Background and purpose The methods of reconstruction for proximal femur bone tumors that are used most often include modular prosthetic replacement and allograft-prosthesis composite reconstruction. In modular prostheses, the abductors are detached from the insertion and then reinserted into the implant, and the iliopsoas is detached and left free. In the allograft-prosthesis composite, the detached tendons are fixated to the graft. We assessed whether the latter procedure provides functional advantages regarding gait.Patients and methods We studied 2 groups of 10 patients, each with prosthetic reconstruction of the proximal femur either with modular prosthetic replacement or with allograft-prosthesis composite. Functional performance was analyzed by gait analysis 2.5–10 years after surgery. At that time, all the patients had good function according to the Musculoskeletal Society score.Results Walking speed was reduced in all patients, and especially in patients with modular prosthetic replacement. Different hip extension patterns during late stance were found in the 2 groups. Surface EMG showed a typical prolonged muscle co-contraction pattern during gait, which was more evident in modular prosthetic patients.Interpretation Although both procedures provided good functional outcome in the long-term follow-up, gait analysis revealed mechanical changes during gait that were probably related to the muscle reinsertion procedure. Direct fixation of the muscles to the bone graft appeared to result in a more efficient muscular recovery.

Walking on a split-belt treadmill (each of the two belts running at a different speed) has been proposed as an experimental paradigm to investigate the flexibility of the neural control of gait and as a form of therapeutic exercise. However, the scarcity of dynamic investigations challenges the validity of the available findings. The aim of the present study was to investigate the dynamic asymmetries of lower limbs of healthy adults during adaptation to gait on a split-belt treadmill. Ten healthy adults walked on a split-belt treadmill mounted on force sensors, with belts running either at the same speed (‘tied’ condition) or at different speeds (‘split’ condition, 0.4 vs. 0.8 or 0.8 vs. 1.2 m/s). The sagittal power and work provided by ankle, knee and hip joints, joint rotations, muscle lengthening, and surface electromyography were recorded simultaneously. Various tied/split walking sequences were requested. In the split condition a marked asymmetry between the parameters recorded from each of the two lower limbs, in particular from the ankle joint, was recorded. The work provided by the ankle (the main engine of body propulsion) was 4.8 and 2.2 times higher (in the 0.4 vs. 0.8, and 0.8 vs. 1.2 m/s conditions, respectively) compared with the slower side, and 1.2 and 1.1 times higher compared with the same speed in the tied condition. Compared with overground gait in hemiplegia, split gait entails an opposite spatial and dynamic asymmetry. The faster leg mimics the paretic limb temporally, but the unimpaired limb from the spatial and dynamic point of view. These differences challenge the proposed protocols of split gait as forms of therapeutic exercise.

Few studies have investigated the kinematic aspects of the body centre of mass motion, that is, its three-dimensional path during strides and their changes with child development. This study aimed to describe the three-dimensional path of the centre of mass in children while walking in order to disentangle the effect of age from that of absolute forward speed and body size and to define preliminary pediatric normative values. The three-dimensional path of the centre of mass during walking was compared across healthy children 5–6− years ( n = 6), 7–8 years ( n = 6), 9–10 years ( n = 5), and 11–13 years of age ( n = 5) and healthy adults (23–48 years, n = 6). Participants walked on a force-sensing treadmill at various speeds, and height normalization of speed was conducted with the dimensionless Froude number. The total length and maximal lateral, vertical, and forward displacements of the centre of mass path were calculated from the ground reaction forces during complete strides and were scaled to the participant’s height. The centre of mass path showed a curved figure-of-eight shape. Once adjusted for speed and participants’ height, as age increased, there was a decrease in the three-dimensional parameters and in the lateral displacement, with values approaching those of adults. At each step, lateral redirection of the centre of mass requires brisk transient muscle power output. The base of support becomes relatively narrower with increasing age. Skilled shortening of the lateral displacement of the centre of mass may therefore decrease the risk of falling sideways. The three-dimensional path of the centre of mass may represent maturation of neural control of gait during growth.

Bimanual coordination underlies many daily activities. It is tested by various versions of the old Minnesota Dexterity Test (dating back to 1931, ‘turning’ subtest). This, however, is ill standardized, may be time-consuming, and has poor normative data. A timed-revised form of the turning subtest (MTTrf) is presented. Age-related norms and test–retest reliability were computed. Sixty-four healthy individuals, 24–79 years, comprising 34 women, were required to pick up 60 small plastic disks from wells, rotate each disk, and transfer it to the other hand, which must replace it, as quickly as possible. Two trials were requested for each hand (ABBA sequence). The average time (seconds) across the 4 trials gave the test score. Participants were grouped (CART algorithm) into 3 statistically distinct (P<0.05) age×score strata, with cutoff 53+ and 73+ years, and tested at baseline and after 1 week. Test–retest reliability was measured both as consistency [intraclass correlation coefficient (ICCs) model 2.1] and as agreement (Bland–Altman plot). From the ICCs, the individual test–retest minimal real difference (in seconds) was computed. The whole MTTrf took less than 4 min to administer. Baseline scores ranged from 40 to 78 s. The ICCs ranged from 0.45 to 0.81 and the minimal real difference ranged from 6.68 to 13.40 s across the age groups. Fifty-nine out of 64 observations (92%) fell within the confidence limits of the Bland–Altman plot. The MTTrf is a reliable and practical test of bimanual coordination. It may be a useful addition to protocols of manual testing in occupational therapy.