Shoulder Complex (Part III) - Anterior/Posterior/Multidirectional Dislocations & Exercise Rehabilitation

Traumatic Anterior Dislocation

Anterior Dislocation

Mechanism:

• Accounts for 75-95% of dislocations
• Forced abduction and external rotation of the shoulder (eg. basketball player attempting to block an overhead pass - watch video here)

Initial Presentation:

• Severe pain
• Lateral outline of shoulder flattened
• Possible bulge under acromion
• Possible nerve +/- vessel injury

Structures affected:

• Bankart lesion (humeral head driven forward --> anterior labral detachment, capsule tear)
• Hill-Sachs lesion (compression fracture at posterolateral margin of humeral head)
• Possible associated fracture of proximal humerus, anterior glenoid and disruption of glenohumeral ligaments

Conservative (non-operative) Management:

1. Reduction (under anaesthesia)

2. Immobilisation in sling for 1-3 weeks

    - No difference in recurrence between immobilisation of 0/52 vs 6/52

    - Recent studies suggest better approximation (less separation and displacement) between the  

      labrum and glenoid in adduction and external rotation (mean ER 35 deg) as opposed to the

      conventional adduction and internal rotation (Itoi et al 2001)

3. Activity restriction

    - 6-8/52 of activity restriction produced better results in the resolution of symptomatic shoulder

      instability compared to less than 6/52

4. Exercise rehabilitation

    - Restore glenohumeral joint stability

    - Retrain synchronous and coordinated scapulohumeral rhythm

    - Restore and retrain proprioception

Surgical Management:

1. Open Bankart Repair:

    - Gold standard

    - Detachment-reattachment of the humeral insertion of 

      subscapularis

    - Reattachment of labrum to anterior glenoid with sutures through 
      bone or with suture anchors

    - Surgeons may also tighten the anterior capsule

    - Associated with a 12 deg loss of external rotation (secondary to 

      shortening of subscapularis tendon after detachment-

      reattachment) (Gill et al 1997)

2. Arthroscopic Repair:

    - Reattachment of labrum without an open incision

    - No detachment of subscapularis

    - Smaller loss of external rotation

Post-Operative Physiotherapy Management:

Day One:

    - Range of motion exercises for neck, elbow, wrist, hand

    - Posture and positioning advice

1-2/52 (as pain allows):

    - Pendular exercises, active-assisted ROM, gentle isometric exercises (care with internal rotation).

    - NB. Avoid combined external rotation and abduction for 6 weeks

3-4/52 or as instructed by surgeon:

    - Active external rotation to neutral (or up to 30 deg)

6-8/52 + (as per non-operative management principles):

    - Muscle strengthening of rotator cuff and scapular stabilisers (theraband, free weights, resistance 

      machines eg. rower, upright rows, lat pull-downs)

    - Scapulohumeral rhythm training and facilitation (lower traps, serratus anterior, postural muscles)

    - Closed-chain proprioceptive exercises (wobble board, ball, joint positioning)

    - Sport-specific activities and technique correction

Posterior Instability (2-5% of dislocations)

Mechanism:

• Forced internal rotation and slight adduction (watch video here)
• Direct trauma to front of shoulder driving humeral head posteriorly
• Fall on outstretched arm
• May occur after an epileptic fit or electric shock

Normal                                        Posterior Dislocation

Initial Presentation:

• Arm held in internal rotation and adduction
• Loss of normal roundness of anterior shoulder
• Prominence of humeral head on posterior shoulder
• Limitation of external rotation due to severe pain

Non-operative Management:

• Reduction (under anaesthesia)
• Immobilisation in 20 deg of external rotation (up to 6/52)
• Activity restriction
• Exercise rehabilitation

Physiotherapy Management:

• Restore painless ROM
• Strengthening of rotator cuff and scapular stabilisers
• Restore and retrain normal scapulohumeral rhythm and proprioception
• NB for posterior instability - avoid combined internal rotation and adduction for 6/52

Multidirectional Instability (instability in 2 or more planes)

Clinical Presentation:

• Vague symptoms, no to little pain
• Complaining of "looseness"
• Positive inferior sulcus sign

Structural Involvement:

• Generalised laxity in multiple joints
• Weak rotator cuff muscles
• Poor scapulohumeral rhythm and control

Surgical Management:

• Anterior capsule shift (open repair with overlaying and shortening of the anterior and inferior capsule)

Physiotherapy Management:

• Progressive resisted strengthening of rotator cuff muscles
• Scapular stabilisation
• Re-education and retraining of scapulohumeral rhythm
• Proprioceptive exercises

Exercise Rehabilitation

Research Evidence

Goals of Exercise Rehabilitation:

1. Restore glenohumeral joint stability

2. Retrain synchronous and coordinated scapulohumeral rhythm

3. Restore and retrain proprioception

References:

1. Bradley and Tibone (1991) Electromyographic analysis of muscle action about the shoulder. Clnical Sports Medicine 10: 789-805.
2. Carmichael and Hart (1985) Anatomy of the shoulder joint. J Orthop Sports Phys Ther 6:225-228.
3. Chen et al (1999) Radiographic evaluation of glenohumeral kinematics: a muscle fatigue model. Journal of Shoulder and Elbow Surgery 8: 49-52.
4. Dang (2007) The nonoperative management of shoulder instability. JAAPA 20(3): 32-38.
5. Hayes et al (2002) Shoulder instability: management and rehabilitation. J Orthop Sports Phys Ther  32:1-13.
6. Gibson et al (2004) The effectiveness of rehabilitation for nonoperative management of shoulder instability: a systematic review. Journal of Hand Therapy 17:229-242.
7. Gill et al (1997) Bankart repair for anterior instability of the shoulder. Long-term outcome. Journal of Bone and Joint Surgery American 79: 850-857.
8. toi et al (2001) Position of immobilization after dislocation of the glenohumeral joint. A study with use of magnetic resonance imaging. Journal of Bone and Joint Surgery American 83A: 661-667.
9. Kronberg and Brostrom (1995) Electromyographic recordings in shoulder muscles during eccentric movements. Clinical Orthopaedics and Related Research 143-151.
10. Rowe (1956) Prognosis in dislocations of the shoulder. Journal of Bone and Joint Surgery 38A: 957-977.
11. Simonet and Cofield (1984) Prognosis in anterior shoulder dislocation. Am J Sports Med 12: 19-24.
12. Vangsness et al (1995) Neural anatomy of the glenohumeral ligaments, labrum, and subacromial bursa. Arthoscopy 11: 180-184.
13. Warner et al (1996) Role of proprioception in pathoetiology of shoulder instability. Clin Orthop 35-39.