Mild untreated hypercholesterolaemia affects mechanical properties of the Achilles tendon but not gastrocnemius muscle.

Tendon xanthoma and altered mechanical properties have been demonstrated in people with familial hypercholesterolaemia. However, it is unclear whether mild, untreated hypercholesterolaemia alters musculotendinous mechanical properties and muscle architecture. We conducted a case-control study of adults aged 50 years and over, without lower limb injury or history of statin medication. Based on fasting low-density lipoprotein (LDL) cholesterol levels, 6 participants had borderline high LDL (>3.33 mmol/L) and 6 had optimal LDL cholesterol (<2.56 mmol/L). Using shear wave elastography, shear wave velocity (SWV) of the Achilles tendon and gastrocnemius medialis muscle (a proxy for stiffness), along with muscle fascicle length and pennation angle were measured under four passive tensile loads (0, 0.5, 1.0, 1.5 kg) applied via a pulley system. Differences between groups were found for tendon SWV but not muscle SWV, fascicle length or pennation angle. Participants with hypercholesterolaemia showed greater SWV (mean difference, 95 % CI: 2.4 m/s, 0.9 to 4.0, P = 0.024) compared to the control group across all loads. These findings suggest that adults with mild hypercholesterolaemia have increased tendon stiffness under low passive loads, while muscle was not affected. Future research is needed to confirm findings in a larger cohort and explore the impact of hypercholesterolaemia on tendon fatigue injury and tendinopathy.

Determinants of muscle preservation in individuals with cerebral palsy across the lifespan: a narrative review of the literature.

In individuals with cerebral palsy (CP), smaller muscle and atrophy are present at young age. Many people with CP also experience a decline in gross motor function as they age, which might be explained by the loss of muscle mass. The clinical observation of muscle wasting has prompted a comparison with sarcopenia in older adults, and the term accelerated musculoskeletal ageing is often used to describe the hallmark phenotype of CP through the lifespan. However, there has been very little research emphasis on the natural history of ageing with CP and even less with respect to the determinants or prevention of muscle loss with CP. Considering the burgeoning interest in the science of muscle preservation, this paper aims to (i) describe the characteristics of accelerated musculoskeletal ageing in people with CP, (ii) describe the pathophysiology of sarcopenia and parallels with CP, and (iii) discuss possible therapeutic approaches, based on established approaches for sarcopenia.

Longitudinal assessment of gait quality in children with bilateral cerebral palsy following repeated lower limb intramuscular Botulinum toxin-A injections.

BACKGROUND: Serial lower limb intramuscular Botulinum toxin-A (BoNT-A) injections are administered to children with bilateral spastic cerebral palsy (BCP) to reduce spasticity, improve walking and functional mobility, and delay the need for orthopaedic surgery. Gait quality is clinically assessed following BoNT-A with 2D video gait assessments (2DVGA) using the Edinburgh Visual Gait Score (EVGS). AIM: To determine the effect of three consecutive treatment cycles of lower limb intramuscular BoNT-A injections on gait quality using the EVGS in children with BCP by retrospectively reviewing repeated 2DVGA measures. METHODS AND PROCEDURES: Seventeen children with BCP and dynamic equinus (8 females and 9 males, age mean (SD), 4.0 (2.2) years, GMFCS I=2 and II=15) were included in the study after a retrospective audit of the records of the Queensland Children's Gait Laboratory (QCGL), Children's Health Queensland, Brisbane. The medical records of children who attended the QCGL between January 2001 and January 2016 were searched for eligibility. Children who had undertaken pre- and post-treatment 2DVGA for the first three lower limb BoNT-A treatment cycles (6 assessments) were reviewed using the EVGS. BoNT-A treatments were administered 7.7 (2.3) months apart and post-BoNT-A reviews occurred 12.6 (6.7) weeks after injection. Mixed-effects linear regression assessed the change from baseline to each subsequent assessment (p<0.05). OUTCOMES AND RESULTS: EVGS reduced significantly by a mean of 2.4 points from pre- to post-BoNT-A in the first treatment cycle (p=0.001). Compared to baseline, mean total EVGS reduced significantly during the second (pre-BoNT-A -1.7 (p=0.020), post BoNT-A -2.8 (p<0.001)) and third (pre-BoNT-A -2.6 (p=0.001), post BoNT-A -2.4 (p=0.002)) treatment cycles. There was no difference in EVGS between post-BoNT-A in the first treatment cycle and scores for the second and third treatment cycles. CONCLUSIONS AND IMPLICATIONS: Improvements in gait quality were statistically significant, but did not reach the EVGS smallest real difference value of 4 points. Repeated lower limb intramuscular BoNT-A injections to improve gait quality in children with BCP should be reconsidered.

PREDICT-CP: study protocol of implementation of comprehensive surveillance to predict outcomes for school-aged children with cerebral palsy.

OBJECTIVES: Cerebral palsy (CP) remains the world's most common childhood physical disability with total annual costs of care and lost well-being of $A3.87b. The PREDICT-CP (NHMRC 1077257 Partnership Project: Comprehensive surveillance to PREDICT outcomes for school age children with CP) study will investigate the influence of brain structure, body composition, dietary intake, oropharyngeal function, habitual physical activity, musculoskeletal development (hip status, bone health) and muscle performance on motor attainment, cognition, executive function, communication, participation, quality of life and related health resource use costs. The PREDICT-CP cohort provides further follow-up at 8-12 years of two overlapping preschool-age cohorts examined from 1.5 to 5 years (NHMRC 465128 motor and brain development; NHMRC 569605 growth, nutrition and physical activity). METHODS AND ANALYSES: This population-based cohort study undertakes state-wide surveillance of 245 children with CP born in Queensland (birth years 2006-2009). Children will be classified for Gross Motor Function Classification System; Manual Ability Classification System, Communication Function Classification System and Eating and Drinking Ability Classification System. Outcomes include gross motor function, musculoskeletal development (hip displacement, spasticity, muscle contracture), upper limb function, communication difficulties, oropharyngeal dysphagia, dietary intake and body composition, participation, parent-reported and child-reported quality of life and medical and allied health resource use. These detailed phenotypical data will be compared with brain macrostructure and microstructure using 3 Tesla MRI (3T MRI). Relationships between brain lesion severity and outcomes will be analysed using multilevel mixed-effects models. ETHICS AND DISSEMINATION: The PREDICT-CP protocol is a prospectively registered and ethically accepted study protocol. The study combines data at 1.5-5 then 8-12 years of direct clinical assessment to enable prediction of outcomes and healthcare needs essential for tailoring interventions (eg, rehabilitation, orthopaedic surgery and nutritional supplements) and the projected healthcare utilisation. TRIAL REGISTRATION NUMBER: ACTRN: 12616001488493.

The effects of botulinum toxin injection frequency on calf muscle growth in young children with spastic cerebral palsy: a 12-month prospective study.

PURPOSE: This study was a 12-month prospective investigation of changes in the medial gastrocnemius (MG) muscle morphology in children aged 2-5 years with spastic cerebral palsy (CP) who had received no previous intramuscular injections of botulinum neurotoxin type-A (BoNT-A) and were randomised to receive either single or multiple (three) BoNT-A injections to the gastrocsoleus. MG morphological changes were compared to age-matched typically developing (TD) peers. METHODS: Thirteen children with spastic CP with a mean age of 45 (15) months and 18 TD children with a mean age of 48 (14) months participated in the study. The principal outcome measures were MG muscle volume, fascicle length, pennation angle and physiological cross-sectional area (PCSA), which were obtained using 2D and 3D ultrasound. RESULTS: The single and multiple injection frequency groups significantly increased MG muscle volume at 12 months relative to the baseline by 13 and 15 %, respectively. There were no significant differences in the MG muscle volume 28.5 (12.3) versus 30.3 (3.8) ml, fascicle length 48.0 (10.4) versus 44.8 (1.2) mm or PCSA 7.0 (1.2) versus 6.6 (1.7) cm(2) between the single and multiple injection groups, respectively, at 12 months follow-up. The change in MG muscle volume in the single and multiple injection groups was significantly lower than the TD peers by 66 and 60 %, respectively. INTERPRETATION: In young children with spastic CP, naive to BoNT-A treatment, MG muscle growth over 12 months does not appear to be influenced by intramuscular BoNT-A injection frequency. However, MG muscle growth in the spastic CP groups was significantly lower than the age-matched TD peers. It is unclear whether this is an effect of intramuscular BoNT-A injections or reduced growth rates in children with spastic CP in general. Controlled investigations and longitudinal studies with multiple measurement time points are required in order to determine the influence of BoNT-A treatment on muscle physiological and mechanical growth factors in young children with spastic CP.

Medial gastrocnemius muscle volume and fascicle length in children aged 2 to 5 years with cerebral palsy.

AIM: The aim of this article was to compare medial gastrocnemius muscle volume, physiological cross-sectional area (PCSA), muscle length, fascicle length, and pennation angle in children aged 2 to 5 years with spastic cerebral palsy (CP) and in typically developing children. method: Fifteen children with spastic CP (11 males, four females; mean age 45 mo [SD 15 mo]; five with hemiplega; 10 with diplega; 10 classified at Gross Motor Function Classification System (GMFCS) level I, five at GMFCS level II) and 20 typically developing children (11 males, nine females; mean age 48 mo [SD 14 mo]) participated in the study. Individuals with spastic CP were included if they had a minimum range of motion of 0° ankle dorsiflexion with the knee extended and were excluded if they had had previous botulinum toxin treatment to the calf muscles or previous calf surgery. Typically developing children were included if they were able to walk independently and were excluded if there was a history of previous lower leg injury or other developmental disorder affecting the lower limb. Freehand two-dimensional and three-dimensional ultrasound was used to assess muscle properties of the relaxed medial gastrocnemius muscle at three ankle joint angles: maximum dorsiflexion, neutral and maximum plantarflexion. PCSA was calculated as a function of muscle volume and muscle fascicle length and pennation angle was recorded at the neutral ankle joint angle. RESULTS: Medial gastrocnemius muscle volume was 22% lower in the group with spastic CP than in the typically developing group, which in the absence of significant group differences in neutral fascicle length gave rise to an equivalent reduction in PCSA for the group with spastic CP. Significant positive correlations were found between muscle volume and age (r=0.63-0.65) and between muscle length and age (r=0.72-0.81) in both groups. Maximum ankle dorsiflexion angle was also reduced in the group with spastic CP (8°) compared with the typically developing group (26°). INTERPRETATION: The observed reduction in muscle PCSA in the group with spastic CP would be expected to contribute to the clinically observed muscle weakness in spastic CP and suggests the need for early intervention in order to minimize loss of muscle PCSA in spastic CP.

Validation of a freehand 3D ultrasound system for morphological measures of the medial gastrocnemius muscle.

Muscle volume and length are important parameters for examining the force-generating capabilities of muscle and their evaluation is necessary in studies that investigate muscle morphology and mechanical changes due to age, function, pathology, surgery and training. In this study, we assessed the validity and reliability of in vivo muscle volume and muscle belly length measurement using a multiple sweeps freehand 3D ultrasound (3DUS). The medial gastrocnemius of 10 subjects was scanned at three ankle joint angles (15 degrees , 0 degrees and -15 degrees dorsiflexion) three times using the freehand 3DUS and once on the following day using magnetic resonance imaging (MRI). All freehand 3DUS and MRI images were segmented, volumes rendered and volumes and muscle belly lengths measured. The freehand 3DUS overestimated muscle volume by 1.9+/-9.1 mL, 1.1+/-3.8% difference and underestimated muscle belly length by 3.0+/-5.4mm, 1.3+/-2.2% difference. The intra-class correlation coefficients (ICC) for repeated freehand 3DUS system measures of muscle volume and muscle belly length were greater than 0.99 and 0.98, respectively. The ICCs for the segmentation process reliability for the freehand 3DUS system and MRI for muscle volume were both greater than 0.99 and muscle belly length were 0.97 and 0.99, respectively. Freehand 3DUS is a valid and reliable method for the measurement of human muscle volume and muscle belly length in vivo. It could be used as an alternative to MRI for measuring in vivo muscle morphology and thus allowing the determination of PCSA and estimation of the force-generating capacity of individual muscles within the setting of a biomechanics laboratory.