250 Injury, 12,250-251 Printedin GreatBritain

Bilateral obturator dislocation of the hip joint

Andrew Gibbs

Royal National Orthopaedic Hospital, London

INTRODUCTION ANTERIOR dislocation of the hip is uncommon and bilateral anterior dislocation rare. Only two cases of bilateral obturator dislocations have been reported in the literature (Aggarwal and Hardas, 1967; M’Bamali, 1975). Neither patient was able to describe what had happened at the time of injury. The present patient was conscious throughout the process of injury and described in graphic detail the events of his accident.

CASE REPORT A young man of 19 years was riding a motorcycle along a country road behind a tractor pulling a two+ wheeled trailer. Exasperated by the slowness of progress, he started to overtake. When he came level with the tractor, it turned suddenly to the right towards the entrance to a held. He was thrown from the motor- cycle, landing face down on the verge of the road with his abdomen across a small shallow ditch. He immediately rose to a semi-crouching position, with the hips semi-flexed, when he felt the wheel of the trailer cross the lower part of his back. His body was violently pushed back towards the ground with the hips remaining semi-flexed, but now forcibly abducted and externally rotated. He experienced severe pain in both groins and was unable to get up.

When examined in the casualty department the hips lay in slight flexion and external rotation with 30’ of abduction (Fig. 1). Active or passive movements ofthe hips were impossible owing to pain. There was no neurological or vascular disorder in either limb. Radiography confirmed the clinical diagnosis of bilateral obturator dislocations (Fig. 2).

Examination under general anaesthesia showed that the hips were in 30” of abduction and could not be adducted. Three hours after the injury the hips were reduced with some difficulty. After attempting various manoeuvres, the left hip was reduced by initial

Fig. I. Hips in slight flexion and external rotation with 30’ of abduction.

Fig. 2. Radiograph confuming diagnosis of bilateral obturator dislocations.

longitudinal traction in 45’ of flexion with some internal rotation and an increase of abduction. After a short period of traction, the hip was externally rotated, with a colleague applying lateral traction on the upper

Gibbs: Bilateral Anterior Hip Dislocation

Fig. 3. Left hip is reduced; right hip is still dislocated.

thigh, and gradually adducted. The reduced left hip and still dislocated right hip are shown in Fig. 3. Reduction ofthe right hip was easier than the left.

The patient was subsequently nursed in bed on skin traction for six weeks and walked with crutches for a further six weeks. Eighteen months later his only complaint was of persistent low back pain, although clinically and radiologically no evidence of injury at this site could be detected. There were no symptoms referable to the hips, which were radiologically normal, as shown in Fig. 4.

DISCUSSION The mechanism of anterior dislocation of the hip was clarified by the experimental work of Pringle and Edwards (1943) and the simple classification used by Epstein and Harvey (1972). A high dislocation or pubic type occurs when violent extension is added to external rotation and abduction. The low dislocation or obturator type occurs when flexion exists in association with external rotation and abduc- tion. The present case illustrates the second type and is unusual in that the patient could describe the manner of the injury in detail.

In contrast to recent reports, we experienced considerable difficulty in reducing these hips by manipulation. By applying a set sequence of manoeuvres the second hip was more easily reduced than the first. Initial longitudinal trac-

Fig. 4. Radiograph eighteen months later showing normal hips.

tion in flexion with internal rotation and increased abduction ‘unlocks’ the femoral head from beneath the acetabular rim. Subsequent lateral traction on the upper part of the thigh by a colleague, with external rotation and adduc- tion, allows the head to be levered into the acetabulum.

This case is interesting in illustrating the mechanism of injury in a fully conscious patient and in suggesting a manoeuvre which may simplify an otherwise difficult procedure.

Acknowledgement 1 would like to thank Mr R. C. Howard, Senior Consultant Orthopaedic Surgeon at the Norfolk and Norwich Hospital, for allowing me to report on his patient.

REFERENCES Aggarwal N. D. and Hardas S. (1967) Unreduced

anterior dislocations of the hip. J. Bone Joint Surg. 49B, 288.

Epstein H. C. and Harvey J. P. jun. (1972) Traumatic dislocations of the hip. J. Bone Joint Surg. 54A, 1561.

M’Bamali E. 1. (1975) Unusual traumatic anterior dislocation ofthe hip. Ir1jur~6,220.

Pringle J. H. and Edwards A. H. (1943) Traumatic dislocation at the hip joint. Experimental study on a cadaver. Glasgow Med. J. 139,25.

~IW.S~.S /br rc~int.~ .hrr/d hr addressed IO; Mr Andrew Gibbs, The lpswich Hospital. Angelsea Road Wing, Ipswich. Suffolk