Association of recurrent anterior dislocation of the shoulder with free-fall parachuting

Association of recurrent anterior dislocation of the shoulder with free-fall parachuting

Injury (1984) 16, 15-l 6 Printed in Great Britain 15 Association of recurrent anterior dislocation shoulder with free-fall parachuting of the R...

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Injury (1984)

16, 15-l 6

Printed in Great Britain

15

Association of recurrent anterior dislocation shoulder with free-fall parachuting

of the

R. N. Villar and I. P. Palmer Cambridge

Military

Hospital,

Aldershot

Summary We describe 2 cases of recurrent dislocation of the shoulder in free-fall parachutists that occurred while falling free. We suggest that in such sportsmen surgical repair should be effected after the first dislocation.

INTRODUCTION

RECURRENTdislocation of the glenohumeral joint is a well-recognized condition of athletes, with a recurrence rate of 90 per cent in one particular activity (Hovelius, 1978). Its occurrence in free-fall parachutists while in mid-air has not been previously recorded, but its significance is of particular relevance to their survival. Two such cases are described. CASE

REPORTS

7 A much-travelled 36-year-old man, veteran of over 400 free-fall parachute descents, gave a 13-year history of recurrent anterior dislocation of the right shoulder. The original dislocation had been due to direct injury, though on this and all other occasions the patient had effected reduction himself. As a result no radiological evidence of dislocation had ever been obtained. On finally seeking medical care his complaint was of an inability to ‘skydive’. On leaving an aircraft over 12 000 ft above ground he would adopt the traditional face downwards position (Fig. 1) to gain stability. On reaching a terminal velocity of 130mph any abrupt movement as he fell would cause dislocation. The patient would then roll over into the back downwards attitude, Case

Fig. 1. Traditional

face downwards

position

effect reduction himself and roll back into a face downwards position before releasing his parachute and reaching the ground. On examination he was a fit, muscular individual. There was a full range of movement at each shoulder, but with marked apprehension on the right in full abduction and external rotation. There was no evidence of axillary nerve damage. Radiographs demonstrated no abnormality. Following a period of vigorous exercise in a gymnasium, the resultant shoulder girdle fatigue was sufficient to produce easy anterior dislocation and radiological evidence of this was obtained. Subsequent repair was by a standard Putti-Platt technique (Osmond-Clarke, 1948); at operation a voluminous and fibrotic capsule was found. No Bankart’s (Bankart, 1938) or Hill-Sachs’ (Hill and Sachs, 1940) lesion was identified and the anterior margin of the glenoid was intact. Following a 3week period of immobilization after operation, vigorous exercises were performed for a further 4 weeks. At the end of this time the shoulder could be actively abducted to 110” and externally rotated 50” in this amount of abduction. External rotation with the elbows by his side was limited to 20”. Despite this, the patient returned to free-fall parachuting within 3 months of repair. Case 2 A 26-year-old man sustained an anterior dislocation of the right glenohumeral joint while on a military assault course. Radiological confirmation was obtained and reduction effected under general anaesthesia. One year later, when in a face downwards skydiving position 1OOOOft above ground, he experienced intense pain in his right shoulder and began to spin

of a free-fall parachutist.

16

Injury: the British Journal of Accident Surgery (1984) Vol. 1 ~/NO. 1

uncontrollably. With difficulty he managed to pull his ripcord handle and deployed his parachute, landing heavily due

Information about the true incidence of redislocation in free-fall parachutists is as yet unavailable, though enquiries made of 4 parachute clubs have revealed 10 further cases of unconfirmed recurrent dislocation, only 2 of which occurred during free-falls. When applied to free-fall parachuting any rate of recurrence cannot be tolerated because of the risks involved. External rotation in 90” abduction at the glenohumeral joint must be a minimum of 45” following rehabilitation to allow the patient to return to free-falls. Though causing some loss of such movement, the Putti-Platt procedure does not reduce it sufficiently to prevent further parachuting and has not prevented our 2 cases from returning to the sport. However, a procedure such as Bankart’s operation, which has been shown not to reduce a shoulder’s movement (Rowe et al., 1978) might be more appropriate in these cases. The alternative is to prohibit individuals with a history of dislocation from taking up the sport, although our experience with the type of person involved indicates this would be hdrd to achieve. We therefore propose that any dislocation of the shoulder in established free-fall parachutists should be considered to require surgical repair without delay.

almost

to impaired control. Reduction was again performed under general anaesthesia and the patient referred for further advice. On examination he was found to be a fit individual with some evidence of axillary nerve damage as shown by cutaneous anaesthesia over the deltoid insertion, though there was no weakness of abduction of the shoulder. A markedly positive apprehension test was found. A standard Putti-Platt procedure was performed; both Bankart’s and Hill-Sachs’ lesions were found. The patient underwent 3 weeks of splintage followed by 4 weeks’ rehabilitation, returning to free-fall parachuting within 5 months of repair. After rehabilitation, the range of movement at the shoulder was 120” of abduction and 60” of external rotation in 90” of abduction. External rotation with his arms by his side was 30”.

DISCUSSION

Free-fall parachuting or skydiving is a popular and growing sport. Jumps vary between 2500 and 25000ft above ground and on occasion even higher. The freefailer leaves the aircraft in a spreadeagled position (Fig. 1) to gain the maximum stability against the cushion of air as he falls face downwards. His arms are held abducted 90” at the shoulder, with 90” of external rotation, and are flexed 90” at the elbow. His legs are fully extended at the hips, slightly abducted and flexed 60” at the knee. By moving his arms and legs into various attitudes as he falls, he can adjust both his rate of descent and direction of travel across the sky. At a predetermined height he will pull the ripcord handle and release his parachute to slow the rate of fall from approximately 130 to 7mph. He can then land with relative impunity. Total free-fall time from 12 000 ft to when the parachute opens at 2500 ft is approximately 55 sec. At 130 mph in a face downwards position the leverage on the glenohumeral joint by air pressure on the outstretched arms is enormous. A tight strap across the clavicle holds the parachute in place on the free-faller’s back, effectively splinting the shoulder girdle and exaggerating the leverage still further. Even slight instability of the joint can result in anterior glenohumeral dislocation, interfering with the free-faller’s ability to pull his ripcord handle and release his canopy. To turn in mid-flight into a back downwards position to reduce a dislocation is a highly skilled manoeuvre and not to be expected of the majority of free-fall parachutists. Life is therefore at risk.

Acknowledgement

We would like to thank Colonel J. T. Coull FRCS for helpful advice.

REFERENCES Bankart

A.

recurrent

The pathology and treatment of of the shoulder joint. Br. J. Surg. 26,

S. B. (1938)

dislocation

23.

Hill H. A. and Sachs M. D. (1940) The grooved defect of the humeral head: a frequently unrecognised complication of dislocations of the shoulder joint. Rudiology 35, 690. Hovelius L. (1978) Shoulder dislocation in Swedish ice hockey players. Am. J. Sports Med. 6, 373. Osmond-Clarke H. (1948) Habitual dislocation of the shoulder: the Putti-Platt operation. J. Bone Joint Surg. 30B, 19. Rowe C. R., Pate1 D. and Southmayd W. W. (1978) The Bankart procedure: a long-term end-result study. J. Bone Joint Surg. 60A, 1. Paper accepted

23 September

1983.

Requests ,for reprinfs should be addressed to: Captain R. N. Villar, Cambridge Military Hospital, Aldershot, Hants GU

112AN.