Anterior Shoulder dislocation

 

Common injury of young people playing contact sport, may progress to recurrent episodes of symptomatic instability.

 

Treatment

 

The usual treatment for a primary anterior dislocation is a short period of immobilisation followed by a programme of rehabilitation and a gradual return to full activity. In young high demand athletes with high energy traumatic dislocations, consideration could be given to primary arthroscopic stabilisation.

At present however the standard treatment remains non operative management.

 

Patients less than 40 (1)

 

30-90 % of  young patients (<30 years of age) may need operative stabilization. Some shoulders with recurrent dislocation become stable over time.

This finding of only 30 % needing surgery in a prospective 10 year follow up study throws questions on prophylactic operative treatment, in the young first time dislocator.
Evidence of a defect of the humeral head after primary dislocation is associated with a higher rate of recurrence.

The same degree of arthropathy is noted in the shoulders that have had recurrent or operatively treated dislocation as those with only one dislocation. Only 10% of the shoulders having a replacement for OA  are associated with recurrent dislocation.

 

In the over 40 age group (2)(5)

Recurrent dislocation occurs in 0-20% of cases.

Rotator cuff tears occur in 30-80% of cases. The persistence of significant pain or weakness 3 weeks after primary dislocation in this age group is an indication for further investigation (arthrography or ultrasound). Beware may have been pre-existing tear. In asymptomatic patients over 70 yrs up to 50% will have asymptomatic rotator cuff tears and in patients over 80, 80% will have asymptomatic tears.
 

Reduction method

Several relocation methods exist.

In the UK conventional practice is intravenous sedation and manipulation in A&E.

 

Recently reported is an interesting technique. (Shown to be safe and as effective)

An  intra-articular injection of 20 mL of 1% lidocaine, injected into the glenohumeral joint, from just off the lateral edge of the acromion, through a 20-gauge, 35-mm needle. The shoulder is then reduced by Stimsons technique, hanging the arm over the edge of the trolley with a weight on it. (6)

 

Immobilisation

Popular practice is to immobilise inside shirt (internal rotation) 3 weeks then in sling outside shirt for further 3 weeks (total 4 to 6 weeks). However some studies show no difference in long term if just treat symptomatically. (1) Perhaps one of the reasons the duration of immobilization inside a sling or shirt does not affect recurrence is because with internal rotation the anterior capsule and labrum ("Bankart lesion") floats away from the glenoid. In external rotation subscapularis becomes taught and coapts the "Bankart" lesion onto the glenoid rim. As shown in an MRI study of dislocated shoulders. (7)

 

Nerve injury (3,4)

The prognosis of nerve lesions after dislocations of the shoulder is favourable, it is not necessary to carry out EMG routinely. In cases of paralysis or severe paresis it is essential to perform an EMG at three weeks. If, after two to three months, no electrophysiological and or clinical improvement occurs, exploration should be undertaken.

The reported prevalence of nerve injury after anterior dislocation of the shoulder ranges from 5% to 55% this tends to increase with advancing age. The more actively you look for it the higher the incidence. The most common nerve injured is the axillary nerve 42%, suprascapular nerve 14%, radial nerve 7%, musculocutaneous nerve 12%, median nerve 4%, ulna nerve 8%. The presence of normal sensation does not exclude a motor injury.

Most nerve injuries will recover  near complete EMG and motor function within a period of 12 to 45 weeks. Ultimate shoulder function depends on active physiotherapy to maintain passive range of motion awaiting recovery.

 

Nerve injury associated with cuff tear.

Rotator cuff tears in association with anterior dislocation occurs in 30%-80% of elderly patients.

Bearing in mind in asymptomatic patients over 70 yrs up to 50% will have asymptomatic rotator cuff tears and in patients over 80, 80% will have asymptomatic tears.

In patients beyond retirement age:

If loss of abduction is due to a nerve lesion, muscle strength will recover spontaneously. If there is, in addition, a ruptured cuff, it is possible that the latter is  long standing. Furthermore, the symptoms of an acute rupture often resolve spontaneously.

In young patients:

With an extensive acute tear of the rotator cuff, restoration of the normal anatomy is important. In these cases, needle electrodiagnosis is essential in order to identify additional nerve lesions.

 

See recurrent instability


References

 

1. Primary Anterior Dislocation of the Shoulder in Young Patients. A Ten-Year Prospective Study . HOVELIUS, B. G. AUGUSTINI, H. FREDIN, O. JOHANSSON, R. NORLIN, and J. THORLING
JBJS - A-1996 78: 1677-84

 

2. Anterior dislocation of the shoulder in elderly patients; S. Gumina; F. Postacchini -JBJS -B1997 (79): 540-543

 

3. The incidence of nerve injury in anterior dislocation of the shoulder and its influence on functional recovery - C. P. J. Visser; L. N. J. E. M. Coene; R. Brand; D. L. J. Tavy - JBJS - B 1999 (81): 679-685

 

4. Isolated and combined lesions of the axillary nerve
C. Bonnard; D. J. Anastakis; G. van Melle; A. O. Narakas
JBJS - B 1999( 81); 2 : 212-21
 

5. C. M. Robinson, M. Kelly, and A. E. Wakefield
Redislocation of the Shoulder During the First Six Weeks After a Primary Anterior Dislocation: Risk Factors and Results of Treatment
J Bone Joint Surg Am 2002 84: 1552-1559

 

6. Suzanne L. Miller, Edmond Cleeman, Joshua Auerbach, and Evan L. Flatow
Comparison of Intra-Articular Lidocaine and Intravenous Sedation for Reduction of Shoulder Dislocations: A Randomized, Prospective Study
J Bone Joint Surg Am 2002 84: 2135-2139.

 

7. Eiji Itoi, Ryuji Sashi, Hiroshi Minagawa, Togo Shimizu, Ikuko Wakabayashi, and Kozo Sato
Position of Immobilization After Dislocation of the Glenohumeral Joint : A Study with Use of Magnetic Resonance Imaging
JBJS - A- 2001 83: 661-667

 


Last updated 10/04/2005
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