1. Dr. D. N. Bid MPT, PGDSPTSenior LecturerSarvajanik College of Physiotherapy, Surat

2. Of the large joints, the shoulder is the onethat most commonly dislocates. This is due to a number of factors: the shallowness of the glenoid socket; the extraordinary range of movement; underlying conditions such as ligamentous laxity orglenoid dysplasia; and the sheer vulnerability of the joint duringstressful activities of the upper limb. Here, acute anterior and posterior dislocations are described. 3. Dislocation is usually caused by a fall on the hand. The head of the humerus is driven forward, tearingthe capsule and producing avulsion of the glenoidlabrum (the Bankart lesion). Occasionally the posterolateral part of the head iscrushed. Rarely, the acromion process levers the headdownwards and the joint dislocates with the armpointing upwards (luxatio erecta); nearly always thearm then drops, bringing the head to its subcoracoidposition. 4. Pain is severe. The patient supports the arm with the oppositehand and is loathe to permit any kind ofexamination. The lateral outline of the shoulder may beattened and, if the patient is not too muscular, abulge may be felt just below the clavicle. The arm must always be examined for nerve andvessel injury before reduction is attempted. 5. Theanteroposterior x-ray will show the overlapping shadows of the humeral head and glenoid fossa, with the head usually lying below and medial to the socket. 6. A lateral view aimed along the blade of thescapula will show the humeral head out ofline with the socket. Ifthe joint has dislocated before, specialviews may show attening or an excavationof the posterolateral contour of the humeralhead, where it has been indented by theanterior edge of the glenoid socket, theHillSachs lesion. 7. Various methods of reduction have beendescribed, some of them now of no more thanhistorical interest. In a patient who has had previousdislocations, simple traction on the arm may besuccessful. Usually, sedation and occasionally generalanaesthesia is required. With Stimsons technique, the patient is left pronewith the arm hanging over the side of the bed. After 15 or 20 minutes the shoulder may reduce. 8. Inthe Hippocratic method, gently increasing traction is applied to the arm with the shoulder in slight abduction, while an assistant applies rm counter-traction to the body (a towel slung around the patients chest, under the axilla, is helpful). 9. WithKochers method, the elbow is bent to 90 and held close to the body; no traction should be applied. The arm is slowly rotated 75 degrees laterally, then the point of the elbow is lifted forwards, and nally the arm is rotated medially. This technique carries the risk of nerve, vessel and bone injury and is not recommended. 10. Another technique has the patient sitting on a reduction chair and with gentle traction of the arm over the back of the padded chair the dislocation is reduced. 11. Anx-ray is taken to conrm reduction and exclude a fracture. Whenthe patient is fully awake, active abduction is gently tested to exclude an axillary nerve injury and rotator cuff tear. Themedian, radial, ulnar and musculocutaneous nerves are also tested and the pulse is felt. 12. The arm is rested in a sling for about three weeks in those under 30 years of age (who are most prone to recurrence) and for only a week in those over 30 (who are most prone to stiffness). Thenmovements are begun, but combined abduction and lateral rotation must be avoided for at least 3 weeks. Throughout this period, elbow and nger movements are practised every day. 13. There has been some interest in the use of external rotation splints, based on the theory that this would reduce the Bankart lesion into a better position for healing. Howevera recent Cochrane review has concluded that there is insufcient evidence to inform on the choices for conservative treatment and that further trials are needed to compare different types and duration of immobilization. 14. Young athletes who dislocate their shouldertraumatically and who continue to pursue theirsports (particularly contact sports) are at a muchhigher risk of re-dislocation in the future. With increasing advances and techniques ofarthroscopy and arthroscopic anteriorstabilization surgery, some are now advocatingearly surgery in this group of patients to repairthe Bankart lesion of the anterior labrum. However a consensus on early surgery has stillnot been reached. 15. EARLYCOMPLICATIONS Rotator cuff tear: This commonly accompanies anterior dislocation, particularly in older people. The patient may have difculty abducting the arm after reduction; palpable contraction of the deltoid muscle excludes an axillary nerve palsy. Most do not require surgical attention, but young active individuals with large tears will benet from early repair. 16. Nerve injury: The axillary nerve is most commonly injured; thepatient is unable to contract the deltoid muscle andthere may be a small patch of anaesthesia over themuscle. The inability to abduct must be distinguished from arotator cuff tear. The nerve lesion is usually a neuropraxia whichrecovers spontaneously after a few weeks; if it doesnot, then surgery should be considered as the resultsof repair are less satisfactory if the delay is morethan a few months. 17. Occasionally the radial nerve, musculocutaneous nerve, median nerve or ulnar nerve can be injured. Rarely there is a complete infra-clavicular brachial plexus palsy. This is somewhat alarming, but fortunately it usually recovers with time. 18. Vascularinjury: The axillary artery may be damaged, particularly in old patients with fragile vessels. This can occur either at the time of injury or during overzealous reduction. The limb should always be examined for signs of ischaemia both before and after reduction. 19. Fracture-dislocation If there is an associated fracture of the proximalhumerus, open reduction and internal xation may benecessary. The greater tuberosity may be sheared off duringdislocation. It usually falls into place during reduction, and no specialtreatment is then required. If it remains displaced, surgical reattachment isrecommended to avoid later subacromial impingement. 20. LATE COMPLICATIONS Shoulder stiffness Prolonged immobilization may lead to stiffness of the shoulder, especially in patients over the age of 40. There is loss of lateral rotation, which automatically limits abduction. Active exercises will usually loosen the joint. They are practised vigorously, bearing in mind that full abduction is not possible until lateral rotation has been regained. Manipulation under anaesthesia or arthroscopic capsular release is advised only if progress has halted and at least 6 months have elapsed since injury. 21. Unreduceddislocation Surprisingly, a dislocation of the shoulder sometimesremains undiagnosed. This is more likely if the patient is either unconsciousor very old. Closed reduction is worth attempting up to 6 weeksafter injury; manipulation later may fracture the boneor tear vessels or nerves. Operative reduction is indicated after 6 weeks onlyin the young, because it is difcult, dangerous andfollowed by prolonged stiffness. 22. An anterior approach is used, and the vessels and nerves are carefully identied before the dislocation is reduced. Active neglect summarizes the treatment of unreduced dislocation in the elderly. The dislocation is disregarded and gentle active movements are encouraged. Moderately good function is often regained. 23. Recurrent dislocation If an anterior dislocation tears the shouldercapsule, repair occurs spontaneously followingreduction and the dislocation may not recur; but if the glenoid labrum is detached, or thecapsule is stripped off the front of the neck of theglenoid, repair is less likely and recurrence ismore common. Detachment of the labrum occurs particularly inyoung patients, and, if at injury a bony defect has been gouged out ofthe posterolateral aspect of the humeralhead, recurrence is even more likely. 24. In older patients, especially if there is a rotator cuff tear or greater tuberosity fracture, recurrent dislocation is unlikely. The period of post-operative immobilization makes no difference. 25. The history is diagnostic. The patient complains that the shoulder dislocates with relatively trivial everyday actions. Often he can reduce the dislocation himself. Any doubt as to diagnosis is quickly resolved by the apprehension test: if the patients arm is passively placed behind the coronal plane in a position of abduction and lateral rotation, his immediate resistance and apprehension are pathognomonic. 26. An anteroposterior x-ray with the shoulder medially rotated may show an indentation in the back of the humeral head (the HillSachs lesion). Even more common, but less readily diagnosed, is recurrent subluxation. 27. Posterior dislocation is rare, accounting for less than 2% of all dislocations around the shoulder. 28. Indirectforce producing marked internal rotation and adduction needs be very severe to cause a dislocation. This happens most commonly during a t or convulsion, or with an electric shock. Posterior dislocation can also follow a fall on to the exed, adducted arm, a direct blow to the front of the shoulder or a fall on the outstretched hand. 29. Thediagnosis is frequently missed partly because reliance is placed on a single anteroposterior x-ray (which may look almost normal) and partly because those attending to the patient fail to think of it. There are, in fact, several well-marked clinical features. 30. Thearm is held in internal rotation and is locked in that position. Thefront of the shoulder looks at with a prominent coracoid, but swelling may obscure this deformity; seen from above, however, the posterior displacement is usually apparent. 31. In the anteroposterior lm the humeral head, because it is medially rotated, looks abnormal in shape (like an electric light bulb) and it stands away somewhat from the glenoid fossa (the empty glenoid sign).A lateral lm and axillary view is essential; it shows posterior subluxation or dislocation and sometimes a deep indentation on the anterior aspect of the humeral head. 32. Posteriordislocationis sometimes complicated by fractures of the humeral neck, posterior glenoid rim or lesser tuberosity. Sometimesthe patient is too uncomfortable to permit adequate imaging and in these difcult cases CT is essential to rule out posterior dislocation of the shoulder. 33. The acute dislocation is reduced (usually under general anaesthesia) by pulling on the arm with the shoulder in adduction;a few minutes are allowed for the head of the humerus to disengage and the arm is then gently rotated laterally while the humeral head is pushed forwards. 34. Ifreduction feels stable the arm isimmobilized in a sling; otherwisethe shoulder is held widelyabducted and laterally rotated in anairplane type splint for 36 weeks toallow the posterior capsule to heal in theshortest position. Shoulder movement isregained by active exercises. 35. Unreduced dislocation At least half the patients with posterior dislocationhave unreduced lesions when rst seen. Sometimes weeks or months elapse before thediagnosis is made and up to two thirds of posteriordislocations are not recognised initially. Typically the patient holds the arm internally rotated;he cannot abduct the arm more than 7080degrees, and if he lifts the extended arm forwards hecannot then turn the palm upwards. 36. If the patient is young, or is uncomfortable andthe dislocation fairly recent, open reduction isindicated. This is a difcult procedure. It is generally done through a deltopectoralapproach; the shoulder is reduced and the defect in thehumeral head can then be treated bytransferring the sub-scapularis tendon into thedefect (McLaughlin procedure). 37. Alternatively, the defect on the humeral head canbe bone grafted. A useful technique for treating a defect smallerthan 40 per cent of the humeral head is totransfer of the lesser tuberosity together with thesubscapularis into the defect. For defects larger than this a hemiarthroplastymay be considered. Late dislocations, especially in the elderly, arebest left, but movement is encouraged. 38. Recurrent dislocation or subluxation 39. Inferior dislocation is rare but it demands early recognition because the consequences are potentially very serious. Dislocationoccurs with the arm in nearly full abduction/elevation. Thehumeral head is levered out of its socket and pokes into the axilla; the arm remains xed in abduction. 40. Theinjury is caused by a severe hyper- abduction force. With the humerus as the lever and the acromion as the fulcrum, the humeral head is lifted across the inferior rim of the glenoid socket; it remains in the subglenoid position, with the humeral shaft pointing upwards. 41. Soft-tissueinjury may be severe and includes avulsion of the capsule and sur- rounding tendons, rupture of muscles, fractures of the glenoid or proximal humerus and damage to the brachial plexus and axillary artery. 42. Thestartling picture of a patient with his arm locked in almost full abduction should make diagnosis quite easy. Thehead of the humerus may be felt in or below the axilla. Always examine for neurovascular damage. 43. The humeral shaft is shown in the abductedposition with the head sitting below the glenoid. It is important to search for associated fracturesof the glenoid or proximal humerus. NOTE: True inferior dislocation must not be confused withpostural downward displacement of the humerus, whichresults quite commonly from weakness and laxity of themuscles around the shoulder, especially after trauma andshoulder splintage; here the shaft of the humerus lies inthe normal anatomical position at the side of the chest. The condition is harmless and resolves as muscle tone isregained. 44. Inferior dislocation can usually be reduced bypulling upwards in the line of the abducted arm, withcounter-traction downwards over the top of theshoulder. If the humeral head is stuck in the soft tissues, openreduction is needed. It is important to examineagain, after reduction, for evidence of neurovascularinjury. The arm is rested in a sling until pain subsides andmovement is then allowed, but avoiding abductionfor 3 weeks to allow the soft tissues to heal. 45. Traumatic dislocation of the shoulder isexceedingly rare in children. Children who give a history of the shoulderslipping out almost invariably have eithervoluntary or involuntary (atraumatic) dislocationor subluxation. With voluntary dislocation, the child candemonstrate the instability at will. With involuntary dislocation, the shoulder slipsout unexpectedly during everyday activities. 46. Mostof these children have generalized joint laxity and some have glenoid dysplasia or muscle patterning disorders. Examination may show that the shoulder subluxates in almost any direction; x-rays may conrm the diagnosis. 47. Atraumatic dislocation should be viewed withgreat caution. Some of these children have behavioural ormuscle patterning problems and this is wheretreat-ment should be directed. A prolonged exercise programme may also help. Only if the child is genuinely distressed by thedisorder, and provided psychological factorshave been excluded, should one considerreconstructive surgery.