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Protective leg restraint garters on ejection seats

aim to maximize lower extremity (LE) injury

prevention. A literature search found no published

studies that evaluated efficacy of leg restraints in

reducing lower extremity injuries.

Assumptions:

Restraints put the body in a better ejection position.

Restraints minimize flail injuries.

INTRODUCTION

The objective of the study was to determine if the

number of LE injuries differed between ejections

occurring in seats with and without leg restraints.

The study hypothesis was that ejections with leg

restraints would result in statistically fewer LE

injuries compared to those without.

OBJECTIVES

A retrospective cohort study was conducted with chi-square analysis to compare the number of lower extremity

injuries occurring between ejections with and without leg restraints. U.S. Naval Safety Center Aviation data

from Navy and Marine Corps ejections between 1980 and 2010 was analyzed. Exclusion criteria were

unknown seat type (could not determine the presence or absence of restraints) and cases in which it was

unknown whether the ejection occurred in versus out of the ejection envelope. SAS® v9.2 Software was used.

METHODS

A total of 983 ejections were analyzed that resulted in 2232 individual injuries. 710 (72%) ejections occurred in

seats with leg restraints and 273 (28%) occurred in seats without restraints. 320 (32.6%) ejections resulted in

one or more lower extremity injuries. There was no statistical difference in the occurrence of lower extremity

injuries between seats with and those without leg restraints.

RESULTS

CONCLUSIONS

Data analysis suggests that leg restraints do not

significantly decrease the number of lower

extremity injuries during ejection.

Limitations:

Data is from Naval Safety Center and subject to

recall bias.

No correlation to severity of LE injuries.

No differentiation between ejection envelopes of

different seats and aircraft.

Injuries due to Parachute Landing Fall (PLF) not

corrected for.

Future Analysis:

Impact of restraints on other body regions (arm

restraints, etc.)

Sub-analysis of injury severity and overall

disability from LE injuries with and without leg

restraints and impact of landing injuries.

This points out the need for careful analysis of

new passive restraint systems.

REFERENCES

1. Data from the Naval Safety Center Aviation Database

2. Collins T., Sawyer C., Ferrari V., Shannon, R. Five-Year

Injury Experience in Escape from USAF Ejection Seat

Equipped Aircraft. Aerospace Medicine. June, 1968. p.

627-632.

3. Hunt J. Ejection Associated Injuries in U.S. Naval and

Marine Corps Aviation, 1 OCT 1990 – 30 SEP 2004: A

Descriptive Study. Project Report for Department of

Preventive Medicine and Biometrics of the Uniformed

Services University of the Health Sciences. June 2005.

DISCLOSURE

Views of the authors do not necessarily reflect the official

policy or position of the Department of the Navy,

Department of Defense, nor the U.S. Government.

I have no financial relationships to disclose.

I will not discuss off-label use and/or

investigational use in my presentation.

Residency in Aerospace Medicine, Naval Aerospace Medical Institute (NAMI)

LCDR Robert J. Krause, MC, USN; CDR John E. Moore, MC, USN; CDR Christopher A. Orsello, MC, USN

ANALYSIS OF THE EFFECT OF PROTECTIVE LEG RESTRAINTS ON LOWER EXTREMITY INJURIES IN U.S. NAVY AND MARINE CORPS EJECTIONS FROM 1980 TO 2010.

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OUTSIDE EJECTION ENVELOPE

F-18E/F SJU-17 (NACES)

Restraints

F-16 ACES II

No Restraints

With Restraints - 31.8%

Without Restraints - 34.4% p= 0.44 Yate’s Χ

2 = 1.7, df = 5, p = 0.89 , n = 983

p= 0.30 p= 0.16