Recognition & diagnosis
- Anterior dislocation (~95% of cases): arm held abducted and externally rotated, loss of the normal deltoid contour, anterior fullness. Usually a clear fall-onto-outstretched-arm or abduction-external-rotation mechanism.
- Posterior dislocation (easily missed): arm held adducted and internally rotated, unable to externally rotate; classically follows a seizure, electrocution or electroconvulsive therapy — the internal rotators (pectoralis major, latissimus dorsi, subscapularis) overpower the smaller external rotators. Up to half are missed on the first attendance if only an AP film is reviewed.
- Document a full neurovascular exam before any reduction attempt, including axillary nerve sensation (see below) and distal pulses.
Imaging pointers
Anterior
- Humeral head sits inferomedial to the glenoid on AP view.
- Look for an associated greater tuberosity or Hill-Sachs fracture.
Posterior
- The "lightbulb sign" — internal rotation makes the humeral head appear symmetrically round on AP view, like a lightbulb.
- An axillary or scapular-Y view confirms the diagnosis when suspected clinically.
Analgesia & preparation
- Titrated IV opioid ± procedural sedation for higher-force techniques or an anxious/distressed patient.
- Intra-articular local anaesthetic injection is a well-supported, lower-risk alternative to sedation for many patients and avoids the monitoring burden of sedation.
- Low-force techniques (below) are specifically designed to work with minimal or no analgesia, using slow, gentle, patient-relaxed movement rather than traction.
- Explain the plan, gain consent, and have a clear escalation plan if the first technique fails.
Reduction technique — anterior dislocation
Start with a low-force, non-traction technique. Reserve traction-countertraction for failure of these, and avoid forceful lever techniques (Kocher's, Hippocratic-foot-in-axilla) which carry higher fracture and neurovascular risk.
Cunningham technique (first-line, minimal analgesia)
Patient seated, arm fully adducted against the trunk with the elbow flexed to 90°. The operator gently massages the trapezius, deltoid and biceps while talking the patient through relaxing the shoulder girdle and gently retracting the shoulders back. Reduction often occurs spontaneously as the biceps and shoulder-girdle muscles relax, without traction.
External rotation technique
Supine, arm adducted at the side, elbow flexed to 90°. Slowly and gently externally rotate the forearm (using the forearm as a lever, not force) pausing at any resistance and waiting for muscle relaxation before continuing. Reduction typically occurs at 70–90° of external rotation, sometimes before full rotation is reached.
Scapular manipulation
Prone with the arm hanging free, or seated. Stabilise the scapular body and rotate the inferior tip medially while gently pushing the acromion down — this can be combined with gentle traction on the hanging arm.
Traction-countertraction (fallback)
Longitudinal traction on the affected arm with countertraction via a sheet around the chest, held by an assistant. Reserve for failure of the low-force techniques above; needs more analgesia/sedation and carries a higher risk of fracture and nerve injury than the gentle methods.
External rotation technique — arm position
Posterior dislocation — reduction principle
- Adduct and internally rotated arm; gentle traction is applied along the humeral axis with the arm slightly abducted, combined with anteriorly directed pressure on the humeral head from behind, and gradual external rotation once the head disengages.
- Post-seizure or post-electrocution dislocations are more often bilateral and more often associated with fracture — have a lower threshold for pre- and post-reduction imaging.
- Posterior dislocation reduction is generally higher-force and more often needs procedural sedation than a straightforward anterior reduction — involve seniors early if uncertain.
Post-reduction checks & aftercare
- Axillary nerve: test sensation over the "regimental badge" area (lateral upper arm, over deltoid) before and after reduction — the commonest nerve injured in shoulder dislocation.
- Reassess the full neurovascular exam and confirm the reduction clinically (restored contour, improved range of movement).
- Post-reduction X-ray to confirm reduction and identify any fracture caused by, or revealed by, the reduction.
- Immobilise in a broad arm sling (internal rotation) for comfort; duration and any specific positioning (e.g. slight external rotation splinting after first-time dislocation in younger patients) per local/orthopaedic guidance.
- Arrange physiotherapy and fracture-clinic or orthopaedic follow-up, particularly for first-time dislocation, older patients, or any associated fracture.
Associated injuries
- Bankart lesion — anteroinferior labral tear, a major cause of recurrent instability, especially in younger patients.
- Hill-Sachs lesion — posterolateral humeral head impaction fracture from impact against the glenoid rim.
- Greater tuberosity fracture — common with anterior dislocation; may reduce spontaneously with the shoulder or need separate management.
- Rotator cuff tear — increasingly likely with age; have a lower threshold to suspect cuff injury (persistent weakness, inability to actively abduct) in patients over about 40.
- Axillary nerve and, less commonly, axillary artery injury.
Supervision pointers
Not a formal RCEM DOPS item, but commonly assessed as a workplace-based procedural skill. Generic entrustment framework:
| 1 | Observed only — can describe anterior vs posterior presentation, and the low-force techniques. |
| 2a | Performs with direct supervision: correct pre-reduction neurovascular exam, selects an appropriate low-force technique first. |
| 2b | Performs with supervisor in the department: manages analgesia, technique selection and escalation to traction-countertraction if needed. |
| 3 | Indirect supervision: recognises and manages posterior dislocation, associated fractures, and failed reduction. |
| 4 | Independent; teaches and supervises trainees in technique selection and safety-netting. |
References
- Alkaduhimi H, et al. A systematic and technical guide on how to reduce a shoulder dislocation. Turk J Emerg Med 2016;16(4):155–168.
- Cunningham N. A new drug free technique for reducing anterior shoulder dislocations. Emerg Med (Fremantle) 2003;15(5-6):521-4; and subsequent published effectiveness series.
- RCEMLearning. Shoulder dislocation and reduction techniques.
- LITFL / AAEM-RSA. The lightbulb sign in posterior shoulder dislocation.