Transcript of "Dislocation of shoulder dnbid 2013"
Dr. D. N. Bid MPT, PGDSPT Senior LecturerSarvajanik College of Physiotherapy, Surat
Of the large joints, the shoulder is the one that 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 or glenoid dysplasia; • and the sheer vulnerability of the joint during stressful activities of the upper limb. Here, acute anterior and posterior dislocations are described.
Dislocation is usually caused by a fall on the hand. The head of the humerus is driven forward, tearing the capsule and producing avulsion of the glenoid labrum (the Bankart lesion). Occasionally the posterolateral part of the head is crushed. Rarely, the acromion process levers the head downwards and the joint dislocates with the arm pointing upwards (luxatio erecta); nearly always the arm then drops, bringing the head to its subcoracoid position.
Pain is severe. The patient supports the arm with the opposite hand and is loathe to permit any kind of examination. The lateral outline of the shoulder may be ﬂattened and, if the patient is not too muscular, a bulge may be felt just below the clavicle. The arm must always be examined for nerve and vessel injury before reduction is attempted.
The anteroposterior 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.
A lateral view aimed along the blade of the scapula will show the humeral head out of line with the socket. Ifthe joint has dislocated before, special views may show ﬂattening or an excavation of the posterolateral contour of the humeral head, where it has been indented by the anterior edge of the glenoid socket, the Hill– Sachs lesion.
Various methods of reduction have been described, some of them now of no more than historical interest. In a patient who has had previous dislocations, simple traction on the arm may be successful. Usually, sedation and occasionally general anaesthesia is required. With Stimson’s technique, the patient is left prone with the arm hanging over the side of the bed. After 15 or 20 minutes the shoulder may reduce.
Inthe Hippocratic method, gently increasing traction is applied to the arm with the shoulder in slight abduction, while an assistant applies ﬁrm counter-traction to the body (a towel slung around the patient’s chest, under the axilla, is helpful).
WithKocher’s method, the elbow is bent to 90° and held close to the body; no traction should be applied. Thearm is slowly rotated 75 degrees laterally, then the point of the elbow is lifted forwards, and ﬁnally the arm is rotated medially. This technique carries the risk of nerve, vessel and bone injury and is not recommended.
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.
Anx-ray is taken to conﬁrm reduction and exclude a fracture. When the 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.
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. this period, elbow and ﬁnger Throughout movements are practised every day.
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. However a recent Cochrane review has concluded that there is insufﬁcient evidence to inform on the choices for conservative treatment and that further trials are needed to compare different types and duration of immobilization.
Young athletes who dislocate their shoulder traumatically and who continue to pursue their sports (particularly contact sports) are at a much higher risk of re-dislocation in the future. With increasing advances and techniques of arthroscopy and arthroscopic anterior stabilization surgery, some are now advocating early surgery in this group of patients to repair the Bankart lesion of the anterior labrum. However a consensus on early surgery has still not been reached.
EARLY COMPLICATIONS Rotator cuff tear: • This commonly accompanies anterior dislocation, particularly in older people. • The patient may have difﬁculty 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 beneﬁt from early repair.
Nerve injury: • The axillary nerve is most commonly injured; the patient is unable to contract the deltoid muscle and there may be a small patch of anaesthesia over the muscle. • The inability to abduct must be distinguished from a rotator cuff tear. • The nerve lesion is usually a neuropraxia which recovers spontaneously after a few weeks; if it does not, then surgery should be considered as the results of repair are less satisfactory if the delay is more than a few months.
• 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.
Vascular injury: • 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.
Fracture-dislocation • If there is an associated fracture of the proximal humerus, open reduction and internal ﬁxation may be necessary. • The greater tuberosity may be sheared off during dislocation. • It usually falls into place during reduction, and no special treatment is then required. • If it remains displaced, surgical reattachment is recommended to avoid later subacromial impingement.
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.
Unreduced dislocation • Surprisingly, a dislocation of the shoulder sometimes remains undiagnosed. • This is more likely if the patient is either unconscious or very old. • Closed reduction is worth attempting up to 6 weeks after injury; manipulation later may fracture the bone or tear vessels or nerves. • Operative reduction is indicated after 6 weeks only in the young, because it is difﬁcult, dangerous and followed by prolonged stiffness. •
• An anterior approach is used, and the vessels and nerves are carefully identiﬁed 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.
Recurrent dislocation • If an anterior dislocation tears the shoulder capsule, repair occurs spontaneously following reduction and the dislocation may not recur; • but if the glenoid labrum is detached, or the capsule is stripped off the front of the neck of the glenoid, repair is less likely and recurrence is more common. • Detachment of the labrum occurs particularly in young patients, and, • if at injury a bony defect has been gouged out of the posterolateral aspect of the humeral head, recurrence is even more likely.
• 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.
• 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 patient’s arm is passively placed behind the coronal plane in a position of abduction and lateral rotation, his immediate resistance and apprehension are pathognomonic.
• An anteroposterior x-ray with the shoulder medially rotated may show an indentation in the back of the humeral head (the Hill–Sachs lesion).• Even more common, but less readily diagnosed, is recurrent subluxation.
Posteriordislocation is rare, accounting for less than 2% of all dislocations around the shoulder.
Indirectforce producing marked internal rotation and adduction needs be very severe to cause a dislocation. happens most commonly during a ﬁt or This convulsion, or with an electric shock. Posterior dislocation can also follow a fall on to the ﬂexed, adducted arm, a direct blow to the front of the shoulder or a fall on the outstretched hand.
The diagnosis 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.
Thearm is held in internal rotation and is locked in that position. Thefront of the shoulder looks ﬂat with a prominent coracoid, but swelling may obscure this deformity; seen from above, however, the posterior displacement is usually apparent.
Inthe anteroposterior ﬁlm 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 ﬁlm and axillary view is essential; it shows posterior subluxation or dislocation and sometimes a deep indentation on the anterior aspect of the humeral head.
Posterior dislocation is sometimes complicated by fractures of the humeral neck, posterior glenoid rim or lesser tuberosity. Sometimes the patient is too uncomfortable to permit adequate imaging and in these difﬁcult cases CT is essential to rule out posterior dislocation of the shoulder.
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.
Ifreduction feels stable the arm is immobilized in a sling; otherwise the shoulder is held widely abducted and laterally rotated in an airplane type splint for 3–6 weeks to allow the posterior capsule to heal in the shortest position. Shoulder movement is regained by active exercises.
Unreduced dislocation At least half the patients with posterior dislocation have ‘unreduced’ lesions when ﬁrst seen. Sometimes weeks or months elapse before the diagnosis is made and up to two thirds of posterior dislocations are not recognised initially. Typically the patient holds the arm internally rotated; he cannot abduct the arm more than 70–80 degrees, and if he lifts the extended arm forwards he cannot then turn the palm upwards.
If the patient is young, or is uncomfortable and the dislocation fairly recent, open reduction is indicated. This is a difﬁcult procedure. It is generally done through a deltopectoral approach; the shoulder is reduced and the defect in the humeral head can then be treated by transferring the sub-scapularis tendon into the defect (McLaughlin procedure).
Alternatively, the defect on the humeral head can be bone grafted. A useful technique for treating a defect smaller than 40 per cent of the humeral head is to transfer of the lesser tuberosity together with the subscapularis into the defect. For defects larger than this a hemiarthroplasty may be considered. Late dislocations, especially in the elderly, are best left, but movement is encouraged.
Inferior dislocation is rare but it demands early recognition because the consequences are potentially very serious. Dislocation occurs with the arm in nearly full abduction/elevation. Thehumeral head is levered out of its socket and pokes into the axilla; the arm remains ﬁxed in abduction.
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.
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.
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.
The humeral shaft is shown in the abducted position with the head sitting below the glenoid. It is important to search for associated fractures of the glenoid or proximal humerus. • NOTE: True inferior dislocation must not be confused with postural downward displacement of the humerus, which results quite commonly from weakness and laxity of the muscles around the shoulder, especially after trauma and shoulder splintage; here the shaft of the humerus lies in the normal anatomical position at the side of the chest. • The condition is harmless and resolves as muscle tone is regained.
Inferior dislocation can usually be reduced by pulling upwards in the line of the abducted arm, with counter- traction downwards over the top of the shoulder. If the humeral head is stuck in the soft tissues, open reduction is needed. It is important to examine again, after reduction, for evidence of neurovascular injury. The arm is rested in a sling until pain subsides and movement is then allowed, but avoiding abduction for 3 weeks to allow the soft tissues to heal.
Traumatic dislocation of the shoulder is exceedingly rare in children. Children who give a history of the shoulder ‘slipping out’ almost invariably have either voluntary or involuntary (atraumatic) dislocation or subluxation. With voluntary dislocation, the child can demonstrate the instability at will. With involuntary dislocation, the shoulder slips out unexpectedly during everyday activities.
Most of 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 conﬁrm the diagnosis.
Atraumatic dislocation should be viewed with great caution. Some of these children have behavioural or muscle patterning problems and this is where treat-ment should be directed. A prolonged exercise programme may also help. Only if the child is genuinely distressed by the disorder, and provided psychological factors have been excluded, should one consider reconstructive surgery.
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