Original Article Retrospective Study of Injuries in Military Parachuting D Dhar* Abstract Background: This paper analyses the rate and patterns of parachuting injuries at the Sultans Oman Parachute Unit (SOPRA) in Oman. Methods: Data on 150 patients referred to Rustaq Regional Referral Hospital was collected and analysed. The injuries were defined as severe (fractures, dislocation, head trauma) or minor (contusion, bruises, sprains). Result: The rate of severe injuries was 9% and ankle fractures were the commonest. The minor injury rate was 13.5%. The injury rate increased in relation to age (p < 0.001). The type and possible mechanisms of injury are discussed with the recommendation for reducing the injury rates. Conclusion: We conclude that our data compares favourably with other studies except for higher incidence of severe injuries. MJAFI 2007; 63 : 353-355 Key Words : Parachute; Paratrooper; Parachuting injuries Introduction arachuting as a sport or military exercise is regarded as one of the most challenging and demanding effort which require high degree of mental and physical fitness. Literature shows injury rates between 2-20 injuries per 1000 jumps [1-8]. Military parachuting involves everything from training jumps over flat terrain in daylight to tactical jumps with combat equipment over unknown terrain at night. Hallel et al [2], found a corresponding variation in injury rates from 2.2 injuries per 1000 jumps for easiest to 25.7 injuries per 1000 jumps for the most difficult jumping conditions. Similar observations were reported by Farrow [3]. The purpose of this study was to obtain a profile of the injuries and risk factors for paratroopers from Gulf region and compare them with those of other western studies. P Material and Methods This is a case study conducted at Rustaq Hospital (Referral Hospital for South Batinah Region), Oman. All paratroopers referred for parachute related injuries from local and military unit even after days of injury were classified as having sustained parachuting injury. Internationally, paratrooper injury rate is defined as “number of injuries related to paratrooping per 1000 jumps” [1,4]. Injuries were classified depending on the site, type and severity. Parachute injuries were also studied in relation to age, experience (number of previous jumps) and cause of accidents as narrated by injured paratrooper. A total of 150 cases were retrospectively analysed from the medical records of all patients treated in Rustaq Hospital with parachute related injuries in the last seven years. Patients were categorized in two groups. First group consisted of those with severe injuries (fractures, dislocations, head injury, spinal and visceral injuries) and second group with minor injuries (contusion, sprains, bruising). The data is presented as percentage and statistically evaluated. Results Out of 150 patients, 99 (66%) were treated as inpatients and the hospitalisation period varied from 3 - 20 days (average 12.2 days). The time off work ranged from 4 -40 weeks. (average 20 weeks) Majority (63.3%) of injured were in age group of 18-25 years (Table 1). Of the severely injured 63.6% patients were in old age group as compared to 26.3% in younger age group, which was statistically significant (Table 2). Most (60%) of the injuries were contusion and sprains, followed by fractures which accounted for 26.6 % cases. Twelve paratroopers suffered varying degrees of spinal injuries (Table 3). Most common sites of sprains were ankle and knee and about 80% injuries were confined to lower limbs. Forty paratroopers sustained fractures that included ankle, calcaneum, lower leg, femur and pelvis (Table 4). Hundred paratropers were jumping for the first time and rest for second time and above. The incidence of severe injuries was same in both groups (Table 5). There were 13.5 % minor injuries as compared to 9% severe injuries per 1000 jumps (Table 6). Improper landing accounted for 53.5% cases and no cause could be ascertained in 51.5% cases. Improper parachute handling or limb getting caught in parachute rope accounted for 25% cases (Table 7). Specialist in Orthopaedics, Department of Orthopaedics, Rustaq Hospital, South Batinah Region, Ministry of Health, Sultanate of Oman Received : 05.09.2006; Accepted : 21.01.2007 354 Dhar Table 1 Age of injured paratroopers (n=150) Age (years) Table 4 Type of fractures (n=40) Number of cases Percentage Fracture type Number of cases Percentage 95 55 63.3 36.6 Ankle / Foot Lower Leg Hip / Femur Pelvis Upper Limb 14 10 5 8 3 35 25 12.5 20 7.5 18 - 25 26 - 35 Table 2 Severity of injuries related to age groups Old (26-35 years) Young (18-25 years) Severe (%) Minor (%) Total 35 (63.6) 25 (26.3) 20 (36.4) 70 (73.7) 55 95 60 90 150 Total Table 5 Injury severity and experience Number of previous jumps Severe (%) Total 60 (60) 30 (60) 100 50 χ2 value = 20.2 ; p = < 0.001 First time Second time and above Table 3 Type of injuries (n=150) Table 6 Parachute injury rate (number of injuries per 1000 jumps) Injury Fractures Head injuries Abdomen / Thorax Contusion /Sprains Spinal injuries Number of cases Percentage 40 5 3 90 12 26.7 3.3 2 60 8 Injury type Minor injuries Severe injuries 40 (40) 20 (40) Minor (%) Number Rate 90 60 13.5 9 Table 7 Cause of parachuting injuries Main cause Discussion All military paratroopers are selected after vigorous physical and medical examination in contrast to a candidate for recreational parachuting who is expected to have only reasonable physical fitness. Military parachuting involves upto four weeks of training, culminating in eight qualifying jumps in the last week, as compared to recreational parachuting where landing techniques involve practice jumps from two and four feet high platform over a weekend course lasting for eight to twelve hours [5,6]. Our definition of severe injury corresponds to that of Ekeland [4] ("fractures and knee ligament ruptures were defined as severe injuries") and that of moderate and severe injury in the study of Hallel et al [2] ("all ligament injuries were labelled as moderate injuries and fractures as severe injuries"). The severe injury rate of 9% in our study was higher as compared to that for military parachuting in other series. Tobin et al [1] , reported an incidence of 2.4%, Hallel et al [2], 0.62%, Ekeland [4] 1.6%, Bar-Dayan [7] 0.89%, and Essex-Lopresti [8] 2.1%. Higher injury rates in our series may be caused by jumping induced stress or lack of jumping experience. Lord et al [9], stated statistically, any parachutist had only 1% chance of being injured in any one descent. The overall admission rate of 66% in our series was higher than that reported in other studies. Tobin et al [1] reported rates of 25% while Essex-Lopresti [8] recorded 24%. The admission rate however was lower as Improper jumps from aircraft Improper landing Rough landing terrain Windy weather Improper parachute handling Exact cause could not be ascertained Number of cases 3 53 10 8 25 51 compared to civilian admission rate of 81.8% as reported by Amamilo et al [6]. In our series we found an increase in severe injury rate in older age group of paratropers (Table 2) which is in agreement with other studies [1-3,5,6], probably due to greater elasticity of tissues in young people to absorb impacts. Majority (60%) of injuries in our series were minor injuries in form of contusions and sprains followed by severe injuries (26.7%). Ankle and foot were the most vulnerable site of injury accounting for 35% fractures. These rates are comparable to those of Hallel et al [2], who reported 35.6% severe injuries but lower incidence of sprain 17.8%. In contrast most (65.8% ) of the civilian injuries reported by Steinberg and Amamilo [5,6], were severe probably due to lack of jumping experience. The injury rates were same for the first jumps and subsequent jumps (Table 5). Ekeland [4] observed that increasing number of jumps did not protect against injury. This may be due to increasing exposure time to risk of jumping. Most (53%) of the injuries occurred during landing MJAFI, Vol. 63, No. 4, 2007 Retrospective Study of Injuries in Military Parachuting (Table 6). Essex-Lopresti [8] remarked “that the euphoria accompanying the glorious sense of isolation whilst floating down is tempered by anticipation of the technical difficulties of meeting the ground. During the last 50 feet, the ground rushes up at an increasing speed and at an angle due to horizontal drift. Quick thinking and determined efforts are necessary to make a correct and safe landing, a challenge to a beginner”. Interview of the injured parachutists yielded five probable causes of injuries (Table 7) and improper landing was the commonest cause. There were increased injuries during night jumps probably due to poor visibility and mental fatigue after a full day’s training. Findings from our study suggest that more time during training should be devoted to demonstrating landing techniques.Simplification of parachute landing fall and development of safer parachutes will help reduce casualties [10] and make parachuting a safer means of conveyance [11]. Other factors such as high wind speed, presence of obstacles in the landing zone, jumps wearing additional equipment and without ankle braces are risk factors relevant to all parachutists. Acknowledgement The contribution of Dr. PJ Kurup in statistical analysis of data is gratefully acknowledged. 355 Conflicts of Interest None identified References 1. Tobin WJ, Cohen LJ, Vandover JT. Parachute Injuries. JAMA 1941; 117:1318-21. 2. Hallel T, Naggan L. Parachuting Injuries : A retrospective study of 83818 jumps. J Trauma 1975; 15:14-9. 3. Farrow GB. Military Static Line Parachute Injuries. Aust NZ J Surg 1992; 62:209-10. 4. Ekeland A. Injuries in Military Parachuting a prospective study of 4499 jumps. Injury 1997; 28:219-22. 5. Steinberg PJ. Injuries to Dutch Sport Parachutists. Br J Sports Med 1988; 22:25-6. 6. Amamilo SC, Samuel AW, Hes Keth KT, Moynihan FJA. Prospective study of Parachute Injuries in Civilians. J Bone Joint Surgery (Br) 1987; 69: 17-9. 7. Bar-Dayan Y, Shemer J. Parachuting Injuries: A retrospective study of 43,542 military jumps. Mil Med 1998; 163: 1-2. 8. Essex-Lopresti P. The hazards of parachuting. Br J Surg 1946; 34:1-13. 9. Lord CD, Coutts JW. Typical parachute injuries: Study of those occurring in 250,000 jumps at the Parachute School. JAMA 1944; 125: 1182-7. 10. Knapik JJ, Craig SC, Hawret KG, Jones BH. Risk Factors for Injuries During Military Parachuting. ASEM 2003; 74: 76874. 11. Keil FW. Hazards of Military Parachuting. Mil Med 1965; 130:512-21. ATTENTION ADVERTISERS Rates of advertisements in Medical Journal Armed Forces India : Black & White Colour Size Full page (per issue) Rs. 5000/Rs. 10000/25 x 18 cms Half page (per issue) Rs. 3000/Rs. 6000/18 x 12 cms (Positive for advertisement to be supplied by client) Inserts (two pages) Rs. 5000/- per insert (Black and White / Colour) (Printed inserts to be supplied by client) Address for Correspondence EDITOR-IN-CHIEF MEDICAL JOURNAL ARMED FORCES INDIA C/O ARMED FORCES MEDICAL COLLEGE, PUNE - 411 040. MJAFI, Vol. 63, No. 4, 2007