Fine-needle percutaneous muscle microbiopsy technique as a feasible tool to address histological analysis in young children with cerebral palsy and age-matched typically developing children.

Cerebral palsy (CP) is a heterogeneous group of motor disorders attributed to a non-progressive lesion in the developing brain. Knowledge on skeletal muscle properties is important to understand the impact of CP and treatment but data at the microscopic levels are limited and inconsistent. Currently, muscle biopsies are collected during surgery and are restricted to CP eligible for such treatment or they may refer to another muscle or older children in typically developing (TD) biopsies. A minimally invasive technique to collect (repeated) muscle biopsies in young CP and TD children is needed to provide insights into the early muscle microscopic alterations and their evolution in CP. This paper describes the protocol used to 1) collect microbiopsies of the medial gastrocnemius (MG) and semitendinosus (ST) in CP children and age-matched TD children, 2) handle the biopsies for histology, 3) stain the biopsies to address muscle structure (Hematoxylin & Eosin), fiber size and proportion (myosin heavy chain), counting of the satellite cells (Pax7) and capillaries (CD31). Technique feasibility and safety as well as staining feasibility and measure accuracy were evaluated. Two microbiopsies per muscle were collected in 56 CP (5.8±1.1 yr) and 32 TD (6±1.1 yr) children using ultrasound-guided percutaneous microbiopsy technique. The biopsy procedure was safe (absence of complications) and well tolerated (Score pain using Wong-Baker faces). Cross-sectionally orientated fibers were found in 86% (CP) and 92% (TD) of the biopsies with 60% (CP) and 85% (TD) containing more than 150 fibers. Fiber staining was successful in all MG biopsies but failed in 30% (CP) and 16% (TD) of the ST biopsies. Satellite cell staining was successful in 89% (CP) and 85% (TD) for MG and in 70% (CP) and 90% (TD) for ST biopsies, while capillary staining was successful in 88% (CP) and 100% (TD) of the MG and in 86% (CP) and 90% (TD) for the ST biopsies. Intraclass coefficient correlation showed reliable and reproducible measures of all outcomes. This study shows that the percutaneous microbiopsy technique is a safe and feasible tool to collect (repeated) muscle biopsies in young CP and TD children for histological analysis and it provides sufficient muscle tissue of good quality for reliable quantification.

Variability of MRI reporting in proximal hamstring avulsion injuries: Are musculoskeletal radiologists and orthopedic surgeons utilizing similar landmarks?

BACKGROUND: Magnetic resonance imaging (MRI) is an integral component of the treatment algorithm for proximal hamstring avulsion injuries. OBJECTIVE: The purpose of this study was to survey orthopedic surgeons and musculoskeletal radiologists on the reporting and analysis of proximal hamstring avulsions on MRI. METHODS: Two online surveys were developed to evaluate musculoskeletal radiologists' and orthopedic surgeons' perceptions of MRI-reporting for proximal hamstring avulsion injuries. Each survey was designed to provide information on physicians' best practices with respect to four primary questions (1) ischial tuberosity landmark determination (2) difficulties associated with measuring tendon retraction, (3) important ancillary findings, and (4) perceived clinical impact of measured retraction. Descriptive statistics were calculated for all categorical variables, which were reported as frequencies with percentages. Chi-squared test was utilized to compare rates of responses between surgeons and radiologists. Statistically significant differences were analyzed with post-hoc Fisher's exact tests; p < 0.05 considered statistically significant. RESULTS: 218-Musculoskeletal radiologists and 33-orthopedic surgeons responded to their respective surveys. There were statistically significant differences with responses to two of the questions asked in both surveys; (1) in cases of complete hamstring avulsion (avulsion of both the semimembranosus and conjoint tendon), which arrow represents the tendon gap measurement used for planning surgery? p = 0.028; (2) in cases of avulsion of only the conjoint tendon, which arrow represents the tendon gap measurement used for planning surgery? p = 0.013. Post-hoc testing demonstrated that for either partial or complete hamstring avulsions, more surgeons use the conjoint tendon origin to measure tendon retraction than radiologists (p < 0.05 for both). Significantly more radiologists use the semimembranosus origin to measure hamstring retraction for partial or complete hamstring tears (p < 0.05 for both). However, for each of these questions, both radiologists and surgeons most frequently stated that the conjoint tendon landmark should be used for surgical planning. CONCLUSION: Musculoskeletal radiologists and orthopedists frequently utilize the conjoint tendon origin as an anatomic landmark for measuring complete and partial proximal hamstring avulsion injuries; though, orthopedists are more likely to utilize this landmark. Additionally, the broad surface area of the ischial tuberosity may lead to variability in measurement. CLINICAL IMPACT: Standard landmarks at the ischial tuberosity and/or detailed descriptions of tendon retractions would improve communication between radiologists and surgeons for proximal hamstring avulsions.

Aponeurotic release of semimembranosus: A technical note to increase correction gained with hamstring lengthening surgery in cerebral palsy.

OBJECTIVE: The aim of this study was to determine the intraoperative corrective effect of the aponeurotic release of semimembranosus (SM) as a single procedure or an adjunct procedure to distal myotendinous release of semitendinosus (ST) and myofascial release of SM lengthening in the correction of knee flexion deformity in cerebral palsy (CP). METHODS: In this prospective study, 46 knees of 23 consecutive ambulatory patients (15 boys and 8 girls; mean age=8.33 years; age range=5-12 years) with spastic diplegic CP with a gross motor function classification system level (GMFCS) II or III were included. The patients were then divided into 2 groups. In group I, there were 10 patients (4 boys, 6 girls; mean age=8.6±2), and combined release of ST in the myotendinous junction and SM in the myofascial junction, followed by aponeurotic release of SM were carried out. In group II, there were 13 patients (2 girls, 11 boys; mean age=8±2.35), and aponeurotic release of SM was done first and followed by the combined release of ST in the distal myotendinous junction and the myofascial release of SM. Intraoperative popliteal angle (PA) measurements were recorded in each group. RESULTS: PA was reduced from 58.1°±7.6° (range=46°-75°) to 41.2°±8.8° (range=20°-54°) in group 1 and from 59.1°±11.3° (range=40°-87°) to 42.7°±10.8° (range=24°-64°) in group 2. No significant difference was observed between the groups in terms of reduction in PA (p=0.867). In group 1, adding the aponeurotic release of SM further reduced the PA to 31.7°± 8.5° (range=14°-47°) (p=0.002). In group 2, adding the myotendinous release of ST and myofascial release of SM further reduced the PA to 32.9°±7.2° (range=16°-44°) (p=0.004). There was no significant difference between the final PA values in the 2 groups (p=0.662). There was no difference in terms of early complications. CONCLUSION: Aponeurotic release of SM is equally effective to reduce the intraoperative PA with combined myotendinous release of ST and myofascial release of SM. Combining all the 3 procedures provides a better correction without forceful manipulation or lengthening of the lateral hamstrings during the correction of knee flexion deformity in CP.

Regenerative peripheral nerve interface free muscle graft mass and function.

BACKGROUND: Regenerative peripheral nerve interfaces (RPNIs) transduce neural signals to provide high-fidelity control of neuroprosthetic devices. Traditionally, rat RPNIs are constructed with ~150 mg of free skeletal muscle grafts. It is unknown whether larger free muscle grafts allow RPNIs to transduce greater signal. METHODS: RPNIs were constructed by securing skeletal muscle grafts of various masses (150, 300, 600, or 1200 mg) to the divided peroneal nerve. In the control group, the peroneal nerve was transected without repair. Endpoint assessments were conducted 3 mo postoperatively. RESULTS: Compound muscle action potentials (CMAPs), maximum tetanic isometric force, and specific muscle force were significantly higher for both the 150 and 300 mg RPNI groups compared to the 600 and 1200 mg RPNIs. Larger RPNI muscle groups contained central areas lacking regenerated muscle fibers. CONCLUSIONS: Electrical signaling and tissue viability are optimal in smaller as opposed to larger RPNI constructs in a rat model.

Skeletal Muscle Magnetic Resonance Biomarkers in GNE Myopathy.

OBJECTIVE: To characterize muscle involvement and evaluate disease severity in patients with GNE myopathy using skeletal muscle MRI and proton magnetic resonance spectroscopy (1H-MRS). METHODS: Skeletal muscle imaging of the lower extremities was performed in 31 patients with genetically confirmed GNE myopathy, including T1-weighted and short tau inversion recovery (STIR) images, T1 and T2 mapping, and 1H-MRS. Measures evaluated included longitudinal relaxation time (T1), transverse relaxation time (T2), and 1H-MRS fat fraction (FF). Thigh muscle volume was correlated with relevant measures of strength, function, and patient-reported outcomes. RESULTS: The cohort was representative of a wide range of disease progression. Contractile thigh muscle volume ranged from 5.51% to 62.95% and correlated with thigh strength (r = 0.91), the 6-minute walk test (r = 0.82), the adult myopathy assessment tool (r = 0.83), the activities-specific balance confidence scale (r = 0.65), and the inclusion body myositis functional rating scale (r = 0.62). Four stages of muscle involvement were distinguished by qualitative (T1W and STIR images) and quantitative methods: stage I: unaffected muscle (T1 = 1,033 ± 74.2 ms, T2 = 40.0 ± 1.9 ms, FF = 7.4 ± 3.5%); stage II: STIR hyperintense muscle with minimal or no fat infiltration (T1 = 1,305 ± 147 ms, T2 = 50.2 ± 3.5 ms, FF = 27.6 ± 12.7%); stage III: fat infiltration and STIR hyperintensity (T1 = 1,209 ± 348 ms, T2 = 73.3 ± 12.6 ms, FF = 57.5 ± 10.6%); and stage IV: complete fat replacement (T1 = 318 ± 39.9 ms, T2 = 114 ± 21.2 ms, FF = 85.6 ± 4.2%). 1H-MRS showed a significant decrease in intramyocellular lipid and trimethylamines between stage I and II, suggesting altered muscle metabolism at early stages. CONCLUSION: MRI biomarkers can monitor muscle involvement and determine disease severity noninvasively in patients with GNE myopathy. CLINICALTRIALSGOV IDENTIFIER: NCT01417533.

Proximal hamstring tendinopathy; expert physiotherapists' perspectives on diagnosis, management and prevention.

OBJECTIVES: To explore and summarise expert physiotherapists' perceptions on their assessment, management and prevention of proximal hamstring tendinopathy (PHT). METHODS: We conducted semi-structured interviews with expert physiotherapists until data saturation was met (n = 13). Interviews were transcribed verbatim and data were analysed systematically and organised into categories and sub-categories according to study aims. RESULTS: Experts report using a clinical reasoning-based approach, incorporating information from the patient interview and results of clinical load-based provocation tests, in the physical examination to diagnose PHT. Experts manage the condition through education and progressive loading targeting the hamstring unit and kinetic chain, avoiding provocative activities in positions of compression in early-mid stage rehab and a gradated and controlled return to sport. Passive therapies including injection therapies and surgery were believed to have limited utility. Prevention of recurrence primarily involved continuation of hamstring and kinetic chain strengthening programs and management of physical workload. CONCLUSION: Experts rely on a combination of information from the patient interview and a battery of pain provocation tests to diagnose PHT. Education and graded exercise of the hamstring group and synergists, minimising early exposure to hip flexion, were the foundation of management of the condition.

Potential prognostic factors for hamstring muscle injury in elite male soccer players: A prospective study.

Hamstring injuries remain the most common injury type across many professional sports. Despite a variety of intervention strategies, its incidence in soccer players playing in the UEFA Champions League has increased by 4% per year over the last decade. Test batteries trying to identify potential risk factors have produced inconclusive results. The purpose of the current study was to prospectively record hamstring injuries, to investigate the incidence and characteristics of the injuries, and to identify possible risk factors in elite male soccer players, playing in the Kosovo national premier league. A total of 143 soccer players from 11 teams in Kosovo were recruited. To identify possible prevalent musculoskeletal or medical conditions a widespread health and fitness assessment was performed including isokinetic strength testing, Nordic hamstring strength test, functional tests, and a comprehensive anamnesis surveying previous hamstring injuries. On average 27.9% of the players sustained at least one hamstring injury with three players suffering bilateral strains with the re-injury rate being 23%. Injured players were significantly older and heavier and had a higher body mass index compared to non-injured ones (p < 0.05). There was a lower passing rate in the Nordic hamstring strength test and a higher injury incidence among the previously injured players compared to non-injured ones (p < 0.05). Except for hamstring/quadriceps ratio and relative torque at 60°/sec (p < 0.05) for dominant and non-dominant leg, there were no other significant differences in isokinetic strength regardless of the angular velocity. No differences were observed for functional tests between cohorts. Regression analysis revealed that age, Nordic hamstring strength test, previous injury history, and isokinetic concentric torque at 240°/sec could determine hamstring injuries by 25.9%, with no other significant predicting risk factors. The battery of laboratory and field-based tests performed during preseason to determine performance related skills showed limited diagnostic conclusiveness, making it difficult to detect players at risk for future hamstring injuries.

A Cadaveric Study of the Distal Biceps Femoris Muscle in relation to the Normal and Variant Course of the Common Peroneal Nerve: A Possible Cause of Common Peroneal Entrapment Neuropathy.

The most frequent mononeuropathy in the lower extremity has been reported as the common peroneal nerve entrapment neuropathy (CPNe) around the head and neck of the fibula, although the mechanism of the neuropathy in this area cannot be fully explained. Therefore, the aim of this cadaveric study was to evaluate the relationship between morphologic variations of the distal biceps femoris muscle (BFM) and the course of the common peroneal nerve (CPN) and to investigate the incidence and morphological characteristics of anatomical variations in the BFM associated with CPNe. The popliteal region and the thigh were dissected in 115 formalin-fixed lower limbs. We evaluated consensus for (1) normal anatomy of the distal BFM, (2) anatomic variations of this muscle, and (3) the relationship of the muscle to the CPN. Measurements of the distal extents of the short and long heads of the BFM from insertion (fibular head) were performed. Two anatomic patterns were seen. First, in 93 knees (80.8%), the CPN ran obliquely along the lateral side of the BFM and then superficial to the lateral head of the gastrocnemius muscle. Second, in 22 cases (19.2%), the CPN coursed within a tunnel between the biceps femoris and lateral head of the gastrocnemius muscle (LGCM). There was a positive correlation between the distal extents of the short heads of the biceps femoris muscle (SHBFM) and the presence of the tunnel. The "popliteal intermuscular tunnel" in which the CPN travels can be produced between the more distal extension variant of the SHBFM and the LGCM. This anatomical variation of BFM may have a clinical significance as an entrapment area of the CPN in the patients in which the mechanism of CPNe around the fibula head and neck is not understood.

Regional differences in hamstring muscle damage after a marathon.

Previous studies suggest that marathon running induces lower extremity muscle damage. This study aimed to examine inter- and intramuscular differences in hamstring muscle damage after a marathon using transverse relaxation time (T2)-weighted magnetic resonance images (MRI). 20 healthy collegiate marathon runners (15 males) were recruited for this study. T2-MRI was performed before (PRE) and at 1 (D1), 3 (D3), and 8 days (D8) after marathon, and the T2 values of each hamstring muscle at the distal, middle, and proximal sites were calculated. Results indicated that no significant intermuscular differences in T2 changes were observed and that, regardless of muscle, the T2 values of the distal and middle sites increased significantly at D1 and D3 and recovered at D8, although those values of the proximal site remained constant. T2 significantly increased at distal and middle sites of the biceps femoris long head on D1 (p = 0.030 and p = 0.004, respectively) and D3 (p = 0.007 and p = 0.041, respectively), distal biceps femoris short head on D1 (p = 0.036), distal semitendinosus on D1 (p = 0.047) and D3 (p = 0.010), middle semitendinosus on D1 (p = 0.005), and distal and middle sites of the semimembranosus on D1 (p = 0.008 and p = 0.040, respectively) and D3 (p = 0.002 and p = 0.018, respectively). These results suggest that the distal and middle sites of the hamstring muscles are more susceptible to damage induced by running a full marathon. Conditioning that focuses on the distal and middle sites of the hamstring muscles may be more useful in improving recovery strategies after prolonged running.

Variante de colgajo de rotación tipo Hamstring para reconstrucción de úlcera isquiática / Hamstring rotation fl ap variant for ischial ulcer reconstruction

Antecedentes. El colgajo Hamstring es una opción válida para la reconstrucción de úlceras isquiáticas. Las úlceras por presión representan un verdadero desafío para el cirujano plástico. Requieren un tratamiento especializado y multidisciplinario por su alta probabilidad de recidiva y las complicaciones en su manejo. Por lo general, ocurren por presión sostenida sobre la tuberosidad isquiática. Caso clínico. Se presenta el caso de un paciente parapléjico desde el nacimiento secundario a mielomeningocele con diagnóstico actual de úlcera isquiática. Se le realizaron durante 3 años múltiples intentos de cierre quirúrgico alternando medidas conservadoras, sin éxito. A la exploración física presenta una úlcera isquiática izquierda de 6x6 cm a la que se le realizó aseo y desbridación quirúrgica más cierre por medio de un colgajo Hamstring modificado. A los 7 días presentó dehiscencia de herida la cual se manejó de manera conservadora y cierre primario diferido a las 4 semanas. A 8 meses de posoperatorio el paciente se encuentra con buena evolución y con resultado estético y funcional aceptable, por otra parte, se encuentra sin recidiva, lo que ha permitido su reinserción laboral y un buen equilibrio físico-psico-emocional. Conclusión. El objetivo de este colgajo es brindar cobertura al área isquiática sin afectar estructuras adyacentes, lo cual requiere de un amplio conocimiento de la anatomía de la región femoral, así como de los colgados tanto locales como regionales que podemos utilizar para la reconstrucción. Actualmente este colgajo es una opción terapéutica efectiva para el tratamiento de úlceras isquiáticas refractarias en centros que cuentan con cirujanos plásticos no especializados en microcirugía.

Background. The Hamstring fl ap is an adequate option for ischial ulcers reconstruction. Pressure ulcers represent a real challenge for the plastic surgeon. They require specialized and multidisciplinary treatment due to their high recurrence probability and complications in their management. Regularly, pressure ulcers occur when sustained pressure is applied on the ischial tuberosity. Case report. We report a case of a 23-year-old paraplegic male with myelomeningocele complaining for an ischial ulcer. Multiple attempts to surgical closure were made during three years along with conservative management, without success. Physical examination revealed a 6x6 cm left ischial ulcer, which was managed with surgical debridement and closure with a modifi ed Hamstring fl ap. After 7 days, the patient presented wound dehiscence, which was managed conservatively and primary delayed closure after 4 weeks. 8 months postoperatively the patient has a good evolution and an acceptable functional and aesthetic result, without recurrence, which has allowed his reintegration into work and a good physical-psycho-emotional balance. Conclusion. The objective of this fl ap is to provide coverage to the ischial area without aff ecting adjacent structures, which requires a broad knowledge of the anatomy of the femoral region, as well as the local and regional fl aps that can be used for reconstruction. Nowadays this fl ap is an eff ective therapeutic option for the treatment of refractary ischial ulcers in plastis suergery centers without microsurgery.

Hamstring muscle activation and morphology are significantly altered 1-6 years after anterior cruciate ligament reconstruction with semitendinosus graft.

PURPOSE: Harvest of the semitendinosus (ST) tendon for anterior cruciate ligament reconstruction (ACLR) causes persistent hypotrophy of this muscle even after a return to sport, although it is unclear if hamstring activation patterns are altered during eccentric exercise. It was hypothesised that in comparison with contralateral control limbs, limbs with previous ACLR involving ST grafts would display (i) deficits in ST activation during maximal eccentric exercise; (ii) smaller ST muscle volumes and anatomical cross-sectional areas (ACSAs); and (iii) lower eccentric knee flexor strength. METHODS: Fourteen athletes who had successfully returned to sport after unilateral ACLR involving ST tendon graft were recruited. Median time since surgery was 49 months (range 12-78 months). Participants underwent functional magnetic resonance imaging (MRI) of their thighs before and after the Nordic hamstring exercise (NHE) and percentage change in transverse (T2) relaxation time was used as an index of hamstring activation. Muscle volumes and ACSAs were determined from MRI and distal ST tendons were evaluated via ultrasound. Eccentric knee flexor strength was determined during the NHE. RESULTS: Exercise-induced T2 change was lower for ST muscles in surgical than control limbs (95% CI - 3.8 to - 16.0%). Both ST muscle volume (95% CI - 57.1 to - 104.7 cm3) and ACSA (95% CI - 1.9 to - 5.0 cm2) were markedly lower in surgical limbs. Semimembranosus (95% CI 5.5-14.0 cm3) and biceps femoris short head (95% CI 0.6-11.0 cm3) volumes were slightly higher in surgical limbs. No between-limb difference in eccentric knee flexor strength was observed (95% CI 33 N to - 74 N). CONCLUSION: ST activation is significantly lower in surgical than control limbs during eccentric knee flexor exercise 1-6 years after ACLR with ST graft. Lower levels of ST activation may partially explain this muscle's persistent hypotrophy post ACLR and have implications for the design of more effective rehabilitation programs. LEVEL OF EVIDENCE: IV.

Atrophy of individual thigh muscles measured by MRI in older adults with knee osteoarthritis: A cross-sectional study.

BACKGROUND: The characteristics of thigh-muscle cross-sectional area (CSA) in older adults with knee osteoarthritis (KOA) remain controversial. OBJECTIVES: This study aimed to evaluate atrophy of individual thigh muscles in older adults with KOA and to determine which muscle CSA should be measured to detect KOA-related muscle atrophy of the thigh. METHODS: In older adults, individual thigh-muscle CSA measured by 1.5 Tesla MRI was analyzed at 5% intervals of the femoral length (FL) around the mid-thigh between the proximal 25% of the FL and the distal 25%. Participants with KOA grade≤1 and grade≥2 were compared for ratios of quadriceps muscle (QM) CSA to total thigh, individual QM CSA to QM, and individual hamstring (HAM) CSA to HAM at 5% intervals. RESULTS: We included 40 older adults [20 males; mean (SD) age 73.3 (4.7) years; 20 with KOA grade≤1 and 20 with KOA grade≥2]. The ratio of vastus medialis (VM) CSA to QM from the proximal 25% to distal 15% and the ratio of semi-membranosus (SM) CSA to HAM at the distal 10% to 25% were significantly lower with KOA grade≥2 than grade≤1; the effect sizes were 0.34 to 0.67 for VM and 0.40 to 0.60 for SM. The effect sizes were greatest for the ratios of VM CSA to QM at the mid-thigh with 5% intervals and the ratio of SM CSA to HAM at the distal 25%. CONCLUSIONS: The ratio of VM CSA to QM and/or that of SM CSA to HAM were low and were the best indicators to detect KOA-related muscle atrophy of the thigh. However, to detect KOA-related muscle atrophy, the VM CSA ratio should be analyzed in the thigh region around the mid-thigh, whereas the SM CSA ratio should be analyzed in the thigh region at the muscle belly.

Temporal Muscle-specific Disuse Atrophy during One Week of Leg Immobilization.

PURPOSE: Musculoskeletal injuries necessitate periods of disuse (i.e., limb immobilization) during which rapid skeletal muscle atrophy occurs. The relative susceptibility of different muscles of the thigh to disuse atrophy remains uninvestigated. We assessed muscle disuse atrophy of individual thigh muscles throughout 1 wk of unilateral knee immobilization. METHODS: Thirteen healthy, young (20.2 ± 0.6 yr) men underwent 7 d of unilateral leg immobilization via knee bracing. Magnetic resonance imaging scans were performed bilaterally prior to, and following 2 and 7 d of immobilization to determine the volume and anatomical cross-sectional area of the individual muscle groups of the upper legs. RESULTS: In contrast to the control leg, total thigh muscle volume had decreased by 1.7% ± 0.3% (P < 0.01) and 5.5% ± 0.6% (P < 0.001) in the immobilized leg after 2 and 7 d of disuse, respectively. Muscle loss was significantly greater in the Musculus quadriceps (day 2; 1.7% ± 0.3% (P < 0.05) and day 7; 6.7% ± 0.6%) when compared with the Musculus hamstrings (day 2; 1.4% ± 0.2% (P < 0.01) and day 7; 3.5% ± 0.3%) after 7 d of disuse (P < 0.001). Individual muscles of the thigh exhibited different atrophy rates with the Musculus vastus lateralis anatomical cross-sectional area showing the greater (2.6% ± 0.4% and 7.2% ± 0.8%), and the Musculus gracilis the lesser (1.1% ± 0.7% and 2.3% ± 1.0%) decline following 2 and 7 d of immobilization, respectively (P < 0.01). CONCLUSIONS: Thigh muscle disuse atrophy occurs rapidly and is already evident within 2 d of leg immobilization and progresses at a similar rate over the next 5 d (~0.8% muscle loss per day). M. quadriceps muscle shows more atrophy when compared with the M. hamstrings.

Effect of Subcutaneous Tissue on Changes in Thigh Circumference Following Anterior Cruciate Ligament Reconstruction.

Circumference measurements have been used to estimate muscle cross-sectional area (CSA) in clinical settings. Measurements of thigh circumference are affected by muscle and subcutaneous fat (SF). In fact, SF could increase over a short period. Therefore, clarifying the relationship between thigh circumference and muscle and SF following ACL reconstruction is important. This study's primary purpose was to examine pre- and post-operative changes in thigh circumference, thigh muscles and SF CSAs in both legs. Secondary, the relationship between thigh circumference and muscle and SF CSAs was examined to demonstrate that circumference measurements could be used to detect atrophy. Quadriceps, hamstrings, and SF CSAs at 15, 10, and 5 cm proximal to the patella were measured by MRI pre- and 4 weeks postoperatively to examine how reconstruction affected those tissues in the thighs. The results showed increases in SF CSA (r=0.72 at 10 cm, r=0.67 at 15 cm) greatly affected thigh circumference in females on the surgical side. In males, increases in SF CSA (r=0.83) at 15- and 5-cm and decreases in quadriceps muscle CSA (r=0.73) at 5 cm affected thigh circumference on the surgical side. Thigh circumference measurements might not reflect actual muscle CSA in ACL patients.

Dissociation between changes in sprinting performance and Nordic hamstring strength in professional male football players.

The aim of the present study was to evaluate the consequence of implementing a Nordic Hamstring exercise (NHE) protocol during the first 15 to 17 weeks of the season to assess the effect on sprinting and NHE strength (NHEs) in professional football players. The study examined 50 healthy male professional football players (age 18.8±0.8yr; height 176.8±6.9cm; weight 71.3±5.7kg) belonging to 3 of the reserve squads of three Spanish La-Liga clubs divided in 2 intervention teams [Nordic-Group1 (NG-1) and Nordic-Group2 (NG-2, extensive experience in NHE)] and 1 team as a control-group (CG). NHEs and linear sprint (T5, T10, T20-m) were evaluated at the beginning of the season and at the end of an intervention period of conditioning and football training, supplemented with a NHE protocol (24 sessions for NG-1 and 22 sessions for NG-2) or without using the NHE at all (CG). Sprint times were substantially improved in all groups (ES from -2.24±0.75 to -0.60±0.37). NHEs was enhanced absolute and relative to body-mass only in NG-1 after the training period (ES from 0.84±0.32 to 0.74±0.26), while in the NG-2 there were only improvements in average NHEs relative to body-mass (ES = 0.39±0.36). The improvements in T20-m were substantially greater in NG-2 vs. NG-1, and there were no differences in sprint performance changes between NG-1 and CG. Changes in sprinting performance and NHEs were unrelated. NHEs was largely correlated with the body-mass of the players. Results indicate that the improvements in sprint are not dependent on the NHEs changes, with no relationships between NHEs and sprint performance, and between sprint changes and changes in NHEs.

Clinical and muscle magnetic resonance image findings in patients with late-onset multiple acyl-CoA dehydrogenase deficiency.

BACKGROUND: Late-onset multiple acyl-coA dehydrogenase deficiency (MADD) is an autosomal recessive inherited metabolic disorder. It is still unclear about the muscle magnetic resonance image (MRI) pattern of the distal lower limb pre- and post-treatment in patients with late-onset MADD. This study described the clinical and genetic findings in a cohort of patients with late-onset MADD, and aimed to characterize the MRI pattern of the lower limbs. METHODS: Clinical data were retrospectively collected from clinic centers of Peking University People's Hospital between February 2014 and February 2018. Muscle biopsy, blood acylcarnitines, and urine organic acids profiles, and genetic analysis were conducted to establish the diagnosis of MADD in 25 patients. Muscle MRI of the thigh and leg were performed in all patients before treatment. Eight patients received MRI re-examinations after treatment. RESULTS: All patients presented with muscle weakness or exercise intolerance associated with variants in the electron transfer flavoprotein dehydrogenase gene. Muscle MRI showed a sign of both edema-like change and fat infiltration selectively involving in the soleus (SO) but sparing of the gastrocnemius (GA) in the leg. Similar sign of selective involvement of the biceps femoris longus (BFL) but sparing of the semitendinosus (ST) was observed in the thigh. The sensitivity and specificity of the combination of either "SO+/GA-" sign or "BFL+/ST-" sign for the diagnosis of late-onset MADD were 80.0% and 83.5%, respectively. Logistic regression model supported the findings. The edema-like change in the SO and BFL muscles were quickly recovered at 1 month after treatment, and the clinical symptom was also relieved. CONCLUSIONS: This study expands the clinical and genetic spectrums of late-onset MADD. Muscle MRI shows a distinct pattern in the lower limb of patients with late-onset MADD. The dynamic change of edema-like change in the affected muscles might be a potential biomarker of treatment response.

Characteristics of individual thigh muscles including cross-sectional area and adipose tissue content measured by magnetic resonance imaging in knee osteoarthritis: a cross-sectional study.

This study aimed to identify the parameters related to the area and adipose tissue content of thigh muscles that are associated with radiographic knee osteoarthritis grade. Fifty patients (mean age ± standard deviation, 73.0 ± 4.5 years) were divided into early osteoarthritis (n = 23) and established osteoarthritis (n = 27) groups based on Kellgren-Lawrence classification. The femorotibial angle was measured from anteroposterior radiographs of the lower limbs. Individual thigh muscle and adipose tissue areas were analyzed using axial T1-weighted magnetic resonance imaging. After intergroup comparison, logistic regression analysis was performed to determine independent parameters associated with established osteoarthritis. Moreover, correlation coefficients were assessed between the left-right differences of osteoarthritis grade and parameters. Established osteoarthritis exhibited a significantly greater femorotibial angle and increased adipose tissue content in the subcutaneous, intermuscle, and intramuscle of the adductor, vastus lateralis, vastus intermedius, as well as a lower vastus medialis area, in comparison to early osteoarthritis. A greater femorotibial angle, increased intermuscular adipose tissue, and a lower vastus medialis area to knee extensor ratio were significantly independently associated with established osteoarthritis (odds ratio 3.2, 1.8, and 2.0, respectively). The left-right differences of femorotibial angle and vastus medialis area were significantly correlated with osteoarthritis grade, whereas adipose tissue content had no significant correlations with osteoarthritis grade. Greater femorotibial angle and lower vastus medialis area were related with higher osteoarthritis grade. Greater intermuscular adipose tissue content was associated with established osteoarthritis; however, in the left-right differences, adipose tissue content was not related with osteoarthritis grade.

Muscle diffusion tensor imaging in glycogen storage disease V (McArdle disease).

PURPOSE: To evaluate differences in diffusion parameters in thigh muscles in patients with glycogen storage disease type V (McArdle disease) using muscle diffusion tensor imaging (mDTI) compared to healthy controls METHODS: In this prospective study, we evaluated thigh muscles from hip to knee of 10 McArdle patients (5 female, mean age 33.7 ± 14.4 years) and 10 healthy age- and gender-matched volunteers. MRI scans were performed at 3 T and comprised mDTI, T1-weighted and T2-weighted imaging between May 2015 and May 2017. Needle biopsy of the vastus lateralis muscle was performed in three McArdle patients. The muscle tissue was analyzed by using histochemical and enzyme-histochemical techniques for glycogen content and histopathological changes. Mean values of the eigenvalues (λ1-λ3), fractional anisotropy (FA), and mean diffusivity (MD) were obtained for the vastus lateralis, vastus medialis, rectus femoris, biceps femoris, semitendinosus, and semimembranosus and compared between groups using Student's t tests, as well as ANCOVA; significance level was set at p < 0.05. RESULTS: Needle biopsy showed intracellular glycogen accumulation in skeletal muscle fibers of three McArdle patients. Extracellular histopathological changes were not found. Muscle DTI analysis did not show statistically significant differences between patients and controls for any of the muscles. CONCLUSION: Despite intracellular glycogen accumulation in the three biopsy samples, mDTI parameters were not altered in McArdle patients compared to controls. We conclude that the currently used mDTI acquisition and processing lack the sensitivity to detect intracellular changes due to accumulated glycogen in this cohort of McArdle patients. KEY POINTS: • Despite intracellular glycogen accumulation in three examined biopsy samples, mDTI parameters were not altered in McArdle patients compared to controls. • In its current form, diffusion MR does not provide additional information in quantifying intracellular glycogen accumulations within skeletal muscle fibers in McArdle patients.