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Three Part Question

[In patients with primary anterior shoulder disclocation] is [immobilisation in internal or external rotation] better at [reducing redislocation rates]

Clinical Scenario

A 25 year old man presents to the emergency department with a first left anterior shoulder dislocation. This is reduced satisfactory under sedation. You decide to put the patient in a collar and cuff in internal rotation (as you have always done). However, your emergency department physio suggests that it should be placed in external rotation. You wonder why?

Search Strategy

Medline 1966 to June 2005 using the OVID interface; Embase 1996 to week 31, 2005: Cochrane 2005, Issue 3.
[shoulder dislocation.mp. or exp Shoulder Dislocation/] and [exp Immobilization/or immobilisation.mp. or exp Casts, Surgical/] and [external.af.].
Cochrane: "shoulder dislocation external".

Search Outcome

Medline: 15 papers found of which four were relevant. See table. Embase: nine papers found, no new references found. Cochrane: 23 citations, no new references found.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Itoi et al, 1999, Japan	Cadaveric study.Ten thawed fresh-frozen cadaveric shoulders with all of the muscles removed. A simulated Bankart lesion was created. Linear transducers attached to the anteroinferior and inferior portions of the Bankart lesion, the opening and closing of the lesion were recorded with the arm in 0, 30, 45, and 60 degrees of elevation in the coronal and sagittal planes as well as with the arm in rotation from full internal to full external rotation in 10-degree increments.	Laboratory Trial	Position of Bankart Lesion to Glenoid	The best coapted positions were 1. adduction plus full internal rotation to 30 degrees of external rotation. 2. 30 degrees of flexion or abduction, neutral and internal rotation	Cadaveric. Theoretical rather than actual clinical outcome.
Itoi et al, 2001, Japan	19 patients with shoulder dislocations.Magnetic resonance imaging, with the arm held at the side of the trunk and positioned first in internal rotation (mean, 29 degrees) and then in external rotation (mean, 35 degrees), in nineteen shoulders	Prospective study.	Position of Bankart Lesion to Glenoid	Separation and displacement of the labrum were both significantly less (p = 0.0047 and p = 0.0017, respectively) when the arm was in external rotation than when it was in internal rotation.	13 shoulders were recurrent dislocations and 6 acute, thus not same.
Itoi et al, 2003, Japan	40 patients with initial shoulder dislocations.Randomised into internal rotation (IR) immobilization and external rotation (ER) immobilization.	Prospective, Randomised study.	Recurrent dislocation rate.	The recurrence rate was 30% in the IR group and 0% in the ER group at a mean 15.5 months.	Early results. Immobilisation position may achieve less compliance in clinical practice.
Miller BS et al, 2005, Australia	10 cadaveric shoulder girdles stripped of major muscles (but rotator cuff intact) and a surgical Bankart lesion fashioned. Contact force was measured between glenoid and humerus in a variety of positions	Laboratory trial	Contact forces in different positions	No contact force in internal rotation. Maximum contact force when arm at 45 degrees of external rotation	Cadaveric. Does not take account of other damage that may occur following a dislocation. Theoretical rather than clinical outcome

Comment(s)

Standard teaching has been to immobilise patients with anterior shoulder dislocations in internal rotation, typically using a collar and cuff system. These interesting studies question this perceived wisdom and suggest that external rotation may be a better position. There is only one clinical study here that suggests good results, though the follow up for the clinical study was short and the position of external rotation immobilisation may not achieve such good compliance in clinical practice.

Clinical Bottom Line

For patients with a first anterior shoulder dislocation immobilisation in external rotation may be of more benefit than immobilisation in internal rotation.

Level of Evidence

Level 3 - Small numbers of small studies or great heterogeneity or very different population.

References

1. Itoi E, Hatakeyama Y, Urayama M et al. Position of immobilization after dislocation of the shoulder. A cadaveric study. J Bone Joint Surg Am 1999;81(3): 385-90.
2. Itoi E, Sashi R, Minagawa H et al. Position of immobilization after dislocation of the glenohumeral joint. A study with use of magnetic resonance imaging. J Bone Joint Surg Am 2001; 83-A(5): 661-7.
3. Itoi E, Hatakeyama Y, Kido T et al. A new method of immobilization after traumatic anterior dislocation of the shoulder: a preliminary study. J Shoulder Elbow Study 2003;12(5): 413-5.
4. Miller BS, Sonnabend DH, Hatrick C et al. Should acute anterior dislocations of the shoulder be immobilized in external rotation? A cadaveric study. J Shoulder Elbow Surg 2004;13:589–92.