Achilles tendon morpho-mechanical parameters are related to triceps surae motor unit firing properties.

Recent studies combining high-density surface electromyography (HD-sEMG) and ultrasound imaging have yielded valuable insights into the relationship between motor unit activity and muscle contractile properties. However, limited evidence exists on the relationship between motor unit firing properties and tendon morpho-mechanical properties. This study aimed to determine the relationship between triceps surae motor unit firing properties and the morpho-mechanical properties of the Achilles tendon (AT). Motor unit firing properties (i.e. mean discharge rate (DR) and coefficient of variation of the interspike interval (COVisi)) and motor unit firing-torque relationships (cross-correlation between cumulative spike train (CST) and torque, and the delay between motor unit firing and torque production (neuromechanical delay)) of the medial gastrocnemius (MG), lateral gastrocnemius (LG), and soleus (SO) muscles were assessed using HD-sEMG during isometric plantarflexion contractions at 10% and 40% of maximal voluntary contraction (MVC). The morpho-mechanical properties of the AT (i.e. length, thickness, cross-sectional area and resting stiffness) were determined using B-mode ultrasonography and shear-wave elastography. Multiple linear regression analysis showed that at 10% MVC, the DR of the triceps surae muscles explained 41.7% of the variance in resting AT stiffness. Additionally, at 10% MVC, COVisi SO predicted 30.4% of the variance in AT length. At 40% MVC, COVisi MG and COVisi SO explained 48.7% of the variance in AT length. Motor unit-torque relationships were not associated with any morpho-mechanical parameter. This study provides novel evidence of a contraction-intensity dependent relationship between motor unit firing parameters of the triceps surae muscle and the morpho-mechanical properties of the AT.

Outcomes After Extracorporeal Shockwave Therapy for Chronic Noninsertional Achilles Tendinopathy Compared With Chronic Insertional Achilles Tendinopathy: A Retrospective Review.

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.

Clinical and biomechanical comparison of suture-external button versus interference screw associated with V-Y advancement or turndown flaps for flexor hallucis longus transfer in chronic Achilles tendon rupture.

PURPOSE: Surgical treatment of chronic Achilles tendon rupture is a technically challenging procedure. We aimed to compare the clinical outcomes, range of motion, and strength of ankle plantar- and dorsiflexors between two techniques for fixation of flexor hallucis longus tendon to the calcaneus: interference screw and suture-external button. METHODS: Twenty-five patients participated in this retrospective comparative study. All patients underwent short harvest FHL tendon transfer for chronic AT rupture were asked for a follow-up visit, at least one year following surgery. The outcomes were evaluated by visual analog scale (VAS), AOFAS ankle-hindfoot score, and VISA-A questionnaire. Ankle ROM with possible restriction in addition to isokinetic strength of ankle plantar- and dorsiflexors was assessed. RESULTS: No statistically significant difference was observed between the groups for pain (P = 0.81), AOFAS ankle-hindfoot scale (P = 0.97), and VISA-A (P = 0.44). Notably, more decrease in ankle dorsiflexion was seen in interference screw group in comparison with suture-external button group (4.4 ± 6.6 vs. 9.5 ± 6.1 degrees, P = 0.06). The difference of active dorsiflexion between operated and non-operated side in interference screw group was statistically significant (P = 0.02). Biotenodesis screw imposed more limb asymmetry in comparison with suture-external button technique. CONCLUSIONS: Fixation of transcalcaneal FHL tendon transfer for chronic AT either by interference screw or suture-external button has encouraging postoperative clinical results. Although ROM of the ankle joint reduced in both techniques, interference screw may result in more reduction in dorsiflexion of the ankle.

Advanced glycation end products impair the repair of injured tendon: a study in rats.

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.

Rehabilitation and Return to Sports after Achilles Tendon Repair.

Rehabilitation protocols post-Achilles tendon repair vary widely, particularly regarding weight bearing (WB) and immobilization duration, impacting recovery trajectories significantly. This commentary focuses on rehabilitation strategies following acute Achilles tendon repair (ATR), emphasizing early mobilization and progressive loading. Techniques such as blood flow restriction training (BFRT) and progressive loading to restore strength and tendon mechanical properties are discussed in the context of optimizing recovery, minimizing tendon elongation and facilitating safe return to sport (RTS). This manuscript highlights current evidence and clinical insights to guide practitioners in optimizing rehabilitation protocols for athletes recovering from ATR, aiming to improve functional outcomes and support safe return to athletic activity.

Beyond pixel: Superpixel-based MRI segmentation through traditional machine learning and graph convolutional network.

BACKGROUND AND OBJECTIVE: Tendon segmentation is crucial for studying tendon-related pathologies like tendinopathy, tendinosis, etc. This step further enables detailed analysis of specific tendon regions using automated or semi-automated methods. This study specifically aims at the segmentation of Achilles tendon, the largest tendon in the human body. METHODS: This study proposes a comprehensive end-to-end tendon segmentation module composed of a preliminary superpixel-based coarse segmentation preceding the final segmentation task. The final segmentation results are obtained through two distinct approaches. In the first approach, the coarsely generated superpixels are subjected to classification using Random Forest (RF) and Support Vector Machine (SVM) classifiers to classify whether each superpixel belongs to a tendon class or not (resulting in tendon segmentation). In the second approach, the arrangements of superpixels are converted to graphs instead of being treated as conventional image grids. This classification process uses a graph-based convolutional network (GCN) to determine whether each superpixel corresponds to a tendon class or not. RESULTS: All experiments are conducted on a custom-made ankle MRI dataset. The dataset comprises 76 subjects and is divided into two sets: one for training (Dataset 1, trained and evaluated using leave-one-group-out cross-validation) and the other as unseen test data (Dataset 2). Using our first approach, the final test AUC (Area Under the ROC Curve) scores using RF and SVM classifiers on the test data (Dataset 2) are 0.992 and 0.987, respectively, with sensitivities of 0.904 and 0.966. On the other hand, using our second approach (GCN-based node classification), the AUC score for the test set is 0.933 with a sensitivity of 0.899. CONCLUSIONS: Our proposed pipeline demonstrates the efficacy of employing superpixel generation as a coarse segmentation technique for the final tendon segmentation. Whether utilizing RF, SVM-based superpixel classification, or GCN-based classification for tendon segmentation, our system consistently achieves commendable AUC scores, especially the non-graph-based approach. Given the limited dataset, our graph-based method did not perform as well as non-graph-based superpixel classifications; however, the results obtained provide valuable insights into how well the models can distinguish between tendons and non-tendons. This opens up opportunities for further exploration and improvement.

Application of real-time shear wave elastography to Achilles tendon hardness evaluation in older adults.

BACKGROUND: Real-time shear wave elastography (SWE) is a non-invasive imaging technique used to measure tissue stiffness by generating and tracking shear waves in real time. This advanced ultrasound-based method provides quantitative information regarding tissue elasticity, offering valuable insights into the mechanical properties of biological tissues. However, the application of real-time SWE in the musculoskeletal system and sports medicine has not been extensively studied. AIM: To explore the practical value of real-time SWE for assessing Achilles tendon hardness in older adults. METHODS: A total of 60 participants were enrolled in the present study, and differences in the elastic moduli of the bilateral Achilles tendons were compared among the following categories: (1) Age: 55-60, 60-65, and 65-70-years-old; (2) Sex: Male and female; (3) Laterality: Left and right sides; (4) Tendon state: Relaxed and tense state; and (5) Tendon segment: Proximal, middle, and distal. RESULTS: There were no significant differences in the elastic moduli of the bilateral Achilles tendons when comparing by age or sex (P > 0.05). There were, however, significant differences when comparing by tendon side, state, or segment (P < 0.05). CONCLUSION: Real-time SWE plays a significant role compared to other examination methods in the evaluation of Achilles tendon hardness in older adults.

Walking in a controlled ankle motion (CAM) boot: In-boot measurement of joint kinematics and kinetics.

Research investigating ankle function during walking in a controlled ankle motion (CAM) boot has either placed markers on the outside of the boot or made major alterations to the structure of the CAM boot to uncover key landmarks. The aim of this study was to quantify joint kinematics and kinetics using "in-boot" skin markers whilst making only minimal structural alterations. Seventeen healthy participants walked at their preferred walking speed in two conditions: (1) in standard athletic trainers (ASICS patriot 8, ASICS Oceania Pty Ltd, USA), and (2) using a hard-cased CAM boot (Rebound® Air Walker, Össur, Iceland) fitted on the right foot. Kinematic measurements revealed that CAM boots restrict sagittal plane ankle range of motion to less than 5°, and to ∼3° in the frontal plane, which is a reduction of 85% and 73% compared to standard footwear, respectively (p < 0.001). This ankle restriction resulted in a reduction of ankle joint total limb work contribution from 38 ± 5% in normal footwear to 13 ± 4% in the CAM boot (p < 0.001). This study suggests that CAM boots do restrict the ankle joint's ability to effectively perform work during walking, which leads to compensatory mechanisms at the ipsilateral and contralateral hip and knee joints. Our findings align with previous research that employed "on-boot" kinematic measurements, so we conclude that in-boot approaches do not offer any benefit to the researcher and instead, on-boot measurements are suitable.

ICON 2023: International Scientific Tendinopathy Symposium Consensus - the core outcome set for Achilles tendinopathy (COS-AT) using a systematic review and a Delphi study of professional participants and patients.

To develop a core outcome set for Achilles tendinopathy (COS-AT) for use in clinical trials we performed a five-step process including (1) a systematic review of available outcome measurement instruments, (2) an online survey on truth and feasibility of the available measurement instruments, (3) an assessment of the methodological quality of the selected outcome measurement instruments, (4) an online survey on the outcome measurement instruments as COS and (5) a consensus in-person meeting. Both surveys were completed by healthcare professionals and patients. The Outcome Measures in Rheumatology guidelines with a 70% threshold for consensus were followed. We identified 233 different outcome measurement instruments from 307 included studies; 177 were mapped within the International Scientific Tendinopathy Symposium Consensus core domains. 31 participants (12 patients) completed the first online survey (response rate 94%). 22/177 (12%) outcome measurement instruments were deemed truthful and feasible and their measurement properties were evaluated. 29 participants (12 patients) completed the second online survey (response rate 88%) and three outcome measurement instruments were endorsed: the Victorian Institute of Sports Assessment-Achilles questionnaire, the single-leg heel rise test and evaluating pain after activity using a Visual Analogue Scale (VAS, 0-10). 12 participants (1 patient) attended the final consensus meeting, and 1 additional outcome measurement instrument was endorsed: evaluating pain during activity/loading using a VAS (0-10). It is recommended that the identified COS-AT will be used in future clinical trials evaluating the effectiveness of an intervention. This will facilitate comparing outcomes of intervention strategies, data pooling and further progression of knowledge about AT. As COS-AT is implemented, further evidence on measurement properties of included measures and new outcome measurement instruments should lead to its review and refinement.

Validation of physical examinations of tendon xanthomas and changes in the cutoff values of Achilles tendon thickness on radiography in the clinical criteria of heterozygous familial hypercholesterolemia in Japan.

BACKGROUND: The 2022 Japan Atherosclerosis Society familial hypercholesterolemia (FH) clinical criteria were modified. In particular, the cutoff value of Achilles tendon thickness (ATT) on radiography was changed from ≥9 mm in both sexes to ≥8.0 mm in men and ≥7.5 mm in women. METHODS: A total of 872 patients with FH were retrospectively reviewed. Patients were categorized by an ATT of <7.5/8.0 mm (group 1), ≥7.5/8.0 and <9.0 mm (group 2, new group with FH by ATT), and ≥9 mm (group 3). RESULTS: In total, 492 patients fell into in group 1, 102 in group 2, and 263 in group 3, and 14.0%, 55.9%, and 79.8% of patients in groups 1, 2, and 3, respectively, were positive for a FH mutation. Further, among patients with an LDL cholesterol >180 mg/dL, 37.3%, 77.3%, and 86.5% of patients had a FH mutation in groups 1, 2, and 3, respectively. The proportion of patients with protein-truncating mutation (3.8%, 16.7%, and 53.2%, respectively) differed significantly across groups 1 through 3, respectively. Interestingly, only a very small proportion of the patients in groups 2 and 3 had palpable xanthomas (3.0% and 14.4% respectively). CONCLUSIONS: This study validates the new radiographic ATT criteria, since the vast majority of patients in the intermediate ATT category had true FH, as shown by positive genetic testing, whereas the old ATT criteria left them with just a deferred diagnosis of FH. In addition, use of physical examination alone for the presence of tendon xanthoma may lead to underdiagnosis of FH.

Estimation of the Achilles tendon twist in vivo by individual triceps surae muscle stimulation.

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.

Tendon structure, clinical tests, and pain during-loading in young female competitive gymnasts.

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.

[Transverse small incision intrathecal "loop" minimally invasive suture for treatment of acute Achilles tendon rupture].

Objective: To evaluate the effectiveness and feasibility of a transverse small incision intrathecal "loop" minimally invasive suture for acute Achilles tendon rupture. Methods: The clinical data of 30 patients with acute Achilles tendon rupture treated with transverse small incision intrathecal "loop" minimally invasive suture between January 2022 and October 2023 was retrospectively analyzed. The patients were all male, aged from 29 to 51 years, with an average of 39.8 years. The cause of injury was acute sports injury, and the time from injury to operation was 1-14 days, with an average of 3.4 days. The operation time, incision length, intraoperative blood loss, intraoperative complications, wound healing, and hospital stay were recorded. Postoperative appearance and function of ankle were evaluated by American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, Vancouver Scar Scale (VSS) score, and Arner-Lindholm score. Results: The operation time ranged from 30 to 90 minutes, with an average of 54.2 minutes; the incision length ranged from 1.3 to 3.5 cm, with an average of 2.2 cm; the intraoperative blood loss ranged from 5 to 70 mL, with an average of 22.3 mL; and the hospital stay ranged from 2 to 6 days, with an average of 3.7 days. All incisions healed by first intention, and there was no incision infection, poor healing, and deep venous thrombosis. All patients were followed up 5.3-22.0 months (mean, 14.7 months). During the follow-up, all the 30 patients had returned to exercise, and there was no complication such as Achilles tendon re-rupture, postoperative infection, and gastrocnemius muscle injury. At last follow-up, the AOFAS ankle-hindfoot score was 82-100, with an average of 95.1; the VSS score was 1-4, with an average of 2.1; according to the Arner-Lindholm score, 24 cases were rated as excellent and 6 cases as good. Conclusion: Transverse small incision intrathecal "loop" minimally invasive suture for the treatment of acute Achilles tendon rupture has the advantages of simple instrument, convenient operation, small trauma, quick recovery, and satisfactory effectiveness.

A new approach for classification of stretch-shortening cycle: Beyond 250 ms of ground contact time.

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.

[Treatment of chronic ruptures and defects of the Achilles tendon]. / Therapie chronischer Rupturen und Defekte der Achillessehne.

BACKGROUND: Achilles tendon ruptures that are older than 4-6 weeks or developed over a more extended period are chronic. Two challenges characterize the treatment. First, defect zones over a length of several centimeters must frequently be bridged. Second, a prolonged loss of function of the muscles leads to an irreversible fatty degeneration of the tissue. So that even if the tendon is restored, significant functional deficits remain. If there are doubts about the ability of the calf muscles to regenerate, regardless of the size of the defect, tendon transfers are recommended to use the power of an additional muscle to support the plantar flexion of the ankle. TREATMENT: Established concepts are the transposition of the flexor hallucis longus or the peroneus brevis muscle. If the muscle is intact, defects of up to 2 cm can be treated with a direct suture. Defects between 2 and 5 cm can be bridged using a VY-plasty or a turndown flap. For larger defects, free tendon transplants can be considered. The technical alternative for larger defects is a tendon transfer of the flexor hallucis longus or the peroneus brevis muscle. Besides bridging the defect, another advantage of tendon transfer is that vital muscle tissue is placed in the bed of the Achilles tendon. Both tendons are covered with muscle tissue over nearly the full length, which offers advantages, especially in patients with critical soft tissue or after infection. FOLLOW-UP TREATMENT AND PROGNOSIS: Follow-up treatment is analogous to an acute Achilles tendon rupture. However, permanent impairments are possible; 75-80% of athletes regain their original performance level.

Predictive Neuromarker Patterns for Calcification Metaplasia in Early Tendon Healing.

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.

Panda Rope Bridge Technique promoted Achilles tendon regeneration in a novel rat tendon defect model.

PURPOSE: This study aimed to determine whether the Achilles tendon tissue can undergo the pathological process of Achilles tendon regeneration after the Panda Rope Bridge Technique (PRBT). METHODS: Rats (n = 120) that operated with Achilles tendon rupture were divided into three treatment groups: Defect group (D group), PRBT group and Defect + Fix group (DF group). The D group represented natural healing with no treatment, the PRBT group represented healing receiving PRBT treatment and the DF group represented healing through conservative treatment by ankle fixation. The morphological, histological and biomechanical properties of the defective Achilles tendon were assessed at 7, 10, 12, 14, 28 and 56 days postoperatively. RESULTS: Compared to that observed in the other two groups, defected rat Achilles tendons that underwent PRBT recruited more cells earlier, eventually forming mature tendons, as revealed by histological analysis. PRBT also enabled defected tendons to regain stronger mechanical properties, thereby improving the prognosis. This improvement may be related to the earlier polarization of macrophages. CONCLUSION: By establishing and using a novel surgical model of Achilles tendon rupture in rats, most injured Achilles tendons can regenerate and regain normal histological properties, whereas tendons with other interventions formed fibrotic scar tissue. The strong regenerative capacity of tendon tissue enabled us to describe the pathological process of tendon regeneration after PRBT surgery in detail, which would aid in the treatment of tendon injuries. PRBT promotes Achilles tendon regeneration and has the potential to become a standard treatment. LEVEL OF EVIDENCE: Not applicable.

Open vs. Percutaneous Achilles Tendon Repair: Experience of Single Orthopedic Institute with Long-Term Follow-Up.

Background and Objectives: There are numerous techniques for the surgical treatment of Achilles tendon lesions described in the literature, and it is possible to distinguish repair techniques as either open surgery or percutaneous repair techniques. Both approaches have advantages and disadvantages. With this retrospective study, we aim to analyze the incidence of re-ruptures and other complications, return to sport and overall quality of life at a long-term follow-up in the treatment of acute ATRs, comparing the results of percutaneous repair with those of open repair. Materials and Methods: This is a retrospective study on a consecutive series of patients with complete tear of the AT who were managed through a surgical approach by the Operative Unit of Orthopaedics and Traumatology of Sant'Anna University Hospital (Ferrara, Emilia-Romagna, Italy) between April 2014 and December 2021. Patients were treated with a percutaneous or an open technique according to the surgeon's preference without randomization. Results: We considered 155 patients who met the established inclusion criteria. Of these, 103 (66.45%) patients underwent percutaneous treatment with the Tenolig® system, and 52 (33.55%) underwent open surgery, with an average ATRS in the first group of 92.5 compared to an average ATRS value of 82 in patients treated with the open technique. Conclusions: In our experience, following overlapping rehabilitation protocols in all patients included, we observed that the Tenolig® repair system led to a better ATRS at long-term follow-up, with comparable complication rates to open surgery.

Ultrasonographic Achilles Tendon Measurements and Static and Dynamic Balance in Prediabetes.

Background and Objectives: There is a lack of studies examining balance problems and Achilles tendon thickness in prediabetes despite their common occurrence in diabetes mellitus. The aim of this study was to evaluate Achilles tendon size and static and dynamic balance, as well as the role of the Achilles tendon in balance, in prediabetic patients. Materials and Methods: A total of 96 participants were divided into three groups: (1) the control group, consisting of participants without diabetes mellitus; (2) the prediabetes group; and (3) the diabetes mellitus group. Ultrasonographic measurements of Achilles tendon sizes (thickness, width and area) were performed. Dynamic balance was assessed using the Berg Balance Scale, and static balance (the Fall and Stability Indices) was assessed using a Tetrax device. The Self-Leeds Assessment of Neuropathic Symptoms and Signs was utilized to identify neuropathic pain. Results: In the prediabetes group, the median dynamic balance scores [54.0 (51.0-56.0)] were lower than those of the control group [55.0 (54.0-56.0)] but higher than those of the patients with diabetes mellitus [52.50 (49.0-54.25)]; however, this difference did not reach statistical significance. The ultrasonographic measurements of the Achilles tendon size were similar among the three groups. On the other hand, in the prediabetes group, a positive correlation was observed between the bilateral Achilles tendon anterior-posterior thickness and Fall Index score (p = 0.045), while a negative correlation was found between the left Achilles tendon anterior-posterior thickness and the Berg Balance Score (p = 0.045). Conclusions: In prediabetes, neither Achilles tendon size nor static or dynamic balance appears to be significantly affected. However, in prediabetic patients, increased Achilles tendon thickness appears to be associated with increased risk of falls and decreased balance.

Ultrasonographic measurements of gastro-soleus fascia thickness in midportion Achilles tendinopathy: A case-control study.

BACKGROUND: The Achilles tendon is one of the thickest, largest, and strongest tendons in the human body. Biomechanically, the AT represents the conjoint tendon of the triceps surae muscle, placed in series with the plantar fascia (PF) to ensure force transmission from the triceps surae toward the toes during walking, running, and jumping. Commonly encountered in the diagnostic evaluation of heel pain, Achilles tendinopathy (AT) refers to a combination of pathological changes affecting the tendon itself often resulting from excessive repetitive stress and overuse. Nevertheless, increasing evidence demonstrates that structural alterations due to overuse or abnormal patterns of skeletal muscle activity are not necessarily restricted to the muscles or tendons but can also affect the fascial tissue. At the same time, there has been recent discussion regarding the role of the fascial tissue as a potential contributor to the pathophysiological mechanisms of the development of several musculoskeletal disorders including tendinopathies. To the best of our knowledge, ultrasound (US) imaging studies on the fascial structures related to the triceps surae complex, as well as their possible correlation with Achillodynia have never been presented in the current literature. METHODS: In the present study, a comparative US imaging evaluation of textural features of the suro-Achilleo-plantar complex was performed in 14 healthy controls and 14 symptomatic subjects complaining of midportion AT. The thickness of the Achilles tendon, paratenon, intermuscular fascia, and PF has been assessed with US. In addition, both groups underwent the Victorian Institute of Sport Assessment-Achilles (VISA-A), a disease-specific questionnaire that measures the severity of symptoms of AT. Correlations between quantitative ultrasound measures and VISA-A scores were determined through Pearson or Spearman's rho correlations. RESULTS: Our ultrasonographic findings revealed statistically significant differences (p<0.05) in Achilles tendon and paratenon thicknesses between AT patients and controls. No significant differences were observed between groups in PF at the calcaneal insertion as all mean measures were within the expected range of a normal PF on US imaging. In contrast, in tendinopathic subjects, the deep intermuscular fascia between medial gastrocnemius (MG) and soleus (SOL) muscles is significantly (p<0.01) and considerably thickened compared to those of healthy subjects. Moderate correlations exist between tendon and paratenon thicknesses (r= 0.54, p= 0.04) and between MG-SOL fascia and tendon thicknesses (r= 0.58, p= 0.03). Regarding symptom severity and US morphological findings, the Spearman ρ test showed no correlation. CONCLUSIONS: Our data demonstrate that, in symptomatic subjects, US alterations are not restricted to paratenon and intratendinous areas, but also affect upstream structures along the myofascial chain, resulting in thickening of the fascia interposed between MG and SOL muscles. Moreover, positive correlations were found between MG-SOL fascia thickening and abnormalities in AT, paratenon, and symptom severity. Thus, US alterations in the fascial system should be interpreted within the clinical context of patients with AT as they may in turn represent important predictors of subsequent clinical outcomes and could help healthcare professionals and clinicians to refine non-operative treatment strategies and rehabilitation protocols for this disease.