Assessment of passive musculoarticular ankle stiffness in children, adolescents and young adults with haemophilic ankle arthropathy.

OBJECTIVES: To measure passive musculoarticular ankle stiffness (PMAAS) and its intra- and interday reliability in adult control subjects without ankle disorders. We also sought to quantify PMAAS in children, adolescents and young adults with haemophilia (CAAwH) taking into account the accurate tibiotalar and subtalar joints structural status obtained by magnetic resonance imaging (MRI). METHODS: We included 23 CAAwH and 23 typically developing boys (TDB) matched by age, weight and height, along with 25 healthy volunteers for reliability assessment. All CAAwH underwent bilateral ankle MRI, with anatomical status assessed using the International Prophylaxis Study Group MRI scale. All CAAwH underwent PMAAS testing for both sides randomly vs the dominant side (DS) in TDBs. For assessing viscous stiffness (VS) and elastic stiffness (ES), eight different oscillation frequencies were randomly repeated three times for each subject. RESULTS: Good-to-excellent intra- and interday reliability was observed for ES and VS variables. No relevant differences were observed between the ankle viscoelastic properties in CAAwH without joint damage and matched TDBs, whereas the study revealed significantly increased ES in the affected ankles of CAAwH with severe unilateral joint involvement compared to the non-affected joint. CONCLUSION: This study confirmed increased ES in the severely affected ankles of CAAwH compared to non-affected sides. No differences in the ankle viscoelastic properties of CAAwH with or without joint damage were observed, however, compared to matched TDB.

The effects of real and artificial Leg Length Discrepancy on mechanical work and energy cost during the gait.

BACKGROUND: The impacts of Leg Length Discrepancy (LLD) on the kinematic and dynamic parameters of walking have been widely discussed. But little is known on total mechanical work and energy cost. These two variables are more representative of the functional impairment undergone by the LLD patients. AIM: To assess the changes of the mechanical work and energy cost of walking in subjects with real LLD and to compare their results with healthy subjects in whom the LLD has been simulated. METHOD: The mechanical work and energy cost data of 60 healthy subjects (speed: 4km/h) with artificial LLD induced by soles (2 and 4cm), 20 patients (speed: 3.75±0.5km/h) with real LLD and 20 matched subjects (speed: 3.75±0.5km/h) were collected. Statistical comparisons between the groups were performed using a t-paired test and ANOVA. RESULTS: Patients with a real LLD showed a significant decrease in mechanical work and energy cost when compared to norms. Patients with real LLD provide a better recovery when compared to subjects with artificial LLD of 2cm, and a decrease of energy cost and higher muscular efficiency (mechanical work/energy cost) when compared to subjects with artificial LLD of 4cm. CONCLUSIONS: Our results showed that patients with a real LLD develop compensatory strategies during gait, probably to minimize the displacement of the body center of mass and consequently reduce the amount of energy expenditure useful for their displacement. Moreover, they adopt a better gait strategy compared to the subjects in whom LLD was simulated.

Clinical assessment of 115 cases of hindfoot fusion with two different types of graft: Allograft+DBM+bone marrow aspirate versus autograft+DBM.

INTRODUCTION: Nonunion is a common complication (15%) of hindfoot and ankle arthrodesis. Autograft can improve the fusion rate because of its osteoconductive, osteoinductive and osteogenic properties. However, autograft harvesting is a source of morbidity. One alternative is to combine allograft with demineralized bone matrix (DBM) and iliac bone marrow aspirate (BMA). This combination graft has similar biological properties to healthy bone. When used alone, allograft has osteoconductive and sometimes structural properties. DBM provides osteoinduction and improves the osteconductivity. BMA adds cells and thereby osteogenic potential. HYPOTHESIS: Given its intrinsic properties, allograft-DBM-BMA is as effective as autograft-DBM treatment while simplifying the clinical practice. MATERIAL AND METHODS: One hundred and fifteen cases of ankle and hindfoot arthrodesis were studied in 82 patients divided in two groups: autograft-DBM vs allograft-DBM-BMA. Treatment effectiveness was assessed using clinical (time to fusion, fusion rate) and radiological (trabecular bone bridge, disappearance of joint space) criteria. A CT scan was done in 60% of cases when fusion could not be confirmed using the clinical and radiological criteria. RESULTS: There was no significant difference between the two groups in terms of fusion rate, time to fusion, number of heterotopic ossifications, revision rate and quantity of DBM used. The nonunion rate was 18% in the autograft group and 13% in the allograft group. The infection rate was 11% in the autograft and 4% in the allograft group. DISCUSSION: Allograft-DBM-BMA is an alternative to autograft-DBM that provides similar effectiveness without increasing the number of nonunion or complications. Osteonecrosis and surgical revision are risk factors. LEVEL OF EVIDENCE: III retrospective study.

Gait in adolescent idiopathic scoliosis: energy cost analysis.

Walking is a very common activity for the human body. It is so common that the musculoskeletal and cardiovascular systems are optimized to have the minimum energetic cost at 4 km/h (spontaneous speed). A previous study showed that lumbar and thoracolumbar adolescent idiopathic scoliosis (AIS) patients exhibit a reduction of shoulder, pelvic, and hip frontal mobility during gait. A longer contraction duration of the spinal and pelvic muscles was also noted. The energetic cost (C) of walking is normally linked to the actual mechanical work muscles have to perform. This total mechanical work (W(tot)) can be divided in two parts: the work needed to move the shoulders and lower limbs relative to the center of mass of the body (COM(b)) is known as the internal work (W(int)), whereas additional work, known as external work (W(ext)), is needed to accelerate and lift up the COM(b) relative to the ground. Normally, the COM(b) goes up and down by 3 cm with every step. Pathological walking usually leads to an increase in W (tot) (often because of increased vertical displacement of the COM(b)), and consequently, it increases the energetic cost. The goal of this study is to investigate the effects of scoliosis and scoliosis severity on the mechanical work and energetic cost of walking. Fifty-four female subjects aged 12 to 17 were used in this study. Thirteen healthy girls were in the control group, 12 were in scoliosis group 1 (Cobb angle [Cb] < or = 20 degrees), 13 were in scoliosis group 2 (20 degrees < Cb < 40 degrees), and 16 were in scoliosis group 3 (Cb > or = 40 degrees). They were assessed by physical examination and gait analysis. The 41 scoliotic patients had an untreated progressive left thoracolumbar or lumbar AIS. During gait analysis, the subject was asked to walk on a treadmill at 4 km h(-1). Movements of the limbs were followed by six infrared cameras, which tracked markers fixed on the body. W(int) was calculated from the kinematics. The movements of the COM(b) were derived from the ground reaction forces, and W(ext) was calculated from the force signal. W(tot) was equal to W(int) + W(ext). Oxygen consumption VO2 was measured with a mask to calculate energetic cost (C) and muscular efficiency (W(tot)/C). Statistical comparisons between the groups were performed using an analysis of variance (ANOVA). The external work (W(ext)) and internal work (W(int)) were both reduced from 7 to 22% as a function of the severity of the scoliosis curve. Overall, the total muscular mechanical work (W(tot)) was reduced from 7% to 13% in the scoliosis patients. Within scoliosis groups, the W(ext) for the group 1 (Cb > or = 20 degrees) and 2 (20 < or = Cb < or = 40 degrees) was significantly different from group 3 (Cb > or = 40 degrees). No significant differences were observed between scoliosis groups for the W(int). The W(tot) did not showed any significant difference between scoliosis groups except between group 1 and 3. The energy cost and VO2 were increased by around 30%. As a result Muscle efficiency was significantly decreased by 23% to 32%, but no significant differences related to the severity of the scoliosis were noted. This study shows that scoliosis patients have inefficient muscles during walking. Muscle efficiency was so severely decreased that it could be used as a diagnostic tool, since every scoliosis patient had an average muscle efficiency below 27%, whereas every control had an average muscle efficiency above 27%. The reduction of mechanical work found in scoliotic patients has never been observed in any pathological gait, but it is interpreted as a long term adaptation to economize energy and face poor muscle efficiency. With a relatively stiff gait, scoliosis patients also limit vertical movement of the COM(b) (smoothing the gait) and consequently, reduce W(ext) and W(int). Inefficiency of scoliosis muscles was obvious even in mild scoliosis (group 1, Cb < 20 degrees) and could be related to the prolonged muscle contraction time observed in a previous study (muscle co-contraction).

Assessment of the Chignon dynamic ankle-foot orthosis using instrumented gait analysis in hemiparetic adults.

OBJECTIVE: In the hemiplegic adult, gait is frequently perturbed by lack of ankle dorsiflexion at toe-off and may prompt prescription of an ankle-foot orthosis (AFO). Our objective was to evaluate the effect on gait of a dynamic AFO (the Chignon orthosis) in comparison with a prefabricated AFO (PAFO). METHOD: Ten chronic hemiplegic patients performed a 10 m gait test and then underwent an instrumented treadmill gait test under three different sets of conditions (without an orthosis, with a PAFO and with a Chignon orthosis). The energy cost was calculated by measuring the oxygen consumption during gait. RESULTS: The patients' free-walking speed was higher with the Chignon orthosis (0.81+/-0.25 ms(-1)) than without it (0.64+/-0.25 ms(-1); p<0.001). The ankle's segmental kinematics were better with the Chignon orthosis than without an orthosis, notably in terms of ankle position at heel strike (-0.8 degrees +/-4.6 versus -7.9 degrees +/-8.3; p=0.009) and ankle dorsiflexion at toe-off (1.7 degrees +/-4.6 versus -5.5 degrees +/-7.2; p=0.006). External mechanical work was lower with both the PAFO (0.61+/-0.2 J kg(-1)m(-1)) and the Chignon orthosis (0.61+/-0.23 J kg(-1)m(-1)), relative to gait without an orthosis (0.73+/-0.25 J kg(-1)m(-1); p=0.003). Total mechanical work was also lower with the PAFO (0.9+/-0.25 J kg(-1)m(-1)) and the Chignon orthosis (0.87+/-0.25 J kg(-1)m(-1)), relative to gait without an orthosis (1.09+/-0.37 J kg(-1)m(-1); p=0.001), whereas the reduction in energy cost with orthosis use was borderline-significant (p=0.06). CONCLUSION: Mechanical work was similarly improved by the two orthoses. The Chignon orthosis improved the free-walking speed and the ankle's segmental kinematics.

Energy cost, mechanical work, and efficiency of hemiparetic walking.

The energy cost of walking (C) in nine chronic hemiparetic patients was calculated by measuring the total mechanical work (Wtot) done by the muscles and the efficiency of this work production (eta). The energy cost was twice normal in slow walkers and 1.3 times greater in fast walkers. The increase in C was proportional to the increase in Wtot and eta was normal at around 20%, despite an increase in muscle tone and muscle co-contractions. This type of approach gives a greater understanding into how segmental impairments increase Wtot and C and contribute to a patient's disability.

Quantitative assessment of intrathecally administered baclofen in spasticity.

OBJECTIVE: To quantitatively assess the antispastic effect of intrathecally administered baclofen on muscle stiffness in spastic patients. DESIGN: Case-control study. SETTING: Clinical laboratory in a university hospital of a city of more than 1,000,000 inhabitants. PARTICIPANTS: Eighteen healthy adult volunteers (9 men, 9 women) were recruited for establishing the normal values. Eleven spastic patients (8 men, 3 women) comprised the study group. MAIN OUTCOME MEASURES: The resistance to passive sinusoidal displacement of 5 degrees imposed to the ankle joint was measured at frequencies from 3 to 12 Hz. Torque and displacement signals were subjected to a Fourier analysis to isolate the elastic and viscous components of the total muscle stiffness. RESULTS: In comparison with the period before intrathecal injection, and with the control group, it was shown that at 4 hours after injection, stretch reflex activity was abolished and elastic and viscous muscle stiffness approached control values. The abnormal residual stiffness concerned only the elastic component due to chronic transformations of the spastic muscle and/or due to changes in joints and periarticular connective tissue. This antispastic effect was completely reversed 36 hours after injection. CONCLUSION: The present study shows that the antispastic effect of intrathecally administered baclofen in spastic patients can be quantitatively assessed by a sensitive method allowing measurement of elastic and viscous components of muscle stiffness.

Assessment of hand function in a patient with chronic sensory demyelinating neuropathy.

A 60-year-old man presented with progressive large fiber sensory loss in the right first three fingers and, to a lesser extent, in both fourth and fifth fingers. Electrophysiologic studies were characteristic of chronic sensory demyelinating polyneuropathy, a variant of chronic inflammatory demyelinating polyneuropathy. Plasma exchange was unsuccessful, but intravenous immunoglobulin (IVIG) led to complete recovery of sensation for 2 months, although neurophysiologic abnormalities persisted. A battery of noninvasive tests to measure hand grip strength, tactile sensation at the fingertips, and motor control of prehension during precision grip revealed marked abnormalities in the right hand before IVIG. One month after IVIG, all test results had normalized, but they returned to pretreatment levels after 3 months. Functional evaluation of the hand may be a sensitive method to objectively quantify loss of and changes in cutaneous mechanoreceptor function of the fingers in large fiber sensory neuropathy.