RESUMEN
BACKGROUND: Persons with transtibial amputation report curb negotiation is more challenging than negotiating stairs. It is unknown if amputation technique influences curb negotiation ability. Traditional transtibial amputation surgical techniques do not join the distal tibia and fibula (non-Ertl), whereas a transtibial osteomyoplastic amputation (Ertl) creates a "bone bridge" connection. The Ertl may facilitate ambulation through greater residual end load bearing. OBJECTIVES: To determine if ability to negotiate a curb differs between Ertl and non-Ertl groups. STUDY DESIGN: Cross-sectional study. METHODS: Non-Ertl (n = 7) and Ertl (n = 5) participants ascended a 16-cm curb using their amputated and intact limb as the lead limb. Motion data and ground reaction forces were used to calculate ankle, knee, hip, and total limb work for ground and curb steps. RESULTS: On the ground, the amputated limb of both groups produced less work than the intact limb. In contrast, on the curb step, the Ertl amputated limb generated more net hip work than the non-Ertl amputated limb. As a result, the net limb work of the Ertl amputated limb did not differ from the non-amputated limbs. CONCLUSION: Comparisons between the amputated limb of Ertl and non-Ertl groups suggest use of a different curb stepping pattern between groups. CLINICAL RELEVANCE: These findings suggest that surgical technique may influence curb negotiation ability in individuals with transtibial amputation. Specifically, the Ertl group is able to produce more hip power than the non-Ertl group while negotiation a curb which may be attributed to the increased ability to end-load bear on the residual limb.
Asunto(s)
Amputación Quirúrgica/métodos , Amputados , Tibia/cirugía , Caminata/fisiología , Anciano , Fenómenos Biomecánicos , Estudios Transversales , Humanos , Persona de Mediana EdadRESUMEN
BACKGROUND: People with transtibial amputation stand ~50times/day. There are two general approaches to transtibial amputation: 1) distal tibia and fibula union using a "bone-bridge" (Ertl), 2) non-union of the tibia and fibula (Non-Ertl). The Ertl technique may improve functional outcomes by increasing the end-bearing ability of the residual limb. We hypothesized individuals with an Ertl would perform a five-time sit-to-stand task faster through greater involvement/end-bearing of the affected limb. METHODS: Ertl (n=11) and Non-Ertl (n=7) participants sat on a chair with each foot on separate force plates and performed the five-time sit-to-stand task. A symmetry index (intact vs affected limbs) was calculated using peak ground reaction forces. FINDINGS: The Ertl group performed the task significantly faster (9.33s (2.66) vs 13.27 (2.83)s). Symmetry index (23.33 (23.83)% Ertl, 36.53 (13.51)% Non-Ertl) indicated the intact limb for both groups produced more force than the affected limb. Ertl affected limb peak ground reaction forces were significantly larger than the Non-Ertl affected limb. Peak knee power and net work of the affected limb were smaller than their respective intact limb for both groups. The Ertl intact limb produced significantly greater peak knee power and net work than the Non-Ertl intact knee. INTERPRETATION: Although loading asymmetries existed between the intact and affected limb of both groups, the Ertl group performed the task ~30% faster. This was driven by greater power and work production of the Ertl intact limb knee. Our results suggest that functional differences exist between the procedures.
Asunto(s)
Amputación Quirúrgica , Movimiento/fisiología , Postura/fisiología , Tibia , Soporte de Peso/fisiología , Adulto , Amputados , Fenómenos Biomecánicos/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Tibia/cirugíaRESUMEN
Lower extremity joint moment magnitudes during swing are dependent on the inertial properties of the prosthesis and residual limb of individuals with transtibial amputation (TTA). Often, intact limb inertial properties (INTACT) are used for prosthetic limb values in an inverse dynamics model even though these values overestimate the amputated limb's inertial properties. The purpose of this study was to use subject-specific (SPECIFIC) measures of prosthesis inertial properties to generate a general model (GENERAL) for estimating TTA prosthesis inertial properties. Subject-specific mass, center of mass, and moment of inertia were determined for the shank and foot segments of the prosthesis (n=11) using an oscillation technique and reaction board. The GENERAL model was derived from the means of the SPECIFIC model. Mass and segment lengths are required GENERAL model inputs. Comparisons of segment inertial properties and joint moments during walking were made using three inertial models (unique sample; n=9): (1) SPECIFIC, (2) GENERAL, and (3) INTACT. Prosthetic shank inertial properties were significantly smaller with the SPECIFIC and GENERAL model than the INTACT model, but the SPECIFIC and GENERAL model did not statistically differ. Peak knee and hip joint moments during swing were significantly smaller for the SPECIFIC and GENERAL model compared with the INTACT model and were not significantly different between SPECIFIC and GENERAL models. When subject-specific measures are unavailable, using the GENERAL model produces a better estimate of prosthetic side inertial properties resulting in more accurate joint moment measurements for individuals with TTA than the INTACT model.
Asunto(s)
Miembros Artificiales , Extremidad Inferior/fisiología , Modelos Biológicos , Adulto , Amputación Quirúrgica , Fenómenos Biomecánicos , Femenino , Articulación de la Cadera/fisiología , Humanos , Articulación de la Rodilla/fisiología , Masculino , Persona de Mediana Edad , Implantación de Prótesis , Caminata/fisiología , Adulto JovenRESUMEN
The purpose of this study was two-fold: (1) demonstrate a technique that can be used to directly estimate the inertial properties of a below-knee prosthesis, and (2) contrast the effects of the proposed technique and that of using intact limb inertial properties on joint kinetic estimates during walking in unilateral, transtibial amputees. An oscillation and reaction board system was validated and shown to be reliable when measuring inertial properties of known geometrical solids. When direct measurements of inertial properties of the prosthesis were used in inverse dynamics modeling of the lower extremity compared with inertial estimates based on an intact shank and foot, joint kinetics at the hip and knee were significantly lower during the swing phase of walking. Differences in joint kinetics during stance, however, were smaller than those observed during swing. Therefore, researchers focusing on the swing phase of walking should consider the impact of prosthesis inertia property estimates on study outcomes. For stance, either one of the two inertial models investigated in our study would likely lead to similar outcomes with an inverse dynamics assessment.
Asunto(s)
Miembros Artificiales , Articulación de la Rodilla/fisiología , Pierna/fisiología , Modelos Biológicos , Adulto , Fenómenos Biomecánicos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Caminata/fisiologíaRESUMEN
OBJECTIVE: To determine whether a powered ankle-foot prosthesis improves gait mechanics, physical performance, and user satisfaction after traumatic transtibial amputation. DESIGN: Pre-post. SETTING: Gait analysis laboratory. PARTICIPANTS: Young individuals with traumatic transtibial amputation (n=11) and matched controls (n=11). INTERVENTIONS: Wearing an energy-storing and -returning (ESR) foot and a powered ankle-foot prosthesis. MAIN OUTCOME MEASURES: Gait mechanics, physical performance, and user satisfaction. RESULTS: The powered prosthesis ankle range of motion (ROM) was significantly larger (â¼30%) than that of the ESR limb. However, both devices demonstrated significantly less ankle ROM than the control and intact limbs. At preswing, the ESR limb generated approximately 40% less peak ankle power than control and intact limbs. In contrast, the powered prosthesis generated significantly greater peak ankle power than control (35%) and ESR (â¼125%) limbs, resulting in the powered limb absorbing twice the peak knee power observed in the control and intact limbs. The powered prosthesis limb peak hip power generation was approximately 45% greater at preswing than that of the intact limb. Walking velocity increased with the powered prosthesis compared with the ESR limb and was greater than that of the control group. However, physical performance measures were not significantly different between ESR and powered conditions. User satisfaction scores indicated a preference for the powered prosthesis over the ESR limb. CONCLUSIONS: Compensatory strategies during gait with the ESR and powered prosthetic devices were similar to those reported in the literature. However, the addition of ankle power and ROM by the powered prosthesis appeared to increase compensatory strategies at proximal joints.