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Objective: Passive stiffness, a biomechanical parameter, has a potential influence on running economy, thus playing a pivotal role in performance. This study aimed to quantify passive stiffness of the Achilles tendon and gastrocnemius muscle using myotonometry throughout an incremental running protocol. Methods: Twenty-one male participants underwent a multistage incremental test (Bordeaux test) on a treadmill until exhaustion. Passive stiffness of the gastrocnemius muscle and Achilles tendon was measured using a MyotonPRO device. Measurements were taken before, during, and after the incremental test. Results: Our findings indicated that passive stiffness of the medial gastrocnemius decreased at rest between prerun and postrun assessments (−20.12 N·m−1, P =.012). Furthermore, during the test, stiffness increased at low intensity (at 50% of maximal aerobic speed: +104.8 N·m−1, P =.042), returning to baseline values as intensity increased. Conclusions: Throughout an incremental running protocol, both Achilles tendon and gastrocnemius muscle stiffness initially increased and then decreased with escalating percentages of maximal aerobic speed. A deeper understanding of stiffness in running can inform more effective recommendations for runners' strengthening and training. [ABSTRACT FROM AUTHOR]

In this narrative review, we explore developments in the field of computational musculoskeletal model personalization using the Physiome and Musculoskeletal Atlas Projects. Model geometry personalization; statistical shape modeling; and its impact on segmentation, classification, and model creation are explored. Examples include the trapeziometacarpal and tibiofemoral joints, Achilles tendon, gastrocnemius muscle, and pediatric lower limb bones. Finally, a more general approach to model personalization is discussed based on the idea of multiscale personalization called scaffolds. [ABSTRACT FROM AUTHOR]

It has been demonstrated in a number of studies that high levels of uric acid can cause crystal deposition in the tendons of the lower extremities, which in turn can impair the Achilles tendon. This study aimed to interpret whether hyperuricemia is relevant with Achilles tendon rupture. Patients diagnosed with Achilles tendon rupture at the same institution between 2013 and 2022 were included in the case group. Healthy subjects who had physical examinations during the same period were included in the control group. Propensity score matching was used to match in a 1:1 ratio. Demographic and clinical characteristics of patients in both groups were compared. Five hundred and fourteen patients were included in the study (ATR=257; Control group=257). The proportion of individuals with hyperuricemia varied significantly between the 2 groups (Achilles tendon rupture group=43.6%; control group=27.6%; p <0.001). The Achilles tendon rupture and hyperuricemia were linked by conditional logistic regression (p <0.001; OR=2.036; 95CI%=1.400-2.961). Compared with healthy subjects, patients with hyperuricemia have a higher risk of Achilles tendon rupture. Further studies are required to verify the effects of hyperuricemia and monosodium urate crystals on Achilles tendon structure. [ABSTRACT FROM AUTHOR]

Background While controversy remains as to the relative benefit of operative (OM) versus non-operative management (NOM) of Achilles tendon (AT) ruptures (ATR), few studies have examined the effect on high impact maneuvers such as jumping and hopping. Hypothesis/Purpose The purpose of this study was to determine if functional performance including strength, jumping, and hopping outcomes differed between OM and NOM of acute ATR. The secondary objective was to assess the degree of association between AT morphology and performance outcomes. Study Design Retrospective cohort with a single prospective evaluation. Methods All patients were treated at an institutional secondary care center. Eligible participants (n=12 OM; 12 NOM) who were treated with OM or NOM of ATR within three weeks of injury were evaluated a minimum 20 months following ATR. AT length, thickness and gastrocnemius muscle thickness were assessed with B-mode ultrasound. Isokinetic plantar flexor strength, hop tests and countermovement and drop jumps were completed. Two-way ANOVAS were completed on all tests with unilateral values, independent t-tests were used for bilateral outcomes, and linear regressions were completed to assess the relationship between normalized AT length and performance. Results Affected limb AT was elongated and thickened (p<0.01), gastrocnemius was atrophied (p< 0.01) and angle-specific plantar flexor torque was reduced at 120°/s when measured at 20° plantar flexion (p = 0.028). Single leg drop vertical jump was higher in OM (p = 0.015) with no difference for hop and jump tests. AT length was related to plantar flexor torque but had no relationship with hopping performance. Conclusions Hop test performance was maintained despite plantarflexion weakness, gastrocnemius atrophy, and AT elongation. This may be the result of compensatory movement patterns. AT length holds limited explanatory power in plantar flexor strength, although this relationship should be evaluated further. Level of Evidence Level III [ABSTRACT FROM AUTHOR]

• Intratendinous pressure of the Achilles tendon increases during tensile loading. It is unknown whether tendinopathic changes, namely fluid and glycosaminoglycan accumulation, may impact this. • Intratendinous pressure of 20 Achilles tendons was measured at rest and during loading under natural conditions and after administration of fluid and glycosaminoglycans. Additionally, half of the tendons were treated with hyaluronidase. • Elevated fluid and glycosaminoglycan content resulted in higher intratendinous pressures. Hyaluronidase reduced glycosaminoglycan content and lowered intratendinous pressures. • These findings show that fluid and glycosaminoglycan accumulation lead to increased intratendinous pressures and that hyaluronidase may serve as a potential treatment by restoring intratendinous pressures. Tendinopathy alters the compositional properties of the Achilles tendon by increasing fluid and glycosaminoglycan content. It has been speculated that these changes may affect intratendinous pressure, but the extent of this relationship remains unclear. Therefore, we aimed to investigate the impact of elevated fluid and glycosaminoglycan content on Achilles tendon intratendinous pressure and to determine whether hyaluronidase (HYAL) therapy can intervene in this potential relationship. Twenty paired fresh-frozen cadaveric Achilles tendons were mounted in a tensile-testing machine and loaded up to 5% strain. Intratendinous resting (at 0% strain) and dynamic pressure (at 5% strain) were assessed using the microcapillary infusion technique. First, intratendinous pressure was measured under native conditions before and after infusion of 2 mL physiological saline. Next, 80 mg of glycosaminoglycans were administered bilaterally to the paired tendons. The right tendons were additionally treated with 1500 units of HYAL. Finally, both groups were retested, and the glycosaminoglycan content was analyzed. It was found that both elevated fluid and glycosaminoglycan content resulted in higher intratendinous resting and dynamic pressures (p < 0.001). HYAL treatment induced a 2.3-fold reduction in glycosaminoglycan content (p = 0.002) and restored intratendinous pressures. The results of this study demonstrated that elevated fluid and glycosaminoglycan content in Achilles tendinopathy contribute to increased intratendinous resting and dynamic pressures, which can be explained by the associated increased volume and reduced permeability of the tendon matrix, respectively. HYAL degrades glycosaminoglycans sufficiently to lower intratendinous pressures and may, therefore, serve as a promising treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

Insertional Achilles tendinopathy is an umbrella medical term referring to pain and swelling on the posterior aspect of the calcaneus. High‐resolution ultrasound imaging is commonly used in daily practice to assess the pathological changes of the Achilles tendon, cortical bone of the calcaneus, and soft tissues located inside the retrocalcaneal space to optimize the management of relevant patients. To the best of our knowledge, a standardized ultrasound protocol to evaluate the retrocalcaneal bursal complex is lacking in the pertinent literature. In this sense, our step‐by‐step sonographic approach is intended to be an easy and ready‐to‐use guide for sonographers/physicians in daily practice to assess this anatomical complex in patients with Achilles tendinopathy. Needless to say, the peculiar histological features of this V‐shaped synovial/fibrocartilaginous bursa surrounding the posteroinferior wedge of the Kager's fat pad and the retrocalcaneal space make the examination challenging. [ABSTRACT FROM AUTHOR]

Sedentary lifestyles reduce muscle mass, strength, power, and alter viscoelastic properties. Plyometric jump training (PJT) shows promise in countering these effects, but the optimal training volume for individuals with low athletic performance remains unclear. This study aimed to determine the minimal PJT volume required to improve muscle and tendon viscoelastic properties, strength, and power in sedentary individuals. A double-blind randomised controlled trial included 44 participants divided into three groups: Control Group (CG) (n = 16), Reduced Volume Training Group (RVTG) (n = 16), and Training Group (TG) (n = 12). The four-week PJT programme involved three weekly sessions with gradual volume increments; RVTG performed 50% less volume than TG. Baseline and follow-up assessments included the isokinetic standing up (SU) and sitting down (SD) phases at 15 cm/s and 5 cm/s, and myotonometer measurements. In the SU phase at 15 cm/s, significant differences were found (p = 0.01) with higher values in TG (10.0 ± 3.3 N/kg) compared to CG and RVTG. At 5 cm/s, differences in SD were observed (p = 0.002). For Achilles tendon properties in RVTG: stiffness (p = 0.04), decrement (p = 0.01), and relaxation (p = 0.02). A PJT volume of 2,414 jumps improved muscle strength, while 1,207 jumps altered tendon properties. [ABSTRACT FROM AUTHOR]

Recently, auxetic metastructures have gained considerable attention in various fields of study due to their unique characteristics. This study aims to design and fabricate bioinspired auxetic structures and comprehensively investigate the static and dynamic mechanical properties of those architectures under tensile and compressive loads. A comparative analysis is carried out with a conventional structure, considering static tensile and compressive tests, as well as dynamic tension–tension and compression–compression assessments. Experimental measurements and finite‐element analysis are utilized to evaluate various parameters of the scaffolds, such as Young's modulus, yield strength, energy absorption, stress distribution, Poisson's ratio, and fatigue properties. The findings reveal that bioinspired auxetic structures can appropriately mimic the physical attributes and stress–strain characteristics of human tissue, such as the Achilles tendon. Furthermore, these bioinspired auxetic structures significantly enhance the cycles to failure compared to conventional structures, accompanied by notable improvements in energy absorption. Among the auxetic structures, the star configuration exhibits remarkable tolerance to tensile fatigue loads, while the sharp sinus structure demonstrates the highest tolerance to cycles to failure under compression–compression loads. The static and fatigue properties of bioinspired auxetic structures indicate their potential for biomedical applications. [ABSTRACT FROM AUTHOR]

Achilles tendinopathy is often attributed to overuse, but its pathophysiology remains poorly understood. Disruption to the molecular structure of collagen is fundamental for the onset and progression of tendinopathy but has mostly been investigated in vitro. Here, we interrogated the in vivo molecular structure changes of collagen in rat Achilles tendons following treadmill running. Unexpectedly, the tendons' collagen molecules were not mechanically unfolded by running but denatured through proteolysis during physiological post-run remodeling. We further revealed that running induces inflammatory gene expressions in Achilles tendons and that long-term running causes prolonged, elevated collagen degradation, leading to the accumulation of denatured collagen and tendinopathy development. For applications, we demonstrated magnetic resonance imaging of collagenase-induced Achilles tendon injury in vivo using a denatured collagen targeting contrast agent. Our findings may help close the knowledge gaps in the mechanobiology and pathogenesis of Achilles tendinopathy and initiate new strategies for its imaging-based diagnosis. [ABSTRACT FROM AUTHOR]

Introduction: Wearables have the potential to provide accurate estimates of tissue loads at common running injury locations. Here we investigate the accuracy by which commercially available instrumented insoles (ARION; ATO-GEAR, Eindhoven, The Netherlands) can predict musculoskeletal loading at common running injury locations. Methods: Nineteen runners (10 males) ran at five different speeds, four slopes, with different step frequencies, and forward trunk lean on an instrumented treadmill while wearing instrumented insoles. The insole data were used as input to an artificial neural network that was trained to predict the Achilles tendon strain, and tibia and patellofemoral stress impulses and weighted impulses (damage proxy) as determined with musculoskeletal modeling. Accuracy was investigated using leave-one-out cross-validation and correlations. The effect of different input metrics was also assessed. Results: The neural network predicted tissue loading with overall relative percentage errors of 1.95 ± 8.40%, −7.37 ± 6.41%, and −12.8 ± 9.44% for the patellofemoral joint, tibia, and Achilles tendon impulse, respectively. The accuracy significantly changed with altered running speed, slope, or step frequency. Mean (95% confidence interval) within-individual correlations between modeled and predicted impulses across conditions were generally nearly perfect, being 0.92 (0.89 to 0.94), 0.95 (0.93 to 0.96), and 0.95 (0.94 to 0.96) for the patellofemoral, tibial, and Achilles tendon stress/strain impulses, respectively. Conclusions: This study shows that commercially available instrumented insoles can predict loading at common running injury locations with variable absolute but (very) high relative accuracy. The absolute error was lower than the methods that measure only the step count or assume a constant load per speed or slope. This developed model may allow for quantification of in-field tissue loading and real-time tissue loading-based feedback to reduce injury risk. [ABSTRACT FROM AUTHOR]

Background: Achilles tendon rupture is a common and primary cause of lower limb tendon injuries suffered during sports-related activities. The causes of Achilles tendon rupture include calf muscle and tendon overuse, steroid local injection in tendon, poor tendon quality, and various medical conditions. Historically, acute Achilles tendon rupture was treated conservatively. However, historical techniques are now associated with an increased risk of rerupture. Aim and Objective: To study of the reconstruction of chronic tendoachilles ruptures with the flexor hallucis longus and peroneus brevis. Material and Method: 30 patients aged between 30 and 60 years underwent reconstruction of chronically ruptured tendon Achilles either with flexor hallucis longus or peroneus brevis. Ruptures are due to stumbling in fields, falling from stairs, and some being uneventful. All these patients attended the department of Orthopaedics OPD and tertiary care of SSIMS, Bhilai. The patients were admitted and surgically treated after appropriate counseling and consent. The results were compared with the Quigley scale and Leppilahti scores. Results: Rupture of the Achilles tendon is more common in middle-aged males. Delay in diagnosis is due to a lack of adequate knowledge by the treating physician and a lack of immediate disability for the patient. The Thompson test has high sensitivity and specificity in diagnosis. Complications such as superficial skin infections and wound dehiscence are more common in patients treated with peroneus Peroneus and Sensory disturbance on foot is post operative complication. Conclusion: Flexor hallucis longus is superior to Peroneus brevis because of its anatomical and technical advantages, less incidence of superficial infections, wound dehiscence, and sensory disturbance, and better weight-bearing times and functional recovery. [ABSTRACT FROM AUTHOR]

Purpose: A persisting gender bias has been recently highlighted in orthopaedics and sports medicine. The aim of this study was to evaluate the volume of gender‐specific data and gender‐specific results in the treatment of a common tendon disease, Achilles tendinopathy. Methods: Pubmed, Cochrane, and Web of Science were searched to identify all clinical studies focusing on Achilles tendinopathy treatment. The Visual Analogue Scale (VAS) and Victorian Institute of Sport Assessment‐Achilles (VISA‐A) data of women and men of the studies that disaggregated results by gender were collected, and a meta‐analysis was conducted. Treatment response within and in between gender categories was evaluated, focusing on overall gender‐disaggregated data, as well as within each of the three treatment categories: conservative treatment, injective treatment and surgical treatment. A formal risk of bias analysis was conducted using Downs and Black's grading system. Results: Out of the 8796 papers screened, 178 were included after the screening. The number of female study participants grew from 20% up to 1990 to 48% in the years 2019–2022. Only 373 out of 3423 (11%) female patients and 685 of 4352 (16%) male patients were found in sex‐disaggregated studies. A meta‐analysis was conducted on the 14 papers that reported sex‐disaggregated data for VAS and VISA‐A. The meta‐analysis revealed that there was no difference in the overall treatment response between women and men and that both genders showed an overall significant treatment benefit in terms of VAS and VISA‐A values. However, significant differences were documented within the treatment categories. While no differences were found in surgical studies, in conservative treatment studies, men experienced lower posttreatment VAS values (p = 0.004). The largest difference was found in injective treatments, with men experiencing a larger change in VAS values (men = −3.0, women = −1.0, p = 0.016) and higher posttreatment VISA‐A values (p = 0.032). Conclusion: This systematic review and meta‐analysis showed a lack of awareness of the importance of sex‐specific data within Achilles tendinopathy treatment research. The proportion of female study subjects has grown over the years, but there is still a large data gap caused by the absence of sex‐disaggregated data. The omission of sex‐disaggregated data causes the loss of valuable knowledge on the true effectiveness of current Achilles tendinopathy treatment. The results of this study indicate that women profit less from available treatments, particularly injective approaches, which prompts further research for treatment adaptation by gender. Level of Evidence: Level IV. [ABSTRACT FROM AUTHOR]

Knowledge of how to treat chronic tendinopathy has advanced in recent years, but the treatment of early tendinopathy is not well understood. The main purpose of this prospective observational study was to investigate if changes occur in clinical and imaging outcomes over 12 weeks in elite athletes with recent debut of tendinopathy. Sixty‐five elite adult athletes (24 ± 5 years) with early Achilles or patellar tendinopathy (symptoms < 3 months) were examined at baseline and after 12 weeks. Patients were divided into groups based on the duration of symptoms at the time of inclusion: (T1): 0–1 month, (T2): 1–2 months, or (T3): 2–3 months. Pain‐guided activity modification was the only intervention. We assessed the following clinical outcomes: Questionnaires (Victorian Institute of Sports Assessment (VISA)) and pain scores (0–10 numeric rating scale, NRS), structural outcomes from ultrasonography: Thickness, echogenicity, and Doppler flow, and from magnetic resonance imaging: Cross‐sectional area (CSA), thickness and length. Tendinopathic Achilles and patellar tendons displayed no significant differences on imaging tendon structural outcomes between T1 (n = 19), T2 (n = 23), and T3 (n = 20) at baseline or after 12 weeks, with one exception: Patellar tendons in T1 were thicker than T2 and T3 at baseline. Although athletes improved clinically on VISA and most NRS scores after 12 weeks, affected tendons with greater thickness, CSA and Doppler flow than contralateral tendons at baseline remained unchanged after 12 weeks. In conclusion, these data suggest that early tendinopathy in elite athletes can improve clinically after 12 weeks while morphology remains unchanged. [ABSTRACT FROM AUTHOR]

Background/Objectives: Tendinopathy of the gluteus medius and minimus tendons is a primary source of lateral hip pain, ranging from interstitial and partial-thickness tears to complete tears. Treatments include muscle transfers, Achilles tendon allograft procedures, and primary repairs with allografts. This study evaluated the one-year outcomes of gluteus medius and minimus reconstruction using an open double-row technique with a partial tensor fasciae latae transfer for severe Trendelenburg post-total hip arthroplasty. Methods: A prospective study involving eight patients who underwent surgery from April to December 2023 was conducted. The surgery involved an open technique with double-row suture reinforcement and tensor fasciae latae autograft. Outcomes were measured using strength, the Harris Hip Score (HHS), 12-Item Short Form Health Survey (SF-12), Hip Outcome Tool (HOT), International Hip Outcome Tool (iHOT), and Visual Analog Scale (VAS). Follow-ups occurred at 1, 3, 6, 9, and 12 months postoperatively. Results: At an average follow-up of 7.17 months, significant improvements in both hip function and quality of life were observed. The SF-12 quality of life score increased from 27 preoperatively to 34 by month 12. Hip functionality, as measured by the HHS, showed a marked improvement from 48 to 94 points, particularly after six months. The HOT score for hip functionality rose by 23 points by the third month, reaching an average of 86 points. Similarly, the iHOT score increased from 20 to 83 points starting at month 3, reflecting substantial improvements in hip function. Statistically significant improvements were noted at as early as month 3 (p = 0.02), with highly significant gains by month 6 (p < 0.01), which remained stable through month 12 (p < 0.01). Conclusions: Reconstruction of the gluteus medius and minimus tendons using an open double-row technique with a partial tensor fasciae latae transfer significantly enhances hip function and quality of life. Over an average follow-up period of 7.17 months, patients experienced notable improvements. This technique is an effective option for treating lateral hip pain due to tendinopathy. [ABSTRACT FROM AUTHOR]

Background/Objectives: An early accelerated rehabilitation is generally recommended after surgery for acute Achilles tendon ruptures (ATRs). The modified side-locking loop suture (MSLLS) is a surgical technique that provides high tensile strength to the repaired Achilles tendon and allows for a safe, early accelerated rehabilitation protocol without requiring postoperative immobilization. However, there are no reports investigating the clinical outcomes of the MSLLS technique with early accelerated rehabilitation for ATRs. To clarify the effectiveness of the MSLLS technique with an early accelerated rehabilitation protocol for ATR in athletes. Methods: We retrospectively analyzed 27 athletes (Tegner activity score ≥ 6) who underwent surgical treatment using the MSLLS technique for ATR between April 2017 and August 2022. All patients underwent an early accelerated rehabilitation protocol without immobilization. Outcome measures included the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale (AOFAS) score taken preoperatively and one year postoperatively, the time required to perform 20 continuous double-leg heel raises (DHR) and single-leg heel raises (SHR), the time to return to the original sport, and the presence of any complications. Results: The mean AOFAS score significantly improved from 37.2 ± 9.7 preoperatively to 96.3 ± 5.3 one year postoperatively. The mean time to be able to perform 20 continuous DHR and SHR was 7.7 ± 1.2 weeks and 11.3 ± 1.6 weeks, respectively. All patients were able to return to their original sport at their pre-injury level in an average of 22.7 ± 3.7 weeks without complication. Conclusions: The MSLLS technique in conjunction with an early accelerated rehabilitation protocol for ATR in athletes produced satisfactory results, with all patients able to return to their original sport at their preinjury level without complication. [ABSTRACT FROM AUTHOR]

Background: It is important to highlight the advantages of ultrasound in assessing muscular and tendinous behavior due to its non-invasive nature and capacity for dynamic studies. However, evaluating tendons via ultrasound can be challenging given the complexity of anisotropic phenomena related to collagen fiber arrangement. This study aims to validate the reliability of fixed ultrasound compared to manual acquisition in measuring Achilles tendon thickness. Method: Twenty participants, six men and fourteen women, were recruited. Ultrasound was used to measure the Achilles tendon's thickness at two specific points (4 and 6 cm from the calcaneal insertion of the Achilles tendon). The measurements were conducted by two examiners, one with previous experience and another without. Results: The measurements at 6 cm from the calcaneal insertion showed α = 0.996, α = 0.998 for measurements at 4 cm using manual acquisition, and α = 0.997 for measurements with fixed ultrasound at rest. For the weight-bearing and ankle dorsiflexion measurements, the reliability was excellent (α = 0.999 and α = 1.000). Conclusions: The findings demonstrated excellent reliability in the ultrasound measurements of the Achilles tendon's thickness, even when performed by different evaluators and under load-bearing conditions. This study suggests the clinical utility of assessing anatomical structures under load, enhancing ultrasound's applicability beyond the examination table. It is concluded that fixed ultrasound acquisition exhibits excellent reliability in measuring the Achilles tendon's thickness, offering potential benefits for precise diagnosis of pathologies, planning surgical interventions, and reducing possible errors related to operator variability. [ABSTRACT FROM AUTHOR]

Tendons play fundamental roles in the execution of human movement and therefore understanding tendon function, health and disease is important for everyday living and sports performance. The acute mechanical behavioural and physiological responses to short-term loading of tendons, as well as more chronic morphological and mechanical adaptations to longer term loading, differ between sexes. This has led some researchers to speculate that there may be a sex-specific injury risk in tendons. However, the link between anatomical, physiological and biomechanical sex-specific differences in tendons and their contributory role in the development of tendon disease injuries has not been critically evaluated. This review outlines the evidence surrounding the sex-specific physiological and biomechanical responses and adaptations to loading and discusses how this evidence compares to clinical evidence on tendon injuries and rehabilitation in the Achilles and patellar tendons in humans. Using the evidence available in both sports science and medicine, this may provide a more holistic understanding to improve our ability to enhance human tendon health and performance in both sexes. [ABSTRACT FROM AUTHOR]

This paper explores the use of biomechanics in identifying the mechanistic causes of musculoskeletal tissue injury and degeneration. It appraises how biomechanics has been used to develop training programmes aiming to maintain or recover tissue health. Tissue health depends on the functional mechanical environment experienced by tissues during daily and rehabilitation activities. These environments are the result of the interactions between tissue motion, loading, biology, and morphology. Maintaining health of and/or repairing musculoskeletal tissues requires targeting the "ideal" in vivo tissue mechanics (i.e., loading and deformation), which may be enabled by appropriate real-time biofeedback. Recent research shows that biofeedback technologies may increase their quality and effectiveness by integrating a personalised neuromusculoskeletal modelling driven by real-time motion capture and medical imaging. Model personalisation is crucial in obtaining physically and physiologically valid predictions of tissue biomechanics. Model real-time execution is crucial and achieved by code optimisation and artificial intelligence methods. Furthermore, recent work has also shown that laboratory-based motion capture biomechanical measurements and modelling can be performed outside the laboratory with wearable sensors and artificial intelligence. The next stage is to combine these technologies into well-designed easy to use products to guide training to maintain or recover tissue health in the real-world. [ABSTRACT FROM AUTHOR]

Achilles tendinopathy is prevalent among Irish dancers, believed to be due to aesthetic technical requirements and high-impact landing tasks. However, the peak Achilles tendon force during Irish dancing-specific landing tasks has not been quantified. Furthermore, the influence of fatigue is unclear. This study aimed to quantify the peak Achilles tendon force during three common Irish dancing landing tasks and investigate the effects of fatigue on this force. Twelve nationally competitive Irish dancers completed the landing tasks prior to and following a fatigue protocol. A Vicon motion analysis system and AMTI force plates were used to calculate sagittal plane ankle joint kinematics during landing to estimate peak Achilles tendon force. Three independent measures (Rating-of-Fatigue scale, Flight time: Contraction during a counter movement jump and jump height during the landing trials) were used to evaluate participant fatigue between conditions. Results revealed a significant difference in peak Achilles tendon force between the three landing tasks, however, no significant difference was observed between pre- and post-fatigue. Further research is required to investigate the effects of the landing technique used in Irish Dancing on peak Achilles tendon force with the aim to reduce peak Achilles tendon force and the risk of developing Achilles tendinopathy. [ABSTRACT FROM AUTHOR]

Mechanical stiffness derived from force-elongation curves is fundamentally different from shear wave (SW) elastography-based tissue properties. We compared these techniques, with a total of five methods of assessing Achilles tendon (AT) stiffness. Seventeen participants (12 male and 5 female) with unilateral AT rupture performed submaximal contractions at 30% and 10% maximal isometric contraction torque of the un-injured limb. SW velocity was acquired at rest. Force-elongation curves were assessed from the free AT and the medial gastrocnemius (MG) tendon. Mechanical stiffness was determined near the end of the linear region of the force-elongation curve and from the toe region. Bivariate correlations between mechanical stiffness and SW velocity, as well as pairwise t -tests between limbs, were computed. In the injured limb, SW velocity correlated with MG tendon and free AT toe-region stiffness during 10% (r = 0.59, p = 0.020 and r = 0.60, p = 0.011, respectively) and 30% of submaximal contractions (r = 0.56, p = 0.018 and r = 0.67, p = 0.004, respectively). The un-injured limb showed no associations. In both limbs pooled together, SW velocity correlated with MG tendon toe-region stiffness in 30% of submaximal contractions (r = 0.43, p = 0.012). Free tendon mechanical stiffness was lower in the injured limb, with a mean difference of 148.5 Nmm⁻¹ (95% CI: 35.6–261.3, p = 0.013), while SW velocity was higher in the injured limb (1.67 m × s⁻¹, 95% CI; -2.4 to -0.9, p < 0.001). SW elastography may reflect AT viscoelastic properties at the initial slope of the force-length curve with strains <1% but cannot offer insight into AT mechanics at higher loads. Extended toe regions in the injured limb could have caused the association between mechanical stiffness and SW-based stiffness. [ABSTRACT FROM AUTHOR]

Background: The calcaneal enthesis, an osseous footprint where the Achilles tendon seamlessly integrates with the bone, represents a complex interface crucial for effective force transmission. Bone adapts to mechanical stress and remodels based on the applied internal and external forces. This study explores the relationship between the elasticity of the Achilles tendon enthesis and the bone microstructure in the calcaneal crescent. Methods: In total, 19 calcaneal-enthesis sections, harvested from 10 fresh-frozen human cadaveric foot-ankle specimens (73.8 ± 6.0 years old, seven female), were used in this study. Indentation tests were performed at the enthesis region, and Hayes' elastic modulus was calculated for each specimen. Micro-CT scanning was performed at 50-micron voxel size to assess trabecular bone microstructure within six regions of interest (ROIs) and the cortical bone thickness along the calcaneal crescent. Results: Significant Spearman correlations were observed between the enthesis elastic modulus and trabecular bone thickness in the distal entheseal (ROI 3) and proximal plantar (ROI 4) regions (R = 0.786 and 0.518, respectively). Conclusion: This study highlights the potential impacts of Achilles tendon enthesis on calcaneal bone microstructure, which was pronounced in the distal calcaneal enthesis, suggesting regional differences in load transfer mechanism that require further investigation. [ABSTRACT FROM AUTHOR]

Copyright of Turkish Journal of Trauma & Emergency Surgery / Ulusal Travma ve Acil Cerrahi Dergisi is the property of KARE Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Die Orthopädie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Achilles tendon (AT) is composed of three distinct subtendons, each arising from one of the three heads of the triceps surae muscles: gastrocnemius medialis (GM), gastrocnemius lateralis (GL), and soleus (SOL). These subtendons exhibit a twisted structure, classified as low (Type I), medium (Type II), and high (Type III) twist, based on cadaveric studies. Nevertheless, the in vivo investigation of AT twist is notably scarce, resulting in a limited understanding of its functional significance. The aim of this study was to give insights into the complex 3D AT structure in vivo. A total of 30 healthy participants underwent individual stimulation of each of the triceps surae muscles at rest with the foot attached to the pedal of an isokinetic dynamometer. Ultrasound images were captured to concomitantly examine the displacement of the superficial, middle and deep AT layers. SOL stimulation resulted in the highest AT displacement followed by GM and GL stimulation. Independent of the muscle stimulated, non‐uniformity within the AT was observed with the deep layer exhibiting more displacement compared to the middle and superficial layers, hence important inter‐individual differences in AT displacement were noticeable. By comparing these individual displacement patterns during targeted stimulations with insights from cadaveric twist classifications on each subtendon area, our classification identified 19 subjects with a ‘low’ twist and 11 subjects with a ‘high’ twist. These findings enable us to move beyond cadaveric studies and relate the twisted microstructure of the AT in vivo to its dynamic behaviour. [ABSTRACT FROM AUTHOR]

The formation of gouty tophi surrounding the prior surgical site years after an Achilles tendon repair is an extremely rare presentation for which only three previous cases have been documented in the literature. In this case, we report the presentation of a 53‐year‐old male who had an Achilles tendon repair two and a half years prior and no clinical history of gout, yet during the necessary revision procedure of his Achilles tendon, he was found to have gouty tophi surrounding the nonabsorbable sutures used during his initial surgical repair. This case presentation and the three prior ones all involve the use of nonabsorbable sutures, and these sutures may potentially serve as a nidus for the formation of gouty tophi years after a surgical procedure, even in patients who do not have a clinical history of gout. It is important for clinicians to be aware of this rare clinical presentation as potential sequelae include infectious processes and the need for revision procedures. [ABSTRACT FROM AUTHOR]

Tunnel widening is a frequent problem following arthroscopic ligament reconstruction surgery that may primarily arise from a graft-tunnel mismatch caused by errors in surgical instruments and methods. The present study aimed to observe the influence of current surgical instruments and methods on graft-tunnel matching. We established an in vitro model using porcine Achilles tendons and tibias, and compared traditional surgical instruments (control group) with custom instruments (experimental group). Graft measurements, bone-tunnel creation, and measurements of the maximum pullout force of the graft from the bone tunnel were performed. Results indicated that the measuring gauge developed by our research group (capable of accurate measurement of graft diameters) may mitigate errors arising from graft-diameter measurement using traditional measuring cylinders. Therefore, errors caused by current surgical instruments and surgical methods led to an increase in graft-tunnel mismatches. The degree of mismatch was greater at the tibial end than at the femoral end. [ABSTRACT FROM AUTHOR]

Background: The AGEs levels in tissues of diabetics and elderly tend to be higher than in normal individuals. This study aims to determine the effects of AGEs on Achilles tendon repair. Materials and methods: Thirty-six male eight-week-old Sprague Dawley rats were selected in this study. The rats were randomly divided into two experimental groups and a control group after the transection of the Achilles tendon. During the tendon repair, the experimental groups were injected around the Achilles tendon with 350mmol/L (low dose group) and 1000mmol/L (high dose group) D-ribose 0.2 ml respectively to increase the AGEs level, while in the control group were given the same amount of PBS. The injections were given twice a week for six weeks. Collagen-I, TNF-α, and IL-6 expression in the healed Achilles tendon was assessed. Additionally, macroscopic, pathological, and biomechanical evaluations of Achilles tendon repair were conducted. Results: The repaired Achilles tendons in the high dose group showed severe swelling and distinctive adhesions. The histological score went up with the increase of the AGEs in the Achilles tendon (p<0.001). TNF- α and IL-6 in the Achilles tendon increased (p<0.001, p<0.001), and the production of collagen-I decreased with the accumulation of AGEs in the repaired Achilles tendon (p<0.001). The tensile strength of Achilles tendon in the high dose group was impaired significantly. Conclusion: In current study, the compromised tendon repair model induced by AGEs was successfully established in rat. The study demonstrated that AGEs significantly impair Achilles tendon repair. [ABSTRACT FROM AUTHOR]

A recent study published in Acta Neuropathologica identified a novel missense mutation of the small muscle protein X-linked (SMPX) gene in a Chinese pedigree. The affected individuals in the pedigree exhibited symptoms of scapuloperoneal myopathy and myofibrillar myopathy, with both proximal and distal muscle weakness and mild sensorineural deafness. Muscle biopsies revealed characteristic pathological features, including atrophic round fibers, rimmed vacuoles, and eosinophilic substances. This study expands our understanding of SMPX-related myopathy and highlights the need for further research to establish a relationship between the mutation and deafness. [Extracted from the article]

Introduction: Achilles tendon injury is common in athletic men. Surgical repair is the usual line of management; however, other lines of treatment were adopted. Platelet-rich plasma (PRP) contains growth factors that accelerate healing. Pentoxifylline (PTX) improves healing by increasing tissue perfusion through vasodilatation. Objective: The aim of the present work was to elucidate the effect of PRP and PTX either alone or in combination on the healing process of injured Achilles tendon in adult male albino rats by histological, morphometric and biomechanical studies. Materials and Methods: Ninety-five healthy laboratory adult male albino rats. Five rats were used as platelet-rich plasma donors. Ninety rats were divided into 5 groups 18 rats each; Group I: control group, Group II: injured untreated group, Group III: received local PRP injection into the operation site, Group IV: received daily IM PTX injections, Group V: combination group received both PRP and PTX. On day 15, the Achilles tendon of eight rats from each group was dissected. Five tendons were used in the light microscopic study and the other three were used in the ultrastructural study by scanning electron microscope to assess the structural properties of the tendon. On day 30, the Achilles tendon of ten rats from each group was dissected. Five tendons were used for the morphometric study while the other five were used for the biomechanical study to assess the functional properties of the tendon. Results: Combined PRP + PTX treated group V showed better healing results than all other experimental groups both histologically and biomechanically. PRP-treated group III showed better healing than PTX-treated group IV which in turn was superior to the untreated group II. Conclusion: There is a benefit of using combined PRP and PTX than either treatment alone in promoting Achilles tendon healing post-injury. [ABSTRACT FROM AUTHOR]

The stretch-shortening cycle (SSC) has been classified into fast (<250 ms) and slow (>250 ms) groups based on ground contact time (GCT) threshold values. However, there are gaps in the literature on how the 250 ms threshold value was found and which variables affect it. The purpose of this study is to validate the 250 ms threshold by investigating the factors affecting this threshold. For this purpose, force–time variables during a drop jump (DJ) with a force plate and achilles tendon (AT) muscle-tendon unit mechanical properties using shear-wave elastography in 46 recreationally active men were analysed. A regression tree analysis was conducted using R studio to classify GCT with correlated variables (p < 0.05). The new GCT threshold values (GCT < 188 ms, 188 ≤ GCT < 222 ms and GCT ≥ 222 ms) were found according to the lowest root mean square error of approximation value (0.1985) at reactive strength index. Comparisons of GCT groups showed significant differences in force, time, power variables and AT length (p < 0.05). AT length is the main variable differentiating GCT groups: Short AT results in a short GCT and long AT results in a long GCT. This study reveals that SSC can be classified into three groups using new GCT threshold values, offering a new perspective for SSC assessment. [ABSTRACT FROM AUTHOR]

To examine the relationship between Achilles-tendon (AT) and patellar-tendon (PT) structure, clinical-examination and tendon pain in young gymnasts; and, to explore the associations between these factors and age, maturation, and training-load. Two hundred and seventy-four female gymnasts (aged 12.1±1.9 yrs) were assessed for anthropometric measures, pubertal-stage, and training-load. They had clinical-tests (pain-on-palpation for AT and pain-on-palpation and Royal-London Hospital-Test for PT), were asked about tendon-pain during-loading and were assessed for tendon-structure. Gymnasts with positive clinical-tests (with and without pain during-loading) presented a significantly higher prevalence of disorganized AT and PT compared to gymnasts with negative clinical-tests (with and without pain during-loading) (p<0.05). A significant pubertyXpositive clinical-test interaction was found for disorganized PT structure, whereby a disorganized structure was more prevalent among post-pubertal gymnasts with positive clinical-tests compared to pre-pubertal participants with negative clinical-tests (F(1, 263)=9.436, p=0.002). In gymnasts with positive clinical-tests, significant correlations were found between disorganized AT and PT structures and age, and training-load (p<0.05). An increased prevalence of disorganized tendon structure (regardless of pain during-loading) was seen in participants with positive clinical-tests. This disorganized tendon-structure was found to be significantly related to increased age, post-pubertal stage, and higher training hours in gymnasts with positive clinical-tests. [ABSTRACT FROM AUTHOR]

BACKGROUND: Ultrasound-guided galvanic electrolysis technique (USGET) is an innovative mini-invasive intervention with the potential to optimise outcomes in the treatment of Achille's tendinopathy (AT). OBJECTIVE: The aim of this pilot study is to evaluate the efficacy of adding USGET to conventional eccentric exercise treatment in patients with chronic AT. METHODS: Inclusion criteria were patients with unilateral non-insertional AT, pain lasting > 3 months, aged 25–60 years. Patients were randomised in two groups receiving the same physiotherapy treatment (2 sessions per week for 8 weeks). In addition, the experimental group received three USGET stimulations, one every 15 days. Outcome measures were assessment of Achilles tendinopathy severity using the Victorian Institute of Sport Assessment-Achilles (VISA-A) and pain intensity using the Visual Analogue Scale (VAS). Assessment points occurred at the onset of treatment (T0), its conclusion (T1), and subsequent follow-ups at one (T2) and two months (T3). RESULTS: Out of the 52 patients who met the study inclusion criteria, two participants withdrew from the study, resulting in a total of 50 subjects who completed the research. None of the parameters showed a different distribution at T1 (p > 0.337). At T2, there was a statistical difference in VISA-A (p = 0.010) and its subscales and VAS (p = 0.002) in the USGET group. At T3, both groups improved with a statistical difference observed in VISA-A (p < 0.001) and its subscales Pain (p = 0.004), Function (p = 0.003) and Sport (p = 0.002), but the EG patients showed a greater improvement. No adverse events were reported. CONCLUSION: The effect of USGET combined with eccentric exercise appears to be a safe and effective technique for achieving pain relief and functional recovery in the medium term, supporting the integrated use of USGET as a rehabilitative treatment option for patients with chronic AT. [ABSTRACT FROM AUTHOR]

This paper aims to review the various surgical techniques for gastrocnemius–soleus recession and Achilles tendon lengthening, with a special focus on the treatment of clubfoot and cerebral palsy (CP) equinus contracture. This descriptive review article comprehensively explores different techniques for gastrocnemius recession, including the Hoke percutaneous triple hemisection, Baker's method (Tongue-in-Groove Gastrocnemius–Soleus Recession), the Vulpius method, the Baumann procedure, and the Strayer procedure (Gastrocnemius Recession). The objective is to present a detailed analysis of these methods, covering their indications, procedural nuances, relevance in clinical practice, and outcomes. [ABSTRACT FROM AUTHOR]

This article provides information on the diagnosis and management of acute Achilles tendon rupture (ATR). It highlights the importance of timely diagnosis and involvement of a multidisciplinary team in the treatment process. The article discusses the ongoing debate between conservative and surgical approaches to treatment, with surgical treatment reducing the risk of re-rupture but having a higher risk of complications. However, recent research has shown similar functional outcomes among different treatment groups. The article emphasizes the importance of patient compliance and referral to an orthopedic surgeon for patients who prefer surgical treatment or are unsure about their management preferences. [Extracted from the article]

Introduction: Controlled ankle motion (CAM) boots are a below‐knee orthotic device prescribed for the management of foot and ankle injuries to reduce ankle range of motion (RoM) and offload the foot and ankle whilst allowing continued ambulation during recovery. There is a lack of clarity within the current literature surrounding the biomechanical understanding and effectiveness of CAM boots. Aims: To summarise the biomechanical effects of CAM boot wear as an orthotic for restricting ankle RoM and offloading the foot. Methods: A systematic literature review was conducted in accordance with the PRISMA 2020 guidelines. All papers were independently screened by two authors for inclusion. Methodological quality was appraised using Joanna Briggs Critical Appraisal checklists. A narrative synthesis of all eligible papers was produced. Results: Thirteen studies involving 197 participants (113 male and 84 female) were included. All studies were quasi‐randomised and employed a within‐study design, of which 12 studies included a control group and a range of CAM boots were investigated. CAM boots can be seen to restrict ankle RoM, however, neighboring joints such as the knee and hip do have kinetic and kinematic compensatory alterations. Plantar pressure of the forefoot is effectively redistributed to the hindfoot by CAM boots. Conclusion: The compensatory mechanisms at the hip and knee joint during CAM boot wear could explain the secondary site pain often reported in patients, specifically at the ipsilateral knee and contralateral hip. Although CAM boots can be used to restrict ankle motion, this review has highlighted a lack of in‐boot kinematic analyses during CAM boot use, where tracking markers are placed on the anatomical structure rather than on the boot, or through video fluoroscopy, urging the need for a more robust methodological approach to achieve this. There is a need for studies to assess the biomechanical alterations caused by CAM boots in populations living with foot and ankle pathologies. Future research, adopting a longitudinal study design, is required to fully understand the effectiveness of CAM boots for rehabilitation. [ABSTRACT FROM AUTHOR]

A reverse sural flap is a surgical procedure to repair soft tissue defects, usually in the ankle region. This procedure involves moving a tissue flap from the calf to cover a defect in the ankle. The flap is turned 180° so that the tissue around the wound is supplied with blood by the vessels at the base of the flap, typically preserving the sural nerve and artery. This method is particularly valuable when thick and robust tissue is required to cover defects resulting from traumatic injuries, chronic wounds, or post-skin tumor removal when the local tissue is insufficient for direct closure. In this case, a patient who had undergone surgery for a chronic ulcerative lesion on the Achilles tendon three years prior to presentation at the authors' hospital was treated using a half-width reverse sural flap. Modifications to the sural flap design may be crucial considering the surgical history, blood supply, and defect size around the lower leg. In particular, previous surgeries for lower leg fractures or ligament damage may limit blood supply and require flap design modifications. [ABSTRACT FROM AUTHOR]

Tendons transmit tensile load from muscles to the skeleton. Differential loading across a tendon can occur, especially when it contains subtendons originating from distinct muscles. Tendon shear wave speed has previously been shown to reflect local tensile stress. Hence, a tool that measures spatial variations in wave speed may reflect differential loading within a tendon during human movement. Do wave speeds measured via high-framerate ultrasound-based tensiometry correspond with differential loading across a tendon? Ultrasound-tensiometry uses an external mechanical actuator to induce waves and high-framerate plane wave ultrasound imaging (20 kHz) to track tissue displacements arising from wave propagation within a tendon. Local tissue displacements are temporally and spatially filtered to remove high-frequency noise and reflected waves. A Radon transform of the spatio-temporal displacement data is used to compute the shear wave speed across the tendon. We evaluated ultrasound-tensiometry's ability to measure differential loading across a tendon using in silico , ex vivo and in vivo approaches. The in silico approach used a finite element model to simulate wave propagation along two adjacent subtendons undergoing differential loading. The ex vivo experiment measured wave speed in adjacent porcine flexor subtendons subjected to differential loading. In vivo , we tracked wave speed across the Achilles tendon while a participant performed calf stretches to differentially load the subtendons, and while walking on a treadmill at 1.5 m/s. Wave speeds modulated with local tendon stress under both in silico and ex vivo conditions, with higher wave speeds observed in subtendons subjected to higher loads (6–16 m/s higher at 1.5× load differential). Spatial variations in in vivo Achilles tendon wave speeds were consistent with differential subtendon loading arising from distinct muscle loads (maximum range: 0–137 m/s, resolution: 0.1 mm×0.2 mm, precision: ±0.2 m/s). High-framerate ultrasound-tensiometry tracks spatial variations in tendon wave speed, which may be useful to investigate local tissue loading and to delineate individual muscle contributions to movement. • Ultrasound-tensiometry combines a mechanical tap with high-framerate ultrasound to measure spatial variations in shear wave speed within a tendon. • Measured spatial variations in wave speed indicate non-uniform loading within a tendon. • These measurements will improve our understanding of muscle-tendon function during dynamic movement. [ABSTRACT FROM AUTHOR]

Tendon injury produces intractable pain and disability in movement, but the medications for analgesia and restoring functional integrity of tendon are still limited. In this study, we report that proteinase-activated receptor 2 (PAR2) activation in dorsal root ganglion (DRG) neurons contributes to chronic pain and tendon histopathological changes produced by Achilles tendon partial transection injury (TTI). Tendon partial transection injury increases the expression of PAR2 protein in both somata of DRG neurons and their peripheral terminals within the injured Achilles tendon. Activation of PAR2 promotes the primary sensory neuron plasticity by activating downstream cAMP-PKA pathway, phosphorylation of PKC, CaMKII, and CREB. Blocking PAR2 signaling by PAR2 small-interference RNA or antagonistic peptide PIP delays the onset of TTI-induced pain, reverses the ongoing pain, as well as inhibits sensory nerve sprouting, and promotes structural remodeling of the injured tendon. Vitamin B complex (VBC), containing thiamine (B1), pyridoxine (B6), and cyanocobalamin (B12), is effective to ameliorate TTI-induced pain, inhibit ectopic nerve sprouting, and accelerate tendon repair, through suppressing PAR2 activation. These findings reveal a critical role of PAR2 signaling in the development of chronic pain and histopathological alterations of injured tendon following Achilles tendon injury. This study suggests that the pharmaceuticals targeting PAR2, such as VBC, may be an effective approach for the treatment of tendon injury-induced pain and promoting tendon repair. [ABSTRACT FROM AUTHOR]

Purpose: Ultrasound shear wave elastography has potential use in assessing tendon tissue; however, reducing measurement variability remains challenging. The primary purpose of this study was to identify the amount of variability accounted for by ultrasound parameter (frequency, harmonics and CrossXBeam) settings on shear wave speed at two testing sites. Methods: Shear wave elastography images of the Achilles tendon were obtained from individuals with healthy tendons (n = 28) at two testing sites with standardised image acquisition/postprocessing protocols. Images were acquired at a range of frequencies (7–15 MHz) with CrossXBeam (a filtering technique) and harmonics settings toggled on and off. Variance decomposition analysis was performed to identify the amount of variability in shear wave speed accounted for by scan acquisition settings and testing sites. Results: Shear wave speed variance was primarily attributed to participants (56.87% of variance; residual error: 35%). All scanning parameters, testing site and interaction terms each accounted for less than 2.5% of the variance. A statistically significant, negative relationship was observed between shear wave speed and image quality (p = 0.001) suggesting poor image quality yields higher shear wave speed estimates. Conclusion: The findings of this study suggest that natural variation in Achilles tendon mechanics between individuals without tendon pathology accounts for most of the shear wave speed variability. Optimising image quality, which may be observed in higher frequencies, should be considered to improve shear wave speed estimation. Clinically, this study highlights the need to take multiple images, maintain consistent ultrasound settings when tracking patient progress over time and use caution when comparing raw values from tendon scans performed in different clinics with shear wave elastography. Level of Evidence: Level III. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effect of aging and resistance training with a moderate load on the size and mechanical properties of the patellar (PT) and Achilles tendon (AT) and their associated aponeuroses; medial gastrocnemius (MG) and vastus lateralis (VL). Young (Y55; 24.8 ± 3.8 yrs, n = 11) and old men (O55; 70.0 ± 4.6 yrs, n = 13) were assigned to undergo a training program (12 weeks; 3 times/week) of moderate slow resistance training [55% of one repetition maximum (RM)] of the triceps surae and quadriceps muscles. Tendon dimensions were assessed using 1.5 T magnetic resonance imaging before and after 12 weeks. AT and PT cross sectional area (CSA) were determined every 10% of tendon length. Mechanical properties of the free AT, MG aponeurosis, PT, and VL aponeurosis were assessed using ultrasonography (deformation) and tendon force measurements. CSA of the AT but not PT was greater in O55 compared with Y55. At baseline, mechanical properties were generally lower in O55 than Y55 for AT, MG aponeurosis and VL aponeurosis (Young's modulus) but not for PT. CSA of the AT and PT increased equally in both groups following training. Further, for a given force, stiffness and Young's modulus also increased equally for VL aponeurosis and AT, for boths groups. The present study highlights that except for the PT, older men have lower tendon (AT, MG aponeurosis, and VL aponeurosis) mechanical properties than young men and 12-weeks of moderate slow resistance training appears sufficient to improve tendon size and mechanical adaptations in both young and older men. New and Noteworthy: These novel findings suggest that short-term moderate slow resistance training induces equal improvements in tendon size and mechanics regardless of age. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study is to determine if ultrasound (US) allows a precise assessment of the paratenon (PT) of the Achilles calcaneal tendon (AT), and to anatomically describe the US-guided paratendinous injection technique. Methods: This study was initially conducted on eight cadaveric specimens using high-resolution ultrasound (HRUS) to examine the PT appearance, thickness, and its relationships with the AT, plantaris tendon (PLT), Kager's fat pad (KFP), sural nerve (SN), and fascia cruris (FC). US-guided paratendinous injection of China ink was performed in all specimens, followed by anatomical dissection to assess injectate distribution. Then, HRUS study of the PT was carried out bilaterally in twenty asymptomatic volunteers (40 legs). Two musculoskeletal radiologists recorded all data in consensus except PT thickness in volunteers which was recorded independently in order to calculate intra and inter-observer reliability. Results: The PT was consistently identified with HRUS along its entire course in both cadaveric specimens (8/8) and volunteers (40/40). The mean PT thickness was 0.54 mm in cadavers and 0.39 mm in vivo, without any correlation with the AT thickness. Intra- and inter observer reliability were respectively excellent and good for PT thickness. All eight (100%) ex vivo China ink injections were accurate, demonstrating a circumferential distribution of the injectate between the PT and the AT, associated with an anterior spread to the KFP. Conclusion: HRUS allows visualization of the PT along its entire length, and assessment of its relationships to adjacent structures. US-guided paratendinous injections can accurately and safely deliver injectates in the paratendinous sheath. [ABSTRACT FROM AUTHOR]

We propose an ultrasonic treatment for collagenase-induced tendinopathy in rat's Achilles tendon using pulses with a low number of cycles, high acoustic pressure and very low duty cycle. Twenty rats were used to perform the experiment. Four experimental groups of calcaneal tendons were studied: control (n = 6), sham (n = 4), collagenase-induced tendinopathy (n = 8) and ultrasound-treated collagenase-induced tendinopathy (n = 8). Surgical intervention was performed to expose the tendons prior to collagenase injection. A 1 MHz ultrasonic tansducer with a focusing lens was used. Ultrasonic treatments were used with an average total treatment time of 2.5 min, 20-cycle pulses, pressure amplitude p = 7 MPa, and 0.02% duty cycle. Histopathology of the samples was performed to evaluate nuclear density, acute inflammation, and signs of neovascularization. Collagen (types I and III), elastic fibers, and glycosaminoglycans were also analyzed. No tendon involvement was found by the surgical process. Ultrasonic treatment is safe, as it does not affect healthy tendons. When collagenase infiltrated animals were treated with US, a clear predominance of type I collagen fibers and a similar collagen ratio profile to that observed in the control and sham groups was observed, with a higher density of elastic fibers compared to the control and sham groups and a significant increase in the density of glycosaminoglycans. The ultrasound treatment proposed reduces the effects of the artificial collagenase lesion to reach the basal level after 45 d. [ABSTRACT FROM AUTHOR]

The human calcaneus is robust and provides a prominent heel for effective bipedal locomotion, although the adjacent talus has no muscle attachments. However, there is incomplete information about the morphological changes in these prominent bones during embryo development. We examined serial histological sections of 23 human embryos and early‐term fetuses (approximately 5–10 weeks' gestational age [GA]). At a GA of 5 weeks, the precartilage talus was parallel to and on the medial side of the calcaneus, which had a prolate spheroid shape and consisted of three masses. At a GA of 6 weeks, the cartilaginous talus extended along the proximodistal axis, and the tuber calcanei became long and bulky, with a small sustentaculum talus at the "distal" side. At a GA of 6 to 8 weeks, the sustentaculum had a medial extension below the talus so that the talus "rode over" the calcaneus. In contrast, the talus had a more complex shape, depending on the growth of adjacent bones. At a GA of 9 to 10 weeks, the talus was above the calcaneus, but the medial part still faced the plantar subcutaneous tissue because of the relatively small sustentaculum. Therefore, the final morphology appeared after an additional several weeks. Muscle activity seemed to facilitate growth of the tuber calcanei, but growth of the other parts of calcaneus, including the sustentaculum, seemed to depend on active proliferation at the different sites of cartilage. Multiple tendons and ligaments seemed to fix the talus so that it remained close to the calcaneus. [ABSTRACT FROM AUTHOR]

Purpose: In correlation with magnetic resonance imaging (MRI), this study attempts to assess the effectiveness of the diagnostic of ultrasonography (US) features and shear wave elastography (SWE) in determining the different causes of heel pain. Materials and Methods: 55 heels with a mean age of 38.33 ± 10.8 were included in the study (10 control cases and 41 cases, 4 of which had bilateral heel pain). There were 23 female cases (56.1%) and 18 male cases (43.95%). Examinations using shear wave elastography (SWE) and ultrasound (US) were done in different positions. MRI and the obtained data were correlated. Results: When used to diagnose different heel pain causes, ultrasound demonstrated great sensitivity and specificity. SWE demonstrated a good correlation with MRI findings and enhanced the ultrasound's diagnostic precision in identifying plantar fasciitis early on (increased accuracy from 88.9 to 93.33% with 100% sensitivity and 83.3% specificity) and Achilles tendinopathy (increased accuracy from 88.9 to 97.8 with 94.7% sensitivity and 100% specificity). Conclusion: In summary, we concluded that heel pain can be efficiently examined by both ultrasound (US) and shear wave elastography (SWE) with the former being used as the primary effective tool and the latter being done to increase diagnostic accuracy. We also concluded that SWE improved the ultrasound's diagnostic precision in identifying patients with early plantar fasciitis and Achilles tendinopathy and showed a robust relationship with clinical outcomes, enhancing patient evaluation and follow-up. [ABSTRACT FROM AUTHOR]

Purpose: Shear wave elastography (SWE) has seen many advancements in Achilles tendon evaluation in recent years, yet standardization of this technique is still problematic due to the lack of knowledge regarding the optimal way to perform the examination. The purpose of this study was to evaluate the effects of ankle position, probe frequency and physical effort on the shear modulus of the Achilles tendon, but also to determine the intra and inter-observer reliability of the technique. Methods: 37 healthy volunteers were included; SWE protocol was performed by two examiners. We analyzed the shear modulus of the tendon with the ankle in neutral, maximum dorsiflexion and maximum plantar flexion using two different high frequency probes. Afterwards, the subjects performed a brief physical exercise and SWE measurements were repeated. Results: The L18-5 probe showed the highest ICC values (ICC = 0.798, 95% CI 0.660–0.880, p < 0.001) when positioned at 2 cm from the calcaneal insertion with the ankle in a neutral state. Conversely, utilizing the same L18-5 probe at 1 cm from the insertion during maximum plantar flexion of the ankle resulted in the lowest ICC (ICC = 0.422, 95% CI 0.032–0.655, p = 0.019). Significant variations in elasticity values were noted among different ankle positions and probe types, while no significant changes in elasticity were observed post-physical exercise. Conclusion: Ankle position and probe frequency are factors that influence elasticity values of the Achilles tendon. An ankle position between 10 and 20 degrees of plantar flexion is the most suitable for SWE evaluation. However, more research focusing on Achilles tendon SWE is essential due to the challenges encountered in standardizing this region. [ABSTRACT FROM AUTHOR]

Background: Extracorporeal shockwave therapy (ESWT) is a noninvasive treatment modality that is used in the treatment of chronic Achilles tendinopathy (AT). Purposes: To (1) retrospectively assess outcomes after ESWT for both noninsertional AT (NAT) and insertional AT (IAT) at >1-year follow-up and (2) identify potential predictors of outcomes. Study Design: Cohort study; Level of evidence, 3. Methods: Chart review was conducted to identify patients who underwent ESWT for AT with a minimum of 1-year follow-up. Data collected and assessed included patient demographic characteristics, pathological characteristics including the location of AT (NAT or IAT), presence of a Haglund deformity, and severity of tendon degeneration on magnetic resonance imaging (MRI), in addition to treatment characteristics including number of sessions and intensity of ESWT. The Victorian Institute of Sports Assessment–Achilles (VISA-A) and visual analog scale (VAS) pain scores were obtained before ESWT, 6 months after ESWT, and at final follow-up. Failures were also recorded, which were defined as no improvement in VISA-A or VAS scores or need for surgical intervention. Linear regression was performed to identify potential predictors of inferior subjective clinical outcomes and failures. Survival analysis was conducted using Kaplan-Meier curves. Results: The study included 52 patients with IAT and 34 patients with NAT. The mean follow-up in the NAT cohort was 22.3 ± 10.2 months and the mean follow-up in the IAT cohort was 26.8 ± 15.8 months. Improvements in VISA-A and VAS scores were observed in the NAT cohort at 6-month follow-up and at final follow-up (P <.05). Improvements in VISA-A and VAS scores were recorded in the IAT cohort at 6-month follow-up, which subsequently deteriorated at final follow-up. In the NAT cohort, the failure rate at 6-month follow-up was 11.8%, which increased to 29.4% at final follow-up. In the IAT cohort, the failure rate at 6-month follow-up was 32.7%, which increased to 59.6% at final follow-up. Predictors of inferior subjective clinical outcomes and failures in the NAT cohort included pre-ESWT subjective clinical score, male sex, presence of a cardiovascular risk factor, and more severe MRI grading of tendinopathy. Predictors of inferior subjective clinical outcomes and failures in the IAT cohort included pre-ESWT subjective clinical score and more severe MRI grading of tendinopathy. Conclusion: Superior subjective clinical outcomes together with a lower failure rate were maintained for >1 year in the NAT cohort compared with the IAT cohort, calling into question the long-term benefit of ESWT for patients with IAT. [ABSTRACT FROM AUTHOR]

Background/Aim: The primary objective of this study was to conduct comprehensive research and analysis of patient-generated content related to Achilles tendon surgery on the social media platform Instagram. The aim was to gain deeper insights into patients' experiences during the perioperative period, which may contain valuable information pertinent to their condition, information of which the physicians may be unaware. Methods: A search was conducted on the Instagram database, covering a period of 78 months from February 2015 to August 2021. Posts utilizing the hashtags "#achillessurgery" and "#achillesrepair" were included in the analysis. Posts were assessed using a binary scoring system, considering variables such as tone, media format, return to work, rehabilitation or physical therapy, return to sports, images related to the ankle (e.g., scars, stitches, casts, dressings, walking boots), activities of daily living, and pain. Results: A total of 500 posts were reviewed, and a positive tone was observed in 77.8% of these. The average Instagram like ratio for these posts was computed as 9%. Statistical analysis revealed a significant relationship between post content and tone status (P=0.001). Specifically, within the positive tone group, informative content about the disease was comparatively lower and statistically significant when compared to exercise training and patient experience (P=0.001). Additionally, exercise training posts were found to be significantly lower than patient experience posts (P=0.001) within the positive tone group. In contrast, within the negative tone group, patient experience posts were significantly higher compared to informative content and exercise training posts (P=0.001). Moreover, the quantity of informative posts markedly surpassed the number of posts related to exercise training (P=0.001). Conclusion: In the positive tone category, people tended to emphasize personal experiences and participate in posts related to exercise training rather than actively seeking or exchanging information about the disorder. On the other hand, within the negative tone group, individuals were more likely to share adverse experiences, pursue support, and seek a deeper understanding from others. Their priority may also lie in sharing and gaining information specifically about the disorder. Our exploration of the use of social media platforms to delve into patient perspectives on Achilles tendon surgery provides an alternative insight into patients' experiences with the surgical process. By comprehending the content shared by patients on social media, surgeons may gain an improved opportunity to assess and address the surgical experience of their patients more effectively, ultimately contributing to enhanced patient care. [ABSTRACT FROM AUTHOR]

Simple Summary: Tendon injuries lead to poor healing with scarring and occasionally calcification. In these metaplastic drifts, mice with injured Achilles tendons (ATs) represent a good preclinical model since about one-third of tissues show calcium deposits (i.e., non-calcified vs. calcified tendons) at 28 days post-injury (p.i.). No information has been collected to date about the role exerted in metaplasia by neuromarkers, which, on the contrary, modulate tendon healing in diverse animal models. In particular, it remains to be clarified whether specific patterns in non-calcified/calcified tendons could be predictive of the tissue healing fate. The present results show that neuromarkers such as neurofilament-200 (NF200), nerve growth factor (NGF), neuropeptide Y (NPY), galanin (GAL), and calcitonin gene-related protein (CGRP) had a dynamic (7 vs. 28 days p.i.) and differentiative expression during early tendon healing. In detail, in non-calcified tendons, NF200 values were similar to pre-injury, whereas, in calcified tendons, NF200 persisted at high levels. Notably, a high CGRP/NPY (vasodilatory/vasoconstrictive) neuromediator ratio characterised tendon healing towards calcification. A novel finding was the contribution of tendon cells in the synthesis of neuromarkers, suggesting a connection between the cells and the nervous system. This research offers novel insights into neurobiological mechanisms during early tendon healing in mice and identifies a neuromarker pattern predictive of tendon metaplastic repair. Unsuccessful tendon healing leads to fibrosis and occasionally calcification. In these metaplastic drifts, the mouse AT preclinical injury model represents a robust experimental setting for studying tendon calcifications. Previously, calcium deposits were found in about 30% of tendons after 28 days post-injury. Although a neuromediated healing process has previously been documented, the expression patterns of NF200, NGF, NPY, GAL, and CGRP in mouse AT and their roles in metaplastic calcific repair remain to be explored. This study included a spatiotemporal analysis of these neuromarkers during the inflammatory phase (7 days p.i.) and the proliferative/early-remodelling phase (28 days p.i.). While the inflammatory phase is characterised by NF200 and CGRP upregulation, in the 28 days p.i., the non-calcified tendons (n = 16/24) showed overall NGF, NPY, GAL, and CGRP upregulation (compared to 7 days post-injury) and a return of NF200 expression to values similar to pre-injury. Presenting a different picture, in calcified tendons (n = 8), NF200 persisted at high levels, while NGF and NPY significantly increased, resulting in a higher NPY/CGRP ratio. Therefore, high levels of NF200 and imbalance between vasoconstrictive (NPY) and vasodilatory (CGRP) neuromarkers may be indicative of calcification. Tendon cells contributed to the synthesis of neuromarkers, suggesting that their neuro-autocrine/paracrine role is exerted by coordinating growth factors, cytokines, and neuropeptides. These findings offer insights into the neurobiological mechanisms of early tendon healing and identify new neuromarker profiles predictive of tendon healing outcomes. [ABSTRACT FROM AUTHOR]

Older adults have difficulty maintaining balance when faced with postural disturbances, a task that is influenced by the stiffness of the triceps surae and Achilles tendon. Age-related changes in Achilles tendon stiffness have been reported at matched levels of effort, but measures typically have not been made at matched loads, which is important due to age-dependent changes in strength. Moreover, there has been limited investigation into age-dependent changes in muscle stiffness. Here, we investigate how age alters muscle and tendon stiffness and their influence on ankle stiffness. We hypothesized that age-related changes in muscle and tendon contribute to reduced ankle stiffness in older adults and evaluated this hypothesis when either load or effort were matched. We used B-mode ultrasound with joint-level perturbations to quantify ankle, muscle, and tendon stiffness across a range of loads and efforts in seventeen healthy younger and older adults. At matched loads relevant to standing and the stance phase of walking, there was no significant difference in ankle, muscle, or tendon stiffness between groups (all p > 0.13). However, at matched effort, older adults exhibited a significant decrease in ankle (27%; p = 0.008), muscle (37%; p = 0.02), and tendon stiffness (22%; p = 0.03) at 30% of maximum effort. This is consistent with our finding that older adults were 36% weaker than younger adults in plantarflexion (p = 0.004). Together, these results indicate that, at the loads tested in this study, there are no age-dependent changes in the mechanical properties of muscle or tendon, only differences in strength that result in altered ankle, muscle, and tendon stiffness at matched levels of effort. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of adipose-derived stem cells (ADSCs) in the treatment of acute rupture of the Achilles tendon. It was a cross-sectional study involving 15 patients. Patients were randomly divided: group 1—rupture; group 2—suture; group 3—rupture + ADSCs. In the AOFAS score, the score was higher in group 3 with a significant difference. In the ATRS score, the score was higher in groups 2 and 3, also with a significant difference. As for the ultrasound score, there was a significant difference between the experimental groups in relation to this score, however, in the multiple comparisons test, comparing two groups at a time, it was possible to observe a significant difference of the experimental groups. It can be concluded that cell therapy in this condition may be a treatment option due to tissue regeneration and significant recovery of function. [ABSTRACT FROM AUTHOR]