A singular case of traumatic total hoof capsule avulsion

Total, full thickness hoof wall avulsion is rare in horses. Sometimes complications such as fracture of the distal phalanx, osteomyelitis, septic arthritis and degenerative joint disease have been reported. Limiting motion at the affected site and hoof stabilisation are essential to obtain a good hoof regeneration. This case report reviews the clinical features including diagnostic techniques (radiographic examination and venography) of a Quarter Horse filly presented with a complete and full‐thickness traumatic hoof capsule avulsion complicated by an open fracture of the third phalanx. A transfixation casting technique was performed followed after one month by 2 short limb casts applied for 2 months each. Twenty‐four months after trauma the foot had completely regrown. The dorsal aspect of the hoof wall appears to be remarkably shorter compared to the heels. From a radiographic viewpoint, the lateral aspect of the left hind foot shows diffuse bone remodelling and a deformed distal phalanx.     

Scintigraphic evaluation of intra-arterial and intravenous regional limb perfusion of allogeneic bone marrow-derived mesenchymal stem cells in the normal equine distal limb using (99m) Tc-HMPAO

Reasons for performing study: Mesenchymal stem cells (MSCs) are commonly injected intralesionally for treatment of soft tissue injuries in the horse. Alternative routes of administration would be beneficial for treatment of lesions that cannot be accessed directly or to limit needle‐induced iatrogenic damage to the surrounding tissue. Objectives: The purpose of our study was to evaluate MSC distribution after intra‐arterial (IA) and intravenous (IV) regional limb perfusions (RLP) using scintigraphy. We hypothesised that MSCs would persist in the distal limb after tourniquet removal and that both techniques would lead to diffuse MSC distribution. Methods: Six horses were used in the study. MSCs were labelled with hexamethyl propylene amine oxime (HMPAO) and technetium‐99m. RLP was performed through the median artery of one forelimb and the cephalic vein of the opposite limb under general anaesthesia. The tourniquet was left in place for 45 min. Scintigraphic images were obtained at 0, 45, 75 min, 6 h and 24 h post injection. Results: Distribution of labelled MSCs through the entire distal limb was achieved with all 6 IA RLP, but 3 out of 6 IV RLP showed poor or absent uptake distal to the metacarpus. Mesenchymal stem cell persistence was 39% (30–60%) and 28% (14–50%) (median [minimum–maximum]) at 6 h for IA and IV RLP, respectively. Severe arterial thrombosis occurred in one horse after IA RLP. Conclusions: Both IA and IV RLP of the distal limb result in MSC persistence in perfused tissues. The IA perfusion resulted in more reliable cell distribution to the pastern and foot area. Potential relevance: Regional limb perfusion of MSCs might be used in cases where intralesional injection is not possible or in order to avoid iatrogenic needle damage. Further work is needed to assess the safety of IA RLP before its clinical use.     

Prolonged, continuous distal limb cryotherapy in the horse

REASONS FOR PERFORMING STUDY: The recommended duration of cryotherapy in horses is currently extrapolated from human medicine. Prolonged, continuous cryotherapy (days rather than minutes) may be of therapeutic value if it is safe and well tolerated. OBJECTIVES: To evaluate the effect of prolonged, continuous application of ice and water to the equine distal limb. METHODS: A slurry of ice and water was applied to the right forelimb of 4 Standardbred horses for 48 h. Hoof temperature, ambient temperature and ice boot temperature were logged continuously and clinical observations recorded every 2 h. Lameness examinations were performed prior to application and 1 week, 6 months and 1 year after removal of the ice boot. RESULTS: Continuous cryotherapy was well tolerated and resulted in marked cooling of the treated foot. No significant variation in clinical parameters was noted, and no lameness or gross pathology noted in the treated limbs at any examination period. CONCLUSIONS: The continuous application of ice and water is a safe and effective means of cooling the equine distal limb. The extremely low, constant temperatures achieved may be of benefit in the management of various distal limb conditions. POTENTIAL RELEVANCE: Providing clinicians and research workers with a potent therapeutic/prophylactic modality for disorders of the equine distal limb.     

Evaluation of regional limb perfusion with amikacin using the saphenous,cephalic, and palmar digital veins in standing horses

Previous studies have shown that regional limb perfusion (RLP) using the palmar digital (PD) vein delivers therapeutic concentration of amikacin to the distal limb. Our hypothesis was that using the cephalic and saphenous veins for RLP will enable delivery of therapeutic concentrations of amikacin to the distal limb. Nineteen healthy horses participated in the study. The cephalic, saphenous, or PD vein was used to perfuse the limb with amikacin. Two grams of amikacin was used for RLP using the saphenous and the cephalic veins, and one gram was used in the PD vein. Synovial samples were collected from the metacarpo‐/metatarsophalangeal (MCP/MTP) joint, and blood samples were collected from the jugular vein. Maximum concentration (Cmax) of amikacin in the MCP/MTP joint using the cephalic and the saphenous vein was 277 and 363 mg/L, respectively. The amikacin concentrations achieved in the synovial fluid of the MCP/MTP joint in the current study were between 69 and 91 times the minimally inhibitory concentration of common susceptible bacterial pathogens causing orthopedic infections in horses. To conclude, this study shows that use of the proximal veins for RLP to treat distal limb infections is a viable alternative to using the palmar or plantar digital vein.     

Is there an association between ossification of the cartilages of the foot and collateral desmopathy of the distal interphalangeal joint or distal phalanx injury?

Reasons for performing study: Associations between degree of ossification of the cartilages of the foot and injuries to other structures of the foot have been suggested, but have not been investigated by large scale studies. Objectives: To describe the frequency of grade >3 ossification of the cartilages of the foot (possibly significant ossification, PSO), mediolateral symmetry of ossification and left‐right symmetry between feet; and to investigate associations between PSO and injury of either the collateral ligaments (CLs) of the distal interphalangeal (DIP) joint or the distal phalanx. Hypotheses: Possibly significant ossification of the cartilages of the foot is associated with CL and distal phalanx injury. Distal phalanx injury is associated with a mediolateral difference in ossification grade of ≥2. Methods: Horses were examined for lameness localised to the foot by perineural analgesia, and underwent radiographic and magnetic resonance imaging examinations. Age, breed, occupation, duration of lameness, lame(st) limb, primary cause of lameness, and presence or absence of CL injury were recorded. Dorsopalmar (dorsoplantar) radiographs were examined and ossification of the cartilages of the foot graded using a modification of a previously published scale. Results: One foot from each of 462 horses was included for analysis. There was left‐right symmetry of ossification between feet, and significant association between grades of each foot, with lateral ≥medial cartilages. Possibly significant ossification occurred in the maximally ossified cartilage in 59 (12.8%) feet. There were significant associations between PSO of the maximally ossified cartilage of the foot and injuries of both the CLs of the DIP joint and the distal phalanx. There was no association between distal phalanx injury and marked asymmetry of the ossified cartilages of the foot. Conclusions and clinical relevance: Extensively ossified cartilages of the foot are significantly associated with CL or distal phalanx injury. Markedly asymmetric ossification did not increase the likelihood of distal phalanx injury and should be considered at a prepurchase examination.     

Sonographic observations of the peripheral vasculature of the equine thoracic limb

Investigations of the equine peripheral vascular system have been constrained by the lack of a non-invasive method of examining the arteries and veins of the limbs of the conscious horse. Precise correlations were established between the gross anatomical features of the peripheral vessels and their B-mode sonographic appearance in each thoracic limb of 35 horses. A sonographic imaging protocol was established. Additional Doppler sonographic recordings defined the arterial waveforms and demonstrated that blood flow to the foot could be evaluated in the lateral proper digital artery, distal to the level of the coronary band. Valves (with 2-4 cusps) were identified in the lumina of the medial and lateral palmar common digital veins and those of the medial and lateral palmar proper digital veins. Spontaneous echo contrast, a smoke-like haze of echoic blood, was seen in the lateral and medial palmar common digital veins, the distal deep palmar venous arch and communicating branches, and the palmar proper digital veins, and occasionally seen in the distal deep palmar arterial arch and distal proper palmar digital arteries. The value of duplex sonography (B-mode and Doppler) for anatomical and physiological studies of the peripheral vasculature of the horse was clearly established. Such data could be applied to the investigation of diseases affecting the peripheral circulation.     

我国奶牛主要疾病研究进展

文章主要分析了影响我国奶牛业发展的主要疾病,如乳房炎、子宫内膜炎、卵巢疾病、营养代谢疾病、胎衣不下、犊牛腹泻、肢蹄病等的防治现状,并提出了今后的研究方向与对策。     

Radiographic Differences Between Uneven Feet in Horses With Foot Lameness and Admitted for MRI Examination

Unevenness is an important feature of foot conformation and coincides with both kinetic and kinematic asymmetrical locomotor differences. It reportedly may lead to early retirement of elite horses from a warmblood population. The aim of this study was to evaluate the radiological consequences of an uneven feet conformation and on distal limb tissue development. In a retrospective study, the complete sets of good quality radiographs of both distal forelimbs were compared objectively for 121 “foot lame” horses that had been admitted for magnetic resonance imaging of one or both front feet (2003–2010). A chi-square test was used to test for significant radiometric differences between the upright and the lower angle foot (P < .05); 60% of the horses were unilaterally lame in the upright foot, whereas 40% were lame in the lower angle foot, which appeared to be a nonsignificant difference. In 84% of the horses, the navicular bone (NB) had a substantially more radiolucent, osteoporotic structure (P < .05). In 88% of the horses, the deep digital flexor tendon (DDFT) in the upright foot was significantly more radiodense and pronounced than in the lower angle foot (P < .05). The NB showed a significantly more osteoporotic structure as scored in the upright foot than in the lower angle foot, whereas the DDFT appeared was scored more compact in the upright foot than in the lower angle foot, suggesting less tension on the DDFT. In conclusion, radiological differences between uneven feet in foot lame horses seem to be related to differences in distal limb locomotor tissue development.     

Musculoskeletal problems associated with lameness and poor performance among horses used for barrel racing: 118 cases (2000-2003)

OBJECTIVE: To identify types of musculoskeletal problems associated with lameness or poor performance in horses used for barrel racing. DESIGN: Retrospective case series. ANIMALS: 118 horses. PROCEDURE: Medical records were reviewed for information on signalment, history, physical and lameness examination findings, diagnostic tests performed, diagnosis, and treatment. RESULTS: Most horses were examined because of lameness (n = 72 [61%]) rather than poor performance (46 [39%]), but owner complaint was not significantly associated with age or body weight of the horse. The most common performance change was refusal or failure to turn properly around the first barrel (19/46 [41%]). The right forelimb (n = 57 [48%]) was most commonly affected, followed by the left forelimb (51 [43%]), the left hind limb (31 [26%]), and the right hind limb (25 [21%]). In 31 horses (26%), both forelimbs were affected, and in 6 (5%), both hind limbs were affected. The most common musculoskeletal problems were forelimb foot pain only (n = 39 [33%]), osteoarthritis of the distal tarsal joints (17 [14%]), suspensory ligament desmitis (15 [13%]), forelimb foot pain with distal tarsal joint osteoarthritis (11 [9%]), and bruised feet (10 [8.5%]). In 81 (69%) horses, the affected joint was treated with intra-articular medications. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in horses used for barrel racing that are examined because of lameness or poor performance, the forelimbs are more likely to be affected than the hind limbs, with forelimb foot pain and osteoarthritis of the distal tarsal joints being the most common underlying abnormalities.     

Ankylosis of the distal interphalangeal joint in a horse after septic arthritis and septic navicular bursitis.

A 6-month-old 300-kg Quarter Horse filly was treated for septic arthritis of the distal interphalangeal joint and septic navicular bursitis that developed as a result of a deep puncture to the foot. Initial treatment consisted of establishing ventral drainage for the navicular bursa, lavage of the distal interphalangeal joint, and administration of broad-spectrum antimicrobial drugs and non-steroidal anti-inflammatory drugs. Because of continuing sepsis in the distal interphalangeal joint, subsequent treatment included packing the defect in the bottom of the foot with cancellous bone in an attempt to prevent ascending contamination of the joint, placing the limb in a short limb cast, and inserting a Penrose drain into the joint for passive drainage of septic exudate. The goal of treatment was to encourage ankylosis of the distal interphalangeal joint. Because of the filly's persistent lameness and laxity of the lateral collateral ligament in the contralateral carpus, the palmar nerves of the affected foot were injected with a long-acting local anesthetic at the level of the proximal sesamoid bones to encourage weight-bearing. Ankylosis of the distal interphalangeal joint was complete 9 months after the puncture, but a grade-2 lameness remained and the horse had a varus deformity resulting from ligamentous laxity of the lateral collateral ligament in the contralateral carpus.     

RADIOGRAPHIC DIAGNOSIS OF LAMENESS IN AFRICAN ELEPHANTS (LOXODONTA AFRICANA)

Lameness in captive elephants is most commonly caused by pododermatitis or degenerative joint disease. Hard surfaces such as concrete, which produce a damp and cold environment, wet and muddy conditions, as well as restricted movement are the major causes of these problems. Radiography was performed in two African elephants at the Schoenbrunn Zoo in Vienna to determine the cause and extent of lameness. Various radiographic techniques are described for use in trained elephants. Low time settings were used to avoid loss of detail through movement and to minimize exposure while observing radiation safety. A 37-year-old elephant had front limb lameness due to an interdigital abscess. In radiographs of the foot an inhomogenous soft-tissue swelling without involvement of the phalanges was seen. Ultrasonography was helpful in visualizing the fluid-filled abscess. In additional joint radiographs severe degenerative joint disease was identified. A 13-year-old elephant had lameness of the hind limb. Radiographs of the hind limb from the foot to the stifle were made. Open physes and early signs of degenerative joint disease were identified on the radiographs.     

Evaluation of safety and pharmacokinetics of vancomycin after intravenous regional limb perfusion in horses

OBJECTIVE: To evaluate clinical variables, regional concentrations, and pharmacokinetics of vancomycin in the synovial fluid of distal forelimb joints of horses after IV regional limb perfusion. ANIMALS: 6 horses. PROCEDURE: Vancomycin was administered via IV regional limb perfusion to the distal portion of the forelimbs of anesthetized horses. Drug (300 mg of vancomycin hydrochloride in 60 mL of saline [0.9% NaCl] solution) was infused into 1 forelimb, whereas the contralateral limb served as a control and was perfused with 60 mL of saline solution. Solutions were injected into the lateral digital vein after digital exsanguination. Synovial fluid from the metacarpophalangeal (MTCP) and distal interphalangeal (DIP) joints and systemic blood were collected prior to perfusion and 15, 30, 45, 65, and 90 minutes after initiation of the infusion. Synovial fluid from the MTCP joint and blood were also obtained at 4, 8, 12, and 24 hours after infusion. Plasma urea and creatinine concentrations, degree of lameness, and certain clinical variables involving the MTCP joint and infusion site were assessed for 7 days. Results were compared between the vancomycin treatment and control groups. RESULTS: No complications or significant differences in renal function, lameness, or clinical variables were observed between groups. Vancomycin concentrations exceeded 4 microg/mL in MTCP joints for approximately 20 hours. Higher concentrations were reached in DIP joints than in MTCP joints. CONCLUSIONS AND CLINICAL RELEVANCE: IV regional limb perfusion with 300 mg of vancomycin as a 0.5% solution was safe and may be useful in horses as treatment for distal limb infections.     

Distal limb radiography, ossification, and growth plate closure in the juvenile Asian elephant (Elephas maximus)

Eleven juvenile Asian elephants (Elephas maximus) were evaluated radiographically to determine the relative times of growth plate closure and phalangeal ossification in the bones of the distal forelimb. Specifically, the first, second, and third phalanges of the third digit (D3) were evaluated, as well as the third phalanx of digits 1, 2, 4, and 5. All elephants were healthy at the time of examination. A retrospective evaluation of radiographs from six of the 11 juvenile elephants was also completed to augment the data set. This study reports the methods used to obtain high-quality radiographs of the distal juvenile elephant limb, ossification characteristics of the phalanges, relative times of growth plate closure within the proximal phalanges of D3, and a method for age estimation based on radiographic findings. This study will help clinicians in conducting elephant foot radiography, in evaluating foot radiographs in juvenile elephants, in recognizing normal versus pathologic change, and in estimating juvenile elephant age based on radiographic ossification characteristics and growth plate closure times. Consistent use of the proposed foot radiograph technique is recommended to facilitate foot disease recognition and as part of the annual examination of captive Asian elephants.     

Laser-Facilitated arthrodesis of the distal tarsal joints

Arthritis of the distal tarsal joints is a common cause of lameness in performance horses. Clinical signs of distal tarsal arthritis are variable and may include gait abnormalities typical for tarsal lameness, including accentuated elevation of the affected limb, shortened cranial phase of the stride, and decreased arc of the foot. Affected horses frequently resent palpation of the lumbar and gluteal musculature. The lameness is usually increased after a hind limb flexion test. This condition is most commonly treated with intra-articular injections of sodium hyaluronate and corticosteroids in conjunction with controlled exercise and systemic nonsteroidal anti-inflammatory medication. Horses that are refractory to this form of treatment have traditionally been treated by cunean tenectomy with inconsistent results. Various surgical techniques have been used to achieve arthrodesis of these joints in an effort to eliminate the lameness associated with arthritic changes in these joints. Laser-assisted arthrodesis offers a minimally invasive surgical procedure with a relatively short convalescent period that eliminates the clinical signs of lameness in a high number of cases.     

Neurofibroma of the ulnar nerve in the carpal canal in a dog: treatment by marginal neurectomy

Peripheral nerve sheath tumours arising in the plexus or peripheral nerves can be treated by limb amputation. There are few reports of these tumours affecting peripheral nerves in the distal regions of the limbs. Here we describe a case of neurofibroma affecting the palmar branch of the ulnar nerve in an Irish setter. Surgical treatment in the region of the carpus by ulnar neurectomy resulted in resolution of chronic thoracic limb lameness. At 11 months following the surgery, clinical examination and MRI did not detect any evidence of recurrence. Neurectomy may be a feasible option for management of selected cases of distally located peripheral nerve sheath tumours.     

Axial Pattern Flap Based on the Genicular Branch of the Saphenous Artery in the Dog

Axial pattern flaps based upon the genicular branch of the saphenous artery and medial saphenous vein were developed in eight dogs. On one hind limb of each dog, the experimental flap was raised and immediately transferred to a cutaneous defect created over the lateral aspect of the lower limb distal to the stifle. A control flap was elevated and transferred on the opposite hind limb with the genicular branches of the saphenous artery and vein ligated and divided at the base of the flap. Eighty-nine per cent of the length of the flap survived in those flaps in which the genicular vessels were left intact, whereas only 54% of the flap's length survived in the control flaps. Postoperatively, all dogs were bearing weight on the limbs normally. The genicular axial pattern flap may have special clinical application in cases of cutaneous defects involving the lateral aspect of the tibia.     

Subjective and quantitative scintigraphic assessment of the equine foot and its relationship with foot pain

It was hypothesised that in solar bone images of the front feet of clinically normal horses, or horses with lameness unrelated to the front feet, there would be less than a 10% difference in the ratio of uptake of radiopharmaceutical in either the region of the navicular bone, or the region of insertion of the deep digital flexor tendon (DDFT), compared to the peripheral regions of the distal phalanx. Nuclear scintigraphic examination of the front feet of 15 Grand Prix show jumping horses, all of which were free from detectable lameness, was performed using dorsal, lateral and solar images. The results were compared with the examinations of 53 horses with primary foot pain, 21 with foot pain accompanying another more severe cause of lameness and 49 with lameness or poor performance unrelated to foot pain. None of the horses with foot pain had radiological changes compatible with navicular disease. All the images were evaluated subjectively. The solar views were assessed quantitatively using regions of interest around the navicular bone, the region of insertion of the deep digital flexor tendon and the toe, medial and lateral aspects of the distal phalanx. In 97% of the feet of normal showjumpers, there was <10% variance of uptake of the radiopharmaceutical in the navicular bone, the region of insertion of the DDFT and the peripheral regions of the distal phalanx. There was a significant difference in uptake of radiopharmaceutical in the region of the navicular bone in horses with foot pain compared to normal horses. There was a large incidence of false positive results related to the region of insertion of the DDFT. Lateral pool phase images appeared more sensitive in identifying potentially important DDFT lesions. There was a good correlation between a positive response to intra-articular analgesia of the distal interphalangeal joint and intrathecal analgesia of the navicular bursa and increased uptake of radiopharmaceutical in the region of the navicular bone in the horses with primary foot pain. It is concluded that quantitative scintigraphic assessment of bone phase images of the foot, in combination with local analgesic techniques, can be helpful in the identification of the potential source of pain causing lameness related to the foot, but false positive results can occur, especially in horses with low heel conformation.     

Equine Granulocytic Anaplasmosis

Equine granulocytic anaplasmosis (EGA) is a seasonal rickettsial disease of horses transmitted by Ixodes spp. ticks. The etiological agent is Anaplasma phagocytophilum, a coccobacillary gram-negative organism with a tropism for granulocytes. Clinical manifestations include fever, partial anorexia, depression, distal limb edema, petechiation, icterus, ataxia, and reluctance to move. Hematologic changes observed are thrombocytopenia, decreased packed-cell volume and marked leukopenia involving first lymphocytes and then granulocytes. Diagnosis is based on awareness of geographic area for infection, typical clinical signs, abnormal laboratory findings, and visualization of characteristic morulae in the cytoplasm of neutrophils and eosinophils in a peripheral blood smear. Treatment consists of the administration of tetracycline. The disease is being diagnosed with increasing frequency in the United States, Canada, Brazil and northern Europe.     

Digital angiography of the feet of horses

OBJECTIVE: To describe the vascular anatomy of the palmar digital artery and its major branches in the equine foot and to quantify the diameter of these vessels by use of digital angiograms. Sample Population-6 thoracic limbs obtained from 6 horses. PROCEDURE: Distal portions of each limb were perfused with aerated Krebs-Henseleit solution. Digital angiograms were acquired in standing and lateral recumbent positions, following an intra-arterial injection of iopamidol. Select vessels were measured on radiographic views, and values were corrected for magnification. RESULTS: The palmar digital artery tapered from 2.28 mm at the coronary region to 1.61 mm at the entrance to the solar canal, and the major arterial branches ranged in diameter from 0.71 to 1.42 mm in the standing position. CONCLUSIONS AND CLINICAL RELEVANCE: Digital angiography is useful for imaging small vessels, but penumbra limits the image resolution of the macrovasculature of the foot. The palmarodorsal projection is more useful for evaluation of the terminal arch and solar branches, but 2 projections are necessary for a thorough examination of the foot. Image magnification, position of horse, and vascular response to contrast medium must be considered in the quantitative assessment of vessel diameter. Digital angiography may be performed in clinical cases and research models for examination of vascular perfusion of the distal portion of the limb.     

Influence of the position of the foot on MRI signal in the deep digital flexor tendon and collateral ligaments of the distal interphalangeal joint in the standing horse

Reasons for performing study: Hyperintense signal is sometimes observed in ligaments and tendons of the equine foot on standing magnetic resonance examination without associated changes in size and shape. In such cases, the presence of a true lesion or an artifact should be considered. A change in position of a ligament or tendon relative to the magnetic field can induce increased signal intensity due to the magic angle effect. Objectives: To assess if positional rotation of the foot in the solar plane could be responsible for artifactual changes in signal intensity in the collateral ligaments of the distal interphalangeal joint and in the deep digital flexor tendon. Methods: Six isolated equine feet were imaged with a standing equine magnetic resonance system in 9 different positions with different degrees of rotation in the solar plane. Results: Rotation of the limb induced a linear hyperintense signal on all feet at the palmar aspect of one of the lobes of the deep digital flexor tendon and at the dorsal aspect of the other lobe. Changes in signal intensity in the collateral ligaments of the distal interphalangeal joint occurred with rotation of the limb only in those feet where mediolateral hoof imbalance was present. Conclusions: The position and conformation of the foot influence the signal intensity in the deep digital flexor tendon and in the collateral ligaments of the distal interphalangeal joint. Potential relevance: The significance of increased signal intensity in the deep digital flexor tendon and in the collateral ligaments of the distal interphalangeal joint should be interpreted with regard to the position and the conformation of the foot.