Treatment of First-Time Shoulder Dislocations
Abstract & CommentarySynopsis: New arthroscopic techniques offer the potential to improve shoulder stability with lower morbidity than open procedures.
Source: Kirkley A, et al. Prospective randomized clinical trial comparing the effectiveness of immediate arthroscopic stabilization versus immobilization and rehabilitation in first traumatic anterior dislocations of the shoulder. Arthroscopy 1999;15(5):507-514.
The shoulder dislocates more frequently than any other large joint; yet, with new arthroscopic stabilization techniques, treatment of first-time dislocations is more controversial now than ever. It is well established that the younger a patient upon initial dislocation, the greater the chances of recurrent instability. Approximately two-thirds of patients younger than 30 years will suffer redislocation based on natural history studies. New arthroscopic techniques offer the potential to improve shoulder stability with lower morbidity than open procedures. However, recurrent instability after arthroscopic procedures is significantly greater than the 5% seen with open Bankart reconstruction, even for patients with chronic instability.1
Even though young patients with shoulder dislocations are likely to suffer recurrent instability, not all of these patients come to surgical stabilization. About two-thirds make lifestyle changes, have sufficiently infrequent episodes of instability, or tighten up with time enough that they manage quite well.2 Prospective, randomized studies are lacking that demonstrate a quality of life benefit to early stabilization beyond decreased recurrence rates compared to patients treated nonoperatively. This paper by Kirkley and associates addresses these issues.
Forty patients younger than 30 years of age with documented, first-time, traumatic, anterior shoulder dislocations were prospectively followed. Patients with multidirectional instability were excluded. Patients were randomized to nonoperative treatment with three weeks of immobilization followed by a prescribed rehabilitation protocol, or early arthroscopic stabilization (within four weeks) using a transglenoid suture technique, followed by the same three weeks of immobilization and subsequent rehabilitation protocol. Return to full-contact sports was allowed at four months for both groups. Randomization was stratified based on age (< 22 years and 22-30 years) and by surgeon to prevent unequal distributions between groups for these potential confounding variables.
Follow-up was available for 38 of 40 patients at a minimum of two years. Evaluation was performed in a blinded fashion. There was a statistically significant difference in the rate of recurrent instability between the two groups. For the surgical group, three of 19 patients (16%) suffered recurrent dislocations, compared to nine of 19 patients (47%) treated nonoperatively. Two patients in both groups had further subluxation events without dislocations. Redislocations tended to occur within the first year after the initial event for patients treated nonoperatively, while redislocations generally did not start to occur until one year after surgical treatment. Seven patients in the nonoperative group and three in the surgical group have had further surgery. There was a trend toward slightly diminished external rotation in the surgical group, but this did not reach statistical significance. One patient suffered a septic joint, postoperatively requiring arthroscopic surgical debridgement.
Patients were further evaluated for quality of life issues using the previously validated Western Ontario Shoulder Instability Index (WOSI), which assesses physical symptoms and pain, sport and work function, lifestyle and social function, and emotional well being. At a mean follow-up of approximately two months, there was a statistically significant difference in quality of life scores between the two groups. The mean score for the nonoperative group was 70% of normal, compared to 86% of normal for the surgical group. The subgroup of patients treated nonoperatively who never experienced further instability had mean scores that were only 85% of normal. The largest differences in scores between the two groups were seen for questions dealing with return to sport and work function with a 20% difference.
Comment by David R. Diduch, MS, MD
This paper by Kirkley et al is a welcome addition to the literature regarding the debate over treatment of initial shoulder dislocations. This is the first paper to truly randomize patients into operative and nonoperative treatment prospectively and evaluate the results in a blinded fashion. Another study by Arciero and colleagues prospectively followed patients with operative vs. nonoperative treatment, but patients selected their treatment group, potentially introducing bias.3 Interestingly, both papers report recurrent dislocations for the surgical groups of about 15%. The nonoperative treatment groups had further instability of 47% in Kirkley’s study vs. 80% in the study by Arciero et al. This is likely due to the mean age being younger (20 years vs 23 years) and the activity level being higher (U.S. Military Academy vs the general population) in Arciero et al’s study.
It is well established that the rate of further dislocation can be decreased by early surgical stabilization for first-time dislocators in this young, high-risk group. What previously has not been well established is that the quality of life can be improved as well. In addition to the careful study design, these outcome measurements represent the strength of this paper. Statistically significant differences in quality of life measurements, especially involving sport and work function, were noted between the two groups. Although not every patient will suffer further dislocations, apprehension and guarding alone can cause major changes in a patient’s lifestyle and activities. These outcome variables need to be examined in future studies, rather than just examining redislocation rates, to better assess any potential benefit of early surgical intervention.
Another important finding in this study is that redislocations begin later for surgical patients than for nonoperatively treated patients. It is likely that patients treated surgically have some protective stiffness initially and may be slower to resume full activities that put the shoulder at risk. Furthermore, some patients treated nonoperatively may improve with time due to activity modification, spontaneous tightening of the capsule, and strengthening of the rotator cuff as secondary stabilizers. These issues illustrate the need for long-term, prospective, randomized outcome studies.
Until arthroscopic stabilization techniques for initial dislocations have success rates approaching those of open stabilization for those patients with recurrent instability, it is likely that the debate will continue. This paper by Kirkley et al is an excellent addition to the literature that measures quality of life variables beyond simple redislocation rates. Ideally, Kirkley et al would have subdivided the results according to age, although a larger sample size may have been necessary to do this. It is possible that these issues of quality of life as well as recurrent instability would reveal more significant differences for younger patients that, in turn, would be more evident with long-term follow-up. It is likely that most surgeons will continue to opt for nonoperative management of first-time dislocators until such long-term studies are available.
References
1. Rowe CR, et al. The Bankart procedure: A long-term end-result study. J Bone Joint Surg Am 1978;6:1-16.
2. Hovelius L, et al. Primary anterior dislocation of the shoulder in young patients, a ten year prospective study. J Bone Joint Surg Am 1996;78:1677-1684.
3. Arciero RA, et al. Arthroscopic Bankart repair versus nonoperative treatment for acute, initial anterior shoulder dislocations. Am J Sports Med 1994;22(5): 589-594.
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