Maintenance of ankle power and decreased inter-limb asymmetry during sprint running in fatigued multi-speed athletes

The ability to shift from walking and jogging to sprinting gaits, even when fatigued after prolonged effort, would have been as useful to our hunter-gatherer ancestors as it is in modern day sports. During prolonged jogging, joint moment and work are reduced in the distal (ankle) joint but increased at proximal (hip/knee) joints as fatigue progresses, and might be expected to occur in sprinting. Fatigue is also thought to increase inter-limb kinematic and force production asymmetries, which are speculated to influence injury risk. However, the effects of running-related fatigue on sprint running gait have been incompletely studied, so these hypotheses remain untested. We studied 3-D kinematics and ground reaction force production in dominant (DL) and non-dominant (NDL) legs during both non-fatigued and fatigue sprinting in habitual but uncoached running athletes. Contrary to the tested hypotheses, relative between-leg differences were greater in non-fatigued than fatigued sprinting. When not fatigued, DL produced greater propulsive impulse through both greater positive and negative work being performed at the ankle, whilst NDL produced more vertical impulse, possibly resulting from the greater hip flexion observed prior to the downwards acceleration of the foot towards the ground. Whilst few changes were detected in DL once fatigued, NDL shifted towards greater horizontal force production, largely resulting from an increase in plantarflexion (distal-joint) moments and power. After fatiguing running, therefore, inter-limb asymmetry was reduced and no distal-to-proximal shift in work/power was detected during sprinting. Speculatively, these adaptations may help to attenuate decreases in running speed whilst minimising injury risk.

Whole exome sequencing revealed a mutation in COL6A1 associated with ullrich congenital muscular dystrophy

Collagen type VI-related disorders consist of Ullrich congenital muscular dystrophies (UCMD) and Bethlem myopathy, in which these entities are at two opposite extremes of the phenotype continuum. Clinical characteristics include proximal joint contracture, distal joint hyperlaxity, generalized muscle weakness, normal cognitive function, and pulmonary insufficiency. Affected individuals have trouble standing up and walking independently. Mutations in 3 genes (COL6A1, COL6A2, and COL6A3) are associated with decreasing collagen-VI production and disrupting the microfibrillar network between skeletal muscles. In the present study, using whole-exome sequencing (WES), a pathogenic variant in the COL6A1 gene (NM_001848, c.868G>C, p.G290R) was detected in a Vietnamese family with UCMD patients. Segregation analysis by Sanger sequencing confirmed that this mutation was inherited in an autosomal dominant pattern. This study expands the breadth of congenital muscular dystrophies research landcape and underscores the efficiency of WES in investigating the etiology of this group of heterogeneous diseases. Insight about the underlying genetic causes could contribute to develop a well-timed treatment regimen and help patients make an informed decision about reproductive health.

Modified Proximal Interphalangeal Joint Arthrodesis in a Yearling Filly with an Osseous Cyst-Like Lesion in the Proximal Phalanx

After the medial femoral condyle (MFC), the phalanges are the second most common site for osseous cyst-like lesions (OCLLs). Conservative treatment of phalangeal cysts on the convex surface of proximal phalanx presents a technical problem with access to the stoma of the cyst. Surgical therapy options usually aim to avoid cyst enlargement through drilling or screw placement or to encourage lesion filling with osteoconductive material. This paper describes a case of treatment of the OCLL in a yearling Czech warmblood filly with surgical arthrodesis, together with the packing of the OCLL with calcium phosphate biocement (CPB). The filly showed a chronic, moderate to severe, intermittent left hindlimb lameness. Dynamic examination combined with regional anesthesia and radiography confirmed a clinically significant large OCLL on the distal joint surface of the first phalanx. Treatment of the OCLL was performed by surgical arthrodesis of the proximal interphalangeal joint, using two paraxial and one axial crossed lag screw, after curetting of the cyst and filling with CPB.

Plastic lengthening amputation with vascularized bone grafts in children with bone sarcoma: a preliminary report

Background At present, amputation was widely adopted for young patients when limb salvage was deemed risky with several surgical strategy such as rotationplasty. However, leg length discrepancies and unfavorable cosmetic results were indispensable complication of this strategy. The purpose of this study was to propose a novel reconstruction strategy and evaluate the early clinical and functional outcomes of the strategy. Methods Plastic lengthening amputation (PLA) has been developed by lengthening the stump to preserve one additional distal joint for fixing the artificial limb well. The surgical technique and postoperative management were documented, and the functional outcomes were compared with those of traditional amputation (TA). Six pairs of patients matched for age, sex, location, pathological type, and final prosthesis underwent individually designed plastic lengthening amputation with vascularized autografts or traditional amputation between January 2005 and December 2007. All patients were followed, and the locomotor index and the musculoskeletal tumor society score (MSTS) were used to describe and quantitatively grade limb functional outcomes after amputation. The complications and functional outcomes of the patients taken two kinds of procedures were compared. Results Twelve patients with osteosarcoma or Ewing’s sarcoma of either the femur or tibia were included in the study. Six patients underwent plastic lengthening amputations, three of whom also underwent vascular anastomosis. Patients were followed for an average of 48.17 months; bone healing required an average of 3.3 months. No local recurrence was found. The average postoperative locomotor index functional score of the affected limb was 32.67 ± 5.89 in the plastic lengthening amputation group while was 19.50 ± 7.87 in the traditional amputation group. The MSTS functional scores were 22.67 ± 1.33 and 24.17 ± 1.45 at 6 and 12 months for patients in PLA group while 17.00 ± 1.549 and 17.83 ± 1.64 at 6 and 12 months for patients in TA group. Conclusions Plastic lengthening amputations with vascularized autografts could preserve the knee joint to improve the function of the amputated limb in selected bone sarcoma patients.

Echography analysis altered in musculoskeletal, heart and liver associated with endothelial dysfunction of obese rat

Background: Modern imaging plays a central role in the care of obese patients, with an integral focus on its use and accessibility in individuals into this condition with alterations of various organs. Objective. To perform an echographical analysis of musculoskeletal system disorders, endothelial dysfunction and the left ventricle in obese rats. Methods. Sprague Dawley rats (250±5 g) were used and divided in two groups: control group (C) fed with a standard diet, and the obese group (Ob) fed with a hyper caloric diet of high fructose-fat for 4 months. Body weight, cholesterol, triglycerides, glucose, inflammatory cytokines and adhesion molecules (ICAM-1, VCAM-1) were measured. Additionally, two-dimensional echocardiography, abdominal ultrasound and musculoskeletal system studies were performed in the lower extremities.Results. Body weight in the Ob group was increased compared to the control group, (p <0.001); in addition, increased glucose, cholesterol and triglycerides were found in the Ob group vs the C group, (p<0.05), and as well as increased adhesion molecules ICAM-1 and, VCAM-1 (p<0.01). On ultrasound, 75% of the Ob group presented, showed 75% fatty liver and distal joint abnormalities. Conclusion. Endothelial dysfunction and changes at the level of the musculoskeletal system with the presence of joint cysts in the posterior region of the distal joint of the lower extremities and fat liver were observed in obese rodents.

4451 On the loss of individual joint controllability and the organization of muscle synergies in the impaired arm following a stroke: A pilot study

OBJECTIVES/GOALS: Damage to the sensorimotor cortex areas or/and motor/sensory pathways after a stroke could lead the motor system to a loss of controllability for joints. We investigate the loss of individual joint controllability called a loss of individualization during arm movement, which would provide an insight into abnormal motor coordination. METHODS/STUDY POPULATION: We recruit 12 chronic stroke survivors with Fugl-Meyer score between 26 and 50. A robotic exoskeleton with minimum mechanical resistance is equipped to measure the movements of the shoulder, elbow and wrist joints, respectively. Surface EMGs on muscles related to the joints are recorded using 11 wireless pre-amplified electrodes. Participants are asked to move the shoulder, elbow, or wrist joint individually throughout their range of motion, without moving the other joints voluntarily. RESULTS/ANTICIPATED RESULTS: It would be expected that participants show more difficulty in individualization of the distal joint in comparison with the proximal joint. A reduced joint range of motion would be observed in a descending order of the wrist, elbow and shoulder. These results are in line with the proximal-to-distal gradient of motor deficits after a stroke. Intention of moving the distal joint would induce a greater deviation in the position of the proximal joint than that of the distal joint when moving the proximal joint. A non-negative matrix factorization algorithm would reveal a decreased number of muscle synergies in the groups with a loss of individuation in comparison with the groups with no loss. DISCUSSION/SIGNIFICANCE OF IMPACT: We demonstrate that a stroke leads to a lack of individual joint controllability, with a greater deficits on the distal joint, and that it is related to a decreased number of muscle synergies across the corresponding joints. CONFLICT OF INTEREST DESCRIPTION: N/A.

Echographic analysis of the alterations musculoskeletal associated with endothelial dysfunction and obesity

Background: Modern imaging plays a central role in the care of obese patients, with an integral focus on its use and accessibility in individuals with this condition with alterations of various organs. Objective. To perform an echographical analysis of musculoskeletal system disorders, endothelial dysfunction and the left ventricle in obese rats. Methods. Sprague Dawley rats (250±5 g) were used and divided into two groups: control group (C) fed a standard diet and the obese group (Ob), fed with a hyper caloric diet of high fructose-fat for 4 mounts. Body weight, cholesterol, triglycerides, glucose, inflammatory cytokines and adhesion molecules (ICAM-1, VCAM-1) were measured. Additionally, two-dimensional echocardiography and abdominal ultrasound and musculoskeletal system studies in the lower extremities were performed. Results . Body weight in the Ob group was increased compared to the control group, (p <0.001); in addition, increased glucose, cholesterol and triglycerides of were found in the Ob group vs the C group, (p <0.05), and as well as increased adhesion molecules ICAM-1 and, VCAM-1 (p <0.01). On ultrasound, 75% of the Ob group presented showed 75% fatty liver and distal joint abnormalities. Conclusion . Endothelial dysfunction and changes at the level of the musculoskeletal system with the presence of joint cysts in the posterior region of the distal joint of the lower extremities were observed in obese rodents.