Deep Digital Flexor Tendon Lesions Research Articles

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.

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.

Sensitivity and specificity of 3 Tesla magnetic resonance imaging and multidetector computed tomographic tenography to identify artificially induced soft tissue lesions in the equine cadaveric digital flexor tendon sheath

SummaryBackgroundA common cause of lameness in horses is tenovaginitis of the digital flexor tendon sheath (DFTS). Ultrasound and contrast tenography have become frequently used diagnostic tools for abnormalities in the DFTS, but are considered insufficiently accurate in describing specific lesions.ObjectivesTo determine the sensitivity and specificity of computed tomographic tenography (CTT) and 3 Tesla magnetic resonance imaging (MRI) to detect artificial lesions within the DFTS.Study designBlinded laboratory study.MethodsUsing an arthroscopic hook knife, lesions (10–20 mm long and 3–5 mm deep; n = 52) were created tenoscopically in the superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), manica flexoria (MF) and proximal scutum in 19 distal limb specimens. MRI and CTT were performed and images were reviewed. Sensitivity and specificity were calculated for each modality and compared.ResultsComputed tomographic tenography and MRI identification of SDFT and MF lesions showed similar sensitivity (75% vs. 85%, respectively; p = 1) and specificity for MF lesions (96% for both). SDFT lesions specificity was similar for CTT versus MRI (85% vs. 77%, respectively; p = 0.88). For DDFT lesions, MRI sensitivity (62%) was higher compared to CTT (38%), although not statistically significant (p = 0.58). MRI specificity (92%) was lower than CTT (96%, p = 1). Lesions in the proximal scutum were more frequently identified by MRI compared to CTT (sensitivity: 93% vs. 57%, p = 0.17; specificity: 96% vs. 100%, p = 1).Main limitationsArtificial, small lesions were assessed. An incomplete arthroscopic portal seal resulted in pressure loss and contrast leakage.ConclusionsThe sensitivity and specificity of both modalities are good to excellent for the diagnosis of most artificially created lesions. CTT performed similarly to MRI in detecting SDFT and MF lesions. MRI showed a higher sensitivity for the diagnosis of DDFT and proximal scutum lesions. The results indicate a future application of CTT for the diagnosis of DFTS pathologies, whenever suspecting MF tears.

Contrast Enhanced Computed Tomography Findings in 105 Horse Distal Extremities

The poor soft tissue conspicuity of CT can be improved by using intra-arterial CT Angiography (CTA), and intra-articular and intra-bursal contrast enhanced CT (CTAR). This retrospective study describes a combination protocol of CT and CTA of the horse's foot, and CTAR of the distal interphalangeal joint and navicular bursa. It is hypothesized this would provide a comprehensive overview of the range and severity of distal limb pathology. Radiology reports of all horses admitted for distal limb CT over a 5 year period were reviewed. All horses with a complete four stage CT examination and radiology report with lameness isolated to the foot were included. Twenty seven imaging findings using a four grade semiquantitative severity scoring system contributing towards six main diagnostic categories were described. One hundred and five examinations on 56 horses revealed a diagnosis of navicular bone disease in 64%, deep digital flexor tendinopathy in 43%, distal interphalangeal osteoarthritis in 35%, navicular bursitis in 31%, distal interphalangeal collateral ligament desmopathy in 26%, and hoof capsule and distal phalanx pathology in 10%. Only 25% of the navicular bone disease cases were considered clinically significant. The majority of deep digital flexor tendon lesions (77%) and distal interphalangeal joint osteoarthritis (51%) were considered significant. Approximately one third of navicular bursa (37%) and collateral ligament (33%) abnormalities were considered significant. Navicular bursa abnormalities were associated with navicular bone and deep digital flexor tendon lesions. The findings support the hypothesis and the use of this protocol for evaluation of foot lameness.

Comparison Between Ultrasonographic and Standing Magnetic Resonance Imaging Findings in the Podotrochlear Apparatus of Horses With Foot Pain.

This prospective study aimed to blindly compare the ultrasonographic and standing magnetic resonance imaging (sMRI) findings in deep digital flexor tendon (DDFT), navicular bone, and navicular bursa in horses with foot pain, positive digital analgesia, and without definitive radiographic diagnosis. Ultrasonography detected more DDFT abnormalities (32/34 feet vs. 27/34 with sMRI) but identified less palmar navicular abnormalities (23/34 feet vs. 30/34 with sMRI). In suprasesamoidean DDFT lesions, which were mainly dorsally located, changes in echogenicity did not correspond to a particular pattern of sMRI signal change. Transcuneal ultrasonography did not allow assessment of morphology and extent of distal DDFT lesions, and sporadically discriminated the affected lobe compared to sMRI. Defects of the palmar compact bone were identified with both modalities except a parasagittal defect, which was only seen at sMRI.

Deep digital flexor tendon lesions in the pastern are associated with the presence of distal tendinopathy.

Correct diagnosis and characterisation of deep digital flexor tendon (DDFT) lesions in equine athletes allows targeted treatment and improved prognostication. To assess the prevalence and character of pathological change within the DDFT in the pastern with concurrent tendon injury distally. It is hypothesised that tendon lesions in the pastern will be associated with tendinopathy within the hoof capsule. Retrospective descriptive case series. Cases with DDFT lesions in the pastern and magnetic resonance imaging (MRI) or ultrasonography of the foot were evaluated retrospectively. Lesion location and type were recorded. Odds ratios were calculated to determine the associations between more distal tendinopathy and the presence of different DDFT lesion types in the pastern. Thirty-four MRI scans of 33 horses and 64 ultrasonographic exams of 58 horses were analysed. Lesion location and type were recorded. Distal DDFT lesions were found in 75% (95% CI: 66.0-84.0) of total cases of pastern DDF tendinopathy and in 97% (95% CI: 91.6-100.0) of cases with core lesions of the DDFT in the pastern. A core lesion in the pastern was significantly more likely (OR=20.7, 95% CI: 2.2-191.0; P=.008) to be associated with injury in the foot than other types of pastern lesion. MRIs of the foot were not obtained on all included limbs which did not allow for fully inclusive evaluation of DDFT lesions distal to the navicular bone. DDFT pathological change in the pastern, particularly core lesions, is associated with additional tendinopathy within the hoof capsule. When a DDFT lesion is found in the pastern, further imaging of the tendon within the foot is indicated to direct appropriate treatment and improve prognostication.

18 Fluorine-fluorodeoxyglucose positron emission tomography for assessment of deep digital flexor tendinopathy: An exploratory study in eight horses with comparison to CT and MRI.

Lesions of the deep digital flexor tendon (DDFT) are a cause for foot lameness in horses. Positron emission tomography (PET) could provide valuable information regarding the metabolic activity of these lesions. The aims of this exploratory, prospective, methods comparison study were to assess the ability of 18 fluorine-fluorodeoxyglucose (18 F-FDG) PET to detect DDFT lesions and to compare the PET findings with CT and MRI findings. Eight horses with lameness due to pain localized to the front feet were included. Both front limbs of all horses were imaged with 18 F-FDG PET, noncontrast CT, and arterial contrast-enhanced CT; 11 limbs were also assessed using MRI. Two observers graded independently 18 F-FDG PET, noncontrast CT, arterial contrast CT, T1-weighted (T1-w) MRI, and T2-weighted (T2-w)/STIR MRI. Maximal standardized uptake values were measured. Lesions were found in seven of 16 DDFT on PET, 12 of 16 DDFT on noncontrast CT, six of 15 DDFT on arterial contrast CT, eight of 11 DDFT on T1-w MRI, and six of 11 DDFT on T2-w/STIR MRI. Positron emission tomography was in better agreement with arterial contrast CT (Kappa-weighted 0.40) and T2-w/STIR MRI (0.35) than with noncontrast CT (0.28) and T1-w MRI (0.20). Maximal standardized uptake values of lesions ranged from 1.9 to 4.6 with a median of 3.1. Chronic lesions with scar tissues identified on noncontrast CT or T1-w MRI did not have increased 18 F-FDG uptake. These results demonstrated that 18 F-FDG PET agreed more closely with modalities previously used to detect active tendon lesions, i.e. arterial contrast CT and T2-w/STIR MRI. 18 Fluorine-fluorodeoxyglucose PET can be used to identify metabolically active DDFT lesions in horses.

Imaging findings and clinical outcome of foot pain attributable to insertional deep digital flexor tendon injury and/or fluid signal within the flexor surface of the distal phalanx

SummaryBackgroundInsertional deep digital flexor tendon (DDFT) lesions with concurrent injury to the flexor surface of the distal phalanx are uncommon and there is limited information regarding prognosis.ObjectivesTo provide descriptive data on horses with insertional DDFT injuries and determine whether there is any association between magnetic resonance imaging (MRI) findings, and outcome.Study designRetrospective case series.MethodsHorses with lameness localised to the foot that underwent low field standing MRI between January 2015 and April 2019 were included. Injury of the DDFT, presence of short tau inversion recovery (STIR) hyperintensity at the flexor surface of the distal phalanx and concurrent lesions were recorded. Follow‐up information was obtained by telephone questionnaire.ResultsThirty‐two horses fulfilled the inclusion criteria. Thirty‐one limbs had DDFT insertional lesions on MRI with three limbs showing hyperintense STIR signal of the flexor surface of the distal phalanx without a tendon lesion. Seventeen DDFT lesions were graded as mild and 14 as severe. Thirteen limbs showed hyperintense STIR signal within the tendon and 15 limbs showed hyperintense STIR signal within the flexor surface of the distal phalanx at the insertion of the DDFT and/or the distal sesamoidean impar ligament (DSIL). Eight horses returned to previous athletic function, 8 returned to a lower level of athletic activity, 4 were retired, 9 were subjected to euthanasia and 3 were lost to follow‐up. No significant association was found between DDFT lesion severity, hyperintense STIR signal within the DDFT, hyperintense STIR signal at the flexor surface of the distal phalanx and outcome post‐injury.Main limitationsSmall sample size and reliance on clients to provide accurate follow‐up information.ConclusionsInsertional DDF tendinopathy carries a guarded prognosis for return to previous athletic function. The presence of hyperintense STIR signal at the flexor surface of the distal phalanx did not appear to influence the prognosis.

Variation in the MRI signal intensity of naturally occurring equine superficial digital flexor tendinopathies over a 12-month period

BackgroundSignal intensity (SI) of equine tendinopathies in MRI differs between the superficial digital flexor tendon (SDFT) and the deep digital flexor tendon (DDFT). In DDFT lesions, short tau inversion recovery...

Accuracy of open magnetic resonance imaging for guiding injection of the equine deep digital flexor tendon within the hoof.

Lesions of the distal deep digital flexor tendon (DDFT) are frequently diagnosed using MRI in horses with foot pain. Intralesional injection of biologic therapeutics shows promise in tendon healing; however, accurate injection of distal deep digital flexor tendon lesions within the hoof is difficult. The aim of this experimental study was to evaluate accuracy of a technique for injection of the deep digital flexor tendon within the hoof using MRI-guidance, which could be performed in standing patients. We hypothesized that injection of the distal deep digital flexor tendon within the hoof could be accurately guided using open low-field MRI to target either the lateral or medial lobe at a specific location. Ten cadaver limbs were positioned in an open, low-field MRI unit. Each distal deep digital flexor tendon lobe was assigned to have a proximal (adjacent to the proximal aspect of the navicular bursa) or distal (adjacent to the navicular bone) injection. A titanium needle was inserted into each tendon lobe, guided by T1-weighted transverse images acquired simultaneously during injection. Colored dye was injected as a marker and postinjection MRI and gross sections were assessed. The success of injection as evaluated on gross section was 85% (70% proximal, 100% distal). The success of injection as evaluated by MRI was 65% (60% proximal, 70% distal). There was no significant difference between the success of injecting the medial versus lateral lobe. The major limitation of this study was the use of cadaver limbs with normal tendons. The authors conclude that injection of the distal deep digital flexor tendon within the hoof is possible using MRI guidance.

Magnetic resonance imaging‐guided injection of platelet‐rich plasma for treatment of an insertional core lesion of the deep digital flexor tendon within the foot of a horse

SummaryDefinitive diagnosis of a deep digital flexor tendon insertional lesion within the right fore foot was made by magnetic resonance imaging (MRI) examination and the lesion subsequently treated by injection with platelet‐rich plasma. MRI was used to guide positioning of the needle to achieve highly accurate injection. The volume injected was found to approximate the calculated lesion volume. On the basis of experience with this case, MRI‐guided injection of insertional deep digital flexor tendon lesions of the foot of horses under general anaesthesia is practicable. This technique is likely to be more accurate than the other techniques described (computed tomography, ultrasonography) and carries no risk of exposure to radiation (radiography).

Deep digital flexor tendon lesions in the foot — a careerending injury for the equine athlete?

Injuries to the deep digital flexor tendon (DDFT) are commonly identified as a cause of forelimb lameness with the increased availability of magnetic resonance imaging in horses. Both conservative and surgical treatments have been shown to result in a guarded to fair prognosis for a return to athletic activity. Several studies have indicated that the outcome after DDFT injuries depends on lesion type, extent, localisation and duration before treatment.

Do low field magnetic resonance imaging abnormalities correlate with macroscopical and histological changes within the equine deep digital flexor tendon?

Correlating magnetic resonance (MR) imaging and histopathological findings is essential to validate low field MR imaging in lame horses. This study aimed to compare signal changes in the deep digital flexor tendon (DDFT) of the distal limb on low field MR imaging with macroscopical and histological findings. Cadaver limbs from lame horses with DDFT lesions were selected. The DDFT MR imaging findings and histopathological results were graded, and macroscopical abnormalities were recorded. There was a strong correlation between MR imaging and histopathology grades (rs = 0.76, p < 0.001) in the foot. There was moderate agreement (Kappa statistic 0.52) between the MR and histopathology grades; agreement was superior further proximal in the foot. The presence and severity of pathology in the DDFT are well represented by the presence and severity of MR imaging signal changes. The study supports the use of low field MR imaging for diagnosis of equine distal limb DDFT lesions.

Does hoof deformation differ between horses with collapsed heels and horses with non-collapsed heels?

s / Journal of Equine Veterinary Science 33 (2013) 838–859 859 of lame horses. We hypothesized that some conformational parameters are significantly different between different types of foot pathology. Materials and Methods: Conformational parameters were measured onmagnetic resonance images in themidsagittal plane of 179 lame horses with lesions involving the deep digital flexor tendon (DDFT), navicular bone (NB), collateral ligaments of the distal interphalangeal joints, or other digital structures. Results: Conformational parameters were significantly different between lesion groups. A greater sole angle decreased the likelihood of combined DDFT and NB lesions, but not NB lesions alone. A more acute angle of the DDFT around the NB was related to DDFT and NB lesions, and a decrease in heel height index was related to DDFT injury. The smaller the sole angle, the higher the likelihood of a DDFT lesion (odds ratio: 0.86) or NB lesion (odds ratio: 0.90). Discussion and Conclusions: Foot conformation is different in horses with DDFT and NB lesions. Optimization of foot conformation is likely to be key in the management of horses with foot lameness, and also an essential preventative measure in the sound horse. 027 Does hoof deformation differ between horses with collapsed heels and horses with non-collapsed heels? Peter Day, Daniel Butts, Thilo Pfau, Chris Pardoe, and Renate Weller Department of Clinical Sciences and Services, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, UK Take-home message: Feet with collapsed heels show less hoof deformation in the heel region, thus decreasing the shock-absorbing effect and possibly influencing the region’s blood supply and predisposing to other foot pathology. Introduction: Collapsed heels are a common problem in horses, especially Thoroughbreds, and are associated with decreased performance and lameness. However, little is known about the mechanism behind this condition. In this study, we investigated the relationship between collapsed heels and hoof deformation and hypothesized that hoof deformationwill be decreasedwith increased heel collapse. Materials and Methods: Twelve cadaver legs with (n1⁄46) and without (n1⁄46) collapsed heels were used, the distinction based on radiographic characteristics. Hoof deformation during loading was determined with a 3D optical motion analysis system. Hoof deformation in both heels was compared between the two groups using an independent t-test (p 2 years of age were evaluated and the presence of SB graded according to the 0–5 point scale of Ruohoniemi et al. (1993). The cartilage with the highest degree of SB determined the score for that horse. Prevalence of SB was compared with earlier reports from these breeds. The BLUP index and reliable sports data were collected from the databases of the Swedish and Norwegian trotting associations. Data were analyzed using general linear models; the models also included the gender of the horse, with p < 0.05 considered significant. Results: The incidence of SB of any degree was 95% in the Ardennes horses and 65% in the trotters. Significant effects of gender were demonstrated on performance, but no correlations were found between different degrees of SB and number of starts, career earnings, running pace, race winnings, number of races completed in a regular gait, or body size. Mean BLUP index was 104 for horses with and without SB. Discussion and Conclusions: Despite the breeding program, there has been no decrease in the prevalence SB in the Swedish cold-blooded horse population. No clinical relevance of SB could be shown in the examined populations.

Deep digital flexor tendon injury within the hoof capsule; does lesion type or location predict prognosis?

The type and location of deep digital flexor tendon (DDFT) lesions may be important in predicting outcome. The objectives of this study were to determine the frequency of different types of DDFT lesions within the hoof capsule and to determine whether lesion type predicts return to athletic activity. Lesions of the DDFT were divided into: core lesions, dorsal border lesions and parasagittal splits. Lesion location was documented, and follow-up information was obtained by telephone survey at least 18 months after diagnosis. Of 168 horses with primary DDFT injury, 54 horses had dorsal border lesions, 59 had parasagittal splits and 55had core lesions. Twenty-five per cent of all horses returned to previous levels of athletic activity within 18 months of MRI evaluation. Horses with complete splits or core lesions of the DDFT were significantly less likely to return to some level of athletic activity than horses with dorsal border lesions P<0.001. Dorsal border lesions of the DDFT appear to have a better prognosis than core lesions or parasagittal splits. This study provides additional information that may help clinicians predict the prognosis for different types of DDFT injury.

Comparisons of computed tomography, contrast‐enhanced computed tomography and standing low‐field magnetic resonance imaging in horses with lameness localised to the foot. Part 2: Lesion identification

No previous study compares computed tomography (CT), contrast-enhanced computed tomography (CECT) and standing low-field magnetic resonance imaging (LFMRI) to detect lesions in horses with lameness localised to the foot. This study will help clinicians understand the limitations of these techniques. To determine if CT, CECT and LFMRI would identify lesions within the distal limb and document discrepancies with lesion distribution and lesion classification. Lesions in specific structures identified on CT and MR images of feet (31 limbs) from the same horse were reviewed and compared. Distributions of lesions were compared using a Chi-squared test and techniques analysed using the paired marginal homogeneity test for concordance. Lesions of the deep digital flexor tendon (DDFT) were most common and CT/CECT identified more lesions than LFMRI. Deep digital flexor tendon lesions seen on LFMRI only were frequently distal to the proximal extent of the distal sesamoid and DDFT lesions seen on CT/CECT only were frequently proximal to the distal sesamoid. Lesions identified on LFMRI only were core (23.3%) or splits (43.3%), whereas lesions identified only on CT were abrasions (29.8%), core (15.8%), enlargement (15.8%) or mineralisation (12.3%). Contrast-enhanced CT improved lesion identification at the DDFT insertion compared to CT and resulted in distal sesamoidean impar ligament and collateral sesamoidean ligament vascular enhancement in 75% of cases. Low-field MRI and CT/CECT failed to identify soft tissue mineralisation and bone oedema, respectively. Multiple lesions are detected with CT, CECT and LFMRI but there is variability in lesion detection and classification. LFMRI centred only on the podotrochlear apparatus may fail to identify lesions of the pastern or soft tissue mineralisation. Computed tomography may fail to identify DDFT lesions distal to the proximal border of the distal sesamoid.

Short‐term temporal alterations in magnetic resonance signal occur in primary lesions identified in the deep digital flexor tendon of the equine digit

Primary lesions of the deep digital flexor tendon (DDFT) within the digit are an important cause of lameness diagnosed using magnetic resonance imaging (MRI) but appearance of these lesions over time has not been documented. To determine whether the magnetic resonance (MR) appearance of different primary DDFT lesions alter over a 6 month period and whether lesion type is a determinant of these changes. Cases included had lameness attributable to a primary lesion involving the DDFT in the digit diagnosed on MRI. Lesions were typed into parasagittal, dorsal border and core lesions. Approximate volumes and intensities were quantified for each lesion type using T2* scan sequences. Follow-up examinations and measurements were repeated at 3 and 6 month periods following conservative management. Twenty-three horses fitted the inclusion criteria. Lesion distribution included: parasagittal (n = 7), dorsal border (n = 11) and core lesions (n = 5). No association was found between age of horse, degree of lameness and lesion type. Only dorsal border lesions showed statistically significant reduction both in volume (initial scan: 0.18 ± 0.14 cm(3) ) at 3 months (0.11 ± 0.10 cm(3) , P<0.05) and 6 months (0.05 ± 0.05 cm(3) , P<0.01) and ratiometric intensity (initial scan: 4.06 ± 1.54) at 6 months (2.00 ± 0.43; P<0.01). Parasagittal and core lesions showed no difference in lesion volume or ratiometric intensity. Lameness improved in all lesion types following conservative management. Dorsal border lesions of the DDFT show reduction in both volume and intensity whereas parasagittal and core lesions do not. Lesion typing may be important in predicting lesion behaviour and short-term outcome using MR imaging.

USE OF CONTRAST‐ENHANCED COMPUTED TOMOGRAPHY TO ASSESS ANGIOGENESIS IN DEEP DIGITAL FLEXOR TENDONOPATHY IN A HORSE

We compared contrast-enhanced computed tomography (CT) and high field magnetic resonance (MR) imaging in a horse with deep digital flexor tendonopathy. Lesions in the distal extremity were documented grossly and histopathologically. In contrast-enhanced CT, the deep digital flexor tendon lesions were markedly contrast enhancing with evidence of angiogenesis in the core and dorsal border lesions. The lesion morphology was clearly delineated on MR imaging, but without contrast media angiogenesis cannot be identified. Gross examination, histopathologic examination, and CD31 immunohistochemistry confirmed the tendonopathy and an increased presence of small blood vessels. In this horse, deep digital flexor tendon lesions appeared similarly on contrast-enhanced CT and MR imaging. Contrast-enhanced CT may be an alternative to MR imaging for assessing tendon and ligament injury in the digit of the horse.

Injection of the insertion of the deep digital flexor tendon in horses using radiographic guidance

SummaryInsertional tendinopathies of the DDFT have been reported both as the sole lesion and as part of a multifocal lesion (Dyson et al. 2003). Computed tomography (CT) and magnetic resonance imaging allow specific diagnosis of deep digital flexor tendon lesions within the hoof capsule; however, direct intralesional treatment of such lesions is difficult because of the hoof's rigid structure. A technique designed to mimic intralesional injection of insertional tendinopathies of the DDFT in the standing horse using radiographic guidance was assessed. Radiographic and contrast CT imaging and sectioning of the limbs confirmed accurate injection in all cases although inadvertant administration of injectate into adjacent structures was also evident.

Magnetic resonance imaging evaluation of 264 horses with foot pain: The podotrochlear apparatus, deep digital flexor tendon and collateral ligaments of the distal interphalangeal joint

To improve understanding of the interrelationships between injuries of the podotrochlear apparatus and deep digital flexor tendon (DDFT). There is a difference in frequency of different types of lesions at different anatomical sites of the DDFT. Lesions of the collateral sesamoidean ligament (CSL), distal sesamoidean impar ligament (DSIL), distal interphalangeal (DIP) joint and navicular bursa are seen in association with lesions of the navicular bone. The magnetic resonance (MR) images of 264 horses with unilateral or bilateral foot pain were analysed and graded. Descriptive statistics were performed to establish the frequency of occurrence of DDFT lesion types at different anatomical levels, and lesions of the CSL, DSIL, navicular bursa, DIP joint and collateral ligaments (CLs) of the DIP joint. A Chi-square test was used to test for a difference in the proportion of navicular bone grades between limbs with and without DDFT lesions at each level, and to compare navicular bone grades for limbs with and without each of DSIL, CSL, navicular bursa or DIP joint lesions. Lesions of the DDFT occurred in 82.6% of limbs, occurring most commonly at the level of the CSL (59.4%) and the navicular bone (59.0%). Core lesions predominated at the level of the proximal phalanx (90.3%), whereas at the level of the CSL and navicular bone core lesions, sagittal splits and dorsal abrasions were most common. There was a positive association between DDFT lesions and navicular bone pathology involving all aspects of the bone. Lesions of the DSIL (38.2% limbs) were more common than those of the CSL (10.5%), but the presence of either was associated with abnormalities of the navicular bone, especially involving the proximal or distal borders and the medulla. There are close interactions between injuries of the components of the podotrochlear apparatus, the DDFT, the navicular bursa and the DIP joint. Further knowledge about the biomechanical risk factors for injury may have importance for both disease prevention and management.