Bilateral posterior dislocation of the shoulder

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Bilateral posterior dislocation of the shoulder M. R. K. Karpinski Senior Registrar, Derbyshire Royal Infirmary, Derby

K. M. Porter Senior Registrar, Royal Orthopaedic Hospital, The Woodlands, Birmingham Summary The purpose of this article is to present two cases of bilateral posterior dislocation of the shoulder. A review of the previously reported cases reveals the rarity of this injury, its association with seizures and the frequency with which it is misdiagnosed. INTRODUCTION POSTERIOR dislocation

of the shoulder is uncommon and simultaneous bilateral posterior dislocation appears to have been reported twenty times. In the largest series, reported by Honner (1969), over half were caused by seizures. CASE REPORTS Case 1 A 70-year-old man asleep at his home awoke in the early hours with pain in the upper part of his chest and both

shoulders and inability to move his arms. He was provisionally diagnosed in the Accident and Emergency Department as having had a myocardial infarction and it was some time later that clinical and radiological evidence of posterior dislocation of both shoulders was recognized. These were easily reduced and he was investigated for seizures. There was no past history of relevance. A brain scan and EEG were normal but he was placed on anticonvulsants because it was thought his injuries may have been sustained during a seizure and this was supported by the fact that this patient suffered transient cerebral ischaemic episodes with seizures when he stopped taking his anticonvulsants (Figs l-5). Case 2 A 6 I -year-old woman was an inpatient in a psycho-geriatric unit. where she was known to have epilepsy. She came with painful stiff shoulders of several weeks’ duration and had been diagnosed as having ‘frozen shoulders’ which failed to respond to physiotherapy. After being refused referral to an

Fig. I. Chest X-ray showing bilateral posterior dislocation.

Karpinski and Porter: Posterior dislocation of shoulder

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Fig. 2. Right posterior shoulder dislocation.

Fig. 3. Lef? posterior shoulder dislocation. clinical and radiological examiorthc bpaedic department. natio n revealed posterior dislocation of both shoulders. The nursi ng records stated that she had had a fit in her sleep reduced the some 4 weeks previously. Closed manipulation dislol cations. DIS CUSSION

Simsultaneous posterior dislocation of the shoulders first described by Mynter in 1902 and he attri-

buted the causes to excessive muscuiar contracti on as the result of an overdose of camphor. Coover in 1932 reported the first case of bilateral posterior disloc ation of the shoulder due to epileptic seizures whilst lying in bed. The association of a posterior dislocation am 1 epileptic seizures was first recorded by Sir Astley Clooper (1839). Malgaigne ( 185 5) described ‘luxatous sous acro-

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Fig. 4. Left shoulder reduced.

miale’ and reported 37 cases including Sir Astley Cooper’s, of which 14 dislocations were associated with seizures. The diagnosis is often not made at the initial examination although there are important characteristic clinical and radiological features. The patient who is conscious complains of pain and stiffness in the shoulders. Examination reveals a fixed internal rotation of the humerus with little or no gleno-humeral movement. There is loss of the normal contour of the shoulder and a prominence posteriorly. The acromion is usually prominent. The antero-posterior X-ray appearance may suggest a posterior dislocation but the axillary view is essential for diagnosis (Kessel, 1982). In all complaints of pain and stiffness in the shoulder, the joint should be examined carefully because it is easy to miss a posterior dislocation and it is necessary to have good quality X-ray films, which should be examined carefully. The frequent association with seizures must be remembered, especially if pain or stiffness in the shoulder complicates any form of cerebral seizure of whatever cause. Early diagnosis allows easy reduction and usually a good functional recovery. By contrast, delay in diagnosis may necessitate open reduction and an incom-

Fig. 5. Right shoulder reduced.

plete functional recovery. Posterior dislocation of the shoulder is according to Rockwood (1965) the most commonly missed major joint dislocation.

REFERENCES

Cooper A. (1839) On the dislocation of the OS Humeri upon the dorsum scapulae and upon fractures near the shoulder joint. Guvs Hospital Report 4, 265. Coover C. (1932) Double posterior luxation of the shoulder. Pennsylvania Med. J. 35, 566. Honner R. (1969) Bilateral posterior dislocation of the shoulder. Amt. NZ. J. Surg. 38, 269. Kessel L. (1982) Clinical Disorders sfthe Shoulder. London, Churchill Livingstone, p. 15 1. Malgaigne J. F. (1855) Trait& des Fractures et des Luxations. Paris, J. B. Bailliere Tome 2, p. 433. Mynter H. (1902) Subacromial dislocation from muscular spasm. Ann. Surg. 36, I 17. Rockwood C. A. (1965) The diagnosis of acute posterior dislocation of the shoulder. J. Bone Joint Surg. 46A, 1220. Paper accepted 23 May 1983

Requests for reprints should be nddressed to: K. M. Porter, Senior Registrar, Royal Orthopaedic Hospital, Woodlands, Birmingham.