Effect of splint on pain, function and quality of life in trapeziometacarpal osteoarthritis patients?

Trapeziometacarpal (TM) Osteoarthritis is one of the most common osteoarthritis. It causes pain, loss of mobility and strength and affected function in daily life. Splint is one of the conservative treatments proposed to patients. The purpose of this study was to assess the effect of this conservative treatment on pain, function and quality of life at long-term. We sent 193 questionnaires to patients who received a CMC splint for their TM osteoarthritis. The CMC splint immobilizes only the TM joint and leaves free the interphalangeal joint of the thumb and the wrist. First, we comptuted how many patients had finally undergone surgical treatment. On the non-operated patients, we analyzed the pain (VAS), the function (QuickDASH score) and the quality of life (SF-12). We compared the results to literature and norms. Finally, 186 people could be included in the study ,115 we answered and 28 were operated on (24%). After 4 years (3.8±1.7 yrs) of conservative treatment, The VAS and QuickDASH scores were significantly worse comparatively to a cohort of healthy patients, trapezectomy and arthrodesis patients. The SF-12 scores were reduced from 20% comparative to norms. In conclusion, few patients had surgery after splinting as a conservative treatment. However, these non- operated patients do not provide good results.

Neutrophil-to-lymphocyte ratio (NLR) distribution shows an advantage compared to C-reactive protein (CRP) for the early inflammation monitoring after total hip arthroplasty.

C-reactive protein (CRP) distribution has been used to monitor early inflammation after total hip arthroplasty (THA). Neutrophil to lymphocyte ratio (NLR) is a new and cheap inflammatory marker. This study aimed to verify whether Neutrophil to lymphocyte ratio (NLR) distribution has an advantage when compared to C-reactive protein (CRP) distribution for the inflammation monitoring after total hip arthroplasty (THA). 116 THA patients were retrospectively selected over a 2 years period. They all had available blood tests preoperatively and at postoperative days 2, 4 and 42. Median peak values were compared between CRP and NLR. The effect of demographics on CRP and NLR was tested. At days 4 and 42, 100% and 16.3% of patients had not reached normal CRP (< 10mg/L) while 56.8% and 6.8% of patients had not reached normal NLR (<5) respectively. There was no effect of demographics on NLR except for age. Older patients had higher NLR (p 0.037). NLR showed a quicker return to normal than CRP. Our results show that NLR seems to be a better marker to follow inflammation after THA than CRP.

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.

[Pelvic floor muscles training, electrical stimulation, bladder training and lifestyle interventions to manage lower urinary tract dysfunction in multiple sclerosis: a systematic review]. / Troubles du bas appareil urinaire chez des patients atteints de la sclérose en plaques et kinésithérapie pelvi-périnéale : revue systématique.

AIM: To assess the effectiveness of conservative therapeutic approaches in a multiple sclerosis population. MATERIAL: Review was performed in PubMed, PEDro, Scopus and Cochrane Library using combinations of the following keywords: multiple sclerosis; bladder dysfunction; overactive bladder; detrusor hyperreflexia; urge incontinence; urgency; stress incontinence; pelvic floor muscle; biofeedback; PTNS; tibial nerve; bladder training; physical therapy; physiotherapy; conservative treatment and behavioral therapy. RESULTS: Six randomized articles including 289 patients were selected. Four papers exhibited strong scores for the methodological quality assessment. The parameters always significantly improved concerned: number of incontinence episodes (decreased from 64% to 86% after treatment versus before treatment), quality of life (P≤0.001), severity of irritative symptoms (decreased by more than 50% after treatment versus before treatment), and nocturia (P=0.035 to P<0.001). Activities and participation, maximum flow rate, mean voided volume and daytime frequency were not significantly improved in all trials. CONCLUSIONS: The physical therapy techniques could be effective for the treatment of urinary disorders in multiple sclerosis populations with mild disability. However, the analyses are based on six studies within only four showed good methodological quality. No strong conclusions regarding treatment approaches can be drawn from this review.

[Physiotherapy and neurogenic lower urinary tract dysfunction in multiple sclerosis patients: a randomized controlled trial]. / Kinésithérapie et symptômes du bas appareil urinaire chez des patients atteints de la sclérose en plaques : étude contrôlée randomisée.

AIM: This randomized controlled trial compare the efficacy of pelvic floor muscle training vs. transcutaneous posterior tibial nerve stimulation. PATIENTS AND METHODS: Inclusion criteria were EDSS score<7 and presence of lower urinary tract symptoms. Exclusion criteria were multiple sclerosis relapse during the study, active urinary tract infection and pregnancy. The primary outcome was quality of life (SF-Qualiveen questionnaire). Secondary outcomes included overactive bladder (USP questionnaire) score and frequency of urgency episodes (3-day bladder diary). Sample size was calculated after 18 patients were included. Data analysis was blinded. Each patient received 9 sessions of 30 minutes weekly. Patients were randomized in pelvic floor muscles exercises with biofeedback group (muscle endurance and relaxation) or transcutaneous posterior tibial nerve stimulation group (rectangular alternative biphasic current with low frequency). RESULTS: A total of 31 patients were included. No difference appeared between groups for quality of life, overactive bladder and frequency of urgency episodes (respectively P=0.197, P=0.532 et P=0.788). These parameters were significantly improved in pelvic floor muscle training group (n=16) (respectively P=0.004, P=0.002 et P=0.006) and in transcutaneous posterior tibial nerve stimulation group (n=15) (respectively P=0.001, P=0.001 et P=0.031). CONCLUSIONS: Pelvic floor muscle training and transcutaneous posterior tibial nerve stimulation improved in the same way symptoms related to urgency in MS patients with mild disability. LEVEL OF EVIDENCE: 2.

Impact of multiple joint impairments on the energetics and mechanics of walking in patients with haemophilia.

Few studies have assessed the changes produced by multiple joint impairments (MJI) of the lower limbs on gait in patients with haemophilia (PWH). In patients with MJI, quantifiable outcome measures are necessary if treatment benefits are to be compared. This study was aimed at observing the metabolic cost, mechanical work and efficiency of walking among PWH with MJI and to investigate the relationship between joint damage and any changes in mechanical and energetic variables. This study used three-dimensional gait analysis to investigate the kinematics, cost, mechanical work and efficiency of walking in 31 PWH with MJI, with the results being compared with speed-matched values from a database of healthy subjects. Regarding energetics, the mass-specific net cost of transport (C(net)) was significantly higher for PWH with MJI compared with control and directly related to a loss in dynamic joint range of motion. Surprisingly, however, there was no substantial increase in mechanical work, with PWH being able to adopt a walking strategy to improve energy recovery via the pendulum mechanism. This probable compensatory mechanism to economize energy likely counterbalances the supplementary work associated with an increased vertical excursion of centre of mass (CoM) and lower muscle efficiency of locomotion. Metabolic variables were probably the most representative variables of gait disability for these subjects with complex orthopaedic degenerative disorders.

Decomposition of the vertical ground reaction forces during gait on a single force plate.

UNLABELLED: Davis and Cavanagh (1993) have proposed a solution to avoid the footstep targeting by using a large force plate but several points of Davis and Cavanagh's method remain unclear and hardly computable. OBJECTIVE: to develop a method that decomposes left and right GRF profiles from the GRF profile recorded on a single platform. This method aims to include a systematic detection of the single to double stand-phase-instants in order to lead to accurate measurement of the vertical GRF component in typically developing children. METHODS: Six children were asked to walk without targeting their footsteps on a set-up composed of independent force platforms. The vertical GRF component, independently measured on the different platforms, was numerically summed to obtain the corresponding global vertical GRF, to which the decomposition method was applied. Then, the validation consisted in comparing the vertical GRF computed from this decomposition to the independently measured vertical GRF. RESULTS: the mean relative error between the computed vertical GRF and the corresponding measured vertical GRF of 36 double stances (6 double stances x 6 children) is equal to 3.8±2.6%. CONCLUSION: implemented a new method to assess with known accuracy the vertical GRF component under each foot using a unique large force platform.

Functional impact of custom-made foot orthoses in patients with haemophilic ankle arthropathy.

Although foot orthoses are often prescribed to patients with haemophilia (PWH) and ankle arthropathy, the efficacy and biomechanical effects of such devices are not fully understood. We experimentally investigated the effects of orthopedic insoles (OI) and shoes (OS) in PWH presenting ankle arthropathy, with specific attention being paid to pain, spatiotemporal parameters, kinematics and kinetics of lower limb joints, as well mechanical and energetic variables. Using three-dimensional gait analysis (3DGA), synchronous kinematics, kinetics, spatiotemporal, mechanics, and metabolic gait parameters were measured in 16 PWH with ankle arthropathy. The revised Foot Function Index (FFI-R) and 3DGA were determined in patients wearing neutral running shoes at two time points (T0 and T1), with OI (n = 11) or OS (n=5) being subsequently prescribed. Patients, while wearing their orthoses, were re-evaluated using 3DGA, FFI-R, and satisfaction questionnaires (T2). OI and OS provided significant pain relief and comfort improvement in more than half of the patients, with minimal side effects. OI had limited impact on gait pattern, whereas OS significantly improved the propulsive function of the ankle. Biomechanical changes induced by OI and OS were independent of their ability to improve comfort, while being insufficient to influence knee and hip kinematics and kinetics, or mechanical and energetic variables. These findings suggest that OI and OS may have beneficial effects on ankle joints in PWH. Self-reported clinical tools such as FFI-R and satisfaction questionnaires are sufficiently sensitive for assessing the efficacy of foot orthoses in PWH.

Biomolecule-based antibacterial coating on a stainless steel surface: multilayer film build-up optimization and stability study.

The goal of this paper was to establish the durability profile of antibacterial multilayer thin films under storage and usage conditions. Thin films were built on stainless steel (SS) by means of a layer-by-layer process alternating a negatively charged polyelectrolyte, polyacrylic acid, with a cationic antibacterial peptide, nisin. SS coupons coated with the antibacterial film were challenged under environmental and usage conditions likely to be encountered in real-world applications. The change in antibacterial activity elicited by the challenge was used as an indicator of multilayer film resistance. Antibacterial SS samples could be stored for several weeks at 4°C in ambient air and antibacterial films were resistant to dipping and mild wiping in water and neutral detergent. The multilayer coating showed some weaknesses, however, that need to be addressed.

A green and bio-inspired process to afford durable anti-biofilm properties to stainless steel.

A bio-inspired durable anti-biofilm coating was developed for industrial stainless steel (SS) surfaces. Two polymers inspired from the adhesive and cross-linking properties of mussels were designed and assembled from aqueous solutions onto SS surfaces to afford durable coatings. Trypsin, a commercially available broad spectrum serine protease, was grafted as the final active layer of the coating. Its proteolytic activity after long immersion periods was demonstrated against several substrata, viz. a synthetic molecule, N-α-benzoyl-DL-arginine-p-nitroanilide hydrochloride (BAPNA), a protein, FTC-casein, and Gram-positive biofilm forming bacterium Staphylococcus epidermidis.

Body structure versus body function in haemophilia: the case of haemophilic ankle arthropathy.

Imaging and clinical scores are the main tools used to evaluate the progression of haemophilic arthropathy (HA). Based on haemophilic ankle arthropathy, this study aimed to explore the concordances between structural and clinical alterations, determined by standard radiological and clinical scores, and functional alterations assessed by three-dimensional gait analysis (3DGA). In total, 21 adult haemophilia patients underwent extensive ankle evaluation using the physical examination part of the World Federation of Haemophilia joint score, the Arnold-Hilgartner and the Pettersson radiological scores, and self-reported ankle function assessment using the revised Foot Function Index. Significant associations were found between self-reported ankle function assessment and the three 3DGA variables representative of joint function (range of motion, peak plantar flexion moment, and peak power generated at the push-off phase). Radiological and clinical scores were compared with ankle muscle peak power measurement, the most reliable 3DGA gait variable for ankle function. No significant associations were found between both clinical and functional scores and the 3DGA functional assessment. This discordance may be explained by the lack of a direct relationship between functional alterations detected by 3DGA and the structural changes assessed using X-ray or clinical scoring. Another explanation may be the limitation of clinical and radiological scoring systems in properly determining the severity of HA. Functional assessments such as 3DGA should be used more frequently when monitoring the progression of ankle arthropathy or the effects of therapeutic interventions in adult haemophilia patients.

Natural progression of blood-induced joint damage in patients with haemophilia: clinical relevance and reproducibility of three-dimensional gait analysis.

SUMMARY: A major complication in haemophilia is the destruction of joint cartilage because of recurrent intraarticular and intramuscular bleeds. Therefore, joint assessment is critical to quantify the extent of joint damage, which has traditionally been evaluated using both radiological and clinical joint scores. Our study aimed to evaluate the natural progression of haemophilic arthopathy using three-dimensional gait analysis (3DGA) and to assess the reproducibility of this technique. We hypothesized that the musculoskeletal function was relatively stable in patients with haemophilia. Eighteen adults with established haemophilic arthropathies were evaluated twice by 3DGA (mean follow-up: 18 +/- 5 weeks). Unexpectedly, our findings revealed infraclinical deterioration of gait pattern, characterized by a 3.2% decrease in the recovery index, which is indicative of the subject's ability to save energy while walking. A tendency towards modification of segmental joint function was also observed. Gait analysis was sufficiently reproducible with regards to spatiotemporal parameters as well as kinetic, mechanical and energetic gait variables. The kinematic variables were reproducible in both the sagittal and frontal planes. In conclusion, 3DGA is a reproducible tool to assess abnormal gait patterns and monitor natural disease progression in haemophilic patients.

Gait in thoracolumbar/lumbar adolescent idiopathic scoliosis: effect of surgery on gait mechanisms.

For patients whose scoliosis progresses, surgery remains the ultimate way to correct and stabilise the deformity while maintaining as many mobile spinal segments as possible. In thoracolumbar/lumbar adolescent idiopathic scoliosis (AIS), the spinal fusion has to be extended to the lumbar spine. The use of anterior spinal fusion (ASF) instead of the classic posterior fusion (PSF) may preserve more distal spinal levels in attempt to limit the consequences of surgery on trunk mobility. The effects of surgery on body shape, pain and the decompensation phenomenon have all been well evaluated. Very few studies have addressed the effect of ASF or PSF on basic activities, such as walking. Before any treatment, AIS patients already have reduced pelvis, hip and shoulder motion when walking at a normal speed compared with adolescents without scoliosis (control group). Additionally, they have longer contraction time of the lumbar and pelvic muscles leading to an excessive energy cost and reduced muscle efficiency. In addition, if these changes are associated with spinal stiffness, spinal fusion could further negatively affect this pre-surgical inefficient walk. The goals of this study were (a) to compare pre- and 1-year post-surgery conditions in order to assess the effects of spinal arthrodesis on gait parameters and (b) to compare the anterior versus the posterior surgical approaches. Nineteen young females with thoracolumbar/lumbar AIS were assessed by radiological and clinical examination and by conventional gait analysis before surgery and at almost 12 months after surgery. Seven subjects underwent surgery using ASF and 12 using PSF. Three-dimensional gait analysis was performed on a motor-driven treadmill at spontaneous self-selected speed to record kinematic, electromyographic (EMG), mechanical and energetic measurements synchronously. Although it was expected that the instrumentation would modify the characteristics of normal walking, this study showed that surgery does not induce asymmetric gait or any significant differences between the ASP and the PSF surgery groups. One year after surgery, the changes observed consisted of improvements in the gait and mechanical parameters. In the PSF group, 11-14 vertebrae were fused while only 3-4 were fused in the ASF group. In both AIS groups, step length was increased by 4% and cadence reduced by 2%. There was a slight increase in pelvis and hip frontal motion. Only the transverse shoulder motion was mildly decreased by 1.5 degrees . All the other gait parameters were left unchanged or were improved by surgery. Notably, the EMG timing activity did not change. The total muscular mechanical work (W (tot)) increased by 6% mainly due to the external work (W (ext)), i.e. the work performed by the body muscles to move the body in its surroundings. The energy cost, although showing a tendency towards a reduction, remained globally excessive, probably due to the excessive co-contraction of the lumbo-pelvic muscles.

Trapeziometacarpal prosthesis: an updated systematic review.

The trapeziometacarpal prosthesis is mostly used in Europe to treat osteoarthritis of the basal joint of the thumb. Its supposed benefits are that it restores the length of the thumb, improves strength, function and mobility while reducing recovery time compared to other surgical treatments. However, previous reviews of the literature could not confirm these assumptions. This article provides an updated systematic review to help answer to these questions through a methodical statistical analysis and to quantify the two main complications, namely failure and deep infection. To achieve these aims, a selection of articles including implant case series was done in the Medline database based on specific criteria. Data about pain, function, strength, infection, and failure were compiled and a statistical analysis was performed. Results show a fast recovery in terms of pain and function but the positive effect on strength seems limited. The failure rate represented by the revision rate is high and the deep infection rate is fairly low. Randomized controlled studies are needed to obtain reliable data to compare the prosthesis to other surgical treatments.

Gait in adolescent idiopathic scoliosis: kinematics and electromyographic analysis.

Adolescent idiopathic scoliosis (AIS) is a progressive growth disease that affects spinal anatomy, mobility, and left-right trunk symmetry. Consequently, AIS can modify human locomotion. Very few studies have investigated a simple activity like walking in a cohort of well-defined untreated patients with scoliosis. The first goal of this study is to evaluate the effects of scoliosis and scoliosis severity on kinematic and electromyographic (EMG) gait variables compared to an able-bodied population. The second goal is to look for any asymmetry in these parameters during walking. Thirteen healthy girls and 41 females with untreated AIS, with left thoracolumbar or lumbar primary structural curves were assessed. AIS patients were divided into three clinical subgroups (group 1 < 20 degrees, group 2 between 20 and 40 degrees, and group 3 > 40 degrees). Gait analysis included synchronous bilateral kinematic and EMG measurements. The subjects walked on a treadmill at 4 km/h (comfortable speed). The tridimensional (3D) shoulder, pelvis, and lower limb motions were measured using 22 reflective markers tracked by four infrared cameras. The EMG timing activity was measured using bipolar surface electrodes on quadratus lumborum, erector spinae, gluteus medius, rectus femoris, semitendinosus, tibialis anterior, and gastrocnemius muscles. Statistical comparisons (ANOVA) were performed across groups and sides for kinematic and EMG parameters. The step length was reduced in AIS compared to normal subjects (7% less). Frontal shoulder, pelvis, and hip motion and transversal hip motion were reduced in scoliosis patients (respectively, 21, 27, 28, and 22% less). The EMG recording during walking showed that the quadratus lumborum, erector spinae, gluteus medius, and semitendinosus muscles contracted during a longer part of the stride in scoliotic patients (46% of the stride) compared with normal subjects (35% of the stride). There was no significant difference between scoliosis groups 1, 2, and 3 for any of the kinematic and EMG parameters, meaning that severe scoliosis was not associated with increased differences in gait parameters compared to mild scoliosis. Scoliosis was not associated with any kinematic or EMG left-right asymmetry. In conclusion, scoliosis patients showed significant but slight modifications in gait, even in cases of mild scoliosis. With the naked eye, one could not see any difference from controls, but with powerful gait analysis technology, the pelvic frontal motion (right-left tilting) was reduced, as was the motion in the hips and shoulder. Surprisingly, no asymmetry was noted but the spine seemed dynamically stiffened by the longer contraction time of major spinal and pelvic muscles. Further studies are needed to evaluate the origin and consequences of these observations.

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).

Effect of speed on kinematic, kinetic, electromyographic and energetic reference values during treadmill walking.

OBJECTIVE: Evaluation of normal and pathological gait on the level ground has drawbacks that could be overcome by walking on a treadmill. The present work was designed to assess the feasibility of extended gait analysis on a treadmill allowing multiple steps recording at a constant speed in young healthy subjects. It also aimed to provide speed-specific kinematic, kinetic, electromyographic and energetic reference values. METHOD: Twelve healthy volunteers (23 +/- two years) walked on a force measuring treadmill at six speeds (1-6 k mh(-1)). Kinematics and kinetics were analysed at the hip, knee and ankle. Electromyographic muscle activity timing of quadriceps femoris, biceps femoris, tibialis anterior and lateral gastrocnemius was recorded. The energy cost was computed from oxygen consumption measurement. RESULTS: All variables were speed-dependent. Kinematics and kinetics peaks amplitude increased and occurred earlier during the walking cycle with increasing walking speed. Muscle activity timing also changed with speed, although the number of bursts remained constant. The energetic cost presented a U-shaped curve, with minimal values around 4 km h(-1). Data were compared to overground walking data obtained by several authors: all results, except kinetic ones, were similar, turning down the thought that biomechanics of treadmill and overground walking could be different. CONCLUSION: This study provides reference values for normal and pathological walking on treadmill and allows speed-dependent comparison between subjects.

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.

Quantification of intervertebral efforts during walking: comparison between a healthy and a scoliotic subject.

The accurate quantification of internal efforts in the human body is still a challenge in biomechanics. The aim of this study is to quantify the intervertebral efforts along the spine during walking, in order to compare the dynamical behaviours between a healthy and a scoliotic subject. Practically, one healthy subject, one scoliotic patient before an instrumentation surgery (Cobb 41 degrees ) and after this instrumentation (Cobb 7.5 degrees ) walked on a treadmill at 4 km/h. The acquisition system included optokinetic sensors, recording the 3D-joint coordinates, a treadmill equipped with strain gauges, measuring the external forces independently applied to both feet, and bi-planar radiographs, enabling the 3D reconstruction of the spine from C7 to L5, using a free form interpolation technique. The intervertebral efforts were computed using an inverse dynamical model of the human body in 3D. As results, significant differences of the spine kinematics were recorded which lead to different internal effort behaviour in magnitude, shift, coordination and pattern when normalized to the subject mass. Particularly, the normalized antero-posterior intervertebral torques are less uniform for the scoliotic patient (from min -2.5 to max 1.9 Nm/kg) than the healthy subject (from -1.5 to 1.5 Nm/kg). This disequilibrium in the left-right balance of the scoliotic patient is a bit rectified after surgery (from -1.3 to 1.1 Nm/kg).

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.