Dr Khahliso Mofokeng 25 February 2012

 24 year old midfield soccer player.  C/O left shoulder pain of sudden onset.  Fell on his left shoulder following a tackle.  2 nd episode according to him.  Similar incident a year ago.  Sent for an X-Ray and anterior shoulder dislocation confirmed.  Without fracture.  Successful closed reduction was done.

 In a couple of weeks he resumed his play.  No other history of note. O/E Healthy looking and in pain. Tramadol 50mg po stat. Reduced ROM left shoulder joint esp. internal rotation. Neurovascular intact. Prominent left acromion process. Differential Diagnoses Shoulder dislocation/subluxation/Humeral fracture.

 X-Ray showed anterior left shoulder dislocation without any fracture.  Closed reduction done to alleviate pain.  Left arm supported in a sling.  Orthopaedic appointment arranged.  MRI confirmed Bankart lesion and no Hill- Sachs lesion.  No sport activity until properly treated.  In 10 days open Bankart repair performed.  Return to play in 3 months following rehabilitation.

 Biologically the player is bothered by this recurrent shoulder dislocation with its pain.  Psychologically the player is worried that his arm might be permanently disabled so reducing his chances of playing sport.  Socially his main concern is loss of income as a result of this injury since he is the sole breadwinner at home.

Epidemiology  Occurs frequently in athletes with peaks in the 2 nd & 6 th decades.  98% of traumatic cases are anterior. dislocations.  2% posterior.  Trauma contributes about 95% of primary shoulder dislocations.

 5% atraumatic e.g. raising the arm or moving during sleeping.  Primary dislocation complicates into recurrent dislocation.  70% of those who have already dislocated are likely to redislocate within two years.  Comparable incidence of primary shoulder dislocation in young & old.  The incidence of recurrence is higher in younger people.

Static shoulder restraints refer to the bony ball and socket configuration of the shoulder and the major soft tissues holding these bones together. The soft tissues include the capsule, the glenohumeral ligament and the glenoid labrum. Dynamic shoulder restraints refer to the neuromuscular system, plus proprioceptive mechanisms & scapulohumeral muscles.

Superior glenohumeral ligament (SGHL) primarily limits anterior and inferior translation of the adducted humerus. Middle glenohumeral ligament (MGHL) primarily limits anterior translation in the lower and middle ranges of abduction. Inferior glenohumeral (IGHL) is the longest and the strongest of the glenohumeral ligaments. IGHL is the primary restraint against anterior, posterior & inferior translations when the humerus is abducted beyond 45 degrees.

The labrum constitutes the fibrocartilagenous rim of the glenoid. Inferiorly it is firmly attached to the glenoid, although it may be loose and mobile anterosuperiorly. The labrum increases resistance to glenohumeral translation by up to 20%. The labrum provides attachment of the glenohumeral ligaments anteriorly, and the biceps tendon superiorly.

Rotator cuff works in a combined synergistic action to create a compressive force at the glenohumeral joint during shoulder movement. The biceps assist the rotator cuff in creating glenohumeral joint compression. Synchronous scapular rotation and humeral elevation is prerequisite for obtaining optimal alignment of the glenoid fossa and humeral head.

Scapulothoracic muscles serve to stabilize the scapula to the thorax since there are no scapulothoracic ligamentous restraints. Stability of the scapula in relation to the moving upper extremity provides a secure platform for the glenohumeral articulation and action of attaching humeral muscles. Proprioceptive mechanisms involving reflective muscular action may protect against excessive translations and rotations of the glenohumeral joint.

Mechanoreceptors (ruffinian and pacinian corpuscles) within capsuloligamentous restraints of the shoulder joint. These specialized nerve endings relay afferent information relating to joint position and joint motion awareness (proprioception) to the central nervous system. The perceived sensation of shoulder joint position and movement is likely to play an important role in coordinating muscular tone and control. It has been suggested that joint instability secondary to trauma may be associated with a decrease in proprioceptive reflexes and thus a predisposition to subsequent reinjury.

 The most common mechanism of anterior shoulder dislocation has been described as forced external rotation and abduction of the humerus e.g. basketball player.  Others include a fall onto outstretched arm and direct force application to the posterior aspect of the humeral head.

 The most significant in terms of recurrent instability are those associated with the inferior glenohumeral ligament complex and its attachment to the labrum and humerus.  Bankart lesion (anterior labral detachment).  Detachment of the anterior labrum and plastic deformation of the capsule and inferior glenohumeral ligament complex contribute to increased anterior humeral translation.

 The most common bony lesion associated with traumatic glenohumeral instability is a compression fracture at the posterolateral margin of the humeral head.  This occurs as the humeral head impacts into the glenoid edge during dislocation.  Hill Sach’s lesion contributes about 80% of traumatic dislocations.  Proprioceptive defects have been shown for patients with traumatic anterior shoulder dislocation.

 The high incidence of recurrent shoulder dislocation in the adolescent population as opposed to recurrence in those over 40 years of age may be explained, in part, by the collagen profile of the encapsulating shoulder tissues.  Collagen is the major protein of ligaments and tendons.  Collagen type I versus III.  Collagen III which is elastic is found in younger individuals hence recurrent shoulder dislocation in this age group.  Collagen I which is non-elastic is found in those over 40 years of age.

Minimal force required and is rare. Multidirectional and less associated with Bankart lesion. Increase in humeral translation and decrease in upward rotation of the glenoid fossa. Deficiency in the rotator cuff interval. Connective tissue abnormalities.

 Chronic stress associated with repetitive overhead sports.  Athletes doing throwing, volleyball and tennis.  Extreme external rotation with the humerus abducted and extended in the horizontal plane.  Repetitive glenohumeral capsular overload in this position of extreme range of motion leads to gradual attenuation of the anteroinferior static restraints, increased glenohumeral translation and a continuum of shoulder pathology.

Primary Traumatic Ant Shoulder Dislocation  Shoulder immobilization 4 to 6 weeks.  High recurrence rate in younger athletes.  Lack of capsulolabral glenoid contact.  Activity restriction 6 to 8 weeks is associated with better outcome.  Exercise rehabilitation program.  Strengthening of rotator cuff, deltoid & scapular stabilizer muscles.

 Shoulder strengthening & coordination exercises.  Rotator cuff and deltoid control glenohumeral joint translation.  Infraspinatus and teres minor strengthening reduces anterior glenohumeral ligament strain during throwing.  Strengthening exercises for biceps brachii, latissimus dorsi, pectoralis major and teres major enhance stabilizing action of rotator cuff muscles at the glenohumeral joint.

1)Stabilizing scapulothoracic articulation:  Isometric exercises and manual stabilization techniques. 2)Restoring normal patterns of scapular muscle activity:  Upper extremity weight-bearing activities. 3)Maximizing scapulothoracic muscle strength and endurance preparing for return to play.  Resistance exercises, plyometric exercises and sport-specific drills.

1) Traumatic Unidirectional Instability Reattach detached labrum and associated glenohumeral ligaments with little disruption to the length or attachment of other structures around the shoulder (Bankart repair). Open Bankart repair associated with a 12 degree loss of external rotation of the shoulder secondary to shortening of the subscapularis tendon during detachment-reattachment. Redislocation rate 11%.

 Reattach the labrum without an open incision and without subscapularis detachment.  Redislocation rate of 18%.  Less loss in external rotation of the shoulder. Multidirectional Instability Anterior capsular shift, an open procedure involving overlaying and shortening of the anterior and inferior capsule. Activity restriction and strict range of motion control post-operatively.

 Similar principles as non-operative rehabilitation.  Cryotherapy applied for 15 minutes every 1to 2 waking hours for the first 24 hours, and 4 to 6 times daily for 9 days reduces the frequency and intensity of shoulder pain both at rest and during rehabilitation.  Activity restriction.  Isometric, rotator cuff & humeral muscle strength exercise.  Scapulothoracic muscle retrainig.  Proprioception (neuromuscular & cardiovascular) for return to normal.

 Hayes K, Callanan M, Walton J, Paxinos A, Murrell GAC. Shoulder Instability: Management and Rehabilitation. J of Orthop & Sports Phys Ther. 2002;32(10):1-10.  Kogon PL. Hill-Sachs lesion – a complication of glenohumeral joint dislocation. JCCA. 1988; 32 (2):89-90.

Shoulder dislocation if not treated properly at the beginning can pose serious complications leading to athlete frustration. Early referral can reduce shoulder dislocation recurrence rate dramatically. I thank you all. Dr Khahliso Mofokeng ( )