The mechanism of femoral fracture in an impact accident.
BACKGROUND
Following the crash of a Boeing 737-400 aircraft on the M1 motorway at Kegworth, near Nottingham, England, on January 8, 1989, it became apparent that a large number of pelvic and lower limb injuries had been sustained by the survivors. Had there been a fire, these injuries would have severely hindered the ability of the occupants to escape. The mechanism of pelvic and lower limb injuries in impact accidents previously has been related to flailing of the limbs and axial loading of the femur as in automobile accidents.


OBJECTIVE
A bending load is the primary mechanism of femoral fracture in an impact aircraft accident rather than an axial load.


METHODS
Two methods of study have been used to investigate the impact biomechanics of the pelvis and lower limb: a) clinical review of the injuries sustained in the M1 Kegworth accident; and b) impact testing.


RESULTS
A clinical review of the M1 aircrash survivors suggested that axial loading was not the primary mechanism causing femoral fractures and suggested that a bending load might be applied to the femur. Impact testing confirmed that axial loading of the femur did not appear to be significant.


CONCLUSIONS
Our study suggests that in the presence of intact occupant protection systems, a femoral bending mechanism involving the front seat spar of passenger seats is a primary cause of femoral fracture in an impact aircraft accident.
Department of Orthopaedic and Accident Surgery, University Hospital, Queens Medical Centre, Nottingham, United Kingdom.
P
P
Brownson
J M
JM
Rowles
W A
WA
Wallace
D J
DJ
Anton
D000060:Accidents, Aviation / Q000706:statistics & numerical data; D001696:Biomechanical Phenomena; D004739:England; D005264:Femoral Fractures / Q000209:etiology* / Q000517:prevention & control; D006801:Humans; D008348:Manikins; D011187:Posture; D012189:Retrospective Studies; D012307:Risk Factors; D012622:Seat Belts; D017741:Survivors; D014743:Videotape Recording