脊柱结核病灶的彻底清除与稳定性重建

脊柱结核是骨关节结核的主要组成部分,据1956至2004年北京市结核病研究所6 140例骨关节患者统计,脊柱结核为4 555例,占74.19%[1].近年来随着人类免疫缺陷病毒(HIV)感染者在国内的增多,骨关节结核发病率又有抬头的趋势,目前也有部分学者对该疾患进行了研究[2-6].因而,作为一名脊柱外科医师,对提高脊柱结核的诊治应有一个新的认识.     

Exploring the role of applied force eccentricity after foot-contact in managing anterior instability among older adults during compensatory stepping responses

BackgroundThe specific mechanisms responsible for age-related decline in forward stability control remain unclear. Previous work has suggested reactive control of net ground reaction force (GRF_net) eccentricity may be responsible for age-related challenges in mediolateral stability control during the restabilisation phase of forward compensatory stepping responses.Research questionsDoes reactive control of GRF_net eccentricity play a role in managing forward stability control during the restabilisation phase of a forward stepping response to external balance perturbation?MethodsHealthy younger (YA) (n = 20) and older adults (OA) (n = 20) were tethered to a rigid frame, via adjustable cable. Participants were released from a standardised initial forward lean and regained their balance using a single step. Whole-body motion analysis and four force platforms were utilised for data acquisition. Forward instability was quantified as centre of mass (COM) incongruity – the difference between the first local peak and final stable anterior COM positions. The extent of GRF_net eccentricity was quantified as the sagittal-plane angle of divergence of the line of action of the GRF_net relative to the COM. Two discrete points during restabilisation were examined (P1 and P2), which have been suggested to be indicative of proactive and reactive COM control, respectively. Age-related differences in magnitude, timing and trial-to-trial variability of kinematic and kinetic outcome variables were analysed using two-factor ANOVAs with repeated-measures.ResultsOA exhibited greater COM incongruity magnitude and variability – both were reduced with trial-repetition. There were no age-related differences in the magnitude or timing of P2. Instead, OA exhibited a reduced magnitude of GRF_net eccentricity at P1. There was a positive correlation between AP COM incongruity magnitude and P1 magnitude.SignificanceDifferent from mediolateral stability control, the present results suggest that OA may experience forward stability control challenges as a function of insufficient preparatory lower limb muscle activation prior to foot-contact.