RESUMEN
PURPOSE: In the present study, knee joint kinematics (e.g. knee flexion/extension) and kinetics (e.g. knee flexion moments) are assessed after total knee arthroplasty (TKA) between patients implanted with either a unilateral posterior stabilized (PS) and a posterior cruciate-retaining (PCR) design. It was hypothesized that maximum knee flexion during the loading response of the stance phase is greater in patients implanted with a PS design than in patients with a PCR design. Secondarily, it was hypothesized that patients with a PS design show decreased knee flexion moments during loading, compared with patients implanted with a PCR design. METHODS: This study examined two groups of TKA patients: one group (n = 12) with a PS design in which the posterior cruciate ligament (PCL) was sacrificed and the other (n = 9) with a PCR design. Gait analysis was used in level walking before and 6-9 months after surgery, to assess knee joint kinematics and kinetics during the loading response of the stance phase. RESULTS: No significant differences in maximum knee flexion between the two groups were found during the loading response of the stance phase. No significant differences in knee flexion moments were found either. Although in both groups knee flexion moments increased postoperatively, this was not statistically significant. In the contralateral (nonimplanted) knees, all mean knee flexion moments decreased postoperatively for both groups, yet this was not significant. CONCLUSIONS: The present gait analysis study showed no differences in kinematics and kinetics between the PS and the PCR TKP design. This might suggest that surgeons do not necessarily need to substitute the PCL by a PS design during TKA. LEVEL OF EVIDENCE: Prospective comparative study, Level II.
Asunto(s)
Artroplastia de Reemplazo de Rodilla/métodos , Marcha , Articulación de la Rodilla/cirugía , Osteoartritis de la Rodilla/cirugía , Anciano , Anciano de 80 o más Años , Fenómenos Biomecánicos , Femenino , Marcha/fisiología , Humanos , Articulación de la Rodilla/fisiopatología , Masculino , Persona de Mediana Edad , Osteoartritis de la Rodilla/fisiopatología , Ligamento Cruzado Posterior/cirugía , Estudios ProspectivosRESUMEN
OBJECTIVE: To describe the adjustments in gait characteristics of obstacle crossing, gait initiation and gait termination that occur in subjects with a recent lower limb amputation during the rehabilitation process. DESIGN: Prospective and descriptive study. SUBJECTS: Fourteen subjects with a recent transfemoral, knee disarticulation or transtibial amputation. METHODS: Subjects stepped over an obstacle and initiated and terminated gait at four different times during the rehabilitation process. OUTCOME MEASURES: Success rate, gait velocity and lower limb joint angles in obstacle crossing, centre of pressure shift and peak anteroposterior ground reaction force in gait initiation and termination. RESULTS: In obstacle crossing amputees increased success rate, gait velocity and swing knee flexion of the prosthetic limb. Knee flexion in transfemoral and knee disarticulation amputees was not sufficient for safe obstacle crossing, which resulted in a circumduction strategy. In gait initiation and termination amputees increased the anteroposterior ground reaction force and the centre of pressure shift in the mediolateral direction in both tasks. Throughout the rehabilitation process the centre of pressure was shifted anteriorly before single-limb stance on the trailing prosthetic limb in gait initiation, whereas in gait termination the centre of pressure in single-limb stance remained posterior when leading with the prosthetic limb. CONCLUSION: Subjects with a recent amputation develop adjustment strategies to improve obstacle crossing, gait initiation and gait termination. Innovations in prosthetic design or training methods may ease the learning process of these tasks.
Asunto(s)
Amputación Quirúrgica/rehabilitación , Amputados/rehabilitación , Marcha/fisiología , Extremidad Inferior/cirugía , Adaptación Fisiológica , Anciano , Articulación del Tobillo/fisiología , Miembros Artificiales , Fenómenos Biomecánicos , Femenino , Articulación de la Cadera/fisiología , Humanos , Articulación de la Rodilla/fisiología , Extremidad Inferior/fisiología , Masculino , Persona de Mediana Edad , Países Bajos , Equilibrio Postural/fisiología , Caminata/fisiologíaRESUMEN
A prosthetic foot is a key element of a prosthetic leg, literally forming the basis for a stable and efficient amputee gait. We determined the roll-over characteristics of a broad range of prosthetic feet and examined the effect of a variety of shoes on these characteristics. The body weight of a person acting on a prosthetic foot during roll-over was emulated by means of an inverted pendulum-like apparatus. Parameters measured were the effective radius of curvature, the forward travel of the center of pressure, and the instantaneous radius of curvature of the prosthetic feet. Finally, we discuss how these parameters relate to amputee gait.
Asunto(s)
Miembros Artificiales , Diseño de Prótesis , Amputados , Fenómenos Biomecánicos , Estatura , Peso Corporal , Pie , Marcha , Humanos , Ensayo de Materiales , Presión , Ajuste de Prótesis , Zapatos , Estrés Mecánico , Soporte de PesoRESUMEN
During prosthetic gait initiation, transfemoral (TF) amputees control the spatial and temporal parameters that modulate the propulsive forces, the positions of the center of pressure (CoP), and the center of mass (CoM). Whether their sound leg or the prosthetic leg is leading, the TF amputees reach the same end velocity. We wondered how the CoM velocity build up is influenced by the differences in propulsive components in the legs and how the trajectory of the CoP differs from the CoP trajectory in able bodied (AB) subjects. Seven TF subjects and eight AB subjects were tested on a force plate and on an 8 m long walkway. On the force plate, they initiated gait two times with their sound leg and two times with their prosthetic leg. Force measurement data were used to calculate the CoM velocity curves in horizontal and vertical directions. Gait initiated on the walkway was used to determine the leg preference. We hypothesized that because of the differences in propulsive components, the motions of the CoP and the CoM have to be different, as ankle muscles are used to help generate horizontal ground reaction force components. Also, due to the absence of an active ankle function in the prosthetic leg, the vertical CoM velocity during gait initiation may be different when leading with the prosthetic leg compared to when leading with the sound leg. The data showed that whether the TF subjects initiated a gait with their prosthetic leg or with their sound leg, their horizontal end velocity was equal. The subjects compensated the loss of propulsive force under the prosthesis with the sound leg, both when the prosthetic leg was leading and when the sound leg was leading. In the vertical CoM velocity, a tendency for differences between the two conditions was found. When initiating gait with the sound leg, the downward vertical CoM velocity at the end of the gait initiation was higher compared to when leading with the prosthetic leg. Our subjects used a gait initiation strategy that depended mainly on the active ankle function of the sound leg; therefore, they changed the relative durations of the gait initiation anticipatory postural adjustment phase and the step execution phase. Both legs were controlled in one single system of gait propulsion. The shape of the CoP trajectories, the applied forces, and the CoM velocity curves are described in this paper.
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Amputados/rehabilitación , Miembros Artificiales , Fémur , Marcha , Pierna/fisiopatología , Locomoción , Modelos Biológicos , Adulto , Simulación por Computador , Retroalimentación/fisiología , Femenino , Humanos , Masculino , Esfuerzo Físico , Presión , Estrés MecánicoRESUMEN
UNLABELLED: The popliteal angle is a widely used clinical measure for hamstring contracture in cerebral palsy (CP) patients and in healthy individuals. The reliability of popliteal angle measurement is being questioned. The aim of this study is to determine the reliability of popliteal angle measurement by means of visual and goniometric assessment. METHODS: Three different observers measured the popliteal angle in 15 CP patients and 15 healthy volunteers. In each subject, popliteal angles were visually estimated and measured with a blinded goniometer twice by all observers with approximately 1 hour between measurement sessions. RESULTS: All intraclass correlation coefficients (ICCs) were lower in the CP group compared with healthy controls. The ICC for intraobserver differences was higher than 0.75 for both groups. The ICC for interobserver reliability of visual estimates and goniometric measurements was low for both groups. Intermethod ICC was higher than 0.75 for both groups. CONCLUSIONS: Measurements in the CP group seemed to be less reliable than measurements in the control group. Intraobserver reliability is reasonable for both groups, but lower in CP patients than in controls. Interobserver reliability of both visual estimates and goniometrical measurements is poor. No significant differences in reliability have been found between visual estimation and goniometric measurement. Because of poor interobserver reliability of popliteal angle measurement, this should not be the only variable in clinical decision making in CP patients.
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Artrometría Articular , Parálisis Cerebral/fisiopatología , Adolescente , Estudios de Casos y Controles , Niño , Preescolar , Contractura/fisiopatología , Femenino , Humanos , Rodilla/fisiopatología , Masculino , Músculo Esquelético/fisiopatología , Variaciones Dependientes del Observador , Rango del Movimiento Articular/fisiología , Reproducibilidad de los Resultados , Programas InformáticosRESUMEN
The paraspinal muscles have been implicated as a major causative factor in the progression of idiopathic scoliosis. Therefore, the objectives of this preliminary study were to measure the electromyographic activity (EMG) of the paraspinal muscles to determine its relationship to progression of the scoliotic curve. Idiopathic scoliotic patients were selected and identified afterwards on curve progression. The EMG activity on both sides of the spine was measured in a set of standardized postures using bipolar surface electrodes at the apex and two end vertebrae of the scoliotic curve. An EMG ratio involving measurements of the EMG activity on the convex and concave sides of the scoliotic curve was used to evaluate the paraspinal muscles. Enhanced EMG ratios at the apex of the scoliotic curve were found in both groups during sitting and standing. The most interesting finding was that children with progression of the curve also showed enhanced EMG ratios at the lower end vertebra of the curve. The EMG ratios between the groups were significantly different from each other at the apex and end vertebrae for several test conditions. Overlap in the EMG-ratio ranges made differentiation difficult for prediction of the progression of the individual scoliosis patient. However, the EMG ratio at the lower end vertebra of the scoliotic curve is significantly higher than 1 in all test conditions in the group of children with subsequent progression of the curve, whereas it is always normal in the non-progressive group. Therefore, EMG of the paraspinal muscles might be of value for prediction of progression in idiopathic scoliosis.
Asunto(s)
Electromiografía , Músculo Esquelético/fisiopatología , Escoliosis/fisiopatología , Adolescente , Niño , Progresión de la Enfermedad , Femenino , Humanos , Masculino , Postura , Columna VertebralRESUMEN
STUDY DESIGN: A prospective study in which patients with idiopathic scoliosis were examined longitudinally by radiographic and electromyographic measurements according to a protocol. OBJECTIVES: To measure the growth velocity of the spine and the electromyographic ratio of the paraspinal muscles to determine their relation to progression of the scoliotic curve. SUMMARY OF BACKGROUND DATA: Several factors have been reported to be involved in the progression of idiopathic scoliosis. Possible factors may be growth disturbances and muscular abnormality. METHODS: Thirty patients with idiopathic scoliosis were examined over periods of 4 to 5 months. The periods were scored for progression, defined as an increase in Cobb angle of >10 degrees. Spinal growth velocity was measured as the length difference of the scoliotic spine between two consecutive radiographs. The electromyographic activity on both sides of the spine expressed as an electromyographic ratio was measured during relaxed upright standing using bipolar surface electrodes. Predictability of progression was evaluated with regression analysis and receiver operating characteristic analysis. RESULTS.: There was an independent association between both spinal growth velocity and electromyographic ratio and progression of the scoliotic curve. An equal sensitivity and specificity of spinal growth velocity for progression of 79.1% was observed at a growth velocity cutoff point of 11 mm/year. Similarly, a cutoff point of 1.25 for the electromyographic ratio could be determined with a predictive value for progression of 68.9%. In the presented nomogram, a spinal growth velocity >15 mm/year combined with an electromyographic ratio >2 gave an 89% probability of progression of the scoliotic deformity. Growth velocities 38 mm/year never resulted in progression. CONCLUSIONS: The combined measurement of spinal growth velocity and electromyographic ratio has significant predictive potential and may be valuable in the evaluation and treatment of idiopathic scoliosis.
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Electromiografía , Músculo Esquelético/fisiopatología , Escoliosis/fisiopatología , Columna Vertebral/crecimiento & desarrollo , Columna Vertebral/fisiopatología , Adolescente , Niño , Progresión de la Enfermedad , Femenino , Humanos , Masculino , Valor Predictivo de las Pruebas , Estudios Prospectivos , Radiografía , Escoliosis/diagnóstico por imagen , Sensibilidad y Especificidad , Columna Vertebral/diagnóstico por imagenRESUMEN
We performed gait analysis in 18 patients with a femoral endoprosthesis: 12 distal, 3 proximal and 3 total. Follow-up after surgery was mean 12 (0.6-19) years. The gait parameters measured were walking velocity, step length, duration of stance phase and swing phase. Goniometry of the hip, knee and ankle in both legs was determined during free-paced walking. The functional outcome score of the Musculoskeletal Tumor Society (MSTS) and the Ambulation score were also assessed in all patients. The mean free-paced walking velocity was 88% of normal. The step length of the uninvolved leg was longer than that of the involved one. The swing phase of the involved leg was longer than that of the uninvolved leg, and the stance phase of the involved leg was shorter than that of the uninvolved leg. Goniometry showed three abnormal patterns in the involved leg: a stiff knee gait in 10 patients, a flexed knee gait in 6, and an abnormal flexion-extension pattern in the hip in 9. Goniometry of the uninvolved leg was normal. The mean MSTS score was 22 points (72%). This showed a significant positive correlation to the Ambulation score, but no correlation to any of the temporal variables. Our findings indicate that the time of load on the involved leg, whether conscious or not, is reduced. Follow-up studies are needed to evaluate the effects of the asymmetrical gait pattern observed and the abnormal goniometric results on the development of endoprosthesis-related complications.