The humeral head sits beneath the glenoid rim with the greater tuberosity wedged underneath the rim. This results in the scapula tip winging out laterally and any movement of either humerus or scapula will see the other moving in tandem due to the fixing of the humeral head beneath the rim.
The patient presents with the humerus fixed in an elevated position. The patient is likely to be attempting to hold the arm up to limit pain and may be fatigued or distressed by this. The mechanism of dislocation is either a sudden force applied to the arm in full abduction (fall onto arm while elevated/abducted, wave hitting while body surfing with arm in this position), or a sudden pull during a fall (grabbing a banister when falling down stairs). Check the axillary nerve as this may be stretched during the dislocation
An AP X-Ray will show the humeral head sitting beneath the glenoid rim in slight internal rotation with the greater tuberosity wedged.
The technique involves reduction from an inferior to a subglenoid or subcoracoid position, followed by a second manoeuvre to complete full reduction. Note, the humeral head may reduce fully just with the first manoeuvre.
- Initial positioning and elevated/upwards adducted ‘hold’
- anterior/posterior movements
- scapular tip manipulation
Click below for a step by step video and demonstration on a patient (with thanks to Dr Brid Reale).
This is the position at which the stretch on the capsule is reduced, and the operator takes over control of the affected limb, allowing the patient to reduce their spasm. A stretched capsule provides a nauseating visceral type of pain so this can result in a marked reduction of pain and distress.
If your patient is too distressed or in pain to cooperate then you should sedate them prior to reduction.
Elevation and upwards adduction - the humeral head is moved closer to the glenoid rim using adduction, and the humerus is placed in a ‘hold.’
‘Hold’– from the starting elevated position this is a firm steady upwards adducted hold (not a pull) of the humerus which is designed to move the humeral head to the edge of the glenoid rim. Leaving the humerus abducted will exaggerate the wedging of the humeral head under the rim and exacerbate the capsular stretch. This position will take off some of the stretch from the capsule (reducing pain), and provide confidence to the patient that you have taken control of the limb. Once you are in this position, it can be useful to ask the patient their pain level, and explain again what you are going to do. Note, the more you pull (upwards traction), the more you will cause the scapula tip move laterally, which causes a more abducted angle between the humeral head and the glenoid rim, effectively wedging the head further under the rim.
This assists the ability of the humeral head to generate a small momentum and dislodge from beneath the rim. The head may reduce at this point. Fix the scapula tip while doing this.
The humeral head is wedged under the glenoid rim and the scapula is seen to move with any movement of the humeral head. The patient is unlikely to be able to voluntarily move their scapula out of the way, they may need some assistance from a second operator. Some traction along the line of the ‘hold’ can assist the dislodgement of the head at this point. Too much traction will also pull the scapula up, moving the tip laterally and further wedging the head. Traction in a direct upwards or abducted position will have the same effect.
Once the humeral head has reduced into a subcoracoid or subglenoid position you can then choose an appropriate anterior shoulder technique for completing the reduction.