Gastrocnemius Tendon Research Articles

Ex Vivo Biomechanical Assessment of Various Repair Techniques in a Rabbit Calcaneal Tendon Avulsion Model: Application of Polycaprolactone Plate

This study was aimed at evaluating the biomechanical properties and gapping characteristics of tendon repair methods using a combination of a three-loop pulley (3LP) pattern, a titanium plate, and a polycaprolactone (PCL) plate in a rabbit gastrocnemius tendon (GT) model (n = 50). GTs were randomly assigned to five groups (n = 10/group). Transected GTs were repaired with a 3LP pattern alone or in conjunction with an epitendinous suture (ES), a 5-hole 1 mm PCL plate, a 5-hole 2 mm PCL plate, or a 5-hole 1.5 mm titanium plate. The yield, peak, and failure force, as well as the occurrence and force of 1-mm and 3-mm gapping were examined. The mean yield, peak, and failure force of the 3LP + titanium plate group were higher than that of other groups. The biomechanical properties of a 3LP + a 2 mm PCL plate were similar to 3LP + ES constructs in this model. In all specimens in all groups, 1 mm gap formation was observed. The frequency of 3 mm gap formation was 70% and 90% in the 3LP + 2 mm PCL plate group and the 3LP + 1.5 mm titanium plate group, respectively. Additional studies evaluating PCL plates to determine the effect on the healing and blood supply of tendon are needed.

The AIUM Practice Parameter for the Performance of the Musculoskeletal Ultrasound Examination.

The AIUM Practice Parameter for the Performance of the Musculoskeletal Ultrasound Examination.

A Stretchable Strain Sensor System for Wireless Measurement of Musculoskeletal Soft Tissue Strains

AbstractMeasurement of in vivo strain patterns of musculoskeletal soft tissues (MSTs) during functional activities reveals their biomechanical function, supports the identification and understanding of pathologies, and quantifies tissue adaptation during healing. These scientific and clinical insights have motivated the development and application of various strain sensors to quantify MST strains in either intraoperative or dynamic in vivo conditions. In this study, a strain sensor system is developed based on stretchable electronics and radio frequency identification technologies. In this system, a flexible inductor‐capacitor‐resistor sensor is fabricated such that it can be wirelessly excited by a custom‐designed readout box through electronic resonance. The resonant frequency of the sensor changes when the capacitor is stretched, which is then also recorded by the readout box at a sampling rate of 1024 Hz. Suturing the stretchable capacitor onto the MST allows it to be stretched in line with musculoskeletal deformations, hence providing an indirect method to assess strain patterns in vivo. Application of the system ex vivo indicates that the signal remains linear between 0 and 25% strain and is electronically stable in a simulated in vivo environment for one week and over 100 000 cycles of fatigue loadings. The strain sensor exhibits excellent resolution (0.1% strain, ≈9 µm) during wireless strain measurement. Finally, sensor implantation and strain measurement onto the medial gastrocnemius tendon of a sheep indicate that the sensor is able to record repetitive strain patterns in vivo during dynamic movements. This study indicates the potential scientific and clinical applicability in vivo.

The Effects of Habitual Foot Strike Patterns on the Morphology and Mechanical Function of the Medial Gastrocnemius–Achilles Tendon Unit

As a crucial and vulnerable component of the lower extremities, the medial gastrocnemius-Achilles tendon unit (gMTU) plays a significant role in sport performance and injury prevention during long-distance running. However, how habitual foot strike patterns influence the morphology of the gMTU remains unclear. Therefore, this study aimed to explore the effects of two main foot strike patterns on the morphological and mechanical characteristics of the gMTU. Long-distance male runners with habitual forefoot (FFS group, n = 10) and rearfoot strike patterns (RFS group, n = 10) and male non-runners (NR group, n = 10) were recruited. A Terason uSmart 3300 ultrasonography system was used to image the medial gastrocnemius (MG) and Achilles tendon, Image J software to analyze the morphology, and a dynamometer to determine plantar flexion torque during maximal voluntary isometric contractions. The participants first performed a 5-minute warm up; then, the morphological measurements of MG and AT were recorded in a static condition; finally, the MVICs test was conducted to investigate the mechanical function of the gMTU. One-way ANOVA and nonparametric tests were used for data analysis. The significance level was set at a p value of <0.05. The muscle fascicle length (FL) (FFS: 67.3 ± 12.7, RFS: 62.5 ± 7.6, NRs: 55.9 ± 2.0, η2 = 0.187), normalized FL (FFS: 0.36 ± 0.48, RFS: 0.18 ± 0.03, NRs: 0.16 ± 0.01, η2 = 0.237), and pennation angle (PA) (FFS: 16.2 ± 1.9, RFS: 18.9 ± 2.8, NRs: 19.3 ± 2.4, η2 = 0.280) significantly differed between the groups. Specifically, the FL and normalized FL were longer in the FFS group than in the NR group (p < 0.05), while the PA was smaller in the FFS group than in the NR group (p < 0.05). Conclusion: Long-term running with a forefoot strike pattern could significantly affect the FL and PA of the MG. A forefoot strike pattern could lead to a longer FL and a smaller PA, indicating an FFS pattern could protect the MG from strain under repetitive high loads.

The influence of wearing an ultrasound device on gait in children with cerebral palsy and typically developing children

BackgroundUltrasonography with motion analysis enables dynamic imaging of medial gastrocnemius (MG) muscles and tendons during gait. This revealed pathological muscle-tendon dynamics in children with spastic cerebral palsy (CP) compared to typically developing (TD) children. However, wearing an ultrasound probe on the lower leg could interfere with gait and bias muscle length changes observed with ultrasound. Research questionDoes wearing an ultrasound probe on the MG influence gait in children with CP and TD children? MethodsEighteen children with spastic CP and 16 age-matched TD children walked at comfortable walking speed on an instrumented treadmill. One baseline gait condition (BASE) and two conditions with an ultrasound probe and custom-made probe holder were measured: on the mid-muscle fascicles (FAS) and on the muscle-tendon junction (MTJ). The effect of condition and group on spatiotemporal parameters, hip, knee and ankle kinematics, ankle moment, ankle power, and modeled MG muscle-tendon unit (MTU) length was assessed using two-way repeated measures ANOVA’s. Statistical non-parametric mapping was applied for time-series. Post-hoc paired-samples t-tests were conducted, and the root mean square difference was calculated for significant parts. ResultsChildren took wider steps during FAS (CP, TD) and MTJ (TD) compared to BASE, and during FAS compared to MTJ (CP). Hip extension was lower (2.7°) during terminal stance for MTJ compared to FAS for TD only. There was less swing knee flexion (FAS 4.9°; MTJ 4.0°) and ankle plantarflexion around toe-off (FAS 3.0°; MTJ 2.4°) for both ultrasound placements, with no group effect. Power absorption during loading response was slightly increased for both ultrasound placements (0.12 W/kg), with no group effect. MTU shortened less in swing for both ultrasound placements (FAS 3.6 mm; MTJ 3.7 mm), with no group effect. SignificanceWearing an ultrasound probe causes minimal lower-limb gait alterations and MTU length changes that are mostly similar in CP and TD.

Avian Reovirus in Israel, Variants and Vaccines-A Review.

Avian reovirus (ARV) has been determined to be the etiologic agent of viral arthritis/tenosynovitis. In Israel, meat-type chickens, including broilers and breeders, are the most affected. Severe disease symptoms can appear in broiler flocks at a very young age because of early exposure and vertical transmission, causing significant welfare problems. Jewish laws define birds with inflamed, damaged, or torn gastrocnemius and digital flexor tendons as religious condemnations (non-kosher), resulting in severe economic losses for the poultry industry. Vaccination of breeders is a strategy to control the disease by reducing vertical transmission and providing maternal-derived antibodies to the progeny. This review describes Israel's ARV variants and the various vaccines developed over the years. Identification of co-circulating variants triggered the development of multivalent autogenous inactivated vaccines. However, the genotype-matched vaccines failed to provide protection, resulting in an increased prevalence of Cluster II ARV (classified as genotyping cluster 5 in the ARV common world classification). Since 2014, ARV Cluster II has been dominant in Israel. In 2015, the dominant variant s7585 tropism changed the virus pathogenesis and affected broilers with severe clinical signs between 12 and 15 days of age. A new vaccine approach developed in Israel used controlled exposure of the breeding flock to virulent ARV at the age when they are resistant to infection. This approach significantly reduced clinical field cases and reovirus isolations of breeding and broiler flocks between 2020 and 2022.

Effect of Myofascial Release (MFR) on Tendo Achilles (TA) Flexibility in Nurses: A Review.

Increased muscle stiffness can result in a reduced range of motion (ROM) and impaired function. An increased ankle injury risk has been associated with reduced ankle dorsiflexion ROM. Although self-myofascial release (SMFR) is commonly used in clinical and sporting settings, little is known about its impact on gastrocnemius and Achilles tendon (AT) stiffness. As a result, we investigated how SMFR using a foam roller (FR) affects gastrocnemius-AT complex stiffness and ankle dorsiflexion ROM. According to these results, self-myofascial relaxation of the gastrocnemius and an improvement in ankle dorsiflexion ROM can be accomplished by rolling an FR along the calf. Myofascial release (MFR) is a type of manual therapy that involves stretching the myofascial complex with a light load and for a long duration in order to restore optimal length, relieve pain, and improve function.Viscoelastic deformation is the rapid increase in muscle length following stretching.

Mechanical and Morphological Changes of the Plantar Flexor Musculotendinous Unit in Children with Unilateral Cerebral Palsy Following 12 Weeks of Plyometric Exercise: A Randomized Controlled Trial.

To investigate how plyometric exercise (PLYO-Ex) affects mechanics and morphometrics of the plantar flexor musculotendinous unit in children with unilateral cerebral palsy, 38 participants (aged 10-16 years) were allocated at random to either the PLYO-Ex group (n = 19; received 24 sessions of plyometric muscle loading, conducted 2 times a week for 3 months in succession) or the control group (n = 19; underwent traditional physical therapy for the same frequency and duration). Measurements were taken pre- and post-intervention. Standard ultrasound imaging was applied to evaluate morphometrics of the gastrocnemius muscle and Achilles tendon unit and an isokinetic dynamometer was used to evaluate maximum voluntary isometric plantar flexors contraction (IVCmax). With controlling for pre-treatment values, significant post-treatment changes favoring the PLYO-Ex group were observed for morphological (tendon (p = 0.003, η2p = 0.23) length; belly length (p = 0.001, η2p = 0.27); tendon thickness (p = 0.035, η2p = 0.35); muscle thickness (p = 0.013, η2p = 0.17); fascicle length (p = 0.009, η2p = 0.18); pennation angle (p = 0.015, η2p = 0.16)) and mechanical and material properties (IVCmax (p = 0.009, η2p = 0.18); tendon's elongation (p = 0.012, η2p = 0.17), stiffness (p = 0.027, η2p = 0.13); stress (p = 0.006, η2p = 0.20); strain (p = 0.004, η2p = 0.21)). In conclusion, plyometric exercise induces significant adaptations within the musculotendinous unit of the plantar flexors in children with unilateral cerebral palsy. These adaptations could improve muscular efficiency and consequently optimize physical/functional performance.

Routine Postoperative Aspirin for VTE Chemoprophylaxis in Primary Total Ankle Arthroplasty

Category: Ankle Arthritis; Ankle; Other Introduction/Purpose: The use of low-dose aspirin for postoperative venous thromboembolism (VTE) chemoprophylaxis has been widely studied and validated in adult reconstruction surgery with little to no reported adverse reactions. In total ankle arthroplasty (TAA) literature, low-molecular-weight heparin (LMWH) has been the predominant chemoprophylactic agent used, despite little evidence supporting it. To date, no studies have assessed the role of aspirin for VTE chemoprophylaxis after total ankle arthroplasty and no formalized clinical practice guideline exists. The purpose of this study was to evaluate outcomes of a large consecutive series of patients undergoing primary TAA at a single institution, in relation to routine postoperative aspirin administration. Methods: A prospective telephone survey and retrospective chart review was performed of patients undergoing primary TAA at a single institution by two fellowship trained foot and ankle surgeons. All patients were prescribed oral aspirin 81 mg BID for at least 2 weeks postoperatively, (or while weight-bearing was restricted). The primary outcome variable was postoperative development of deep vein thrombosis (DVT), pulmonary embolism (PE), or VTE related mortality within 3 months postoperatively. Venous ultrasounds were also queried. The secondary outcome variable was assessment of aspirin related adverse reaction including delayed wound healing and gastrointestinal (GI) bleeding. Patients with a history of bleeding disorder or history of prior VTE requiring non-Aspirin VTE chemoprophylaxis were excluded. Results: There were 217 patients included for retrospective review, and 81 patients completed the telephone survey (34% response rate). Concomitant procedures included gastrocnemius recession (104), teno-Achilles lengthening (20), ligament repair (17), tendon repair (3), tendon transfer (12), and plantar fasciectomy (1). The cohort included 119 males (54.8%), with a mean age 62.6 +/- 10.3 years (range 24 to 88), and mean BMI 30.6 +/- 5.6 (range 21.3 to 52.6). There were no GI bleeding or VTE events, yet 46/217 (21.2%) cases of delayed wound healing. Eleven patients underwent venous ultrasounds that all were negative. Sex (p=0.458), age (p=0.443), and BMI (p=0.335) were not associated with delayed wound healing, but current/former smoking status trended toward significant association (p=0.077). Time to weight-bearing was mostly bi-modal, between 1.5-3.5 weeks (37.8%) or 5.5-7.5 weeks (45.1%). Time to weight-bearing approached significance with delayed wound healing (p=0.05), which may represent surgeon intervention to promote healing. Conclusion: This study demonstrates effective use of aspirin in preventing VTE events after primary TAA in patients without risk factors for VTE and PE, which is cheaper and more widely available all around the world. Further randomized controlled studies may better elucidate any role of aspirin with regards to delayed wound healing, which had an an approximate incidence of 20% in our cohort. Limitations of the study include those inherent to a retrospective review, such as lack of a control group.

Needle-based gastrocnemius lengthening: a novel ultrasound-guided noninvasive technique

BackgroundGastrocnemius tendon lengthening is performed to treat numerous conditions of the foot and ankle. Gastrocnemius shortening has been associated with more than 30 lower limb disorders, including plantar heel pain/plantar fasciitis, Achilles tendinosis, equinus foot, adult flat foot deformity, and metatarsalgia. Ultrasound-guided ultraminimally invasive lengthening of the gastrocnemius is a step forward in this type of surgery. It can be performed in both legs simultaneously without ischemia using only local anesthesia plus sedation and without the need for a cast or immobilization. The truly novel advantage of the procedure is that it can be performed in the office, without specific surgical instruments. The aim of our research was to prove the effectiveness and safety of a new closed needle-based ultrasound-guided surgical procedure for lengthening the gastrocnemius tendon.Methods and resultsWe performed ultrasound-guided gastrocnemius tendon lengthening using a needle in eight fresh frozen specimens (3 left and 5 right). None of the specimens had been affected by disease or undergone previous surgery that could have affected the surgical technique. We used a linear transducer with an 8- to 17-MHz linear transducer and the beveled tip of an Abbocath as a surgical blade to perform the lengthening procedure. The gastrocnemius Achilles tendon recession was entirely transected in all eight specimens, with no damage to the sural nerve or vessels. The improvement in dorsal flexion was 15°.ConclusionNeedle-based ultrasound-guided gastrocnemius tendon lengthening is safe, since the surgeon can see all structures clearly, thus minimizing the risk of damage. The absence of a wound obviates the need for stitches, and recovery seems to be faster. The procedure can be performed in a specialist's office, as no specific surgical instruments are required. This technique could be a valid option for gastrocnemius lengthening and may even be less traumatic than using a hook-knife, as in our previous description.

Infection and transmission dynamics of Turkey arthritis reovirus in different age Turkeys

Turkey arthritis reovirus (TARV) has been established as a cause of lameness in meat type turkeys in the past decade. However, no information is available on the age susceptibility of TARV or its transmission dynamics. We conducted this study to determine the age at which turkey poults are susceptible to TARV infection and whether infected birds can horizontally transmit the virus to their non-infected pen mates (sentinels). Five groups of turkeys were orally inoculated with TARV (∼106 TCID50/ml) at 2, 7, 14, 21 and 28 days of age (DOA). Two days after each challenge, four uninfected sentinel turkeys of equal age were added to the virus-inoculated groups. At one- and two-weeks post infection, turkeys from each group, including two sentinels, were euthanized followed by necropsy. Inoculated birds in all age groups had TARV replication in the intestine and gastrocnemius tendon with no statistically significant variation at p < 0.5. Furthermore, the inoculated birds at different age groups showed consistently high gastrocnemius tendon histologic lesion scores while birds in the 28-days-old age group had numerically lower lesion scores at 14 days post inoculation (dpi). The sentinels, in turn, also showed virus replication in their intestines and tendons and histologic lesions in gastrocnemius tendons. The findings indicate that turkeys at the age of 28 days or less are susceptible to infection with TARV following oral challenge. It was also found that TARV-infected birds could transmit the infection to naïve sentinel turkeys of the same age.

Superficial digital flexor tendon graft augmentation improves the tensile strength and resistance to gap formation following primary gastrocnemius tendon repair in dogs.

To evaluate the influence of superficial digital flexor tendon (SDFT) graft augmentation on the biomechanical properties and resistance to gap formation in a canine gastrocnemius tendon repair model. 28 canine cadaveric hind limbs. Respective hindlimbs from each dog were randomized to one of two groups (n = 14/group) using a 3-loop-pulley (3LP) pattern alone or 3LP + SDFT graft augmentation. Biomechanical parameters evaluated included yield, peak, and failure loads; tensile loads required to create 1- and 3-mm gap formations; and mode of construct failure. Mean yield and failure loads for the 3LP + SDFT graft group were 483.6 ± 148.0 N and 478.3 ± 147.9 N, respectively, and were greater compared to the 3LP group (34.2 ± 6.7 N and 34.0 ± 8.0 N, P < .0001). Loads to both 1- and 3-mm gap formations for the 3LP + SDFT graft group were greater compared to 3LP alone (P < .001). Failure modes did not differ between groups (P = .120), with constructs failing most commonly by suture pulling through opposed tendinous tissues whereas SDFT grafts remained intact. SDFT graft augmentation increased yield, peak, and failure forces 14-fold across all examined biomechanical variables compared to the 3LP group. The 3LP + SDFT graft group required 3.6X and 6.5X greater loads to cause a 1- and 3-mm gap, respectively, between tendon ends. These data support the biomechanical advantages of SDFT graft augmentation to increase repair-site strength and to promote resistance to gap formation of the tenorrhaphy. Additional in vivo studies are required to determine the effect of SDFT augmentation on clinical function and active limb use after graft harvest in dogs.

Investigation of Factors Associated with Leg Trimmings at Processing: A 12-Year Review.

Gastrocnemius tendon injury or rupture is a common consequence from various etiologies and conditions in poultry production. The occurrence of tendon injury can cause significant morbidity and lameness in chickens, as well as quality downgrades and increased trimming on carcasses at processing. In this study, 12 yr of data from a poultry processing plant on leg trim only were compiled and analyzed. The association between grower, season, shift, and time were investigated in relation to the prevalence of ruptured tendons and carcass condemnations. A total of 8585 separate data entries from 195 growers were analyzed. Problem flocks were defined as those that had a carcass trimming rate of the percentage change equal to or above the 95th percentile of all data points (0.603%). We identified 430 instances of high trimmings in this study period, involving 90 growers. Of those, eight growers had 10 or more problem flocks in the study period. Overall, there were no differences in trimming rates due to shift; however, problem flocks had a higher trimming rate (percentage) during the night shift. A significantly higher rate of carcass trimmings was noted in the winter months. In problem flocks, a second and lower peak of a higher trimming was also observed in August. There was an upward trending carcass trimming that peaked in 2014, and it trended downward each year through 2020 overall. However, when the problem flocks were excluded, the trimming rate percentage change of trimming decreased slightly from 2008 to 2012 and remained steady through 2020. In conclusion, this study was able to demonstrate noninfectious causes that may be associated with increased leg trimmings and consequently made it possible to narrow down management practices to help decrease the instances of leg trimmings in the processing plant.

Medial gastrocnemius muscle–tendon unit ratios of young females and males

A muscle’s contractile element length relative to its muscle–tendon unit (MTU) length is a fundamental design feature affecting MTU function, with high (0.9) or low ratios (0.1) favouring either rapid or economical force production, respectively. Despite the importance for MTU function, little in vivo work has been done to understand contractile element-MTU length ratio variability between individuals and sexes. We therefore compared the medial gastrocnemius (MG) MTU ratios of thirteen females and eighteen males, and explored whether individual ratios could be predicted based on anatomical features.At the presumed tendon slack length ankle joint angle, lengths of MG’s MTU, Achilles tendon, muscle belly and its muscle fascicles were measured from B-mode ultrasound images. Contractile element length was represented by the in-series muscle fascicle length (FL) and was calculated by multiplying FL by the cosine of fascicle angle.The mean ± standard deviation in-series FL-MTU length ratio was 0.09 ± 0.02 and ranged from 0.06 to 0.11, whereas the muscle belly length-MTU length ratio was 0.54 ± 0.38 and ranged from 0.47 to 0.60. Neither ratio was significantly different between females and males (p ≥ 0.116). In-series FL was not significantly correlated with MTU length (r = -0.115, p =.538), muscle belly length (r = 0.05, p =.788), or shank length (r = 0.169, p =.364), but MTU length was significantly correlated with muscle belly length (r = 0.641, p <.001), and shank length (r = 0.575, p =.001).A low in-series FL-MTU length ratio suggests that the MG of young, healthy individuals is specialised for energy-efficient stretch–shortening cycles. These findings provide useful inputs for the MTU actuator design of Hill-type models.

Examining the intrinsic foot muscles’ capacity to modulate plantar flexor gearing and ankle joint contributions to propulsion in vertical jumping

BackgroundDuring human locomotion, a sufficiently stiff foot allows the ankle plantar flexors to generate large propulsive powers. Increasing foot stiffness (e.g., via a carbon plate) increases the ankle's external moment arm in relation to the internal moment arm (i.e., increasing gear ratio), reduces plantar flexor muscles’ shortening velocity, and enhances muscle force production. In contrast, when activation of the foot's intrinsic muscles is impaired, there is a reduction in foot and ankle work and metatarsophalangeal joint stiffness. We speculated that the reduced capacity to actively control metatarsophalangeal joint stiffness may impair the gearing function of the foot at the ankle. MethodsWe used a tibial nerve block to examine the direct effects of the intrinsic foot muscles on ankle joint kinetics, in vivo medial gastrocnemius’ musculotendinous dynamics, and ankle gear ratio on 14 participants during maximal vertical jumping. ResultsUnder the nerve block, the internal ankle plantar flexion moment decreased (p = 0.004) alongside a reduction in external moment arm length (p = 0.021) and ankle joint gear ratio (p = 0.049) when compared to the non-blocked condition. Although medial gastrocnemius muscle–tendon unit and fascicle velocity were not different between conditions, the Achilles tendon was shorter during propulsion in the nerve block condition (p < 0.001). ConclusionIn addition to their known role of regulating the energetic function of the foot, our data indicate that the intrinsic foot muscles also act to optimize ankle joint torque production and leverage during the propulsion phase of vertical jumping.

Neurogranin inhibits calcineurin in murine soleus muscle: Effects of heterozygous knockdown on muscle adaptations to tenotomy and fatigue resistance

Neurogranin (Ng) is a calmodulin (CaM) binding protein that negatively regulates calcineurin - a Ca2+/CaM-dependent phosphatase that can mitigate the slow-to-fast fibre type shift observed with muscle unloading. Here, we questioned whether heterozygous deletion of Ng (Ng+/−) would enhance calcineurin activity, thereby minimizing the slow-to-fast fibre type shift caused by muscle unloading. As expected, soleus muscles from young adult (3–4 months old) Ng± mice had lowered Ng content and enhanced calcineurin activity when compared to soleus muscles obtained from male age-matched wild-type (WT) mice. Two weeks after tenotomy surgery, where the soleus and gastrocnemius tendons were severed, soleus total fibre count were found to be similarly reduced across both genotypes. However, significant reductions in myofibre cross-sectional area were only found in WT mice and not Ng± mice. Furthermore, while soleus muscles from both WT and Ng± mice exhibited a slow-to-fast fibre type shift with tenotomy, soleus muscles from Ng± mice, in both sham and tenotomized conditions, had a greater proportion of oxidative fibres (type I and IIA) compared with that of WT mice. Corresponding well with this, we found that soleus muscles from Ng± mice were more fatigue resistant compared with those obtained from their WT counterparts. Collectively, these findings show that heterozygous Ng deletion increases calcineurin activation, preserves myofibre size in response to unloading, and promotes the oxidative fibre type to ultimately enhance fatigue resistance. This study demonstrates the role of Ng in regulating calcineurin in vivo and its influence on skeletal muscle form and function.

Effect of varying dietary crude protein and metabolizable energy levels on leg abnormalities and performance in broiler chickens

Background: Nutrient restriction is a common strategy to prevent metabolic disorders in fast growing broiler chickens, but limited information is available regarding the impact of diets with low protein and energy on leg abnormalities. Objective: Two experiments were conducted to evaluate the effect of varying crude protein (CP) and metabolizable energy (ME) levels on gastrocnemius tendon (GTeBS) and tibia breaking strength (TiBS), gait score (GS) and valgus/varus angulation (VAng). Methods: In Experiment 1, eight-d-old Ross 308 broilers (n=90) were randomly assigned into three treatments: 13/2,900 (13% CP and 2,900 kcal ME kg-1 of diet), 17/3,000 (17% CP and 3,000 kcal ME kg-1 of diet), and 21/3,025 or control (21% CP and 3,025 kcal ME kg-1 of diet). In Experiment 2, six-d-old Ross 308 chickens (n=192) were randomly distributed into two treatments: 16/3,000; 16% CP and 3,000 kcal ME kg-1 of diet and 21/3,000 or control; 21% CP and 3,000 kcal ME kg-1 of diet. In both experiments data were analyzed as one-way ANOVA. Results: In Experiment 1, broilers in the 17/3,000 and control treatments had similar (p&gt;0.05) GTeBS (202 and 224 N, respectively), and TiBS (338 and 332 N, respectively). Birds in the 13/2,900 treatment showed higher GS (lower walking ability; 80% of birds with score &gt;3), and greater VAng (53% of birds with score &gt;2) than broilers in the control treatment (0% of birds with GS score &gt;3 and 0% of birds with VAng score &gt;2). Experiment 2, broilers in the 16/3,000 showed similar VAng, GS and TiBS than birds in the control treatment. However, birds in the 16/3,000 treatment showed lower (-26%) GTeBS than birds in the control treatment (p&lt;0.05). Conclusions: Feeding broilers with 16% CP and 3,000 kcal ME kg-1 of diet did not affect tibia breaking strength, gait score and valgus/varus angulation. A diet containing 16% CP or less and 2,900-3,000 kcal ME kg-1 reduces tendon and tibia breaking strength.

Effect of epitendinous suture augmentation to a double Krackow suture pattern for canine gastrocnemius tendon repair.

To evaluate the effect of a double Krackow suture pattern (DK), with and without epitendinous suture augmentation (ES), in a canine gastrocnemius tendon (GT) model. Paired GTs from 12 adult dog cadavers and 4 control GT. GTs were assigned to 2 groups (n = 12/group). Transverse tenotomy was performed and repaired with a DK or DK + ES. Yield, peak, and failure force, stiffness, occurrence of 1-and 3-mm gapping, and failure mode were examined. Yield, peak, and failure loads were greater for DK + ES. Yield force was 48% greater for DK + ES (mean ± SD, 149.56 ± 53.26 N) versus DK (101.27 ± 37.17 N; P = 0.017). Peak force was 45% greater for DK + ES P < 0.001). Failure force was 47% greater for DK + ES (193.752 ± 31.43 N) versus DK (131.54 ± 22.28 N; P < 0.001). Construct stiffness was 36% greater for DK + ES (P = 0.04). All 12 DK and 10 of 12 DK + ES repairs produced a 1-mm gap, with all DK and 4 DK + ES repairs producing a 3-mm gap (P < 0.001). Loads required to create a 3-mm gap were significantly greater for DK + ES (P < 0.013). Suture breakage occurred in all DK repairs, which differed from DK + ES, where suture breakage (7/12) and tissue failure (5/12; P = 0.037) predominated. Augmentation of a primary DK repair with an ES significantly improved construct strength in canine GT constructs while increasing loads required to cause 1- and 3-mm gap formation, respectively. ES augmentation is a simple technique modification that can be used to significantly increase construct strength, compared with DK alone.

Morphometric profile of achilles tendon in male - a cadaveric study

The Achilles tendon is a conjoined tendon of gastrocnemius and soleus muscles and occasionally may have a small contribution from plantaris muscle. Despite being the strongest and thickest tendon in the body it is a frequent site of degenerative changes, inflammation and rupture. The main objective of this study was to measure and analyze the various parameters of Achilles tendon in cadavers. An observational, descriptive study was conducted from August 2021 to February 2022 in the Department of Human Anatomy of Nepal Medical College Teaching Hospital, Attarkhel, Gokarneshwor – 8, Kathmandu, Nepal which included forty lower limbs of twenty male cadavers. The various parameters recorded were (a) mean length of right Achilles tendon was 16.65 ± 1.72 cm, (b) mean proximal width of right Achilles tendon was 5.50 ± 1.07 cm, (c) mean proximal circumference of right Achilles tendon was 10.67 ± 2.20 cm, (d) mean distal width of right Achilles tendon was 2.22 ± 0.54 cm, (e) mean distal circumference of right Achilles tendon was 4.27 ± 0.67 cm, (f ) mean length of left Achilles tendon was 16.35 ± 1.49 cm, (g) mean proximal width of left Achilles tendon was 5.25 ± 0.88 cm, (h) mean proximal circumference of left Achilles tendon was 10.57 ± 1.78 cm, (i) mean distal width of left Achilles tendon was 2.05 ± 0.27 cm and mean distal circumference of left Achilles tendon was 4.0 ± 0.42 cm. The present morphometric evaluation of Achilles tendon in cadavers can be of substantial help to clinicians before determining its pathological conditions and can also be of help to surgeons during the surgical repair and reconstruction of damaged tendon.

Biomechanical Comparison of a 3-Loop Pulley and a 4-Loop Pulley Suture for Tenorrhaphy in the Canine Gastrocnemius Tendon.

The aim of this study was to compare a 3-loop pulley (3LP) suture pattern with a 4-loop pulley (4LP) suture pattern for the tenorrhaphy of the canine gastrocnemius tendon STUDY DESIGN: Randomized, cadaveric, biomechanical study of 30 canine gastrocnemius tendons. Tendons were transected and repaired with either 3LP or 4LP suture pattern with 2-0 polypropylene. A tensile load was applied at 25 mm/min until construct failure. The load required to form a 1 mm gap, 3 mm gap and maximum load at failure was recorded and compared between groups. The estimated mean load to form a 1 mm gap for the 3LP and 4LP was 28.4 N (95% confidence interval [CI]: 24.0-32.6N) and 45.5 N (95% CI: 40.7-50.1N) respectively. The 4LP mean load to form a 1 mm gap was 17.1 N (95% CI: 11.7-22.5N) greater than the 3LP. The estimated mean load to form a 3mm gap for the 3LP and 4LP was 39.7 N (95% CI: 34.1-45.4N) and 55.0 N (95% CI: 49.3-60.9N) respectively. The mean load to form a 3mm gap was 15.3 N (95% CI: 8.5-21.9N) greater in the 4LP than the 3LP. The estimated mean load for failure in the 3LP and 4LP was 41.2 N (95% CI: 35.6-46.9 N) and 54.3 N (95% CI: 48.7-60.3 N) respectively. A 4LP pattern was biomechanically superior to a 3LP pattern, as demonstrated by a greater load required to form both a 1 and 3 mm gap and a greater load for failure CLINICAL SIGNIFICANCE: A 4LP suture pattern better resists gap formation and requires greater load prior to construct failure compared with a 3LP, in this canine gastrocnemius model.