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EVALUATION OF HIP MOMENT CHANGES AND MECHANICAL WORK DURING TRANSFEMORAL AMPUTEE GAIT
S520
Presentation 1520 − Topic 36. Orthotics and prosthetics
EVALUATION OF HIP MOMENT CHANGES AND MECHANICAL WORK DURING TRANSFEMORAL AMPUTEE GAIT Coralie Villa (1), Xavier Bonnet (2), Hélène Pillet (1), Pascale Fodé (3), François Lavaste (1,3)
1. Arts et Metiers ParisTech, LBM, France; 2. PROTEOR, Handicap Technologie, France; 3. INI, Centre d’Etude et de Recherche sur l’Appareillage des Handicapés, France.
Introduction People with transfemoral amputation have to cope with the lack of prosthetic push-off and the control of the prosthetic knee. It induces compensation during gait such as the alteration of the moment created by transfemoral amputees in the hip during the double stance phase of a gait cycle [Radcliffe, 1977; Schmalz, 2002]. Schmalz also showed an increase of energy expenditure of transfemoral amputees evaluating oxygen consumption during gait. However, the link between mechanical parameter and metabolic energy could not be made. On the other hand, several inverted pendulum models of walking have been developed to investigate mechanical work of human walking [Kuo, 2007]. In particular, Donelan proposed a method to estimate the mechanical work in the lower limbs for the step to step transition [Donelan, 2000]. Houdijk showed that this parameter was a major determinant of the metabolic cost of walking for transtibial amputees [Houdijk, 2009]. However, to date there has been no study investigating this transition for transfemoral amputees. The aim of this study was to evaluate the mechanical work performed during step to step transition for transfemoral amputees compared to able-bodied subjects and to understand the consequences of hip moment modifications on this mechanical work.
Methods Six active transfemoral amputees and six control subjects participated in this study. The subjects walked at three self-selected different speeds along a 9m walkway equipped with two force plates. An optoelectronic system was used to determine segmental and articular kinematics of the lower limbs. Hip moments were calculated using inverse dynamics methods. The position and velocity of the centre of masse of the body were estimated. The mechanical work was computed using the method proposed by Donelan [Donelan, 2000].
Results The terms representing the contribution of each limb in the mechanical powers are symmetrical for asymptomatic subjects. Regarding the transfemoral amputees, these terms are no longer symmetrical Journal of Biomechanics 45(S1)
especially during the double stance phase in which the mechanical work created by the sound limb (0.27±0.09 J/kg) is much more important than the one created by the prosthetic limb (0.08±0.01 J/kg) (Figure 1). In addition, hip moments were different between able-bodied subjects (0.80±0.24 N.m/kg) and transfemoral amputees (sound side 0.70±0.28 N.m/kg, prosthetic side 0.88±0.28 N.m/kg).
Figure 1: Internal power during a gait cycle of transfemoral amputee
Discussion The increased hip extension moment in the prosthetic limb of transfemoral amputees enables them to unlock the prosthetic knee at the end of the step to step transition to start knee flexion. The increase of the prosthetic hip moment reduces the fore-aft ground reaction force applied on the prosthetic limb and induces a lower mechanical work. This loss of work is compensated by the sound limb to ensure the propulsion during gait. The perspective of the study would be to complete the data by the evaluation of metabolic energy.
References Donelan et al, Arch Physiol Biochem, 108(1-2):17, 2000. Houdijk et al, Gait Posture, 30(1):35–40, 2009. Kuo, Hum Movement Sci, 26(4):617–656, 2007. Radcliffe, Prosthet Orthot Int, 1(3):146–160, 1977. Schmalz et al, Gait Posture, 16(3):255–263, 2002.
ESB2012: 18th Congress of the European Society of Biomechanics
Presentation 1520 − Topic 36. Orthotics and prosthetics
EVALUATION OF HIP MOMENT CHANGES AND MECHANICAL WORK DURING TRANSFEMORAL AMPUTEE GAIT Coralie Villa (1), Xavier Bonnet (2), Hélène Pillet (1), Pascale Fodé (3), François Lavaste (1,3)
1. Arts et Metiers ParisTech, LBM, France; 2. PROTEOR, Handicap Technologie, France; 3. INI, Centre d’Etude et de Recherche sur l’Appareillage des Handicapés, France.
Introduction People with transfemoral amputation have to cope with the lack of prosthetic push-off and the control of the prosthetic knee. It induces compensation during gait such as the alteration of the moment created by transfemoral amputees in the hip during the double stance phase of a gait cycle [Radcliffe, 1977; Schmalz, 2002]. Schmalz also showed an increase of energy expenditure of transfemoral amputees evaluating oxygen consumption during gait. However, the link between mechanical parameter and metabolic energy could not be made. On the other hand, several inverted pendulum models of walking have been developed to investigate mechanical work of human walking [Kuo, 2007]. In particular, Donelan proposed a method to estimate the mechanical work in the lower limbs for the step to step transition [Donelan, 2000]. Houdijk showed that this parameter was a major determinant of the metabolic cost of walking for transtibial amputees [Houdijk, 2009]. However, to date there has been no study investigating this transition for transfemoral amputees. The aim of this study was to evaluate the mechanical work performed during step to step transition for transfemoral amputees compared to able-bodied subjects and to understand the consequences of hip moment modifications on this mechanical work.
Methods Six active transfemoral amputees and six control subjects participated in this study. The subjects walked at three self-selected different speeds along a 9m walkway equipped with two force plates. An optoelectronic system was used to determine segmental and articular kinematics of the lower limbs. Hip moments were calculated using inverse dynamics methods. The position and velocity of the centre of masse of the body were estimated. The mechanical work was computed using the method proposed by Donelan [Donelan, 2000].
Results The terms representing the contribution of each limb in the mechanical powers are symmetrical for asymptomatic subjects. Regarding the transfemoral amputees, these terms are no longer symmetrical Journal of Biomechanics 45(S1)
especially during the double stance phase in which the mechanical work created by the sound limb (0.27±0.09 J/kg) is much more important than the one created by the prosthetic limb (0.08±0.01 J/kg) (Figure 1). In addition, hip moments were different between able-bodied subjects (0.80±0.24 N.m/kg) and transfemoral amputees (sound side 0.70±0.28 N.m/kg, prosthetic side 0.88±0.28 N.m/kg).
Figure 1: Internal power during a gait cycle of transfemoral amputee
Discussion The increased hip extension moment in the prosthetic limb of transfemoral amputees enables them to unlock the prosthetic knee at the end of the step to step transition to start knee flexion. The increase of the prosthetic hip moment reduces the fore-aft ground reaction force applied on the prosthetic limb and induces a lower mechanical work. This loss of work is compensated by the sound limb to ensure the propulsion during gait. The perspective of the study would be to complete the data by the evaluation of metabolic energy.
References Donelan et al, Arch Physiol Biochem, 108(1-2):17, 2000. Houdijk et al, Gait Posture, 30(1):35–40, 2009. Kuo, Hum Movement Sci, 26(4):617–656, 2007. Radcliffe, Prosthet Orthot Int, 1(3):146–160, 1977. Schmalz et al, Gait Posture, 16(3):255–263, 2002.
ESB2012: 18th Congress of the European Society of Biomechanics