Coralie Villa

Vaulting quantification during level walking of transfemoral amputees

BACKGROUND Vaulting is a gait compensatory mechanism used by transfemoral amputees to assist toe clearance during the prosthetic swing phase. It is defined by a plantar flexion of the contralateral ankle during the single-limb support phase. The aim of the study is to propose a method to quantify vaulting of transfemoral amputees. METHODS 17 transfemoral amputees and 28 asymptomatic subjects participated in the data collection. Kinematics and kinetics of the whole body were recorded while subjects were walking on a level surface. Biomechanical gait analysis was focused on a reduced set of parameters linked to the contralateral ankle, the contralateral knee and the trajectory of the center of pressure. The patients were classified in two groups: with or without vaulting using video recordings. Differences between both groups and the control group were analyzed. FINDINGS A higher generated ankle power was found during the single support phase of the contralateral limb of transfemoral amputees presenting vaulting. These subjects presented also a higher dissipated knee flexion power before the peak in ankle flexion power. The trajectory of the center of pressure was also modified by the vaulting. INTERPRETATION Vaulting for transfemoral amputees is characterized by a propulsive plantar flexion at the contralateral ankle. Quantifying the ankle flexion power during the contralateral single support phase will help in understanding vaulting.

Evolution of vaulting strategy during locomotion of individuals with transfemoral amputation on slopes and cross-slopes compared to level walking

BACKGROUND Vaulting is a walking strategy qualitatively characterized in clinics by the sound ankle plantiflexion in midstance to assist prosthetic foot clearance. Even though potentially harmful, this strategy is often observed among people with transfemoral amputation to secure clearance of the prosthetic limb during swing phase. The aim of the study is to provide a quantitative analysis of the evolution of the vaulting strategy in challenging situations of daily living. METHODS 17 persons with transfemoral amputation and 17 able-bodied people participated in the study. Kinematic and kinetic gait analyses were performed for level walking, 10% inclined cross-slope walking, 5% and 12% inclined slope ascending. To study vaulting strategy, peak of generated power at the sound ankle at midstance was identified and quantified in the different walking situations. In particular, values were compared to a vaulting threshold corresponding to a peak of generated power superior to 0.15 W/kg. FINDINGS The vaulting threshold was exceeded for a larger proportion of people with amputation during cross-slope locomotion and slope ascent than during level walking. In addition, magnitude of the peak of generated power increased significantly compared to level walking in these situations. INTERPRETATION Vaulting seems to be widely used by patients with transfemoral amputation in daily living situations. The number of patients using vaulting increased with the difficulty of the walking situation. Results also suggested that patients could dose the amount of vaulting according to gait environment to secure prosthetic toe clearance. During rehabilitation, vaulting should also be corrected or prevented in daily living tasks.

Mechanical work performed by individual limbs of transfemoral amputees during step-to-step transitions: Effect of walking velocity

The greater metabolic demand during the gait of people with a transfemoral amputation limits their autonomy and walking velocity. Major modifications of the kinematic and kinetic patterns of transfemoral amputee gait quantified using gait analysis may explain their greater energy cost. Donelan et al. proposed a method called the individual limb method to explore the relationships between the gait biomechanics and metabolic cost. In the present study, we applied this method to quantify mechanical work performed by the affected and intact limbs of transfemoral amputees. We compared a cohort of six active unilateral transfemoral amputees to a control group of six asymptomatic subjects. Compared to the control group, we found that there was significantly less mechanical work produced by the affected leg and significantly more work performed by the unaffected leg during the step-to-step transition. We also found that this mechanical work increased with walking velocity; the increase was less pronounced for the affected leg and substantial for the unaffected leg. Finally, we observed that the lesser work produced by the affected leg was linked to the increase in the hip flexion moment during the late stance phase, which is necessary for initiating knee flexion in the affected leg. It is possible to quantify the mechanical work performed during gait by people with a transfemoral amputation, using the individual limb method and conventional gait laboratory equipment. The method provides information that is useful for prosthetic fitting and rehabilitation.

Influence of physical capacities of males with transtibial amputation on gait adjustments on sloped surfaces

The aim of the study was to investigate how kinematic and kinetic adjustments between level and slope locomotion of persons with transtibial amputation are related to their individual muscular and functional capacities. A quantified gait analysis was conducted on flat and slope surfaces for seven patients with transtibial amputation and a control group of eight subjects to obtain biomechanical parameters. In addition, maximal isometric muscular strength (knee and hip extensors) and functional scores were measured. The results of this study showed that most of the persons with transtibial amputation could adapt to ramp ascent either by increasing ankle, knee, and hip flexion angles of the residual limb and/or by recruiting their hip extensors to guarantee enough hip extension power during early stance. Besides, 6-minute walk test score was shown to be a good predictor of adaptation capacities to slope ascent. In ramp descent, the increase of knee flexion moment was correlated with knee extensor strength and residual-limb length. However, no correlation was observed with functional parameters. Results show that the walking strategy adopted by persons with transtibial amputation to negotiate ramp locomotion mainly depends on their muscular capacities. Therefore, muscular strengthening should be a priority during rehabilitation.

Whole limb push-off work in people with transtibial amputation during slope ascent.

Unilateral transtibial amputation impairs locomotion, especially in daily living outdoor situations. As an example, slope ascent requires specific gait adjustments such as hip power generation during single support followed by ankle power generation during second double support. Hip extensor strengthening could help people with transtibial amputation for hip propulsion in slope ascent (Langlois et al. 2014). Energy storage and return (ESAR) foot-ankle prostheses have been designed to absorb and release elastic energy in an attempt to restore some functions of the amputated limb. However, it remains unclear how ESAR feet contribute to center of mass propulsion, especially during slope ascent. Simple models were recently developed to globally analyze gait in an energetic point of view by computing the center of mass mechanical work (Donelan et al. 2002; Kuo et al. 2005). Particularly, several hypotheses permit to estimate for each lower limb the whole limb push-off work during double support (Kuo et al. 2005). Using this approach, step-to-step transition was investigated during level walking, in ablebodied subjects wearing prosthetic foot (Caputo & Collins 2014) and in people with transtibial and transfemoral amputation (Houdijk et al. 2009; Bonnet et al. 2014), and in slopes in able-bodied subjects (Franz et al. 2012). Up to now, no study quantified prosthetic and contralateral push-off work during slope ascent in a below-knee amputee population. Thus, the aim of the study is to investigate center of mass mechanical work adjustments during the propulsion period during slope ascent for two inclinations of slopes compared to level walking in people with transtibial amputation.

Measurement of wheelchair adjustment effects on turning deceleration

Manual wheelchair (MWC) locomotion combines straightforward and turning motions, in everyday life as well as in sport practice. Many authors demonstrated the effects of various MWC properties, such as geometry or wheel type, for straightforward displacements (Brubaker 1986; Medola et al. 2014), while only few studies have investigated their influence for turning motion (Bascou et al. 2014; Caspall et al. 2013; Kauzlarich, Bruning, and Thacker 1984). In particular, the impact of wheelchair setup on its turning deceleration, which characterizes the MWC tendency to stop its turning motion, is unclear. This study aims at clarifying the effects of MWC adjustments on turning deceleration in the field, using a fractional factorial design.

Analysis of ankle stiffness for asymptomatic subjects and transfemoral amputees in daily living situations

in daily living situations X. Drevelle*, C. Villa, X. Bonnet, J. Bascou, I. Loiret and H. Pillet INI, Centre d’Etude et de Recherche sur l’Appareillage des Handicapés, BP 50719 57147 Woippy Cedex, France; Arts et Métiers ParisTech, LBM, 151 boulevard de l’Hôpital, 75013 Paris, France; PROTEOR, 6 rue de la redoute 21250 Seurre, France; Centre de médecine physique et de réadaptation Louis Pierquin IRR-UGECAM Nord – Est 75, Boulevard Lobau, CS 34209, 54042 Nancy Cedex, France

Vaulting quantification for transfemoral amputees in different gait situations.

X. Drevelle*, C. Villa, C. Sauret, P. Fode, N. Martinet, H. Pillet and F. Lavaste INI, Centre d’Etude et de Recherche sur l’Appareillage des Handicapés, BP 50719 57147 Woippy Cédex, France; Arts et Metiers ParisTech, LBM, 151 boulevard de l’Hôpital, 75013 Paris, France; Centre de médecine physique et de réadaptation Louis Pierquin IRR-UGECAM Nord – Est 75, Boulevard Lobau, CS 34209, 54042 Nancy Cedex, France

Gait analysis of amputee people in limiting situations of daily living

C. Villa*, H. Pillet, P. Fode, J. Paysant, C. Sauret, N. Martinet and F. Lavaste Arts et Metiers ParisTech, LBM, 151 boulevard de l’Hôpital, 75013 Paris, France; INI, Centre d’Etude et de Recherche sur l’Appareillage des Handicapés, BP 50719 57147, Woippy Cédex, France; Centre de médecine physique et de réadaptation Louis Pierquin IRR-UGECAM Nord -Est 75, Boulevard Lobau, CS 34209, 54042 Nancy Cedex, France

Evaluation of a scapula spinal marker cluster to track the scapula kinematics during manual wheelchair propulsion

Manual wheelchair (MWC) propulsion is a constraining mode of locomotion for the musculoskeletal system. It results that 30–70% of the MWC users suffer from musculoskeletal disorders, in particular at the shoulder joints (Finley and Rodgers 2004). Hence, there is a high interest in investigating shoulder biomechanics during MWC locomotion. However, tracking the scapula motion during MWC locomotion is not obvious because high soft tissue artifact can occur using skin markers. Some studies reported the use of a scapula locator during pseudo-kinematics acquisitions and showed a non-negligible motion of the scapula during MWC propulsion (Koontz et al. 2003). However, this methodology cannot be used to track dynamically the scapula during MWC locomotion. For that purpose, others methods were developed, such as multiple-calibration method (de Groot and Brand 2001). Nevertheless, this method can be time consuming for the patient. Finally, other studies used a technical cluster composed of at least 3 markers placed on the acromion (Shaheen et al. 2011) or on the scapula spine (Prinold and Bull 2015). These techniques seem to be efficient for tracking the scapula orientation but failed for the translation (Naaim et al. 2017). In addition, validation data did not concern MWC locomotion. The goal of this study was to evaluate the accuracy of a spinal marker cluster to track the scapula motion during MWC locomotion.