Inferior Dislocation of the Shoulder (Luxatio Erecta Humeri) Associated with Fracture and Transient Neurovascular Compromise

Transcription

1 J Med Sci ;():5- Copyright JMS Hsieh-Hsing Lee, et al. Inferior Dislocation of the Shoulder (Luxatio Erecta Humeri) Associated with Fracture and Transient Neurovascular Compromise Hsieh-Hsing Lee, Kuo-Hua Chao *, and Shing-Sheng Wu Department of Orthopedics, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China Inferior dislocation of the shoulder, also known as luxatio erecta humeri, is extremely rare with an incidence reported to be.5% of all shoulder dislocations. The injury can occur in any age group and present in a unique and unusual fashion. The injury is most often unilateral. Several degrees of neurovascular injuries may be associated with the injury. Concomitant fracture of the coracoid, clavicle, acromion, greater tuberosity, and humeral head may also be noted. We report a case in which inferior dislocation of the shoulder occurred with an avulsion fracture of the greater tuberosity and transient neurovascular compromise. Key words: inferior shoulder dislocation, luxatio erecta, neurovascular compromise INTRODUCTION Luxatio erecta humeri occurs mainly as the result of severe abduction force of the arm. The neck of the humerus is levered against the acromion and the inferior capsule tears as the hemural head is forced out inferiorly. The other mechanism of injury is hyperabduction of the arm at the shoulder with extension at the elbow; the forearm is pronated. Direct or violent force is applied to the shoulder from a superior direction, causing inferior movement of the humeral head relative to the glenoid fossa. The inferior portion of the glenohumeral capsule is then disrupted, and inferior shoulder dislocation occurs. There are few reports regarding associated injuries accompanying inferior shoulder dislocation. We report a -year-old man who sustained inferior dislocation of the right shoulder with an avulsion fracture of the greater tuberosity and transient neurovascular compromise. CASE REPORT A -year-old man sustained a tumbling injury due to insertion of an umbrella into the anterior wheel when Received: August 11, 3; Revised: November 1, 3; Accepted: December 9, 3. * Corresponding author: Kuo-Hua Chao, Department of Orthopedics, Tri-Service General Hospital, 35, Cheng- Kung Road Section, Taipei 11, Taiwan, Republic of China. Tel: ; Fax: ; j3@ms3.hinet.net Fig. 1 The right humerus was hyperabducted, with flexion at the elbow and the forearm resting on the patient s head. riding a bicycle. When he attempted to stand up, he found that his right arm was painfully locked in an overhead position and he was unable to lower it. He was transported by ambulance to the emergency department of our hospital. Physical examination revealed that the right shoulder was in the hyperabduction position, with flexion at the elbow and with the forearm resting on the patient s head (Fig. 1). Severe pain rendered him unable to move his right shoulder. The head of the humerus was palpable against the lateral thoracic wall near the axilla. The radial pulse could not be detected at the right wrist. An area of hypesthesia with muscle weakness was noted over the right forearm and hand. The function of the axillary nerve could not be tested due to severe pain. 5

2 Inferior dislocation of the shoulder 3A 3B Fig. The radiograph before close reduction showed the humeral head below the glenoid fossa, while the shaft of the humerus pointed up and was in a rotated position. The fractured fragment could be noted on this film and marked by the white arrow. The radiographic film of the right shoulder showed the shaft of the humerus pointed up and was in a rotated position, with the dislocated humeral head below the glenoid fossa (Fig. ). Manipulative reduction by traction-counter-traction was performed immediately after the prescription of adequate analgesics. The forearm was straightened and in-line traction was applied to the fully abducted arm while firm cephalad pressure was maintained on the humeral head. Counter-traction was applied with a rolled bed sheet placed superior to the shoulder. When the humeral head was reduced into the glenoid fossa, an arc was swept in the coronal plane from the accentuated hyperabducted position medially and the arm was adducted toward the body and the forearm supinated. There was no audible clunk during reduction. The radiographic studies, which included anteroposterior and axillary views, were checked immediately after close reduction, and these films revealed anatomic reduction of the humeral head into the glenoid fossa (Fig. 3A,B). Hypesthesia of the forearm and hand disappeared after reduction. The pulse of radial artery was returned to normal. Tenderness of the greater tuberosity increased clinical awareness of associated injury, and an avulsion fracture of the greater tuberosity was evident in the post-reduction film, which revealed a displacement of greater than 5 mm. Fig. 3 (A) The radiograph of axillary view revealed anatomic reduction with the humeral head into the glenoid fossa. (B) The avulsion fracture of the greater tuberosity was noted on anteroposterior view after close reduction with the displacement greater than 5 mm. In consideration of which if left untreated, residual displacement greater than 5 mm could result in impingement against the acromion in elevation or abutment against the glenoid in external rotation 1. The patient s arm was temporarily placed in a sling and surgery was scheduled with open reduction and internal fixation of the avulsion fracture of the greater tuberosity. General anesthesia was used before the surgical procedure. With the patient lying in a beach-chair position, the arm was placed in the neutral position and the proce-

3 Hsieh-Hsing Lee, et al. Table 1 The Constant-Murley clinical method of functional assessment of the shoulder Reference weeks 1 weeks* PAIN (15) None Mild Moderate Severe 15 5 (15) ACTIVITIES TO DAILY LIVING () Activity Level Full work Full Recreation/Sport Unaffected Sleep () () () Positioning Up to Waist Up to Xiphoid Up to Neck Up to Top of Head Above Head () () RANGE OF MOTION () Forward Elevation () -3 o 31- o 1-9 o 91- o o o () () Lateral Elevation () -3 o 31- o 1-9 o 91- o o o () () External Rotation () Hand behind Head-Elbow Forward Hand behind Head-Elbow Back Hand on Top of Head-Elbow Forward Hand on Top of Head-Elbow Back Full Elevation from Top of Head () () () () () Internal Rotation () Dorsum of Hand to Lateral Thigh Dorsum of Hand to Buttock Dorsum of Hand to Lumbosacral Junction Dorsum of Hand to Waist (3rd Lumbar Vertebra) Dorsum of Hand to 1th Dorsal Vertebra Dorsum of Hand to Intercapsular Region (7th Dorsal Vertebra) () () POWER (5) (With a spring balance or a Cybex ) 5 (15) () TOTAL 5 9 * We used the rating system to evaluate the patient s shoulder at and 1 weeks after the operation,3. dure was performed using a deltopectoral approach. The fragment of the greater tuberosity was found to be a large one that could support plate and screw fixation, and a cloverleaf plate with screws was applied. Immobilization with a sling was applied postoperatively to allow the soft tissue of the inferior capsule to heal. His sling was removed weeks after the surgical procedure, and a program of rehabilitation began thereafter. We used the Constant-Murley rating system to evaluate the functional improvement of the affected shoulder weeks postoperatively, in the outpatient department. The patient score was 5 points,3. The same evaluation was done again at the 1th week postoperatively, with the score improving to 9 (Table 1). 7

4 Inferior dislocation of the shoulder At months postoperatively, the patient returned to the outpatient department of our hospital for another followup. He did not complain of pain and his upper extremity remained neurologically intact. He had regained a nearly full active range of motion in the shoulder and had no apprehension or instability toward elevation or rotation. There was full recovery of motor power. Radiographic study showed retention of implants and bony union of the greater tuberosity. He could return to preinjury activities, and he was back at work as a laborer. DISCUSSION Luxatio erecta, or inferior shoulder dislocation, is an extremely uncommon variety of the very common problem of shoulder dislocations, and was first described in 159 by Middledorpf and Scharm. This rare shoulder dislocation accounts for less than 1% of all shoulder dislocations. This injury can occur at any age 5. The classical presentation is with the arm fully abducted, elbow flexed, and the forearm resting on or behind the patient s head. Creases may be present over the superior aspect of the shoulder and the glenoid fossa will be empty with the humeral head palpable on the lateral chest wall. The patient will generally resist any attempt at movement of the affected arm. Neurovascular compromise involving the axillary artery and the brachial plexus may be present 7. The mechanism of injury involves hyperabduction of the humerus. As the humerus is abducted, it impinges upon the acromion, causing a tear in the inferior glenohumeral capsule and disruption of the rotator cuff. Fractures of the acromion, inferior glenoid, and greater tuberosity of the humerus can occur 9. The force of the injury can be great enough to cause an open fracture-dislocation. The clinical presentation of luxatio erecta humeri is dramatic. The initial impression may suggest hysteria. The arm, which is locked in severe abduction, points straight upward alongside the head with the elbow flexed. The forearm frequently rests behind the head or across the top of the head. The glenoid fossa is empty and the humeral head is palpated in the axilla adjacent to the lateral chest wall. Skin creases are noted on the superior aspect of the shoulder, indicating the acute angle formed by the acromion and humerus. It is impossible to lower the arm from this position without causing excruciating pain. On radiographs, the head of the humerus is seen below the glenoid, while the shaft of the humerus points up and is in a rotated position. Therefore, the radiological evaluation of the shoulder should include the injured part, in two views at right angles to each other 7. A lateral film, in addition to the anteroposterior views, must be obtained to complete the shoulder series. Anteroposterior views are taken of internal and external rotation of the humerus (routine anteroposterior) with the tube angled 5 o laterally from the midline (true anteroposterior). Lateral views are taken in the plane of the scapula (Y view) or in the plane of axilla (axillary) 7. Both views allow the relationship of the humeral head to the glenoid and be evaluated further, and show possible fractures of the glenoid, coracoid process, and humeral head. The Y view has the benefit of being taken without moving the upper extremity. Careful attention must be directed toward making the distinction between anterior and inferior shoulder dislocations. A recent report describing luxatio erecta suggests it was initially misdiagnosed as an anterior dislocation 11, and standard approaches to reduction of anterior dislocation were unsuccessful. Complications may be found: 1) Recurrence: Recurrent inferior dislocation of the shoulder is very unusual. ) Softtissue injuries: Disruptions of various shoulder muscles (supraspinatus, infraspinatus, subscapularis, and pectoralis major). 3) Fractures: Fractures of the clavicle, coracoid, acromion, inferior glenoid, and greater tuberosity of the humerus. Concomitant fracture or rotator cuff injury is reported in % of cases. Fracture of the greater tuberosity of the humerus reportedly spares injury to the rotator cuff. ) Neurologic injury: % of cases manifest neurologic injury on presentation, most commonly to the axillary nerve. The neurologic deficits usually resolve in rapid fashion. 5) Vascular injury: A small percentage of cases are complicated by vascular injury, which is usually associated with a decreased radial pulse. Our case presented with the last three clinical symptoms. The greater tuberosity was avulsed by the rotator cuff when the humeral head dislocated inferiorly. All the three cords of the brachial plexus pass through the axilla and would be tethered in the dislocated position, and accordingly, our case presented the symptoms of hypesthesia and muscle weakness over the right forearm and hand before closed reduction. The axillary vessels might be compressed in the dislocated position and therefore the radial pulse could not be palpated in our case. Notwithstanding the severity of neurovascular symptoms, disability in our case was transient and significant improvement was noted after reduction of his shoulder joint. Most cases of luxatio erecta can be managed by closed reduction in the emergency department, unless a buttonhole incarceration of the inferior capsule exists; then open reduction may be necessary. Adequate muscle relaxation and anesthesia are essential for reduction. One method of

5 Hsieh-Hsing Lee, et al. reduction involves in-line traction of the fully abducted arm superiorly as upward pressure is applied to the humeral head. Simultaneous counter-traction is applied inferiorly with a folded sheet placed over the top of the shoulder. When the humeral head is reduced into the glenoid fossa, the arm is adducted in an arc toward the body 1. The shoulder is then immobilized with a shoulder immobilizer or a sling and swathe. Postreduction anteroposterior and lateral radiographs are examined for adequate reduction and associated fractures. Accurate diagnosis of inferior shoulder dislocation, with attention to neurovascular compromise, will prevent iatrogenic injuries and complications during close reduction. If the technique of close reduction is correctly applied and the associated fractures are adequately treated, the functional recovery of the shoulder joint is nearly complete and the clinical result will be excellent. REFERENCES 1. Dirschl DR. Shoulder trauma: bone. In: Koval KJ, ed. Orthopaedic Knowledge Update 7: Home Study Syllabus. Rosemont: American Academy of Orthopaedic Surgeons, :3-.. Welsh P. Standardized assessment of shoulder function. Presented at the meeting of the American Shoulder and Elbow Surgeons, Los Angeles, Oct, 195 (including the Constant-Murley assessment method). 3. Constant CR, Murley AH. A clinical method of functional assessment of the shoulder. Clin Orthop Relat R 197;1:1-1.. Middledorpf M, Scharm B. De nova humeri luxationis specie. Clinique Europenne 159;: Laskin RS. Luxatio erecta in infancy. Clin Orthop 1971;71: Zimmers T. Luxatio erecta: an uncommon shoulder dislocation. Ann Emerg Med 193;1: Wirth MA, Rockwood CA. Subluxations and dislocations about the glenohumeral joint. In: Bucholz RW, Heckman JD, eds. Fractures in Adults. 5th ed. Philadelphia, PA: Williams & Wilkins, 1: Simon RR, Koenigshnecht SJ. Emergency Orthopedics. nd ed. Norwalk, CT: Appleton & Lange, 197: Kothari K, Bernstein RM, Griffiths HJ, Standertskjold- Nordenstam CG, Choi PK. Luxatio erecta. Skeletal Radiol 19;11:7-9.. Harris HJ, Harris WH. Radiology of Emergency Medicine. 1st ed. Baltimore, MD: Williams & Wilkins, 1975: Pirrallo RG, Bridges TP. Luxatio erecta: a missed diagnosis. Am J Emerg Med 199;: Freundlich BD. Luxatio erecta. J Trauma 193;5:3-3. 9

6 Inferior dislocation of the shoulder