Importance of the Topic
Shoulder dislocations are the most-frequent major joint dislocation in adults ; more than 90% of them are traumatic anterior dislocations [13, 16]. Affecting predominantly men in their late teens or early 20s, shoulder dislocations commonly occur while playing contact sports, specifically those with high upper-extremity demand like rugby or American football .
After dislocation, the shoulder is less stable and more prone to re-dislocation, particularly in younger patients . After a closed reduction, most patients undergone conservative treatment being generally immobilized for 2 to 6 weeks, dependent on patient age, followed by physiotherapy rehabilitation. The typical immobilization protocol involves internal rotation with a sling. There is a trend towards shorter immobilization time  and, lately, interest has been focused on alternative immobilization protocols such as immobilization in external rotation of the shoulder [10, 14]. Theoretically, external rotation allows damaged structures to heal better by holding them closer to their anatomic position, therefore diminishing future re-dislocations and instability [10, 12]. Notwithstanding these theoretical advantages, few surgeons choose this alternative [1, 2] probably because of the compliance issues with external rotation bracing  and the lower cost and greater availability of internal rotation slings .
Although previous Cochrane reviews have addressed the non-surgical management of shoulder dislocation [7, 8],those reviewers  deemed the evidence insufficient as only one study (and, in the subsequent update , four trials), showed no difference between both immobilization positions at 2-year follow-up. Therefore, it seemed appropriate to update this review as new evidence emerged addressing immobilization position and duration of post-reduction immobilization.
Upon Closer Inspection
This updated Cochrane review  contains six randomized controlled trials and one quasi-randomized controlled trial involving a total 704 participants. Although the authors intended to incorporate trials addressing a variety of questions on the topic of non-surgical management of shoulder dislocations, the available trials compared only internal versus external rotation immobilization protocols, so the Cochrane review necessarily focused on that topic. Some aspects of the interventions differed slightly among the included randomized controlled trials, such as the timing of immobilization and the degree of external rotation and abduction, but despite sensitivity analyses that sought to address these differences, the Cochrane review could draw no firm conclusions about the superiority of one position of immobilization over the other.
While this update included three new randomized trials, there is considerable ongoing research on this topic that might be informative. The authors identified six unpublished, completed trials, as well as five more that are ongoing. When data from these become available, we expect greater clarity on this important topic.
Although this study included six randomized trials (compared with three in the prior Cochrane review ), the key finding remained the same: There was no difference with the numbers available between immobilization in external rotation compared to internal rotation with respect to the risk of repeat shoulder dislocation among the 488 patients in the pooled analysis (relative risk [RR] 0.67 [95% CI 0.38 to 1.19]; p = 0.17). Additionally, there was no evidence of a clinically relevant difference in patient-reported outcome measures (PROMs) for shoulder instability. However, the high degree of imprecision makes these results very uncertain. As re-dislocations are relatively infrequent, larger sample sizes are needed to obtain narrower confidence intervals. Furthermore, intervention effects on the resumption of pre-injury activities or sports remain uncertain. Although the young population (mean age: 29 years) and high percentage of men (82%) are typical for the injury, none of the trials specified the prevalence and/or characteristics of concurrent injuries within their samples, which makes the findings even harder to apply in practice.
Of note, Chan and colleagues  found that the external rotation group had more difficulties wearing the sling (27 out of 34 [79%]) than the internal rotation group (13 out of 28 [46%]; p = 0.007). Four studies reported adverse events and divided them into two groups: Transient/resolved and important adverse events. From the four studies, a total of nine patients out of 196 had shoulder stiffness in the external rotation group compared to two patients out of 181 who had an axillary rash in the internal rotation group (RR 2.73 [95% CI 0.83 to 9.02]; p = 0.10). These adverse events were considered transient and resolved. The authors found a total of three important adverse events: One out of 134 patients in the external rotation group and two out of 134 patients in the internal rotation group, but the difference was not significant (RR 0.61 [95% CI 0.08 to 4.46]; p = 0.62) .
Unfortunately, adverse events reports were done incompletely and ad hoc making it difficult to draw conclusions. Since there is still no conclusive evidence favoring external rotation over internal rotation, it is particularly important that future studies report harms and adverse events as an a priori outcome.
The ideal treatment following closed reduction remains controversial. Immobilization in internal rotation  and external rotation [9, 11] have their adherents, but this Cochrane review—which is the most-robust evidence now available—showed no clear advantage to one over the other in terms of efficacy, and it tended to suggest that external rotation may be more difficult for patients to tolerate.
Given that immobilization in external rotation may be less-well tolerated, the existing evidence does not support its routine use. However, the fact that we have identified six unpublished and five ongoing trials gives us some hope that soon we will have a more-definitive answer to this important question. Future research should try to address (1) immobilization duration, (2) immobilization protocol details, (3) timing to safely resume activities, and (4) rehabilitation protocol. In addition, future research also should pay particular attention to adverse effects and include PROMs, measures of validated health-related quality of life, treatment satisfaction, and cost-effectiveness analyses.
In light of current uncertainty, the choice of immobilization position should be driven by patients’ and surgeons’ preferences until more definitive data are available but keeping in mind that adverse events has been seen less frequently with the traditional sling in internal rotation.
1. Balke M, Shafizadeh S, Bouillon B, Banerjee M. Management of shoulder instability: The current state of treatment among German orthopaedic surgeons. Arch Orthop Trauma Surg. 2016;136:1717–1721.
2. Berendes TD, Pilot P, Nagels J, Vochteloo AJH, Nelissen RGHH. Survey on the management of acute first-time anterior shoulder dislocation amongst Dutch public hospitals. Arch Orthop Trauma Surg. 2015;135:447–454.
3. Braun C, McRobert CJ. Conservative management following closed reduction of traumatic anterior dislocation of the shoulder. Cochrane Database Syst Rev. 2019;5:CD004962.
4. Cameron KL, Mauntel TC, Owens BD. The epidemiology of glenohumeral joint instability: incidence, burden, and long-term consequences. Sports Med Arthrosc. 2017;25:144–149.
5. Chan SK, Bentick KR, Kuiper JH, Kelly CP. External rotation bracing for first-time anterior dislocation of the shoulder: A discontinued randomised controlled trial comparing external rotation bracing with conventional sling. Shoulder Elb. 2018:175857321876852.
6. Chong M, Karataglis D, Learmonth D. Survey of the management of acute traumatic first-time anterior shoulder dislocation among trauma clinicians in the UK. Ann R Coll Surg Engl. 2006;88:454–458.
7. Hanchard NC, Goodchild LM, Kottam L. Conservative management following closed reduction of traumatic anterior dislocation of the shoulder. Cochrane Database Syst Rev. 2014:CD004962.
8. Handoll HH, Hanchard NC, Goodchild LM, Feary J. Conservative management following closed reduction of traumatic anterior dislocation of the shoulder. In: Hanchard NC, ed. Cochrane Database of Systematic Reviews. Chichester, UK: John Wiley & Sons, Ltd; 2006:CD004962.
9. Heidari K, Asadollahi S, Vafaee R, Barfehei A, Kamalifar H, Chaboksavar ZA, Sabbaghi M. Immobilization in external rotation combined with abduction reduces the risk of recurrence after primary anterior shoulder dislocation. J Shoulder Elb Surg. 2014;23:759–766.
10. Itoi E, Hatakeyama Y, Kido T, Sato T, Minagawa H, Wakabayashi I, Kobayashi M. A new method of immobilization after traumatic anterior dislocation of the shoulder: A preliminary study. J Shoulder Elb Surg. 2013;12:413–415.
11. Itoi E, Hatakeyama Y, Sato T, Kido T, Minagawa H, Yamamoto N, Wakabayashi I, Nozaka K. Immobilization in external rotation after shoulder dislocation reduces the risk of recurrence. A randomized controlled trial. J Bone Joint Surg Am. 2007;89:2124–2131
12. Itoi E, Hatakeyama Y, Urayama M, Pradhan Rl, Kido T, Sato K. Position of immobilization after dislocation of the shoulder. A cadaveric study. J Bone Joint Surg Am. 1999;81:385–390.
13. Khiami F, Gérometta A, Loriaut P. Management of recent first-time anterior shoulder dislocations. Orthop Traumatol Surg Res. 2015;101:S51–S57.
14. Sullivan LG, Bailie R, Weiss N, Miller BS. An evaluation of shoulder external rotation braces. Arthrosc J Arthrosc Relat Surg. 2007;23:129–134.
15. Wasserstein DN, Sheth U, Colbenson K, Henry PDG, Chahal J, Dwyer T, Kuhn JE. The true recurrence rate and factors predicting recurrent instability after nonsurgical management of traumatic primary anterior shoulder dislocation: A systematic review. Arthrosc J Arthrosc. Relat Surg. 2016;32:2616–2625.
16. Youm T, Takemoto R, Park BK-H. Acute management of shoulder dislocations. J Am Acad. Orthop Surg. 2014;22:761–771.
17. Zacchilli MA, Owens BD. Epidemiology of shoulder dislocations presenting to emergency departments in the United States. J Bone Joint Surg Am. 2010;92:542–549.