Tendon Structure Research Articles

Tendon-targeted knockout of collagen XI disrupts patellar and Achilles tendon structure and mechanical properties during murine postnatal development

ABSTRACT Background Collagen XI is a fibril-forming collagen typically associated with type II collagen tissues but is also expressed in type I collagen-rich tendons, especially during development. We previously showed that tendon-targeted (Scx-Cre) Col11a1 knockout mice have smaller tendons in adulthood with aberrant fibril structure and impaired mechanical properties. However, the manifestation of this phenotype is not clearly understood. Therefore, our objective is to define the spatiotemporal roles of collagen XI in tendon structure-function during postnatal development. Given the high expression of collagen XI during embryonic development, we hypothesized that collagen XI knockout leads to the deposition of weakened extracellular matrix during early postnatal timepoints, disrupting the establishment of tendon structure and function. Methods Patellar and Achilles tendons from postnatal (P) days 0, 10, 20, and 30 tendon-targeted scleraxis-Cre heterozygous and homozygous Col11a1 knockout mice were evaluated for morphology, nuclear organization, fibril morphology, mechanical properties, and gene expression. Results At P0, there were no differences in tendon length or fibril diameter of either tendon. By P10, striking structural and functional differences emerged, with collagen XI deficiency resulting in increased tendon length, a heterogeneous and larger diameter population of fibrils, and inferior mechanical properties in both patellar and Achilles tendons. Differences increased in magnitude through P30, supporting our hypothesis that impaired structure-function during postnatal development may drive tendon lengthening and reduced mechanical properties. Conclusions Though collagen XI is a quantitatively minor component of the tendon extracellular matrix, these results highlight the critical role of collagen XI in the acquisition of tendon structure-function.

Direct Anatomical Reconstruction of the Achilles Tendon and Its Application for Surgical Treatment of Acute Achilles Tendon Ruptures

Background/Objectives: Acute ruptures of the Achilles Tendon (AT) are common injuries in the active population, in particular among men aged 30 to 50. Full functional recovery after this kind of injury is long and challenging and nowadays there is no universal “gold standard” strategy when dealing with them. Methods: When it comes to surgical treatment, various techniques have been described: in case of a typical lesion at the midportion of the tendon (which is the most common type), the basic principle of surgical repair is the end-to-end suture of the tendon stumps. The AT (“calcaneal tendon” according to the International Anatomical Terminology) is the strongest tendon of the human body, it is the conjunct tendon of the two Gastrocnemii Muscles and the Soleus Muscle and has a well-recognizable twisted structure: the subtendon from the Medial Head of the Gastrocnemius attaches postero-laterally on the calcaneal tendon footprint, the subtendon from the Lateral Head of the Gastrocnemius attaches antero-laterally and the subtendon from the Soleus attaches medially, therefore creating a 90° twist of the tendon structure. Results: the twisted structure of the human AT is of central importance to its biomechanics, since it gives the tendon a higher resistance to deformation and concurs in supination of the subtalar joint during gait. Conclusions: given the abovementioned anatomical and biomechanical premises, we believe that the restoration of the subtendons anatomy can lead to a better functional recovery of the Triceps Surae—Achilles Tendon complex, therefore we recently decided to adopt for open surgical repair the Direct Anatomical Reconstruction of the Achilles Tendon, which we describe in the present article.

Optimizing Rehabilitation Outcomes Through Rehabilitative Ultrasonography: Applications in Musculoskeletal Care

Rehabilitative ultrasonography (RUS) has significantly enhanced musculoskeletal care by providing real-time, detailed visualizations of muscle, tendon, and soft tissue structures. This symposium explores the diverse applications of RUS, highlighting its advantages over traditional imaging methods. In muscle rehabilitation, RUS is pivotal for assessing muscle morphology, activation patterns, and providing biofeedback, thereby optimizing personalized rehabilitation programs. For tendon injuries, RUS facilitates precise evaluation of tendon integrity, enabling accurate diagnosis, monitoring, and guiding therapeutic interventions. Beyond muscles and tendons, RUS is invaluable in diagnosing and managing soft tissue pathologies, such as ligament and fascia injuries, allowing for targeted treatment strategies. By offering superior precision, safety, and cost-effectiveness, RUS sets a new benchmark in rehabilitation practices, leading to improved patient outcomes and a deeper understanding of musculoskeletal conditions. The integration of RUS into rehabilitation medicine represents a transformative advancement in patient care and treatment efficacy.

Loss of Cochlin drives impairments in tendon structure and function.

Aging tendons undergo disruptions in homeostasis, increased susceptibility to injury, and reduced capacity for healing. Exploring the mechanisms behind this disruption in homeostasis is essential for developing therapeutics aimed at maintaining tendon health through the lifespan. We have previously identified that the extracellular matrix protein, Cochlin , which is highly expressed in healthy flexor tendon, is consistently lost during both natural aging and upon depletion of Scleraxis-lineage cells in young animals, which recapitulates many aging-associated homeostatic disruptions. Therefore, we hypothesized that loss of Cochlin would disrupt tendon homeostasis, including alterations in collagen fibril organization, and impaired tendon mechanics. By 3-months of age, Cochlin -/- flexor tendons exhibited altered collagen structure, with these changes persisting through at least 9-months. In addition, Cochlin -/- tendons demonstrated significant declines in structural and material properties at 6-months, and structural properties at 9-months. While Cochlin -/- did not drastically change the overall tendon proteome, consistent decreases in proteins associated with RNA metabolism, extracellular matrix production and the cytoskeleton were observed in Cochlin -/- . Interestingly, homeostatic disruption via Cochlin -/- did not impair the tendon healing process. Taken together, these data define a critical role for Cochlin in maintaining tendon homeostasis and suggest retention or restoration of Cochlin as a potential therapeutic approach to retain tendon structure and function through the lifespan.

Increased risk of major adverse cardiovascular events in patients with deep and infected diabetes-related foot ulcers.

Diabetes-related foot ulceration (DFU) is associated with increased cardiovascular risk, but the mechanisms remain unclear. Inflammation and infection are mediators of CVD, which may be important in DFU. Prospectively collected data from patients attending a multidisciplinary DFU service were analysed. A deep ulcer was defined as one that reached muscle, tendon or deeper structures. Patients were categorised into four DFU groups: not deep and no infection (D-/I-), not deep but infected (D-/I+), deep with no infection (D+/I-) or deep with infection (D+/I+). Incident major adverse cardiovascular events (MACE) were defined as hospitalisation for myocardial infarction, stroke or transient ischaemic attack, or heart failure. Survival analyses were performed using the logrank test and multivariate Cox regression. Of 513 patients, 241 (47.0%) were in the D-/I- group, 110 (21.4%) were in the D-/I+ group, 35 (6.8%) were in the D+/I- group and 127 (24.8%) were in the D+/I+ group. MACE or all-cause mortality occurred in 75 patients (14.6%), and MACE alone occurred in 46 patients (9.0%) after median follow-up of 381 days (IQR 220-551) and 404 days (IQR 228-576), respectively. Infection was associated with significantly higher MACE or all-cause mortality (21.5% vs 8.7%; p<0.001) and MACE alone (13.5% vs 5.1%; p=0.003). MACE or all-cause mortality was significantly higher in the D+/I+ group (D-/I- 7.9%; D-/I+ 15.5%; D+/I- 14.3%; D+/I+ 26.8%; p<0.001), as was MACE alone (D-/I- 5.0%; D-/I+ 10.9%; D+/I- 5.7%; D+/I+ 15.7%; p=0.017). Infection and a deep ulcer were independent predictors of adverse outcomes. Deep and/or infected DFUs are associated with increased cardiovascular risk compared with DFUs that are not deep or infected. These findings provide a potential mechanistic explanation that requires investigation.

Tenascin-C-Matrix Metalloproteinase-3 Phenotype and the Risk of Tendinopathy in High-Performance Athletes: A Case-Control Study.

Background/Objectives: Tendon structure is predominantly composed of the extracellular matrix (ECM), and genetic variants in non-collagenous ECM components may influence susceptibility to tendinopathy. We investigated the potential influence of single nucleotide polymorphisms (SNPs) in fibrillin-2 (FBN2), tenascin-C (TNC), and matrix metalloproteinase-3 (MMP3) on the tendon regeneration failure phenotype and impact on the susceptibility to tendinopathy in Brazilian high-performance athletes. Methods: This case-control study was conducted with 397 high-performance athletes from different sports modalities (197 tendinopathy cases and 200 controls), and they were analyzed by validated TaqManTM SNP genotyping assays of the SNPs FBN2 (rs331079), TNC (rs2104772), and MMP3 (rs591058). Results: Out of the 197 tendinopathy cases, 63% suffered from chronic tendon pain and 22% experienced more than three episodes of disease manifestation. The TNC-rs2104772-A allele was significantly associated with tendinopathy (OR: 1.4; 95% CI: 1.1-1.8), while athletes carrying the MMP3-rs591058-T allele were linked to an increased risk of more episodes of disease manifestation (OR: 1.7; 95% CI: 1.1-2.8). The TNC-MMP3 tendon regeneration failure phenotype (TNC-A/MMP3-T) was associated with an increased risk of tendinopathy (OR: 1.4; 95% CI: 1.1-2.0) and episodes of disease manifestation (OR: 2.0; 95% CI: 1.2-3.5). Athletes with tendinopathy who had the TNC-A/MMP3-T interaction were more prone to experiencing more than three disease exacerbations (OR: 4.3; 95% CI: 1.8-10.5) compared to TNC-A/TNC-C. Conclusions: This study suggests that rs2104772 and rs591058 SNPs could be involved in the tendon regeneration failure phenotype and may influence the molecular mechanism related to the regulation of the tendon ECM during training workload.

Towards Achilles Tendon Injury Prevention in Athletes with Structural MRI Biomarkers: A Machine Learning Approach.

Recent advancements in artificial intelligence have proven their effectiveness in orthopaedic settings, especially in tasks like medical image analysis. This study compares human musculoskeletal radiologists to artificial intelligence in a novel, detailed, short, and cost-effective examination of Achilles tendon magnetic resonance images to uncover potential disparities in their reasoning approaches. Aiming to identify relationships between the structured assessment of the Achilles tendon and its function that could support injury prevention. We examined 72 athletes to investigate the link between Achilles tendon structure, as visualised in magnetic resonance images using a precise T2*-weighted gradient echo sequence with very short echo times, and its functional attributes. The acquired data were analysed using advanced artificial intelligence techniques and reviewed by radiologists. Additionally, we conducted statistical assessments to explore relationships with functional studies in four meaningful groups: dynamic strength, range of motion, muscle torque and stabilography. The results show notable linear or non-linear relationships between functional indicators and structural alterations (maximal obtained Spearman correlation coefficients ranged from 0.3 to 0.36 for radiological assessment and from 0.33 to 0.49 for artificial intelligence assessment, while maximal normalised mutual information ranged from 0.52 to 0.57 for radiological assessment and from 0.42 to 0.6 for artificial intelligence assessment). Moreover, when artificial intelligence-based magnetic resonance assessment was utilised as an input, the associations consistently proved more robust, or the count of significant relationships surpassed that derived from radiological assessment. Ultimately, utilising only structural parameters as inputs enabled us to explain up to 59% of the variance within specific functional groups. This analysis revealed that structural parameters influence four key functional aspects related to the Achilles tendon. Furthermore, we found that relying solely on subjective radiologist opinions limited our ability to reason effectively, in contrast to the structured artificial intelligence assessment. Cross-sectional studies.

The impact of diabetes mellitus on tendon pathology: a review.

Diabetes is one of the most common metabolic diseases worldwide, leading to complications, mortality, and significant healthcare expenditures, which impose a substantial social and financial burden globally. A diabetic environment can induce metabolic changes, negatively affecting tendon homeostasis, leading to alterations in biomechanical properties and histopathology. Numerous studies have investigated the mechanisms through which diabetes exerts pathological effects on tendons, including increased free radical production, oxidative stress, inflammatory responses, deposition of advanced glycation end products (AGEs), and microvascular changes. These metabolic changes damages tendon structure, biomechanics, and tendon repair processes. The proliferation of tendon stem cells decreases, apoptosis increases, and abnormal differentiation, along with abnormal expression of myofibroblasts, ultimately lead to insufficient tendon repair, fibrosis, and remodeling. Although researches unveiling the effects of diabetes on tendinopathy, fibrosis or contracture, and tendon injury healing are growing, systematic understanding is still lacking. Therefore, this review summarizes the current research status and provides a comprehensive overview, offering theoretical guidance for future in-depth exploration of the impact of diabetes on tendons and the development of treatments for diabetes-related tendon diseases.

Structural and Functional Properties of Lower Extremity Tendons in Men.

Comstock, BA, Flanagan, SD, Denegar, CR, Newton, RU, Häkkinen, K, Volek, JS, Maresh, CM, Kraemer, WJ. Structural and functional properties of lower extremity tendons in men. J Strength Cond Res XX(X): 000-000, 2024-The purpose of this study was to understand further patellar and Achilles tendon structure and function, body composition, and serum collagen turnover biomarkers in young men who performed heavy resistance training (RT, n = 13, age: 22.2 ± 1.4 years) compared with recreationally active men who were not resistance-trained (NR, n = 13, age: 22.8 ± 2.2 years). Tendon properties were measured at rest and during maximal voluntary isometric efforts using ultrasonography and dynamometry. Lean body mass (LBM) and bone mineral density (BMD) were assessed with dual X-ray absorptiometry. Serum collagen turnover markers were analyzed and related to tendon measures. Resistance-trained men had significantly (p ≤ 0.05) greater LBM and BMD compared with recreationally active men. Resistance-trained men also showed significantly greater patellar tendon (PT) stiffness (45%) and Young's modulus (36%), though the PT cross-sectional area (CSA) did not differ significantly between groups. Achilles tendon CSA was significantly larger in resistance-trained men. Still, other properties such as stiffness and modulus did not differ significantly between the groups. Serum collagen turnover markers showed no significant differences between groups and were not correlated to any tendon or bone biomarkers. The findings support that resistance-trained men have greater LBM and BMD. However now, it reveals that tendon adaptations differ, as not all measures were similarly affected in both tendons. The blood biomarkers did not show any obvious roles in explaining the differential changes in tendons. Heavy RT induces differential tendon changes potentially due to complex interactions of training variables.

Congruency of Ultrasound Measure Changes Against Patient-Reported Outcome Measures in Patellar Tendinopathy: A Systematic Review and Meta-Analysis.

Patellar tendinopathy is a highly prevalent clinical diagnosis supported by ultrasound changes. Numerous interventions are targeted at improving both symptoms and structure of dysfunctional tendons, however little is known of the diagnostic value in a changing ultrasound profile whilst patient-reported outcome measures (PROMs) determine recovery.The aim is to assess if changes in ultrasound measures are congruent with changes in Victorian Institute of Sports Assessment - Patella (VISA-P) scores, thereby supporting the use of ultrasound to assess patellar tendinopathy during symptom improvement. Four databases (PubMed, Web of Science, Embase, CINAHL) were searched in January 2019. Studies selected contained ultrasound and VISA-P scores from ≥ 2 type points. All included studies were quality assessed depending on the type and available data and underwent meta-analysis. A total of 10 papers of varying study types,limited to high quality, were synthesized. The meta-analysis indicated that changes in ultrasound measures were not congruent with changes in the VISA-P score. The variation in study quality, along with significant heterogeneity of ultrasound measure outcomes and reporting may influence the congruency of the data, but the association between gradual structure change and varying vascularity with pain or function is questionable throughout tendinopathy literature. The small study yield coupled with omission of data, along with alterations to form coherent analysis may impact outcomes, with an absence of homogeneity throughout studies. Ultrasound assessment is not useful in the follow-up of patellar tendinopathy after treatment and is of limited use as an indicator of normal function.

Long-term Prognosis of Patellar Tendinopathy (Jumper’s Knee) in Young, Elite Volleyball Players: Tendon Changes 11 Years After Baseline

Background: The long-term prognosis of jumper's knee and whether structural changes in the patellar tendon persist is unknown. Purpose: To investigate whether limitations in knee function and structural changes persisted beyond the athletic career of young elite volleyball players. Study Design: Cohort study; Level of evidence, 2. Methods: Volleyball players (mean ± SD age, 18 ± 0.8 years) enrolled in 2006-2011 in a prospective cohort study were invited in 2020-2022 to a follow-up study. Participants rated their knee function with the Victorian Institute of Sport Assessment–Patellar Tendon (VISA-P) score (baseline and follow-up) and the International Knee Documentation Committee (IKDC) score (follow-up) and reported if jumper's knee had influenced their decision to retire from sport. Tendon thickness and structural changes were assessed with ultrasound (baseline) and magnetic resonance imaging (MRI) (follow-up) of both patellar tendons. Results: We included 138 of 143 former athletes (97%) 11.4 ± 1.6 years after their baseline examination. At baseline, 37 persons (52 knees) had developed jumper's knee. At follow-up, participants reported lower knee function scores in knees diagnosed with jumper's knee at baseline than healthy knees (VISA-P scores: jumper's knee, 81 [95% CI, 70-92]; healthy, 90 [95% CI, 86-94]; P < .001; IKDC scores: jumper's knee, 82 [95% CI, 75-89]; healthy, 92 [95% CI, 91-95]; P < .001). Jumper's knee problems directly caused 7 of the 37 athletes (19%) with jumper's knee at baseline to retire from competitive volleyball. Of the 138 players included, 97 (70%) completed a bilateral MRI examination (194 knees). At follow-up, 38 of the 54 abnormal tendons (70%) had no structural changes (P < .001 vs baseline) while 22 of the 140 normal tendons (16%) had developed structural changes. Clinical symptoms were not correlated with tendon structure at follow-up (VISA-P scores for normal tendons: 85 [95% CI, 73-87]; abnormal: 89 [95% CI, 85-92]; P = .48). Conclusion: Jumper’s knee is not a self-limiting condition; volleyball players who had developed jumper's knee during adolescence reported persistent reductions in knee function 11 years later, leading one-fifth to retire from competitive volleyball. Although approximately 70% of tendons with structural changes at baseline were normal at follow-up, there was no clear relationship between structure and function.

Patellar Tendon Thermographic Reference Values in Healthy People: A Systematic Review

Introduction: The physiological response of the tendon structure has been the subject of several studies using clinical thermography, although the lack of normal values limits clinical practice despite being, according to several authors, an optimal diagnostic tool for the study and therapeutic monitoring of soft tissues. To this end, the aim of this systematic review was to explore all the scientific information on thermography and reference values in the patellar tendon. Method: A search was carried out in different health science databases using the MeSH terms “Health”, “Patellar Ligament”, and “Thermography” with their synonyms in free terms to collect the studies to be included in the systematic review. This review was conducted according with PRISMA guidelines and includes all of the literature up to 19 December 2023. All studies that were in accordance with the PICOS strategy in title and abstract were included in this review, while studies that performed the baseline thermographic test in an altered physiological state were excluded after reading the full text. The TISEM scale was used to assess the quality of the studies; the risk of bias was assessed with the QUADAS-2 scale. Result: A total of 6 articles was selected (n = 148); these were analyzed for quality and found to be highly heterogenous; the risk of bias was low in most domains of the QUADAS-2 scale. Discussion and Conclusion: There are several variabilities that can induce changes in the thermoregulation process distorting the thermograms. Looking deeper into the evidence behind each item, we can deduce the need to follow the TISEM protocol as closely as possible for an accurate response. The heterogeneity in the way the results were provided and the low quality in some of the studies did not allow for a reference of thermographic values to be obtained.

Comparison of short term recovery in patients with midportion Achilles tendinopathy with varying degrees of kinesiophobia treated with the Silbernagel protocol: A prospective single cohort analysis

ObjectiveTo assess short term recovery between individuals with Achilles tendinopathy with varying degrees of kinesiophobia when treated with the Silbernagel protocol. Secondarily to investigate short term change in degree of kinesiophobia. DesignProspective single cohort analysis. SettingUniversity/Clinical. Participants116 participants with midportion Achilles tendinopathy were grouped from their baseline Tampa Scale of Kinesiophobia (TSK) score: Low (≤33), Medium (34–41), and High (≥42). Main outcome measuresSymptom severity, Achilles tendon structure, and function were assessed at baseline and 8-weeks following initiation of the Silbernagel protocol. Differences in recovery between TSK groups were analyzed. ResultsNo group by time interactions were observed for symptoms, structure, or function. A significant interaction of group by time was observed for TSK score. The Medium (n = 66) and High (n = 28) TSK groups significantly decreased TSK score after 8 weeks by 2.4 and 4.4 points respectively while the Low TSK group (n = 22) did not change. ConclusionThere were no differences in short term recovery of symptoms, Achilles tendon structure, and function in individuals with midportion Achilles tendinopathy treated with the Silbernagel protocol regardless of baseline degree of kinesiophobia. Those with moderate and high levels of kinesiophobia at baseline decreased TSK score in the short term.

THE INFLUENCE OF THE CULTURE OF FIBROBLASTIC CELL ELEMENTS ON THE INDICATORS OF THE METABOLISM OF CONNECTIVE TISSUE IN EXPERIMENTAL ANIMALS

The number of patients with degenerative tendon disease affects millions of people both among athletes and the general population, causing significant socio-economic consequences. Despite the availability of various methods of conservative and surgical treatment, more than a third of patients experience constant pain. Objective. To study the indicators of the metabolism of connective tissue in animals with a model of degenerative damage to tendons against the background of the introduction of a culture of fibroblastic cell elements. Methods. Therefore, the development of methods for restoring the structure of tendons using cell cultures, in particular fibroblasts, will allow to optimize the course of reparative processes, reduce the risk of complications during surgical intervention and accelerate healing, and at the molecular level — to improve the structure of collagen fibers. Laboratory studies of biochemical markers of a tendon with a degenerative-dystrophic lesion and against the background of the introduction of cell culture can help in the differential diagnosis of its extracellular matrix. Results. The experimental data obtained by us indicate the presence of differences in the biochemical markers of tendons with degenerative-dystrophic lesions in rats 7, 21, and 45 days after the introduction of culture of fibroblastic cell elements. However, 45 days after the introduction of the culture of fibroblast cell elements, the normalization of metabolic processes in the extracellular matrix of connective tissue occurs, namely, the activity of collagenase and the concentration of protein-bound hydroxyproline approaches normal values. This indicates the predominance of the synthetic phase over the catabolic one in collagen metabolism. Conclusions. In this context, the introduction of culture of fibroblastic cell elements, as an alternative anti-inflammatory method, may provide another potential opportunity in the treatment of chronic degenerative-dystrophic lesions of the Achilles tendon.

Clinical Outcomes and Tendon Structure at 3- to 4-Year Follow-up After Exercise-Based Treatment of Patellar Tendinopathy: A Prospective Study.

The long-term recovery (in years) of patellar tendinopathy treated with loading-based rehabilitation remains largely unknown. To examine the clinical outcome and tendon structure years after exercise-based treatment of chronic patellar tendinopathy. Case series; Level of evidence, 4. This was a 3- to 4-year follow-up evaluation of participants (N = 28) from a previous randomized clinical trial by the author group. All participants received loading-based rehabilitation for 12 weeks with either moderate-slow resistance (55% of 1 repetition maximum) or heavy-slow resistance (up to 90% of 1 repetition maximum). Both groups showed similar improvements after 3 and 12 months and were therefore collapsed in the present analysis. Function and symptoms (the Victorian Institute of Sport Assessment-Patella [VISA-P] questionnaire), tendon pain (numeric rating scale [NRS] during activity and during a single-leg decline squat test), and tendon structure (tendon vascularization and thickness on ultrasound) were assessed. The mean follow-up was 3.6 ± 0.4 years after the baseline assessment in the original clinical trial. The VISA-P score was 83.9 ± 11.9 (95% CI, 79.3-88.5) at the latest follow-up and did not differ from the 1-year follow-up score (P = .54). Similarly, NRS score during preferred sport (1.6 ± 1.7; 95% CI, 0.9-2.2) and single-leg decline squat (1.0 ± 1.8; 95% CI, 0.3-1.7) did not differ from the 1-year values and remained elevated. Power Doppler area and tendon thickness decreased significantly from 1 year to latest follow-up (P < .0001 and P = .02, respectively), but power Doppler area >1 mm2 was still present in 43% of the participants after 3 to 4 years, and the tendon thickness was still mildly elevated (6.4 ± 1.8 mm; 95% CI, 5.7-7.1 mm). Sports participation after 3 to 4 years (3.9 ± 2.7 h/wk; 95% CI, 2.9-7.1 h/wk) was significantly lower compared with preinjury levels (P < .0001). Clinical symptoms remained even years after loading-based treatment for patellar tendinopathy, whereas some but not all tendon structures normalized in this longer term follow-up.

Is Achilles tendon structure associated with functional ability and chronic ankle instability in military recruits?

ObjectiveTo determine the relationship between Achilles tendon (AT) structure, functional ability and chronic ankle instability (CAI) in military recruits. MethodsThree hundred and sixty newly recruited infantry male soldiers recruited in April 2022 were assessed for AT structure by Ultrasound Tissue Characterization (UTC), for functional abilities (included proprioception ability, heel-raise test, dynamic postural balance, and hopping agility ability) and for CAI (recurrent sprains and a positive perceived instability). ResultsSoldiers that were identified with disorganized tendon had significantly lower heel-raise and agility scores compared to those with organized tendon structures (33.6 ± 18.1(n) vs. 49.9 ± 28.9(n), p < 0.001; and 5.39 ± 2.12(n) vs. 6.16 ± 1.90(n), p = 0.002, respectively). The best discriminator between soldiers with organized vs. disorganized structure, was heel-raise test (AUC = 0.741). Moreover, soldiers with disorganized AT structure had a higher prevalence of CAI compared with those with organized tendon structures (p < 0.05). ConclusionRecruits with disorganized tendon structures displayed reduced heel-raise score, agility ability and dynamic postural-balance and greater ankle instability. Inferior tendon quality at the onset of military service is an important physical indicator to consider when seeking to manage future injuries and potential for physical performance. Pre-recruitment screening of the AT structure, CAI, and functional abilities, especially in high-intensity infantry programs, needs to be considered.

Ankle sprains in male Israeli infantry soldiers during training: prevalence and risk factors

BackgroundGiven the high incidence and heavy burden of ankle sprains in recruits, large-scale, multifactorial investigations into potential risk factors are warranted. This study aimed to identify the incidence of ankle...

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

ABSTRACT 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.

Achilles tendon regeneration after experimental transverse tenotomy with preserved peritenon and the structures

Introduction The Ponseti method is the first choice for congenital clubfoot with the possibilities of transverse tenotomy being underexplored in repair of the Achilles tendon in pediatric patients.The objective was to identify specific features of the Achilles tendon repair after experimental transverse intersection and preserved peritenon, vessels and nerves of growing rabbits.Material and methods The experimental study included 20 Chinchilla rabbits of both sexes aged 1.0–1.5 months used as a biomodel with a weight of 1476.0 ± 114.3 g. Rabbits were sacrificed in groups of five by air embolism under local anesthesia at 15, 30, 60 and 90 days of surgery.Results The tendon defect zone was represented by small areas of dense fibrous scar tissue with some cellular fibroblasts, and tendon fibers of unremarkable architectonics arranged in a mutually parallel waves could be seen in the layers of connective tissue at 90 days. The thickness of the first-order collagen fibers increased to 8.9 ± 1.32 µm and comparison with the normal value of 9.2 ± 1.88 µm showed no statistically significant difference (p = 0.38). The thickness of the second-order collagen fibers increased to 28.1 ± 1.28 µm during the time, and comparison with the standard measurements of 28.3 ± 2.23 µm demonstrated no statistically significant difference (p = 0.64).Discussion According to the literature, the ability of the tenoblast to synthesize structural proteins and regulatory biomolecules after injury decreases with age and leads to fibrous restoration of the tendon and formation of a permanent scar. Our study on growing rabbits showed that the organotypic structure of the experimental tendon restored at the intersection site at 60 days with the Achilles tendon defect being represented by the tendon-like tissue at 90 days.Conclusion The Achilles tendon was shown to regenerate in optimal conditions after the dissection and preservation of the peritenon, vessels and nerves with tendon tissue being formed within a short time (3 months after the intervention) being identical to the original.

Fascia Lata Allograft Medial Patellofemoral Ligament Reconstruction—Restore the Nature as Close as Possible

Various surgical techniques for medial patellofemoral ligament (MPFL) reconstruction have been described, commonly using hamstring auto- or allografts. Despite their widespread use, these techniques have limitations due to the tubular structure of the hamstring tendons, which does not match the flat, sail-like anatomy of the MPFL. Furthermore, over- or undertensioning of the graft due to tunnel misplacement remains a significant risk, even if anatomic and radiologic landmarks are used. To address these issues, a fascia lata allograft MPFL reconstruction with assessment of angular anisometry is presented. This technique allows for reconstruction of the MPFL as close as possible to its nature with a flat and wide patellar attachment and a gradual transition of maximal tension across the graft fibers, depending on the knee flexion angle. Precise intraoperative control of predefined graft angular anisometry allows for achievement of the desired amount of tension at specific flexion angles. This mitigates the risk of under- or overtensioning and subsequently ensures proper medial-lateral mobility of the patella.