Question:
In patients with a primary traumatic anterior dislocation of the shoulder, is immobilization in external rotation more effective than in internal rotation in preventing recurrent dislocation?
Design:
Randomized (allocation not concealed), unblinded controlled trial with 4-year follow-up.
Setting:
Emergency department of a university hospital in Jerusalem, Israel.
Patients:
51 patients, 17 to 27 years old (mean age, 20 y; 100% men, 78% soldiers), who had sustained a traumatic anterior dislocation of the shoulder. Patients were excluded if the injury was received in a motor vehicle accident or if they had a concurrent fracture of the greater tuberosity. Patient follow-up was complete.
Intervention:
Patients were allocated to shoulder immobilization with an external (n = 27) or internal rotation brace (n = 24) after closed reduction of the initial dislocation with use of the Milch technique (41 patients) or the Hippocratic technique (10 patients). The external device immobilized the shoulder at 15° to 20° of external rotation. Patients in both groups had the shoulder immobilized for 4 weeks and then began a standard physiotherapy regimen.
Main outcome measures:
The primary outcome was recurrent dislocation.
Main results:
An 80% power calculation to detect a significant difference between groups was based on an expected dislocation rate of 50% in the internal rotation group, with a reduction to 10% in the external rotation group. The groups did not differ in regard to rates of recurrent dislocation (Table). Recurrent dislocation occurred at a mean of 13.8 months in the external rotation group and a mean of 12.4 months in the internal rotation group.
Conclusion:
In patients with a primary traumatic anterior dislocation of the shoulder, immobilization in external rotation is not different from immobilization in internal rotation in preventing recurrent dislocation.
In a compelling series of investigations over the past decade, Itoi et al. presented the original concept for the use of immobilization in external rotation (ER) following a shoulder dislocation, demonstrated cadaveric and basic-science evidence of its efficacy, and subsequently performed a randomized trial1-4. In the latest study4, patients who had the shoulder immobilized in the ER brace had a significantly lower incidence of recurrent instability compared with those who had been managed with a sling.
The randomized trial by Finestone et al. is an important contribution as it is the first independent clinical assessment of the ER bracing concept by investigators other than the originators. In a high-risk cohort of 51 young male patients, the ER brace did not demonstrate a benefit in preventing recurrent dislocation compared with a standard sling at an average of 33 months after the injury.
The study described only recurrent dislocation, omitting important measures of symptomatic subluxation, patient satisfaction, range of motion, and functionality. Although an a priori sample size calculation was performed, the authors were optimistic in their estimates of treatment effect and the study is admittedly underpowered. This is likely of little clinical importance, given the similarity of the event rates within the two groups. The study also did not provide the time interval between reduction of the dislocation and subsequent immobilization. Itoi et al. reported that a delay in the application of the ER brace may reduce its effectiveness.
While immobilizing shoulders in external rotation following a first-time dislocation has gained popularity, the study by Finestone et al. should prompt readers to be cautious in their approach to implementing this device in their practice pending further evidence.
References
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;81:385-90.[PubMed][CrossRef]
Itoi
E;
Sashi
R;
Minagawa
H;
Shimizu
T;
Wakabayashi
I;
Sato
K. Position of immobilization after dislocation of the glenohumeral joint. A study with use of magnetic resonance imaging. J Bone Joint Surg Am.
2001;83:661-7.[PubMed]
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 Elbow Surg.
2003;12:413-5.[PubMed][CrossRef]
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;89:2124-31.[PubMed] [CrossRef]