic, anterior subluxation events has not been defined, to our knowledge.
Methods: As part of a prospective evaluation of all cases of shoulder instability sustained during one academic year in a closed cohort of military academy cadets, a total of thirty-eight first-time, traumatic, anterior glenohumeral subluxation events were documented. Clinical subluxation events were defined as incomplete instability events that did not require a manual reduction maneuver. Twenty-seven of those events were evaluated with plain radiographs and magnetic resonance imaging within two weeks after the injury and constitute the cohort studied. Magnetic resonance imaging studies were independently evaluated by a musculoskeletal radiologist blinded to the clinical history. Arthroscopic findings were available for the fourteen patients who underwent arthroscopic surgery.
Results: Of the twenty-seven patients who sustained a first-time, traumatic, anterior subluxation, twenty-two were male and five were female, and their mean age was twenty years. Plain radiographs revealed three osseous Bankart lesions and two Hill-Sachs lesions. Magnetic resonance imaging revealed a Bankart lesion in twenty-six of the twenty-seven patients and a Hill-Sachs lesion in twenty-five of the twenty-seven patients. Of the fourteen patients who underwent surgery, thirteen had a Bankart lesion noted during the procedure. Of the thirteen patients who chose nonoperative management, four experienced recurrent instability. Two of the thirteen patients left the academy for nonmedical reasons and were lost to follow-up. The remaining seven patients continued on active-duty service and had not sought care for a recurrent instability event at the time of writing.
Conclusions: First-time, traumatic, anterior subluxation events result in a high rate of labral and Hill-Sachs lesions. These findings suggest that clinical subluxation events encompass a broad spectrum of incomplete events, including complete separations of the articular surfaces with spontaneous reduction. A high index of suspicion for this injury in young athletes is warranted, and magnetic resonance imaging may reveal a high rate of pathologic changes, suggesting that a complete, transient luxation of the glenohumeral joint has occurred.
1Keller Army Hospital, 900 Washington Road, West Point, NY 10996. E-mail address for B.D. Owens: firstname.lastname@example.org
2Department of Orthopaedic Surgery, University of Minnesota, 2512 South 7th Street, Suite R200, Minneapolis, MN 55454
3Department of Kinesiology, Pennsylvania State University, 271A Recreation Building, University Park, PA 16802
4University of Kansas Medical Center, 3901 Rainbow Boulevard, MS 1008, Kansas City, KS 66160
5Duke Sports Medicine, Finch-Yeager Building, 300 Frank Bassett Drive, Box 3615, Durham, NC 27710
6Department of Radiology, Wilford Hall Medical Center, 2200 Bergquist Drive, San Antonio, TX 78236
7New England Musculoskeletal Institute, UConn Health Center, 263 Farmington Avenue, Farmington, CT 06030
A commentary by Jeffrey S. Abrams, MD, is available at www.jbjs.org/commentary and as supplemental material to the online version of this article.