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Abstracts & Commentary
Synopsis: A long-term study of the natural history of recurrent shoulder instability after a primary traumatic anterior dislocation demonstrated a recurrence rate of 66%, while in another study, arthroscopic repair after first-time dislocation resulted in a recurrence rate of 14%.
Sources: Hovelius L, et al. Primary anterior dislocation of the shoulder in young patients, a ten-year prospective study. J Bone Joint Surg 1996;78(A):1677-1684; Arciero RA, et al. Arthroscopic Bankart repair versus nonoperative treatment for acute, initial anterior shoulder dislocations. Am J Sports Med 1994;22:589-594.
An interesting and controversial topic currently exists in musculoskeletal sports medicine , involving the initial treatment of a primary anterior shoulder dislocation. This controversy is best highlighted by reviewing two different studies from 1996 and 1994.
The controversy, simply stated, involves both the natural history and treatment of primary anterior shoulder dislocations. As a background, the orthopaedic literature supports a high recurrence rate in patients younger than 20 years of age. In a retrospective review of shoulder dislocations, McLaughlin and MacLellan found a recurrence rate of 95% of 181 primary dislocations in patients 11-20 years of age.1 Rowe also noted a recurrence rate of 83% in 107 patients younger than 20 years of age.2 As one ages, the recurrence rate decreases. Initial treatment involved either immobilization (usually 4 weeks) or early range of motion exercises, with surgery being considered only after multiple recurrences of the dislocation. Classically, most shoulder dislocations have been treated with open surgery using the classic Bankart repair (reattaching the shoulder labrum to the glenoid edge), with a well-established success rate of 95%.3 In 1977, Hovelius began a prospective trial evaluating initial treatment of primary shoulder dislocations. Performing his study in the medical system of his native Sweden afforded Hovelius the unique opportunity of having exacting follow-up, which led to a subsequent five-year follow-up study showing no difference in initial management of the dislocation. With reevaluation at 10 years, this clinical trial became a landmark natural history study of primary shoulder dislocations.
This unique prospective study of primary anterior shoulder dislocations in patients younger than 40 years of age provides tremendous information about the natural history of this injury, based on its one-of-a-kind follow-up. Of the original 245 dislocators, only 10 were lost to follow-up before 10 years (9 died, 1 left Sweden). Of the remaining patients, 211 were evaluated with a physical examination and follow-up interview, and 34 were evaluated by telephone interview or by a mailed questionnaire. Two hundred eight shoulders were examined radiographically at 10 years.
At the 10-year follow-up of patients between the ages of 12 and 22 years, recurrent dislocation requiring operative stabilization had been performed in 34 of 99 shoulders (34%). With increasing age, the percentage of operative stabilization for recurrent instability decreased to 28% for patients 23-29 years and to 9% in patients 30-40 years of age at the time of initial dislocation. Hovelius et al noted a phenomenon of spontaneous stabilization of recurrent shoulder instability in 24 of 107 (22%) shoulders (in other words, patients who had had a recurrence, with time stabilized and did not require treatment). Hovelius et al noted the reason for spontaneous stabilization was unclear but suggested it could be related to decreased shoulder external rotation with age, less physical activity, or decreased range of motion due to arthropathy.
Radiographic findings of arthropathy were noted in 41 of 208 shoulders studied. There was a lower incidence in arthropathy in the asymptomatic contralateral shoulder, implying that, as has long been suspected, the etiology of arthropathy may related to the dislocation event(s).
Recurrence was an interesting phenomenon. Of those patients 12-22 years of age with no recurrent dislocation at the earlier two-year follow-up, 34 continued to have no recurrent dislocations at 10 years. Of those shoulders injured in patients between 12 and 22 years of age, 102 were followed at two years. At 10 years, 99 remained in this group, with 38 having no or one recurrence (38%, 34 of 99 or 34% with no recurrence), 34 (34%) having surgery, 13 of 99 (13%) being considered symptomatic, and another 13 of 99 (13%) being considered healed. In summary, based on approximately 100 patients younger than the age of 22, at 10 years, there was a recurrence rate of 66%.
The difference in recurrence rate from previous studies underlies the concept of the need for natural history studies of any injury or disease as well as the long opined need for prospective follow-up. This study gave both. Previous studies were retrospective and of surgically treated patients. Although the findings in this study may be disputed (especially documentation of activity and functional level of the patients), this paper should be in every teaching file for sports medicine as a true attempt to prospectively document the natural history of primary anterior shoulder dislocations in young patients in a general population.
This leads us to review another paper that should also be in one’s personal sports medicine teaching file.
The unique study by Arciero and colleagues was conducted on a specialized population of United States Military Academy cadet-athletes who must return to their preinjury activity levels in an environment where activity modification is not an option.4 Arciero et al had experienced a high recurrence rate after closed initial treatment and early success with arthroscopic repair techniques; therefore, they designed a prospective, nonrandomized trial of arthroscopic Bankart repair vs. four weeks of immobilization for treatment of an initial anterior shoulder dislocation. This unique population allowed for excellent follow-up, a single source of medical care, and one single-age group in a demanding athletic environment.
A total of 36 patients were enrolled and completed the study. Fifteen patients selected nonoperative treatment and 21 patients chose early arthroscopic evaluation and Bankart repair. Age demographics were similar, while the mechanism of injury in one subset of limited contact was higher in the surgically treated group. Follow-up differed in the two groups, with patients with nonoperative management averaging 23 months (range, 15-39 months) and surgically managed patients averaging 32 months (range, 15-45 months) of follow-up.
Of the 15 treated nonoperatively, the recurrence rate was 80% (12 of 15 patients) with seven of the 12 (58%) patients requiring a subsequent open Bankart repair. Of the three remaining patients without a recurrence in the nonoperative group, two were functionally rated as excellent and one as good. In the operatively managed group, 18 of 21 (86%) patients had no recurrent instability, with one patient subsequently requiring a Bankart repair. Of the two remaining operative patients, one had a single episode of instability and returned to contact sports without further recurrence and the other had only one recurrence but no longer participates in contact sports.
Comment by Robert C. Schenck, Jr., MD
In the study by Arciero et al, early arthroscopic repair decreased the rate of recurrent dislocation as compared to nonoperative management. Unfortunately, there were failures in the arthroscopic group (3 patients) and, furthermore, three of 15 patients avoided surgery with nonoperative management. Hence, six of 36 (17%) patients with a primary dislocation either were not benefited by (3 patients in the operative group) or would not have required an initial surgical approach (3 patients in the nonoperative group). Although Arciero et al clearly show a decreased incidence of recurrence with early arthroscopic repair, the take-away message must include the 8% who were not benefited by surgery and the 8% who did not need surgery. Early arthroscopic treatment of primary shoulder dislocations may have its benefits (time of disability, early treatment of pathology such as a Bankart lesion, and a predictable recovery) but, in any informed decision, the benefits of nonoperative management must be also considered and discussed with the patient.5
The controversy around these two papers stems from the current orthopaedic (and albeit American) trend of early arthroscopic stabilization in primary anterior shoulder dislocations in a young (< 20 years of age) athletic population. The uniqueness of both studies stems from the well-defined and captured populations of shoulder patients. Hovelius et al document the natural history of all comers (patient activity, sporting, and gender) with a shoulder dislocation in one country where excellent follow-up is feasible. The initial intent of the Hovelius study was to compare nonoperative treatment methods and evaluate their effect on the eventual rate of recurrence. They found no difference when comparing immobilization vs. range of motion; however, it is in the current era of arthroscopic shoulder stabilization that this natural history study creates controversy.
What is the clinician to do or at least recommend? Despite the advances in arthroscopic shoulder stabilization, open surgery for recurrent instability after an anterior dislocation remains the gold standard with a 95% success rate. Arthroscopic repair (especially early) is attractive based upon reparability of a Bankart lesion combined with the demands of the athletic population younger than the age of 20. Nonetheless, arthroscopic repairs have a higher failure rate (14% in this study by Arciero et al) when compared to open methods. Depending upon the population being treated, it may be logical to delay surgery until recurrence and its disability are experienced by the patient. Then the most successful operative stabilization procedure, namely open repair, should be pursued. In a high demand athlete younger than the age of 22, other issues, such as disability and time lost because of conservative care, play a role in treatment decisions. When arthroscopic shoulder repair success becomes comparable to open surgery, this controversy will quiet in this specialized athletic population.
In summary, with the dogged persistence of Hovelius, a prospective clinical trial has become a classic natural history study of primary anterior shoulder dislocations. As Hovelius candidly noted in a postpublication editorial, "within six years, we hope (if we are still alive) to start the 25-year follow-up," which will further our understanding of such injuries. Early shoulder surgery will remain controversial as techniques evolve and appropriate populations are further defined. We must remember to carefully consider the population (age, athletic demands, system demands) being treated as well as the successes and failures before recommending or condemning early surgery.
1. McLaughlin HL, MacLellan DI. Recurrent anterior dislocation of the shoulder. A comparative study. J Trauma 1967;7:191-201.
2. Rowe CR, Sakellarides HT. Factors related to recurrences of anterior dislocations of the shoulder. Clin Orthop 1961;20:40-48.
3. Rowe CR, et al. The Bankart procedure: A long-term end-result study. J Bone Joint Surg 1978;6(A):1-16.
4. Arciero RA, et al. Letter to the editor. J Bone Joint Surg 1998;80(A):299-301.
5. Shea KP. Arthroscopic Bankart repair. Clin Sports Med 1996;15(4):737-751.