Deep Digital Flexor Tendon Research Articles

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.

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.

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.

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.

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.

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.

Equine bone marrow MSC-derived extracellular vesicles mitigate the inflammatory effects of interleukin-1β on navicular tissues in vitro.

Safe, efficacious therapy for treating degenerate deep digital flexor tendon (DDFT) and navicular bone fibrocartilage (NBF) in navicular horses is critically necessary. While archetypal orthobiologic therapies for navicular disease are used empirically, their safety and efficacy are unknown. Mesenchymal stem cell-derived extracellular vesicles (EV) may overcome several limitations of current orthobiologic therapies. To (1) characterise cytokine and growth factor profiles of equine bone marrow mesenchymal stem cell (BM-MSC)-derived extracellular vesicles (BM-EV) and (2) evaluate the in vitro anti-inflammatory and extracellular matrix (ECM) protective potentials of BM-EV on DDFT and NBF explant co-cultures in an IL-1β inflammatory environment. In vitro experimental study. Cytokines (IL-1β, IL-6, IL-10, IL-1ra and TNF-α) and growth factors (TGFβ1, VEGF, IGF1 and PDGF) in equine BM-EV isolated via ultracentrifugation and precipitation methods were profiled. Forelimb DDFT and NBF explant co-cultures from seven horses were exposed to media alone, or media containing 2 × 109 ± 0.1 × 109 particles/mL or 10 μg/mL BM-EV (BM-EV), 10 ng/mL interleukin-1β (IL-1β), or IL-1β + BM-EV for 48 h. Co-culture media IL-6, TNF-α, MMP-3, MMP-13 concentrations and explant sulphated glycosaminoglycan (sGAG) content were quantified. IL-6, IGF1 and VEGF concentrations were 102.1 (37.61-256.2) and 182.3 (163.1-226.3), 72.3 (8-175.6) and 2.4 (0.1-2.6), 108.3 (38.3-709.1) and 211.4 (189.1-318.2) pg/mL per 2 × 109 ± 0.1 × 109 particles/mL or 10 μg/mL 10 μg of BM-EV isolated via ultracentrifugation and precipitation methods, respectively. Co-culture media MMP-3 in BM-EV- (p = 0.03) and BM-EV + IL-1β-treated (p = 0.01) groups were significantly lower than the respective media and IL-1β groups. DDFT explant sGAG content of BM-EV (p = 0.003) and BM-EV + IL-1β groups were significantly higher compared with IL-1β group. Specimen numbers are limited, in vitro model may not replicate clinical case conditions, lack of non-MSC-derived EV control group. Equine BM-EV contains IL-6 and growth factors, IGF1 and VEGF. The anti-inflammatory and ECM protective potentials of BM-EV were evident as increased IL-6 and decreased MMP-3 concentrations in the DDFT-NBF explant co-culture media. These results support further evaluation of BM-EV as an acellular and 'off-the-shelf' intra-bursal/intrasynovial therapy for navicular pathologies.

Surgical excision of P3 fragments in 86 declawed cats: case series (2013-2023).

This case series describes the clinical findings and surgical intervention of 86 declawed cats; 52 from a shelter or rescue and 34 owned cats. Historical reports from owners and shelter staff included house-soiling, biting behavior, repelling behavior, barbering, lameness, chronic digit infection and nail regrowth. All the cats had fragments of the third phalanx (P3) of varying sizes diagnosed on radiographs. Pathology visible on examination included digital subcutaneous swelling, ecchymosis, malaligned digital pads, ulcerations, exudate, tendon contracture, nail regrowth and callusing. Surgery was pursued in these cases to remove the P3 fragments, relieve tendon contracture and reposition the digital pads with an anchoring suture. Gross findings intraoperatively included fragmented growth of cornified and non-cornified nail tissue, osteophytes on the surface of the second phalanx, deep digital flexor tendon calcification, and both bacterial and sterile exudate. The most common complication 14 days postoperatively was mild (14%) to moderate (1%) lameness. All historical parameters recorded improved in both populations of cats (house-soiling, biting behavior, repelling behavior, barbering, lameness, tendon contracture and chronic digit infection). Postoperatively, 1/47 cats exhibited continued malalignment of two digital pads and there were no reports of long-term postoperative lameness. Two methods of declawing cats are detailed in the veterinary literature, including partial amputation of P3 and disarticulation of the entire P3 bone. The novel information in this report includes historical and clinical signs of declawed cats with P3 fragments, intraoperative gross pathology, surgical intervention and the postoperative follow-up results.

Fratura in uterus de metacarpo em neonato bovino

Long bone fractures are common in juvenile cattle, however, cases of fractures occurring in the intrauterine environment during pregnancy are rare. The objective of this report is to present a case of an open consolidated fracture of the metacarpal that occurred in uterus, in a newborn calf, in which the surgical approach used was successful. A 48-hour-old female bovine was treated at the Veterinary Hospital of Paranaense University, who presented a complete, open and poorly consolidated transverse diaphyseal fracture in uterus during the gestational period on clinical and radiographic examination. As a therapeutic approach, open reduction was chosen, with ostectomy followed by stabilization with type IA external skeletal fixator. Four 4mm transcortical pins were positioned proximally and distally to the newly formed fracture line, followed by two more pins in the proximal phalanges region, seeking to stabilize the metacarpophalangeal joint, since flexural deformity of that joint was observed after the realignment of the longitudinal axis of the metacarpal, even after the section of the superficial and deep digital flexor tendons and suspensory ligament. The ESF was removed after 32 days, when radiographic signs of neoproliferation and bone consolidation were observed. In a last evaluation 15 months after the surgical correction, a complete and satisfactory recovery was observed regarding the development and well-being of the animal.

Ex vivo study shows novel, rapid, suture-free tenotomy technique for the equine deep digital flexor tendon.

To describe the feasibility of a novel thread-transecting technique for the tenotomy of the equine deep digital flexor tendon (DDFT). 39 equine distal limb specimens. Under ultrasonographic guidance, a surgical thread was percutaneously placed around the DDFT through 2 needle punctures (lateral and medial) using a Tuohy needle in equine limbs (22 forelimbs, 17 hindlimbs). The DDFT was transected by a back-and-forth motion of the thread until the loop emerged from the entry puncture site. Each specimen was dissected and assessed for completeness of transection and iatrogenic damage under direct visualization. Descriptive statistics were reported. Complete DDFT transection was achieved in all 39 limbs, taking an average of 8.6 minutes per procedure. Iatrogenic damage to surrounding structures occurred in 17 (44%) limbs, with 6 (15%) limbs having more than 1 structure damaged. Damage to the communicating branch of the palmar or plantar nerves was the most commonly seen. DDFT tenotomy in equine limb specimens was effectively performed using a novel thread-transecting technique. The procedure is quick, and no suturing is needed, but damage to surrounding structures is possible. Further assessment of the procedure and clinical significance of its potential iatrogenic damage in clinical cases is needed.

Presence and size of synovial masses within the navicular bursa correlate well between magnetic resonance imaging and bursoscopy and have a guarded prognosis.

Focal hyperintense lesions within the navicular bursa emanating from the dorsal border of the deep digital flexor tendon (DDFT) can be recognised on T1-weighted magnetic resonance images (MRI) and have been attributed to lameness in horses. Removal of these lesions, also referred to as synovial masses, by navicular bursoscopy is currently recommended. To investigate the correlation between MRI and navicular bursoscopic findings. It is hypothesised that the prognosis following surgery is proportional to the size of the DDFT lesion. Retrospective analysis of clinical records. Horses undergoing standing low-field MRI and navicular bursoscopy with >1 year follow-up were included. A grading system was developed to classify the size of synovial mass(es) and lesion(s) of the DDFT on MRI and at surgery. Generalised estimating equations were used to evaluate the association between MRI findings and surgery and between outcome and severity of the tendon injury. Fifty-nine horses presenting over a 15-year period (2006-2021) fulfilled inclusion criteria. Ninety navicular bursae were examined both on MRI and endoscopically. There was strong correlation between the size of synovial masses and tendon lesions on MRI and bursoscopy (p < 0.001, OR: 25.61, 95% CI 8.71-75.29 and p < 0.001, OR: 7.34, 95% CI 2.70-19.92, respectively). Size of tendon lesion and synovial mass had no impact on prognosis (p = 0.3, OR: 1, 95% CI 1-1 and p = 0.1, OR: 1, 95% CI 1-1, respectively), which was guarded (30.5% return to previous level of exercise). Performance data for conservatively treated horses with MRI-detected synovial masses was not considered, nor was the effect of navicular bursal effusion. Horses were not randomly assigned to treatment protocols. There is good correlation between MRI and bursoscopic findings of DDFT lesions and synovial masses within the navicular bursa, with no false positives. Size of the synovial masses and DDFT lesions does not influence prognosis following navicular bursoscopy.

Computed tomographic contrast tenography aids pre‐operative diagnosis in clinical conditions of the digital flexor tendon sheath

SummaryCommon pathology within the digital flexor tendon sheath (DFTS) includes tearing of the manica flexoria, marginal longitudinal lesions of the deep digital flexor tendon and fetlock canal constriction. These are a frequent cause of lameness in cob‐type breeds where skin thickness can make obtaining diagnostic ultrasound images difficult. Radiographic contrast tenography in the standing patient can be used to identify pathology but provides limited information on the exact lesion configuration. This report describes the use of computed tomographic contrast tenography under general anaesthesia to identify and detail the configuration of intrathecal DFTS pathology in four clinical cases (six limbs) subsequently assessed with DFTS tenoscopy. Computed tomography findings altered surgical planning in two cases, and in all cases computed tomography findings were confirmed by tenoscopy. Computed tomographic contrast tenography correctly predicted all lesions observed during tenoscopy: manica flexoria pathology including laterality (4/4 torn and 2/2 intact), fetlock canal constriction (3/3 limbs), deep digital flexor tendon injury (1/1) and intrathecal adhesions (5/5 limbs). Computed tomographic contrast tenography was a useful pre‐operative imaging modality which aided surgical planning. The technique may be applicable for use in standing computed tomography systems where it would provide the diagnostic benefits listed without the associated risk of prolonging anaesthesia.

Does Direct MRI Tenography Improve the Diagnostic Performance of Low-Field MRI to Identify Artificially Created Soft-Tissue Lesions within the Equine Cadaveric Digital Flexor Tendon Sheath?

Tenosynovitis of the digital flexor tendon sheath (DFTS) is diagnosed using ultrasonography and contrast tenography. Nevertheless, making a precise preoperative diagnosis is challenging. This study aimed to determine and compare the sensitivity and specificity of low-field MRI and MRI tenography (MRIt) to detect artificially created soft-tissue lesions in the DFTS. In 21 DFTSs, 118 lesions were made tenoscopically in the superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), manica flexoria (MF) and proximal scutum. MRI and MRI, following intrathecal gadolinium administration (MRIt), were performed. The sensitivity and specificity of MRI and MRIt were calculated and compared. Proximal scutum lesions were less frequently identified by MRI (Sensitivity 38%, specificity 96%) compared to MRIt (Sensitivity: 50%, p = 0.80; specificity: 96%, p = 1). This was similar for SDFT lesions (Sensitivity: 39% versus 54%, p = 0.72; specificity: 93% versus 96%, p = 1). MRI detected DDFT lesions (sensitivity 34%; specificity 100%) better than MRIt (sensitivity 32%, p = 0.77; specificity 98%, p = 1). This was similar for MF lesions (MRI sensitivity 61%; specificity 100% vs. MRIt sensitivity 50%, p = 0.68; specificity 96%, p = 1). Lesion size was significantly associated with MRI or MRIt diagnosis (p = 0.001). The intrathecal administration of gadolinium did not significantly improve the ability of low-field MRI to diagnose artificial DFTS tendon lesions. Small lesion length was a significant discriminating factor for lesion detection. MRI and MRIt specificity were high, thus being helpful in diagnosing an intact structure.

Minimally invasive ultrasound-assisted cutting thread tenotomy of the deep digital flexor tendon in horses: An ex vivo study.

To evaluate the feasibility and limitations associated with a minimally invasive ultrasound-assisted cutting thread technique for tenotomy of the deep digital flexor tendon (DDFT) in horses. Ex vivo study. Twenty cadaveric forelimbs. Forelimbs were placed on a jig to mimic a standing semiflexed position and the midmetacarpal region was prepared to perform tenotomy of the DDFT using a percutaneous technique with a cutting thread. For that purpose, the thread was placed percutaneously around the DDFT (first dorsally and then palmarly) with the aid of a curved 20 gauge spinal needle. Tendon palpation/manipulation and ultrasonographic assessment assisted thread placement. Procedure time and skin puncture size were recorded. Limbs were then dissected to evaluate the degree of DDFT transection and the presence of any iatrogenic lesions. The DDFT was completely transected in all cases. Minor lesions of the superficial digital flexor tendon were found in 11/20 limbs and considered clinically irrelevant. However, the neurovascular bundle was damaged in 6/20 limbs (four limbs had nerve damage and two limbs had a nerve and either a palmar artery or vein damaged). The skin puncture hole sizes ranged from undetectable to 5 mm long. The average duration of the procedure was 7 min and 38 s (range: 4 min 56 s to 10 min 19 s). A DDFT tenotomy can be performed reliably with a percutaneous cutting thread technique. However, refinement of the technique is required to minimize iatrogenic damage. The reported technique allows a DDFT tenotomy to be performed in a minimally invasive manner and has the potential to be clinically applicable.

Correction of a Hyperflexed Hallux in a Saker Falcon (Falco cherrug) by Hemisectioning the Deep Digital Flexor Tendon.

A 3-year-old male saker falcon (Falco cherrug) was presented with a history of hyperflexion of the first digit of the left pelvic limb with what appeared to be a hypercontracted distal end of the deep digital flexor tendon (m. flexor hallucis longus). Conservative treatment, bandaging, and splinting techniques failed to resolve the hypercontraction of the deep digital flexor tendon and improve digit function. Intraoperatively, the deep digital flexor tendon was found to have formed adhesions with the tendon sheath as well as the bone and soft tissue structures underneath it, impeding its ability to move freely within the tendon sheath. The adhesions were surgically resolved, and the tendon was lengthened by hemisectioning the deep digital flexor tendon at its distal end. Postsurgically, the digit was maintained in an extended position by bandaging. Mild physiotherapy was provided at 5-day intervals to retain function and prevent adhesions. Digit extensibility and function were restored to nearly normal levels after 4 weeks.

Desmitis of the accessory ligament of the deep digital flexor tendon in the forelimb: A retrospective case study of 91 horses.

Desmitis of the accessory ligament of the deep digital flexor tendon (ALDDFT) is a commonly reported injury. Despite the commonality of this injury, the literature is limited to small case series, with the reported success following treatment varying from 18% to 75%. To identify the prognosis and factors associated with a return to work following ALDDFT injury. Retrospective case series. Medical records of horses from four equine hospitals (January 2000 and December 2018) with a diagnosis of desmitis of ALDDFT were reviewed. Data retrieved included case detail, use, history, lameness treatment and follow-up. Success was defined as returning to work. Backward stepwise logistic regression was used to identify variables significantly associated with return to work. Ninety-one horses were included. The mean age was 13.5 years (standard deviation 4.9 years). Thirty-four percent (28/91) of horses were sound at the initial presentation. Sixty-eight percent (62/91) of horses were managed using controlled exercise alone, 28% (29/91) were treated with intra-lesional injection, therapeutic ultrasound, extracorporeal shockwave therapy or desmectomy of the ALDDFT and 3% (3/91) were euthanased without treatment. Sixty-four percent (54/85) of horses returned to work. Horses that were lame at follow-up were less likely to return to work (odds ratio [OR] 107.93, 95% confidence interval [CI] 20.06-580.61, p < 0.001) than those that returned to soundness. Identification of adhesions on ultrasonography was also associated with having reduced odds for return to work when compared to horses without adhesions (OR 0.10, 95% CI 0.01-0.76, p = 0.03). Retrospective nature of the study, the potential of selection bias with regards to follow-up. Sixty-four percent (54/85) of horses returned to work following injury of the ALDDFT. Persistence of lameness and adhesion formation were significantly associated with a poor outcome.

Macrophage phenotype impacts in vitro equine intrasynovial deep digital flexor tenocyte matrix metalloproteinase gene expression and secretion.

To investigate matrix metalloproteinase (MMP) and their inhibitors tissue inhibitor matrix metalloproteinase (TIMP) gene expression and secretion during equine deep digital flexor tendon (DDFT) tenocyte and macrophage (undifferentiated, proinflammatory, and regulatory) co-culture. Third passage DDF tenocytes and donor-matched macrophages differentiated from peripheral blood CD14+ monocytes from 5 healthy horses ages 9-11 years, euthanized for reasons unrelated to musculoskeletal conditions. Passage 3 DDT tenocyte aggregate cultures were co-cultured with undifferentiated (control), proinflammatory (granulocyte-macrophage colony-stimulating factor; GM-CSF pretreated and lipopolysaccharide + interferon gamma-primed; LPS+IFN-γ) or regulatory (interleukin-4 and interleukin-10-primed; IL-4 + IL-10) macrophages in direct and transwell co-cultures for 72 hours. MMP-1, -2, -3, -9, -13, and TIMP -1, -2 mRNA were measured via real-time Polymerase Chain Reaction (rtPCR). Co-culture media MMP -3, -9, and TIMP -1, -2 concentrations were quantified via ELISA. Direct co-culture of DDF tenocytes with proinflammatory macrophages for 72 hours increased MMP-1, -3, and -13 mRNA levels whereas, MMP-9 mRNA levels decreased. Direct and transwell co-culture with proinflammatory and regulatory macrophages resulted in increased MMP-3 and decreased MMP-9 media concentrations. While direct co-culture with regulatory macrophages significantly increased TIMP-1 mRNA, overall, TIMP mRNA and culture media concentrations were largely unchanged. Cell-to-cell contact between DDF tenocytes and macrophages is not essential to induce MMP gene expression and secretion. Co-culture systems offer a viable in vitro platform to screen and evaluate immunomodulatory properties of therapies aimed at improving equine intrasynovial tendon healing.

Ultrasonographic description of tendons and ligaments at the palmar (plantar) aspect of the distal limb in the one humped camel (Camelus dromedarius).

To provide complete anatomical and ultrasonographic description of tendons and ligaments at the palmar (plantar) aspect of the cannon and phalangeal regions of the one-humped camel. Forty-two (21 fore and 21 hind) clinically normal camel cadavers' limbs disarticulated at the carpal and tarsal joints and three clinically normal mature camels were included in the study. Six cadaver limbs (three fore and three hind) were dissected, and another six limbs specimens (three fore and three hind) were frozen at -20° for 1 week then sectioned transversely with an electric band saw at different distances distal to the carpometacarpal and tarsometatarsal joints. The ultrasonographic study was carried out on the live camels and 30 cadaveric limbs. The shape, echogenicity and measurements (thickness, width and cross-sectional area) of superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), suspensory ligament (SL), and sesamoidean ligaments were recorded and the differences in values between live animals and cadaveric specimens were statistically analysed. The shape and echogenicity of SDFT, DDFT, and SL, varied between proximal, middle, and distal thirds of the cannon bone and the phalangeal region. There was no significant difference between live animal and cadaveric specimens. This study provided complete description of tendons and ligaments at the palmar (plantar) aspect of the cannon and phalangeal region of the one humped camel. The data obtained serves as a reference guide for practicing veterinarians and for future studies on injury to ligaments and tendons of camel's distal extremity.

Comparison of Ultrasound and Magnetic Resonance Imaging for Identifying Soft Tissue Abnormalities in the Palmar Aspect of the Equine Digit.

Damage to the soft tissue structures of the digit is a common source of equine lameness. While magnetic resonance imaging (MRI) allows for the most complete diagnostic imaging of the equine digit, ultrasound is more readily available and less expensive. This prospective diagnostic accuracy study compares ultrasound to MRI for the diagnosis of injuries visible with ultrasound within the digit, including the deep digital flexor tendon (DDFT), collateral sesamoidean ligament (CSL), and navicular bursa. Clinical patients underwent an MRI of the digit and a blinded ultrasound of the digit between the heel bulbs, and results of the two modalities were compared. A total of 70 ultrasound and MRI exams of 45 horses were included. Ultrasound had good sensitivity (85%), moderate specificity (60%), and accuracy of 70% for evaluating the dorsal tearing of the DDFT. Accuracy was lower for navicular bursa effusion (67%), navicular bursa proliferation (61%), and CSL enlargement (61%). Tearing of the DDFT distal to the navicular bone was identified with MRI in 27 limbs, 20 of which also had dorsal damage proximal to the navicular bone identified with ultrasound. Ultrasound evaluation remains a useful screening tool, particularly for the assessment of DDFT tearing proximal to the navicular bone but risks under-diagnosing pathology to the navicular bursa and CSL. Clinically significant concurrent damage to the distal DDFT and other osseous and soft tissues in the hoof capsule is unlikely to be identified without MRI.