Establishment and Validation of a Predictive Model for Sarcopenia Based on 2-D Ultrasound and Shear Wave Elastography in the Medial Gastrocnemius Muscle.

OBJECTIVE: To develop and validate a predictive model for sarcopenia. METHODS: A total of 240 subjects who visited our hospital between August 2021 and May 2023 were randomly divided by time of entry into a training set containing 2/3 of patients and a validation set containing 1/3 of patients. The muscle thickness (MT), echo intensity (EI), and shear wave velocity (SWV) of the medial gastrocnemius muscle were measured. Indicators that were meaningful in the univariate analysis in the training set were included in a binary logistic regression to derive a regression model, and the model was evaluated using a consistency index, calibration plot, and clinical validity curve. Diagnostic efficacy and clinical applicability were compared between the model and unifactorial indicators. RESULTS: Four meaningful variables, age, body mass index (BMI), MT, and SWV, were screened into the predictive model. The model was Logit Y = 21.292 + 0.065 × Age - 0.411 × BMI - 0.524 × MT - 3.072 × SWV. The model was well differentiated with an internally validated C-index of 0.924 and an external validation C-index of 0.914. The calibration plot predicted probabilities against actual probabilities showed excellent agreement. The specificity, sensitivity, and Youden's index of the model were 73.80%, 97.40%, and 71.20%, respectively, when using the diagnostic cut-off value of >0.279 for sarcopenia. The logistic model had higher diagnostic efficacy (p < 0.001) and higher net clinical benefit (p < 0.001) over the same threshold range compared to indicators. CONCLUSION: The logistic model of sarcopenia has been justified to have good discriminatory, calibrated, and clinical validity, and has higher diagnostic value than indicators.

[Translated article] Medial gastrocnemius proximal fasciotomy in patients with chronic plantar fasciitis: A systematic review. / [Artículo traducido] Fasciotomía proximal de gemelo interno en pacientes con fascitis plantar crónica: una revisión sistemática.

INTRODUCTION: Plantar fasciitis is the main cause of heel pain in middle-aged patients. In chronic cases, limited ankle dorsiflexion caused by isolated gastrocnemius contracture is considered the main risk factor for suffering it. Therefore, in recent years the number of patients operated on by proximal medial gastrocnemius release (PMGR) has increased to treat chronic plantar fasciitis. MATERIAL AND METHODS: Systematic review following the PRISMA guidelines. We have carried out a bibliographic search in Pubmed, Science Direct, Cochrane Library and Web of Science databases. One hundred and eighty-four articles were found. Data extraction was performed using the Covidence software, and a quality and risk of bias analysis of the included articles was performed based on the Cochrane risk of bias Tool 2.0. RESULTS: Three articles were included in the review: two randomized clinical trials and one cohort study with a total of 138 patients. In the analyzed studies, patients after proximal fasciotomy of the medial gastrocnemius showed significant improvements in pain and in the AOFAS score with high levels of patient satisfaction. Increases in ankle dorsiflexion angle were found after 12 months of follow-up, with no loss of gastrocnemius strength. The complication rate was low and fewer occurred in the proximal fasciotomy compared to plantar fasciotomy. CONCLUSION: Proximal fasciotomy of the medial gastrocnemius provides clinical benefit in patients with chronic plantar fasciitis, with a low probability of complications and high patient satisfaction.

Trans-medial gastrocnemius approach (Badet approach) for displaced posterior cruciate ligament tibial avulsion.

Avulsions of the retrospinal surface are rare injuries resulting from high-energy trauma. Displacement of this fracture frequently indicates a surgical treatment to restore posterior cruciate ligament function. Several approaches have been proposed in the literature, either open or arthroscopic, which can be tricky due to the fracture's proximity to the popliteal vascular-nervous elements. Badet's open approach is a medial trans-gastrocnemius approach, providing a direct access to the retro-spinal surface for osteosynthesis. In this technique, an L-shaped incision is made along precise skin lines, followed by discision of the muscle fibers. The capsule is then approached, allowing a view of the retro-spinal surface protected from the popliteal vasculo-nervous elements by the muscular lateral lip of the gastrocnemius. A reduction followed by screw osteosynthesis is usually performed, allowing early mobilization of the patient. In this technical note, we describe the Badet approach supporting by video and case series. LEVEL OF EVIDENCE: IV.

Influence of preconditioning on morphological and mechanical properties of human Achilles tendon in vivo.

The present study aimed 1) to verify whether the effect of preconditioning was observed in the measured variables during the measurement of the human tendon in vivo (i.e., repeated contractions with breaks between trials) and 2) to determine the changes in tendon properties and their mechanisms due to submaximal repetitive contractions. Twelve healthy males participated in this study. To eliminate the effects of preconditioning, the participants rested on the measurement bed for 2 h before the start of both experiment-1 and experiment-2. In experiment-1, the measurements of elongation and hysteresis of the Achilles tendon for ramp and ballistic conditions were repeated ten times every 2 min. In experiment-2, participants performed submaximal repetitive contractions at 50 % of MVC and a frequency of 1 Hz for 10 min with a 30 s break every 2 min. Tendon mechanical properties were measured during contractions (starting 30 s and last 20 s of every 2 min), and the mean and coefficient variation (CV) of echogenicity were assessed during a 30-s rest every 2 min. In experiment-1, no significant differences in elongation and hysteresis of the tendon for ramp and ballistic contractions were found among the trials. In experiment 2, there were no significant differences in tendon elongation and hysteresis among all measurement times. Mean echogenicity increased significantly after 2 min, and CV of echogenicity decreased significantly after 4 min. These results suggest that preconditioning does not affect the elongation and hysteresis of the Achilles tendon in measuring tendon mechanical properties and submaximal repetitive contractions.

Effects of gait retraining using minimalist shoes on the medial gastrocnemius muscle-tendon unit behavior and dynamics during running.

The effects of a 12-week gait retraining program on the adaptation of the medial gastrocnemius (MG) and muscle-tendon unit (MTU) were investigated. 26 runners with a rearfoot strike pattern (RFS) were randomly assigned to one of two groups: gait retraining (GR) or control group (CON). MG ultrasound images, marker positions, and ground reaction forces (GRF) were collected twice during 9 km/h of treadmill running before and after the intervention. Ankle kinetics and the MG and MTU behavior and dynamics were quantified. Runners in the GR performed gradual 12-week gait retraining transitioning to a forefoot strike pattern. After 12-week, (1) ten participants in each group completed the training; eight participants in GR transitioned to non-RFS with reduced foot strike angles; (2) MG fascicle contraction length and velocity significantly decreased after the intervention for both groups, whereas MG forces increased after intervention for both groups; (3) significant increases in MTU stretching length for GR and peak MTU recoiling velocity for both groups were observed after the intervention, respectively; (4) no significant difference was found for all parameters of the series elastic element. Gait retraining might potentially influence the MG to operate at lower fascicle contraction lengths and velocities and produce greater peak forces. The gait retraining had no effect on SEE behavior and dynamics but did impact MTU, suggesting that the training was insufficient to induce mechanical loading changes on SEE behavior and dynamics.

Association of the rate of torque development and joint angle with passive muscle stiffness.

PURPOSE: The purpose of this study was to statistically compare the rate of torque development normalized by maximal strength (relative RTD) across ankle angles. Additionally, this study was aimed at exploring the correlation coefficients between relative RTD and passive stiffness of the medial gastrocnemius (MG) at different ankle angles. METHODS: Twenty-two healthy men and women (age: 31 ± 4 years) performed randomly-ordered explosive isometric plantar flexions at plantarflexed (15°), neutral (0°), and dorsiflexed (- 15°) angles; relative RTD comprised the slope of the time-torque curve normalized to maximal torque. The shear wave velocity (SWV; index of stiffness) of the MG at rest was measured at each angle using ultrasound shear wave elastography. RESULTS: The relative RTD was greater at 15° than - 15° for 0-50, 0-100, and 0-150 ms time-windows and at 15° than 0° for the 0-150 ms time-window (P < 0.05), although peak torque was lower at 15° than 0° and - 15° (P < 0.05). The relative RTD for the 0-50 ms time-window correlated with SWV at - 15° (rs = 0.475, P < 0.05), but not at 15º and 0º. Furthermore, the correlation coefficient of RTD for the 0-100 ms time-window with SWV was significantly greater at - 15° (rs = 0.420) than 0 ° (rs = - 0.109). CONCLUSIONS: A greater relative RTD occurs at plantarflexed angles (i.e., the ascending limb of the force-length curve) in the triceps surae, and relative RTD is strongly related to passive MG stiffness at dorsiflexed angles (i.e., longer muscle lengths).

Effects of 12-week gait retraining on plantar flexion torque, architecture, and behavior of the medial gastrocnemius in vivo.

Objective: This study aims to explore the effects of 12-week gait retraining (GR) on plantar flexion torque, architecture, and behavior of the medial gastrocnemius (MG) during maximal voluntary isometric contraction (MVIC). Methods: Thirty healthy male rearfoot strikers were randomly assigned to the GR group (n = 15) and the control (CON) group (n = 15). The GR group was instructed to wear minimalist shoes and run with a forefoot strike pattern for the 12-week GR (3 times per week), whereas the CON group wore their own running shoes and ran with their original foot strike pattern. Participants were required to share screenshots of running tracks each time to ensure training supervision. The architecture and behavior of MG, as well as ankle torque data, were collected before and after the intervention. The architecture of MG, including fascicle length (FL), pennation angle, and muscle thickness, was obtained by measuring muscle morphology at rest using an ultrasound device. Ankle torque data during plantar flexion MVIC were obtained using a dynamometer, from which peak torque and early rate of torque development (RTD50) were calculated. The fascicle behavior of MG was simultaneously captured using an ultrasound device to calculate fascicle shortening, fascicle rotation, and maximal fascicle shortening velocity (Vmax). Results: After 12-week GR, 1) the RTD50 increased significantly in the GR group (p = 0.038), 2) normalized FL increased significantly in the GR group (p = 0.003), and 3) Vmax increased significantly in the GR group (p = 0.018). Conclusion: Compared to running training, GR significantly enhanced the rapid strength development capacity and contraction velocity of the MG. This indicates the potential of GR as a strategy to improve muscle function and mechanical efficiency, particularly in enhancing the ability of MG to generate and transmit force as well as the rapid contraction capability. Further research is necessary to explore the effects of GR on MG behavior during running in vivo.

A Novel Surgical Technique for the Reconstruction of Chronic Tennis Leg Injury.

Tennis leg, a rupture of the medial head of the gastrocnemius muscle at the musculotendinous junction (MTJ), is common, particularly among middle-aged sports enthusiasts. While acute cases usually resolve with conservative care, optimal surgical strategies for the treatment of chronic injuries remain undefined. This study reviews the current literature and details the successful operative treatment of a 37-year-old male with a 12-month history of tennis leg, employing a novel reverse flap technique from the MTJ's aponeurosis and augmented by a facia lata allograft.

The interaction of in vivo muscle operating lengths and passive stiffness in rat hindlimbs.

The operating length of a muscle is a key determinant of its ability to produce force in vivo. Muscles that operate near the peak of their force-length relationship will generate higher forces whereas muscle operating at relatively short length may be safe from sudden lengthening perturbations and subsequent damage. At longer lengths, passive mechanical properties have the potential to contribute to force or constrain operating length with stiffer muscle-tendon units theoretically being restricted to shorter lengths. Connective tissues typically increase in density during aging, thus increasing passive muscle stiffness and potentially limiting the operating lengths of muscle during locomotion. Here, we compare in vivo and in situ muscle strain from the medial gastrocnemius in young (7 months old) and aged (30-32 months old) rats presumed to have varying passive tissue stiffness to test the hypothesis that stiffer muscles operate at shorter lengths relative to their force-length relationship. We measured in vivo muscle operating length during voluntary locomotion on inclines and flat trackways and characterized the muscle force-length relationship of the medial gastrocnemius using fluoromicrometry. Although no age-related results were evident, rats of both age groups demonstrated a clear relationship between passive stiffness and in vivo operating length, such that shorter operating lengths were significantly correlated with greater passive stiffness. Our results suggest that increased passive stiffness may restrict muscles to operating lengths shorter than optimal lengths, potentially limiting force capacity during locomotion.

Outcomes After Proximal Medial Gastrocnemius Recession and Stretching vs Stretching as Treatment of Chronic Plantar Fasciitis at 6-Year Follow-up.

BACKGROUND: Evidence from prospective short-term studies suggest that proximal medial gastrocnemius recession is a safe and efficient procedure to treat chronic plantar fasciitis resistant to nonoperative treatment. The aim of this study was to evaluate the long-term clinical outcomes of proximal medial gastrocnemius recession and stretching compared to a stretching exercise protocol for patients with chronic plantar fasciitis and an isolated gastrocnemius contracture (IGC). METHODS: Forty patients with plantar fasciitis lasting more than 1 year were prospectively randomized to a home stretching exercise program only, or to proximal medial gastrocnemius recession in addition to the stretching program. Clinical and functional data in this study were obtained at baseline and 6-year follow-up. The main outcome was the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score. Secondary outcomes were the visual analog scale (VAS) for pain, the Manchester Oxford Foot Questionnaire (MOxFQ), ankle dorsiflexion, and Achilles complex performance. RESULTS: Thirty-three of 40 patients completed the 6-year follow-up. Seven patients had crossed over from nonoperative treatment to operative treatment. At 6 years, the operative group demonstrated significantly better outcomes with AOFAS (88.9 vs 78.6, P = .012), for pain measured by VAS (2.5 vs 5.5, P < .001) and with the MOxFQ total score (24.4 vs 45.9, P = .05) (per protocol analysis excluding crossovers). No between-group differences were observed for ankle dorsiflexion or Achilles complex performance at 6 years. CONCLUSION: This study demonstrates that the improved function and reduced level of pain by proximal medial gastrocnemius recession and stretching is better compared to stretching alone after 6 years of follow-up for patients with chronic plantar fasciitis and a concomitant isolated gastrocnemius contracture. LEVEL OF EVIDENCE: Level I, randomized controlled trial.

Effects of Low-Dye Tape on Arch Height and Its Impact on the Medial Gastrocnemius Electromyographic Activity in Structurally Differentiable Foot Types: A Cross-Sectional Observational Study.

BACKGROUND: Low-Dye tape (LDT) is a short-term treatment for plantar fasciitis, where external stabilization by means of the tape improves kinetics, kinematics, pain level, and electromyography (EMG). PURPOSE: The purpose of this study was to compare the EMG of the medial gastrocnemius (MG) and changes in arch height (AH) based on the type of foot. METHODS: A total of 30 subjects participated in this study; they walked on a treadmill barefoot and when taped, where the average activity and changes in AH were measured over a 30 s period. The statistical intraclass correlation coefficient (ICC) to test for reliability was calculated, and the Wilcoxon test was determined for measures of EMG and AH. RESULTS: The reliability of the values of EMG was almost perfect. The data show that there was an increase in height in the comparison of the moment pre-baseline walking and post-taped walking on neutral feet (5.61 ± 0.46 vs. 5.77 ± 0.39 cm, p < 0.05), on pronated feet (5.67 ± 0.57 vs. 6.01 ± 0.53 cm, p < 0.001) and on supinated feet (5.97 ± 0.36 vs. 6.28 ± 0.27 cm, p < 0.05). In the MG, EMG activity decreased significantly in the taped condition compared to the baseline condition in neutral subjects (0.0081 ± 0.016 vs. 0.076 ± 0.016 mV, p < 0.05) and in pronated subjects (0.081 ± 0.022 vs. 0.068 ± 0.025 mV, p < 0.05). CONCLUSIONS: It was demonstrated that with the use of LDT, there was an improvement in the average activity in the MG in pronated and neutral feet. All foot types improved in arch height with the use of tape.

Effect of M-wave Amplitude on Inter-evaluator Concordance and Number of Detected Innervation Zones in the Medial Gastrocnemius Using Multichannel Electromyography / Efecto de la Amplitud de la Onda M sobre la Concordancia entre Evaluadores y el Número de Zonas de Inervación Detectadas en el Gastrocnemio Medial Mediante Electromiografía Multicanal

SUMMARY: The Innervation Zones (IZ) correspond to clusters of neuromuscular junctions. The traditional method of locating IZs through voluntary muscle contractions may not be feasible in individuals with motor disorders. Imposed contractions by electrostimulation are an alternative. However, there is limited evidence regarding the factors that affect inter-evaluator concordance and the number of localized IZs when using imposed contraction. The main objective of this research was to determine the effect of the amplitude of compound motor action potentials (CMAPs) containing the M-wave on inter-evaluator agreement. As a secondary objective, was investigate the effect on the number of detected IZs. Twenty-four healthy volunteers (age: 21.2 ± 1.5years, weight: 67.4 ± 13.2kg, height: 1.68 ± 0.80m) participated in the study. Electrostimulation was applied to the tibial nerve to induce contraction of the medial gastrocnemius. The IZ were identified based on the M-wave recorded through multichannel electromyography. A receiver operating characteristic (ROC) analysis was conducted to assess sensitivity and specificity in detecting the IZs. Inter-rater agreement was evaluated using a two-way mixed effects test to determine the intraclass correlation coefficients (ICC). A p-value less than 0.05 was considered statistically significant. The ROC analysis revealed that for both evaluators, a specificity of 95% was achieved with an amplitude ≥30 %. The area under the ROC curve was 0.980 [0.964, 0.996], indicating a strong influence of CMAP amplitude on detection of IZs. The highest level of agreement (ICC = 0.788 [0.713, 0.844]) among the evaluators was observed with CMAP amplitudes equal to or greater than 80 % of the maximum M-wave. The findings of this study demonstrate that both the number and the inter-evaluator concordance for detecting IZs using imposed contractions are strongly influenced by the amplitude of the M-wave. Higher M-wave amplitudes were associated with improved concordance and increased IZ detection, making it crucial to standardize amplitude settings for reliable outcomes.

Las Zonas de Inervación (IZ) corresponden a grupos de uniones neuromusculares. El método tradicional para localizar IZs mediante contracciones musculares voluntarias puede no ser factible en personas con trastornos motores. Las contracciones impuestas mediante electro estimulación son una alternativa. Sin embargo, existe poca evidencia sobre los factores que afectan la concordancia entre evaluadores y el número de IZs localizadas al usar este tipo de contracciones. El objetivo de esta investigación fue determinar el efecto de la amplitud de los potenciales de acción motores compuestos (PAMCs) que contienen la onda M sobre la concordancia entre evaluadores. Como objetivo secundario, se investigó el efecto sobre el número de IZs detectadas. Veinticuatro voluntarios sanos (edad: 21.2 ± 1.5 años, peso: 67.4 ± 13.2 kg, altura: 1.68 ± 0.80 m) participaron en el estudio. Se aplicó electroestimulación al nervio tibial para inducir la contracción del gastrocnemio medial. Las IZs se identificaron según la onda M registrada mediante electromiografía multicanal. Se realizó un análisis de curva de las característica del receptor (ROC) para evaluar la sensibilidad y especificidad en la detección de las IZs. La concordancia entre evaluadores se evaluó utilizando una prueba de efectos mixtos de dos vías para determinar los coeficientes de correlación intraclase (ICC). Se consideró un valor de p menor que 0.05 como estadísticamente significativo. El análisis ROC reveló que para ambos evaluadores se logró una especificidad del 95% con una amplitud ≥30 %. El área bajo la curva ROC fue de 0.980 [0.964, 0.996], lo que indica una fuerte influencia de la amplitud del CMAP en la detección de las IZs. El nivel más alto de concordancia (ICC = 0.788 [0.713, 0.844]) entre los evaluadores se observó con amplitudes de CMAP iguales o mayores al 80 % de la onda M máxima. Los hallazgos de este estudio demuestran que tanto el número como la concordancia entre evaluadores para detectar IZs mediante contracciones impuestas están fuertemente influenciados por la amplitud de la onda M. Las amplitudes más altas de la onda M se asociaron con una concordancia mejorada y un aumento en la detección de IZs, lo que hace crucial estandarizar los ajustes de amplitud para obtener resultados confiables.

Effects of tendon elastic energy and electromyographic activity pattern on jumping height and pre-stretch augmentation during jumps with different pre-stretch intensity.

The present study aimed to investigate the effects of tendon elastic energy and electromyographic activity patterns (ratio of pre-landing to concentric: mEMG PLA/CON; ratio of eccentric to concentric; mEMG ECC/CON) on jump performance. Twenty-nine males performed five kinds of unilateral jumps using only ankle joint (no-countermovement jump: noCMJ; countermovement jump: CMJ; drop jumps at 10, 20 and 30 cm drop height: DJ10, DJ20 and DJ30). Jumping height, pre-stretch augmentation and electromyographic activity of the plantar flexor muscles were measured. The elastic energy of the Achilles tendon was measured during isometric contractions. Relative tendon elastic energy (to body mass) was highly correlated with jumping heights of CMJ, DJ10 and DJ20 but not with noCMJ and DJ30, whereas that was significantly correlated with pre-stretch augmentation in CMJ, but not with three DJs. The mEMG PLA/CON was significantly correlated with the pre-stretch augmentation of DJ20 and DJ30, but not with DJ10, whereas the mEMG ECC/CON was significantly correlated with the pre-stretch augmentation of DJ20 and DJ30, but not with CMJ and DJ10. These results suggested that jumping exercises with low pre-stretch intensity benefited from tendon elastic energy, but those with high pre-stretch intensity benefited from electromyographic activity patterns.

Mechanics of The Medial Gastrocnemius-Tendon Unit in Behaving more Efficiently in Habitual Non-Rearfoot Strikers than in Rearfoot Strikers during Running.

This study aims to quantify how habitual foot strike patterns would affect ankle kinetics and the behavior and mechanics of the medial gastrocnemius-tendon unit (MTU) during running. A total of 14 runners with non-rearfoot strike patterns (NRFS) and 15 runners with rearfoot strike patterns (RFS) ran on an instrumented treadmill at a speed of 9 km/h. An ultrasound system and a motion capture system were synchronously triggered to collect the ultrasound images of the medial gastrocnemius (MG) and marker positions along with ground reaction forces (GRF) during running. Ankle kinetics (moment and power) and MG/MTU behavior and mechanical properties (MG shortening length, velocity, force, power, MTU shortening/lengthening length, velocity, and power) were calculated. Independent t-tests were performed to compare the two groups of runners. Pearson correlation was conducted to detect the relationship between foot strike angle and the MTU behavior and mechanics. Compared with RFS runners, NRFS runners had 1) lower foot strike angles and greater peak ankle moments; 2) lower shortening/change length and contraction velocity and greater MG peak force; 3) greater MTU lengthening, MTU shortening length and MTU lengthening velocity and power; 4) the foot strike angle was positively related to the change of fascicle length, fascicle contraction length, and MTU shortening length during the stance phase. The foot strike angle was negatively related to the MG force and MTU lengthening power. The MG in NRFS runners appears to contract with greater force in relatively isometric behavior and at a slower shortening velocity. Moreover, the lengthening length, the lengthening velocity of MTU, and the MG force were greater in habitual NRFS runners, leading to a stronger stretch reflex response potentially.

Medial gastrocnemius proximal fasciotomy in patients with chronic plantar fasciitis: A systematic review. / Fasciotomía proximal de gemelo interno en pacientes con fascitis plantar crónica: una revisión sistemática.

INTRODUCTION: Plantar fasciitis is the main cause of heel pain in middle-aged patients. In chronic cases, limited ankle dorsiflexion caused by isolated gastrocnemius contracture is considered the main risk factor for suffering it. Therefore, in recent years the number of patients operated on by proximal fasciotomy of the medial gastrocnemius (FPGM) has increased to treat chronic plantar fasciitis. MATERIAL AND METHODS: Systematic review following the PRISMA guidelines. We have carried out a bibliographic search in Pubmed, Science Direct, Cochrane Library and Web of Science databases. One hundred and eighty-four articles were found. Data extraction was performed using the Covidence software, and a quality and risk of bias analysis of the included articles was performed based on the Cochrane risk of bias Tool 2.0. RESULTS: Three articles were included in the review: two randomized clinical trials and one cohort study with a total of 138 patients. In the analyzed studies, patients after proximal fasciotomy of the medial gastrocnemius showed significant improvements in pain and in the AOFAS score with high levels of patient satisfaction. Increases in ankle dorsiflexion angle were found after 12 months of follow-up, with no loss of gastrocnemius strength. The complication rate was low and fewer occurred in the proximal fasciotomy compared to plantar fasciotomy. CONCLUSION: Proximal fasciotomy of the medial gastrocnemius provides clinical benefit in patients with chronic plantar fasciitis, with a low probability of complications and high patient satisfaction.

Hematoma gigante coagulado del gastrocnemio medial de localización atípica. Tratamiento con fibrinolíticos en el drenaje ecoguiado: a propósito de un caso / Giant coagulated hematoma of the medial gastrocnemius of atypical location. Treatment with fibrinolytics in ultrasound-guided drainage: a case report

A propósito de un paciente de 57 años con rotura de gastrocnemio medial y hematoma gigante coagulado de localización atípica, se revisan las consideraciones epidemiológicas, las pruebas de diagnóstico a realizar y el tratamiento utilizado (drenaje del hematoma mediante punciones seriadas ecoguiadas con la utilización de urocinasa intracavitaria), además de describir su evolución clínica.(AU)

Regarding a 57-year-old patient with medial gastrocnemius tear and a giant coagulated hematoma of atypical location, the epidemiology, diagnostic test and treatment used are reviewed (hematoma drainage by means of serial punctures, echo-guided, with the use of intracavitary urokinase), as well as its clinical evolution is described.(AU)

Ex vivo adult stem cell characterization from multiple muscles in ambulatory children with cerebral palsy during early development of contractures.

Cerebral palsy (CP) is one of the most common conditions leading to lifelong childhood physical disability. Literature reported previously altered muscle properties such as lower number of satellite cells (SCs), with altered fusion capacity. However, these observations highly vary among studies, possibly due to heterogeneity in patient population, lack of appropriate control data, methodology and different assessed muscle. In this study we aimed to strengthen previous observations and to understand the heterogeneity of CP muscle pathology. Myogenic differentiation of SCs from the Medial Gastrocnemius (MG) muscle of patients with CP (n = 16, 3-9 years old) showed higher fusion capacity compared to age-matched typically developing children (TD, n = 13). Furthermore, we uniquely assessed cells of two different lower limb muscles and showed a decreased myogenic potency in cells from the Semitendinosus (ST) compared to the MG (TD: n = 3, CP: n = 6). Longitudinal assessments, one year after the first botulinum toxin treatment, showed slightly reduced SC representations and lower fusion capacity (n = 4). Finally, we proved the robustness of our data, by assessing in parallel the myogenic capacity of two samples from the same TD muscle. In conclusion, these data confirmed previous findings of increased SC fusion capacity from MG muscle of young patients with CP compared to age-matched TD. Further elaboration is reported on potential factors contributing to heterogeneity, such as assessed muscle, CP progression and reliability of primary outcome parameters.

Determinants of joint stiffness and jumping height during drop jump.

The present study aimed to examine the effects of muscle-tendon mechanical properties and electromyographic activity on joint stiffness and jumping height and to explore the determinants of joint stiffness and jumping height. Twenty-nine males performed unilateral drop jumps at three drop heights (10, 20, and 30 cm) using only the ankle joint on the sledge apparatus. Ankle joint stiffness, jumping height, and electromyographic activity of the plantar flexor muscles were measured during drop jumps. Active muscle stiffness of the medial gastrocnemius muscle was calculated according to changes in the estimated muscle force and fascicle length during fast stretching at five different angular velocities (100, 200, 300, 500, and 600 deg s-1 ) after submaximal isometric contractions. Tendon stiffness and elastic energy were measured during ramp and ballistic contractions. Active muscle stiffness was significantly correlated with joint stiffness, except for a few conditions. Tendon stiffness measured during ramp and ballistic contractions was not significantly correlated with joint stiffness. The ratios of electromyographic activity before landing and during the eccentric phase to that during the concentric phase were significantly correlated with joint stiffness. In addition, jumping heights at 10 and 20 cm (except for 30 cm) drop heights were strongly associated with the tendon elastic energy, whereas no other measured variables showed significant correlations with jumping heights. These results suggested that (1) joint stiffness is determined by active muscle stiffness and electromyographic activity patterns during jumping, and (2) jumping height is determined by tendon elastic energy.

[Giant coagulated hematoma of the medial gastrocnemius of atypical location. Treatment with fibrinolytics in ultrasound-guided drainage: a case report]. / Hematoma gigante coagulado del gastrocnemio medial de localización atípica. Tratamiento con fibrinolíticos en el drenaje ecoguiado: a propósito de un caso.

Regarding a 57-year-old patient with medial gastrocnemius tear and a giant coagulated hematoma of atypical location, the epidemiology, diagnostic test and treatment used are reviewed (hematoma drainage by means of serial punctures, echo-guided, with the use of intracavitary urokinase), as well as its clinical evolution is described.

Outcome following soft tissue coverage with a medial gastrocnemius flap of an exposed or infected total knee arthroplasty.

BACKGROUND: Soft tissue defects or periprosthetic infections after total knee arthroplasty (TKA) are severe complications that may lead to loss of the arthroplasty or the limb. Reconstructions with medial gastrocnemius flaps (MGF) are occasionally used to provide soft tissue coverage around the knee. AIMS: The study aimed to establish the rate of implant survivorship after MGF reconstruction for soft tissue coverage in the treatment of exposed or infected TKA and to establish functional outcome. METHODS: A retrospective analysis was performed on all patients who received soft tissue coverage with an MGF of an exposed or infected TKA between 2000 and 2017 at the Department of Hand and Plastic Surgery at Umeå University Hospital. The outcomes were implant survivorship and patient-reported outcome measures (PROMs) using the five-level EQ-5D version and The Knee Injury and Osteoarthritis Outcome Score. RESULTS: Forty-seven patients (mean age = 67 years, 30 women) were included. The mean time between flap coverage and follow-up was 6.7 (±3.4) years. Implant survivorship was observed in 28 of 47 (59.6%) patients at follow-up. Flap failure was rare, with only 3 of 47 (6.4%) cases. Of the 20 patients who answered the PROMs, 10 of 20 experienced moderate to severe pain or discomfort. CONCLUSIONS: Due to unfavorable underlying conditions, MGF reconstruction after TKA is often associated with a compromised functional outcome. Because donor site morbidity is limited and flap failure is unusual, the procedure can be considered prophylactically in a small subset of patients with risk factors to prevent soft tissue defects and periprosthetic joint infection.