Dynamic response and injury mechanism in the human foot and ankle and an analysis of dummy biofidelity

Manning, Paul; Wallace, Angus; Owen, Clare; Roberts, Adrian; Oakley, Charles; Lowne, Richard

Lower leg injuries are the most frequent severe injury (AIS/3) to car occupants resulting from frontal impacts. Consequently it is important to be able to detect and quantify the risk of these injuries from car impact tests. The need for a more biofidelic instrumented lower leg and the development of well-founded injury criteria has been clearly identified. At present there are insufficient biomechanical data available to aid the design and construction of such a dummy leg or to define injury risk criteria.

Three phases of a research programme are reported. In phase one, a driving simulator trial was carried out using 24 subjects to investigate the positioning and bracing of the driver’s lower leg prior to an emergencybraking event. In the second phase of the work, low energy impact tests have been carried out’ on post mortem human surrogate (PMHS) legs and volunteers. Comparative tests were performed on existing Hybrid III and GM/FTSS dummy feet/ankles. A new method to generate an Achilles force is reported which has been used to enable studies to be carried out into the effect of bracing by plantar flexion, such as emergency braking. Dynamic tests were based on the EEVC foot certification test procedure. The programme included tests to produce inversion and eversion. Additional toe impact tests were performed to assess lower leg behaviour with pre-impact bracing, allowing for future comparisons wiRichard Lowneth the ALEX leg.

Difficulties inherent in the interpretation of PMHS testing are reviewed and comparisons between tests on PMHS subjects and human volunteers are presented.

The final part of the paper reports the findings of an in-depth retrospective accident analysis based on data in the UK Co-operative Crash Injury Study database. Accidents in which the front seat occupant had sustained a lower leg injury of AIS/ in a frontal collision were examined along with the associated hospital notes and X-rays. The injuries are ranked in terms of frequency, severity and impairment in order to determine which lower leg injuries that are a priority for prevention.

Year

Entry

1995

Klopp GS, Crandall JR, Sieveka EM, Pilkey WD. Simulation of muscle tensing in pre-impact bracing. In: Proceedings of the 1995 International IRCOBI Conference on the Biomechanics of Impact. September 13-15, 1995; Brunnen, Switzerland.171-182.

1995

Schueler F, Mattern R, Zeidler F, Scheunert D. Injuries of the lower legs - foot, ankle joint, tibia; mechanisms, tolerance limits, injury-criteria evaluation of a recent biomechanic experiment-series (impact-tests with a pneumatic-biomechanic-impactor). In: Proceedings of the 1995 International IRCOBI Conference on the Biomechanics of Impact. September 13-15, 1995; Brunnen, Switzerland.33-45.

1997

Portier L, Petit P, Dômont A, Trosseille X, Le Coz J-Y, Tarrière C, Lassau J-P. Dynamic biomechanical dorsiflexion responses and tolerances of the ankle joint complex. In: Proceedings of the 41st Stapp Car Crash Conference. November 13-14, 1997; Lake Buena Vista, FL. Warrendale, PA: Society of Automotive Engineers:207-224. SAE 973330.

1997

Manning P, Wallace WA, Roberts AK, Owen CJ, Lowne RW. The position and movement of the foot in emergency manoeuvres and the influence of tension in the Achilles tendon. In: Proceedings of the 41st Stapp Car Crash Conference. November 13-14, 1997; Lake Buena Vista, FL. Warrendale, PA: Society of Automotive Engineers:195-206. SAE 973329.

1996

Crandall JR, Portier L, Petit P, Hall GW, Bass CR, Klopp GS, Hurwitz S, Pilkey WD, Trosseille X, Tarrière C, Lassau J-P. Biomechanical response and physical properties of the leg, foot, and ankle. In: Proceedings of the 40th Stapp Car Crash Conference. November 4-6, 1996; Albuquerque, NM. Warrendale, PA: Society of Automotive Engineers:173-192. SAE 962424.