Biomechanical responses of young adults with unilateral transfemoral amputation using two types of mechanical stance control prosthetic knee joints.

BACKGROUND: Prosthetic knee joint function is important in the rehabilitation of individuals with transfemoral amputation. OBJECTIVES: The objective of this study was to assess the gait patterns associated with two types of mechanical stance control prosthetic knee joints-weight-activated braking knee and automatic stance-phase lock knee. It was hypothesized that biomechanical differences exist between the two knee types, including a prolonged swing-phase duration and exaggerated pelvic movements for the weight-activated braking knee during gait. STUDY DESIGN: Prospective crossover study. METHODS: Spatiotemporal, kinematic, and kinetic parameters were obtained via instrumented gait analysis for 10 young adults with a unilateral transfemoral amputation. Discrete gait parameters were extracted based on their magnitudes and timing. RESULTS: A 1.01% ± 1.14% longer swing-phase was found for the weight-activated braking knee (p < 0.05). The prosthetic ankle push-off also occurred earlier in the gait cycle for the weight-activated braking knee. Anterior pelvic tilt was 3.3 ± 3.0 degrees greater for the weight-activated braking knee. This range of motion was also higher (p < 0.05) and associated with greater hip flexion angles. CONCLUSIONS: Stance control affects biomechanics primarily in the early and late stance associated with prosthetic limb loading and unloading. The prolonged swing-phase time for the weight-activated braking knee may be associated with the need for knee unloading to initiate knee flexion during gait. The differences in pelvic tilt may be related to knee stability and possibly the different knee joint stance control mechanisms. CLINICAL RELEVANCE: Understanding the influence of knee function on gait biomechanics is important in selecting and improving treatments and outcomes for individuals with lower-limb amputations. Weight-activated knee joints may result in undesired gait deviations associated with stability in early stance-phase, and swing-phase initiation in the late stance-phase of gait.

Long-term clinical evaluation of the automatic stance-phase lock-controlled prosthetic knee joint in young adults with unilateral above-knee amputation.

PURPOSE: The purpose of this study was to clinically evaluate the automatic stance-phase lock (ASPL) knee mechanism against participants' existing weight-activated braking (WAB) prosthetic knee joint. METHOD: This prospective crossover study involved 10 young adults with an above-knee amputation. Primary measurements consisted of tests of walking speeds and capacity. Heart rate was measured during the six-minute walk test and the Physiological Cost Index (PCI) which was calculated from heart rate estimated energy expenditure. Activity was measured with a pedometer. User function and quality of life were assessed using the Lower Limb Function Questionnaire (LLFQ) and Prosthetic Evaluation Questionnaire (PEQ). Long-term follow-up over 12 months were completed. RESULTS: Walking speeds were the same for WAB and APSL knees. Energy expenditure (PCI) was lower for the ASPL knees (p = 0.007). Step counts were the same for both knees, and questionnaires indicated ASPL knee preference attributed primarily to knee stability and improved walking, while limitations included terminal impact noise. Nine of 10 participants chose to keep using the ASPL knee as part of the long-term follow-up. CONCLUSIONS: Potential benefits of the ASPL knee were identified in this study by functional measures, questionnaires and user feedback, but not changes in activity or the PEQ.

Evaluación del seguimiento auditivo del recién nacido prematuro extremo en el Hospital San Juan de Dios / Evaluation of auditory follow-up in extreme premature newborns at the San Juan de Dios hospital

La hipoacusia sensorioneural profunda a severa tiene una incidencia de 1 a 2 por ciento en recién nacidos con factores de riesgo. El objetivo del presente trabajo es evaluar el seguimiento auditivo de los recién nacidos prematuros extremos del Hospital San Juan de Dios. Entre 1995 y 1997 nacieron 214 niños de estas características, sobreviviendo 141. De estos niños sólo en un 60 por ciento se realizó examen de potenciales auditivos evocados; de estos exámenes, un 61 por ciento umbral superior a 30 dB HL. De los 141 niños que sobrevivieron, se logró realizar 35 audiometrías sin pesquizar hipoacusia sensorioneural. Se concluye que el programa en uso no es efectivo, proponiéndose un nuevo esquema de evaluación