Digital Flexor Tendon Research Articles

Thermomechanobiology as a new research field in soft tissues

During intense galloping, the difference in temperature between the external and the central part of an equine superficial digital flexor tendon can be as high as 7°C. Thirty minutes of jogging modifies the temperature in human knee cartilage from 32°C to 37°C. Intrinsic dissipative phenomena related to the viscoelastic behavior of soft tissues have been identified to be primarily responsible for the observed temperature increase, a situation referred to as self-heating in mechanics. While a 5°C increase may be considered negligible from a mechanical point of view in the cartilage at first sight, it can have a significant biological impact. It has been recently proposed that self-heating and the resulting increase of temperature in cartilage following mechanical stimulation can be necessary for its maintenance. This new concept complements the general acceptance that mechanobiology is central to the homeostasis of musculoskeletal tissues. In most biomechanical and biological studies on cartilage or other soft tissues, the temperature is set at 37°C and considered constant, despite human knee cartilage at rest being around 32°C, for example. Therefore, there is a deficit of information on the role and effect of physiological temperature variation induced through mechanical loading in soft tissues, opening a new research avenue that we coin thermomechanobiology.

Intrathecal enalapril reduces adhesion formation in experimentally induced digital flexor tendon sheath injuries in horses.

The objectives of the study were to describe a standing percutaneous adhesion induction model in the digital flexor tendon sheath (DFTS) of horses and to evaluate the effect of intrathecal administration of the angiotensin-converting enzyme (ACE) inhibitor enalapril on tendon healing and adhesion formation. Randomized, blinded, controlled experimental study. Eight healthy horses. A collagenase-induced adhesion model was implemented in the deep digital flexor tendon (DDFT) of both forelimbs under standing ultrasonographic guidance. Daily intrathecal injections of 5 mg enalapril (the treatment condition) were administered to a randomly assigned forelimb for 5 days, with the contralateral limb receiving an equivalent volume of 0.9% NaCl (the control). Lameness and limb circumference were recorded weekly. Horses were euthanized after 8 weeks and evaluated for gross digital flexor tendon sheath (DFTS) adhesions. Tendons were collected for histopathologic scoring of DDFT healing. Paired data were analyzed using a one-sided alternative sign test and longitudinal regression. Multiple DFTS adhesions were formed in control limbs of all horses. The median number of gross DFTS adhesions in treated limbs was less than in control limbs (p = .0039). The average reduction in limb circumference and lameness scores over time occurred faster in treated versus control limbs (p < .025). There were no differences in DDFT histopathologic scores between groups. The standing percutaneous DFTS adhesion induction model demonstrated that intrathecal enalapril reduced DFTS adhesion formation, lameness scores, and limb circumference over time. Intrathecal enalapril administration may reduce morbidity in horses with naturally occurring tendon injuries.

Two-Stage Flexor Tendon Reconstruction for Finger Contracture Secondary to Phlegmon: A Case Report

Flexor tendon reconstruction is a complex surgical procedure that requires great precision and specialized expertise. It remains a preferred treatment for patients with neglected lacerations of the digital flexor tendon and after the failure of flexor tendon repair. Improvements in tendon repair methods and follow-up techniques have enhanced outcomes after flexor tendon grafting. Case Presentation: A 14-year-old girl with a history of a phlegmon of the 4th finger of the right hand, treated with antibiotics and drainage. The evolution is marked after 2 years by the progressive development of a flexion contracture of the proximal interphalangeal (PIP) joint. On examination, there is a flexion attitude and an inability to extend the PIP joint without vascular or nervous disorders. A two-stage reconstruction was performed using the palmaris longus tendon as a graft. With a follow-up of 3 years, the girl has recovered complete flexion and has limited extension to 25° at the PIP joint. An arthrolysis was proposed, but the girl refused, and she is satisfied with the results.

Which is the best imaging modality to diagnose a manica flexoria tear?

SummaryThe manica flexoria (MF) is an extension of the medial and lateral borders of the superficial digital flexor tendon (SDFT) that forms a sleeve around the deep digital flexor tendon (DDFT), within the digital flexor tendon sheath (DFTS), just proximal to the metacarpo/metatarsophalangeal joint. Tears of the MF have been described associated with cases of nonseptic tenosynovitis presenting with lameness, with ponies and cobs being over‐represented. Ultrasonography and contrast tenography are the predominant imaging modalities used to diagnose tears of the MF, with tenoscopic evaluation still serving as the gold standard. However, the sensitivity and specificity of additional techniques such as contrast computed tomographic tenography and MRI are now being investigated as other modalities that could be of value to identify MF tears. Additional techniques have been described to combine with traditional ultrasonography, with the aim to improve the sensitivity of identifying MF tears, such as dynamic extension/flexion techniques and saline injections of the DFTS. The overall aim of this paper was to review current evidence to determine the best noninvasive diagnostic imaging modality, with a high sensitivity and specificity, to more accurately diagnose MF tears and aid more thorough surgical planning.

Accessory Ligament of the Deep Digital Flexor Tendon of the Horse Forelimb and Its Relationship with the Superficial Digital Flexor Tendon: A Plastination, Histological, and Morphometry Study.

The accessory ligament of the deep digital flexor tendon (AL-DDFT) plays a crucial role in the stay apparatus of the horse. This study aimed to investigate the anatomical relationship between the AL-DDFT, the superficial digital flexor tendon (SDFT), and other structures in the metacarpal region. Sixteen distal forelimbs from eight horses, aged 1 to 6 years, were evaluated through macroscopic, microscopic, and morphometric analyses, utilizing detailed dissection, E12 plastinated sections, and histological analysis. During lateral dissection, a connection was observed between the AL-DDFT and the SDFT. Histological evaluation revealed that this connection was a fibrous band (FB), extending the common synovial sheath (CSS) to the SDFT, along with associated collagen fibrils of the epiligament and peritenon. Additionally, two distinct forms of the AL-DDFT were identified, Type I and Type II, with Type II showing a greater cross-sectional area (CSA) than Type I. While numerous morphological and morphometric studies have explored the AL-DDFT and related structures, research incorporating plastination-based morphological and histological evaluations remains scarce. The findings provide valuable insights for both the morphological and clinical assessment of structures within the metacarpal region.

Effect of hydroalcoholic extract of Sambucus nigra on superficial digital flexor tendon repair in rabbit by ultrasonography and histopathology.

Adult tendon tissue has limited and slow regenerative capacity. Sambucus nigra plant possesses antioxidant and anti-inflammatory attributes. This study aimed to evaluate the effect of hydroalcoholic extract of this plant's fruit on superficial digital flexor tendon repair in rabbits (SDFT). Twenty-five male New Zealand white rabbits weighing 1.5-2kg were selected, quarantined and randomly divided into four groups of six. By performing a partial left posterior limb tenotomy, differentiating the SDFT and creating multiple scrapes were performed. During 3 consecutive days post-surgery, the positive control group was injected with 0.5mg/kg dexamethasone, whereas the treatment groups received extract doses of 200 and 400mg/kg, respectively. The negative control group did not receive any medication. Evaluation of sonographic and histopathological parameters was conducted on days 0, 7 and 28 post-surgeries. Findings were analysed and compared using SPSS22. Both treatment groups showed significant differences in echogenicity, and collagen fibre alignment compared to the control and positive control groups, in sonographic evaluation. Histopathological examination revealed fewer inflammatory cells and increased collagen fibre formation in the treatment groups compared to the other two groups. No significant difference in angiogenesis was observed among the groups on days 7 and 28 (p value <0.05). The results indicate that the S. nigra fruit extract, by stimulating collagen synthesis and reducing inflammation, effectively accelerates the healing process of injured tendons.

Intra‐arterial contrast enhanced computed tomography of the deep digital flexor tendon and palmar veins in the distal forelimb in Jeju horses: Evaluating contrast‐enhancing factors

AbstractBackgroundFew studies have investigated the adequate contrast enhancement (CE) evaluation depending on concentration, volume, and rate of administration of contrast media (CM) and the scan parameters in equine contrast enhanced computed tomography (CECT).ObjectivesTo investigate CE of the deep digital flexor tendon (DDFT) and veins depending on the computed tomography (CT) voltage and concentration, volume, and rate of CM administration during intra‐arterial CECT of equine distal forelimbs.Study DesignIn vivo experiments.MethodsSix horses underwent 54 CT scans. First, the CE of DDFT and veins was evaluated depending on the voltage (80 kV and 250 mA or 120 kV and 150 mA) and CM concentration (150, 120, or 90 mg I/mL in 50 mL of CM). Second, CE of DDFT and veins was evaluated depending on the CM volume (50, 100, or 150 mL) and administration rate (2, 4, or 6 mL/s) with a fixed iodine delivery rate (IDR; 300 or 180 mg I/s).ResultsContrast enhancement of DDFT was significantly higher at 80 kV of voltage and 150 mg I/mL of CM concentration (Median: 29.65; IQR: 1.74; p &lt; 0.05). CE of the DDFT positively correlated with CM concentration (p &lt; 0.001; r = 0.75). At 180 mg I/s IDR, contrast attenuation in the medial and lateral palmar veins significantly decreased at a CM of 30 mg I/mL, rate of 6 mL/s, and volume of 150 mL (median and IQR: 985.93 and 71.8 Hounsfield units [HU] and 988.73 and 41.16 HU, respectively); the CE was sufficient to distinguish between the vessels and the adjacent structures.Main LimitationsThe number of animals was small.ConclusionsOur results suggest that a low CM concentration could yield sufficient CE of the DDFT and arteries with adjusted CT scanning parameters or volume and injection rate of CM.

Effect of breed, obturator type and surgical experience on tenoscopic portal creation into the digital flexor tendon sheath in horses.

To determine the influence of breed (cob [CB] and non-cob [NC]), obturator type and surgical experience on the number of attempts, time taken and iatrogenic damage (ID) created when entering the digital flexor tendon sheath (DFTS) tenoscopically. Prospective experimental cadaveric study. A total of 104 cadaver limbs. An equal number of randomly selected CB and NC limbs were operated using a conical obturator (OB) or a switching stick (SS) by one boarded (BS) and one resident surgeon (RS). Skin measurements, number of attempts and time taken to enter the DFTS were recorded. The DFTS was endoscopically examined and then dissected to record ID and cumulative ID calculated. Mean CB skin thickness (8.4 mm) was nearly twice that of NC limbs (4.5 mm) (p < .001). Mean DFTS entry took longer in CB limbs (133 s) compared to NC limbs (112 s) (p = .02). BS mean entry time in CB limbs was 115 s compared to 46 s in NC limbs (p < .001). Cumulative ID was greater in CB limbs (25 of 52 limbs with ID) compared to NC limbs (14 of 52 limbs with ID) (p = .04). No difference was noted between obturators. Surgical experience reduced attempts and time entering the DFTS. Surgeons take longer to enter DFTS in CB limbs and more cumulative ID is created, regardless of obturator type used. Skin thickness is a major determinant of time taken to enter the DFTS and increases the risk of ID. Awareness of the challenges in CB limbs is important.

Injury to the palmar supporting structures of the fetlock alters limb stiffness and fetlock angle.

In vivo measurement of limb stiffness and conformation provides a non-invasive proxy assessment of superficial digital flexor tendon (SDFT) and suspensory ligament (SL) function. Here, we compared it in fore and hindlimbs and after injury. To compare the limb stiffness and conformation in forelimbs and hindlimbs, changes with age, and following injury to the SDFT and SL. Retrospective cohort study. Limb stiffness was calculated using floor scales and an electrogoniometer taped to the dorsal fetlock. The fetlock angle and weight were simultaneously recorded five times with the limb weight-bearing and when the opposite limb was picked up (increased load). Limb stiffness of both limbs was calculated from the gradient of the regression line of angle versus load. Fetlock angle when the weight was zero was extrapolated from the graph and used as a measure of conformation. Limb stiffness was measured in uninjured forelimbs (n = 42 limbs), hindlimbs (n = 19 limbs), forelimbs with SDFT injury (n = 18) and hindlimbs with SL injury (n = 5). Limb stiffness correlated with weight in forelimbs as shown previously (p < 0.001) but also in hindlimbs (p = 0.006). When normalised to the horse's weight (503 kg, IQR 471.5-560), forelimb stiffness was significantly higher (22.3 [±4.5] × 10-3 degree-1) than for the hindlimb (16.4 [±4.0] × 10-3 degree-1; p < 0.001). While there were no significant differences between forelimb and hindlimb conformation in unaffected or SDFT injury, both limb stiffness and conformation was significantly greater in limbs with SL injury (p = 0.009 and p = 0.002, respectively). Small sample size, lack of clinical data including lameness and quantification of injuries. Injury to the forelimb SDFT does not alter limb stiffness or conformation in the long-term, while hindlimb SL injury simultaneously increases limb stiffness and fetlock angle, suggesting an increase in SL length following injury.

Tenoscopic‐assisted subcutaneous approach to a plantar annular ligament desmotomy in a horse with severe constriction of the fetlock canal

SummaryThe desmotomy of the palmar/plantar annular ligament (PAL) is recommended when it hinders the sliding motion of the flexor tendons in the sesamoidean canal, leading to persistent lameness that often does not improve with conservative treatment. Tenoscopic‐assisted PAL desmotomy can be accomplished with various instruments via an intrathecal approach. However, severe constriction or adhesions within the fetlock canal can restrict manoeuvrability and access of instruments within the sheath, preventing safe and effective transection of the ligament. This case report describes the successful use of a hook knife via a subcutaneous approach to safely transect the PAL under tenoscopic visualisation in a horse where severe constriction of the fetlock canal prohibited the standard intrathecal approach. In similar chronic tenosynovitis cases, a subcutaneous approach to PAL transection at the start of the tenoscopic examination of the digital flexor tendon sheath may minimise iatrogenic injury to intrathecal structures.

Click phenomenon in acquired Jaensch-Brown syndrome and trigger finger/thumb: the Notta syndrome

The click phenomenon occurs when an acquired mechanical restriction of the elevation in adduction of the eye or of the extension of the finger/thumb, is forcefully overcome. The common cause is anodule either of the superior oblique tendon posterior to the trochlea in the case of aJaensch-Brown syndrome or of the digital flexor tendon anterior to the A1 annular pulley in the case of atrigger finger. Both locations share similar anatomical conditions for the development of the nodule and the pathomechanism of the click. From these identical findings in the eye and the hand in small children it can be assumed that the results from the studies of the hand in newborns and infants with atrigger thumb/finger are also applicable to the situation of the eye. 1.This motility disorder is not congenital. This is most likely due to an incomplete development at the time of birth of the sliding factors needed for afree passage of the tendon through the trochlea and the A1 annular pulley. 2.Adistinction must be made between stages 0-3: stage0 = no more restriction of the motility and no click phenomenon; stage1 = forced active extension/elevation possible; stage2 = only passive extension/elevation, each with aclick phenomenon; stage3 = no extension/elevation possible and no click phenomenon. 3.In most cases in early childhood there is aspontaneous complete recovery (75% after 6-7years). In the eye this spontaneous course can only limitedly be shortened with motility exercises in combination with segmental occlusion. The click phenomenon is asymptom of stages1 and2 of an acquired mechanical restriction of the elevation in adduction of the eye or the extension of the finger/thumb. It should not be called asyndrome.

Cone beam computed tomography and cross-sectional anatomy of the region of the fetlock in the horse (Equus caballus).

This study aimed to delineate the detailed anatomy of the metacarpophalangeal (MCP) and metatarsophalangeal (MTP) joints in healthy horses using cone beam computed tomography (CBCT). The fetlock region of 15 cadaveric forelimbs and 14 cadaveric hindlimbs from nine adult horses without orthopaedic disease underwent CBCT scanning. Additionally, arthrography CBCT scans were conducted following intra-articular injection of a radiopaque contrast medium containing blue epoxy resin dye. Subsequently, limbs were frozen and sectioned to visualize anatomical structures in sectional planes corresponding to selected CBCT images. CBCT proved suitable for detailed visualization of the bony components of the fetlock region. Furthermore, the common digital extensor tendon, superficial and deep digital flexor tendons, suspensory ligament, and straight and oblique sesamoidean ligaments were identifiable on CBCT images. However, certain ligaments, such as the collateral sesamoidean ligaments and intersesamoidean ligaments, were not clearly identified. The hyaline cartilage of the MCP and MTP joint facets was assessable on the post-contrast sequence. In cases where a radiographic or ultrasound examination cannot provide a definitive diagnosis and determine the extent of disease, CBCT can provide additional valuable data on the equine MCP and MTP joint. The images obtained in this study can serve as a reference for CBCT examination of the equine MCP and MTP joint.

Prognostic value of power doppler ultrasonography for equine superficial digital flexor tendon injury in thoroughbred racehorses

The potential value of hypervascularity detected with power Doppler ultrasonography (PDU) within equine superficial digital flexor tendon (SDFT) as a prognostic factor of SDFT injury is not clear. The purpose of this study was to test the hypothesis that hypervascularity within SDFT is one of the risk factors for subsequent severe SDFT injury and to evaluate the prognostic value. A prospective cohort study of 97 Thoroughbred racehorses without any clinical signs of SDFT injury was conducted. Six variables of age, body weight, sex, the cross-sectional area of SDFT, PDU signal within SDFT and experience of steeplechase were assessed for the possibility of risk factors of subsequent SDFT injury in follow-up period of 1 year. Multivariable logistic regression analyses were used for assessment of the odds ratios (ORs) and 95 % confidence intervals (CIs) of SDFT injury. Multivariable logistic regression analysis revealed that the PDU signal within SDFT was a risk factor for the development of SDFT injury in follow-up period (P = 0.017). The adjusted OR of SDFT injury was significantly higher in PDU positive group than in PDU negative group (OR 3.17, 95 % CIs 1.20–8.35). Although further studies are required, these results would be useful for early detection and/or prevention of development for clinical severe SDFT injury.

Health of Polo Horses.

This literature review analyzes the historical development of polo, its organizational structure, the course of the game, as well as the breeding, rearing, and training practices of polo horses. Frequently occurring ailments, such as musculoskeletal injuries, respiratory diseases, and internal illnesses, are highlighted. Lameness is a major problem, with injuries to the superficial digital flexor tendon being the most common cause. Other notable diseases include exercise-induced pulmonary hemorrhage (EIPH), myositis, rhabdomyolysis, and equine infectious anemia (EIA). To ensure the welfare of polo horses, effective prevention and management strategies are crucial. These include proper training, the adaptation of the ground surface, appropriate shoeing, and compliance with animal welfare guidelines and association rules. Collaboration between associations, players, organizers, and veterinarians is crucial. Promoting responsible management practices and raising awareness among stakeholders can help ensure that polo continues to thrive while maintaining high animal welfare standards.

Computed tomographic evaluation of the proximity of needles placed for perineural anesthesia of the palmar digital nerves to synovial structures in the foot: an ex vivo study.

Potential synovial penetration following palmar digital nerve blocks has not been investigated. To evaluate the proximity of needles placed for palmar digital nerve blocks to nearby synovial structures using computed tomography (CT). Descriptive observational study. In 18 cadaver forelimbs, sequential injection of the navicular bursa (NB), distal interphalangeal joint (DIPJ) and digital flexor tendon sheath (DFTS) was performed using 3, 5 and 10 mL diluted radiodense contrast medium, respectively. After each synovial injection, 25 gage needles were placed over the palmar digital nerves at the proximal aspect of the ungular cartilages (distal injections) and 1 cm further proximally (proximal injections), and CT examination was performed. Subsequently, needles were removed, and the synovial structures further distended with the same volume as for the first injection. Perineural needle placement and image acquisition were repeated. The distance between the needle tip and adjacent synovial structures was measured (mm) in reconstructed images. Results were analyzed in separate general linear mixed models, to determine the effect of needle position and synovial distension on the distance from the tip of the needle to the NB, DFTS and DIPJ. Synovial penetration was confirmed following 12/420 (3%) needle placements (NB n = 5, 1 after proximal and 4 after distal injections; DIPJ n = 2, DFTS n = 2, NB or DIPJ n = 3, all after distal injections). The mean distance from the needle tip to the NB and DIPJ was significantly smaller after the second distension (NB: p = 0.025; DIPJ: p < 0.001) and with the distal needle placements (NB: p < 0.001; DIPJ: p < 0.001). For the DFTS, the distance from the needle tip was significantly smaller with the proximal needle placements (p = 0.001). Ex-vivo study. There is a small risk of synovial penetration when performing palmar digital nerve blocks, especially when distension of adjacent synovial structures is present.

Outcome of tenoscopically guided palmar/plantar annular ligament desmotomy for the treatment of palmar/plantar annular ligament constriction without concurrent intrathecal soft-tissue injury in a UK horse population.

To determine the outcome of tenoscopically guided palmar/plantar annular ligament (PAL) desmotomy to treat PAL constriction without concurrent intrathecal soft-tissue injury, notably of the digital flexor tendons and manica flexoria. Retrospective multicenter cohort study. Sixty-five horses. Horses from four UK equine hospitals, with digital flexor tendon sheath (DFTS) tenosynovitis, which underwent tenoscopically guided PAL desmotomy for treatment of PAL constriction between 2017 and 2022 were included. All horses had lameness isolated to the DFTS/PAL, and PAL constriction was diagnosed tenoscopically when there was difficulty maneuvering the endoscope into or through the fetlock canal. Horses with tearing of the digital flexor tendons and/or manica flexoria, or any other intrathecal pathology, were excluded. Follow up was via structured telephone questionnaire. Follow up (median 25 months) was available for 61 horses with cobs and ponies predominating. Forty-two returned to their previous level of work, or a higher level, postoperatively and 50 owners were satisfied with the outcome of surgery. Eleven horses returned to lower level exercise, and six were retired/euthanized as they did not regain soundness. Fifty-two horses achieved soundness (median 3 months postoperatively). Tenoscopically guided PAL desmotomy for the treatment of PAL constriction in the absence of intrathecal soft tissue injury had a good prognosis for return to previous levels of exercise in a UK horse population. The prognosis for horses undergoing tenoscopically guided PAL desmotomy to treat PAL constriction in the absence of intrathecal injury is better than previously described. Cobs and ponies seem to be predisposed to PAL constrictionin agreement with the previous literature.

EFFECTS OF RIBOSE-INDUCED GLYCATION ON THE ELASTIC MODULUS OF COLLAGEN FIBRILS OBSERVED BY ATOMIC FORCE MICROSCOPY

The interplay between diabetes mellitus and the structural integrity of collagen has significant implications for tissue functionality and disease progression. The aim of this study was to empirically investigate the effects of ribose-induced glycation on the biomechanical properties of collagen fibrils, using atomic force microscopy for precise measurements. Methodology. We used collagen fibrils from the common digital extensor (CDE) and superficial digital flexor (SDF) tendons of an adult bovine model to mimic the glycation processes that occur in diabetic pathology. The samples underwent controlled glycation by incubation with ribose for 24 hours and 14 days compared to phosphate buffered saline treated controls. A Bioscope Catalyst atomic force microscope (Bruker, USA) was used for all atomic force microscopy imaging in this study. Scientific novelty. Our results show a marked increase in the elastic modulus of collagen fibrils after ribose treatment, indicating stiffening with glycation. Notably, SDF fibrils showed a greater increase in stiffness after 24 hours of ribose exposure compared to CDE fibrils, suggesting variations in glycation rates relative to fibril anatomy. Statistical analyses confirmed the significance of these findings and provided a model for understanding similar processes in human diabetes. Conclusions. The different response to glycation observed between CDE and SDF fibrils prompts further investigation into the role of anatomical and structural factors in glycation susceptibility. Identification of tissues at higher risk of glycation-induced damage could lead to the development of targeted prevention strategies for diabetic complications. In addition, the potential for pharmacological intervention to inhibit glycation processes or enhance advanced glycation end products (AGEs) degradation offers a promising avenue for mitigating the progression of diabetes-related complications. The results of this study highlight the potential of ribose-induced changes in collagen as a model for diabetes-related tissue changes and propose a mechanistic framework that could guide the development of interventions aimed at mitigating the effects of collagen-related diabetic complications.

Comparative imaging of septic navicular osteomyelitis caused by a solar penetration injury in a 15‐day‐old Shire foal

SummaryA 15‐day‐old female Shire foal presented for acute lameness after sustaining a solar penetration injury, due to a nail, to the right hind sole 4 days previously. The foal was moderately lame at walk; all vital parameters were within normal limits. Clinical examination of the foot found a 2 mm long slit‐like defect in the plantar third of the lateral body of the frog. Radiographs revealed an ill‐defined rounded radiolucency within the navicular spongiosa that was surrounded by a halo of increased radiopacity. Transcuneal ultrasound corroborated the findings and found the navicular bone lesion to be closely associated with a hypoechogenic region within the lateral lobe of the deep digital flexor tendon (DDFT) all of which was continuous with a hypoechogenic tract extending from the sole. Computed tomographic examination confirmed a tract extending from the solar surface into the lateral portion of the navicular bone and confirmed a suspected impacted bone fragment. A diagnosis of septic navicular osteomyelitis and bursitis was made. The tract, navicular bone and DDFT were surgically debrided and navicular bursa lavage performed. The foal initially recovered well but navicular bursal sepsis recurred 6 days post‐operatively and the foal was euthanised. This report provides comprehensive comparative imaging of septic navicular osteomyelitis and bursitis secondary to a solar penetration in a 15‐day‐old foal and highlights the importance of different imaging modalities in case assessment and management.

Mechanical properties, collagen and glycosaminoglycan content of equine superficial digital flexor tendons are not affected by training.

Physical activity can activate extracellular matrix (ECM) protein synthesis and influence the size and mechanical properties of tendon. In this study, we aimed to investigate whether different training histories of horses would influence the synthesis of collagen and other matrix proteins and alter the mechanical properties of tendon. Samples from superficial digital flexor tendon (SDFT) from horses that were either (a) currently race trained (n = 5), (b) previously race trained (n = 5) or (c) untrained (n = 4) were analysed for matrix protein abundance (mass spectrometry), collagen and glycosaminoglycan (GAG) content, ECM gene expression and mechanical properties. It was found that ECM synthesis by tendon fibroblasts invitro varied depending upon the previous training history. In contrast, fascicle morphology, collagen and GAG content, mechanical properties and ECM gene expression of the tendon did not reveal any significant differences between groups. In conclusion, although we could not identify any direct impact of the physical training history on the mechanical properties or major ECM components of the tendon, it is evident that horse tendon cells are responsive to loading invivo, and the training background may lead to a modification in the composition of newly synthesised matrix.

Ultrasonographic evaluation of morphometric measurements of plantar metatarsal tendons and ligaments in Colombian Creole horses

Objective. The objective of the present study was to determine the morphometric values ​​of the plantar metatarsal tendons and ligaments in clinically healthy animals. Materials and methods. Thirty animals were used throughout the study, the plantar metatarsal tendons and ligaments were evaluated starting from the plantaromedial aspect of the proximal region to the insertion of the suspensory branches in the sesamoids bones. The variables to be studied in each structure were cross-sectional area (cm2), lateral medial width (ALM) (cm) and dorsal palmar thickness (EDP) (cm). Results. It was found that the structure with the largest area in the proximal regions was the suspensory ligament (0.858 cm2) followed by the lateral digital flexor (0.759 cm2), in regions 1B and 2A the largest structure remained the suspensory ligament and in the region 2B, the deep digital flexor tendon was the largest structure (0.804 cm2). Conclusions. The behavior of the variables in the Colombian Creole Horse is similar to that reported in the literature and finally the reference values ​​of the morphometric measurements of plantar metatarsal tendons and ligaments in this breed are presented.