Anterior Shoulder Dislocation - Dushan Atkinson FRCS Tr & Orth 15/2/2007

Egyptian tomb murals 3000 BC : manipulations resembling Kocher technique Hippocrates described oldest known reduction method and treated chronic shoulder instability with cautery of deep tissues of the anterior shoulder.

PubMed search back to 1980s

Incidence:

• USA 11.2 per 100,000 person-years
• Simonet 1984 Clinical Orthopaedics: 0.7% men; 0.3% women up to 70 years.
• Dutch study 17 per 100,000.
• Hovelius 1982 Clinical Orthopaedics. Swedish population. random sample of 2092, 18-70 yrs, reported dislocation (1.7%) M:F 3:1; M:F 9:1 21-30 yrs age group

> 50% of major joint dislocations in A&E.

Sex: Bimodal distrib Male 20-30 years (M:F 9:1); female 61-80 years (F:M 3:1).

A dolescents > children: weaker growth plates fracture before dislocation occurs.

In elderly: collagen fibres have fewer cross-links. joint capsule, tendons and ligs weaker so dislocation more likely. + increased frequency of falls

1) Anterior dislocations >95%

2) Posterior 4%: seizures: imbalance IRs (SSc LD, Pmaj) + ERs (Tmin InfSp)

3) Inferior (luxatio erecta) 0.5%. high incidence of complications . Axillary N - 60%, RC tears 80-100%, GT and pect major avulsion.

4) Superior and intrathoracic extremely rare. ass/wi ACJ, and tuberosity #s

Atraumatic instability: MDI, generalized hyperlaxity, Ehlers-Danlos, Marfans. Small/flat glenoid fossa, excessive anteversion or retroversion of the glenoid, weak RC muscles, NM disorders, psych illnesses, attention seeking behaviour <30 years, familial, bilateral. Avoid surgery- instability likely to recur.

Older patients less likely to have a Bankart lesion more likely to have RC tear, greater tuberosity fracture, or an avulsion of the capsule and subscapularis from the lesser tuberosity.

Younger patients more commonly have labral tears. Coracoid fractures may also occur as a result of an anterior dislocation or a difficult reduction attempt.

Rotator cuff tears rare in young. 30% > 40s; 80% in > 60s.

Greater tuberosity #s associated with a lower incidence of recurrent dislocations.

Closed reduction

Hippocratic= longitudinal traction on arm, countertraction to axilla, heel of foot.

Kocher= traction to elbow, ER humerus, adduct elbow to chest. NV and hum #s

ER method = flex elbow 90, slowly adduct arm. ER slowly, stop every few degs

Stimson= patient prone, arm hangs over bed edge, weight hanging from wrist.

Milch= Abduct arm while applying pressure to the humeral head. When fully abducted, ER and traction. success 72-89%, only 1/3 require sedation or analgesia.

Spaso= vertical traction while grasping wrist/forearm; Pat supine. Keep on traction as shoulder ER; push head posteriorly. Continual traction several mins overcomes spastic RC muscles; more relaxed when forward-flexed(at 90°). success rate 87.5%.

Qu.1) Duration of immobilization? Debatable.

Most recommend 3-4 weeks in patients < 30 years and 7-10 days if >30-40 years.

But…..

• Maeda J Orthop Sci 2002 Longer immobilization extends the "symptom-free" period following primary shoulder dislocation in young rugby players

Significant reduction in the recurrence rate from 78% to 44% at 1 year and from 85% to 69% at 2 years if the arm was immobilized for 4-7 weeks instead of 0-3 wks.

Recurrence-free period also extended from 4 to 14 months with longer treatment.

• Hovelius 1996 JBJS(A) Primary anterior dislocation of the shoulder in young patients. A 10 year prospective study

Duration of immobilization had no effect on the long-term recurrence rate.

Qu.2) Rehabilitation?

3 weeks of immobilization

3-4 weeks active assisted ROM with external rotation limited to 20°.

4-6 weeks Pendulum exercises and scapular retractions

7-8 weeks, active ROM. ER limited to 45°, isometric cuff strengthening.

9-12 weeks active ROM with terminal stretch, isotonics, and scapular strengthening.

3 months return to noncontact sports with no overhead.

4 months contact and overhead sports

Qu. 3) Which type immobilisation? Controversial

Traditionally, placed in sling with or without an immobilizer strap for 1-6 weeks. Internal rotation and adduction is the classic position of immobilization, avoiding external rotation and abduction.

But……

• Bonutti J Comput Assist Tomogr. 1993 Tense subscapularis keeps capsule in contact with the underlying bone structures in external rotation, whereas in internal rotation the subscapularis became redundant and the labrum and the capsule folded into the joint
• Perugia et al, JSES, 1996 112 shoulders. First time anterior dislocations

Group 1 - IR bandage for 3/52; at 4.2 years, the recurrence 74%

Group 2 - shoulder spica 60 deg abduction, at 4.2 years, the recurrence 21%

• Itoi JBJS(Am)1999 10 thawed fresh-frozen cadavers with simulated Bankart lesion.

Opening and closing of the lesion 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 full internal to full external rotation in 10-degree increments.

Best coapted positions were: Adduction + full IR to 30 degrees of ER.

30 degrees of f lexion or abduction tends to displace the labrum.