Magnetic resonance and radiographic imaging of a case of bilateral bipartite navicular bones in a horse.

CASE REPORT: We describe the radiographic and magnetic resonance imaging findings associated with a case of bilateral forelimb bipartite navicular disease in a 7-year-old Warmblood gelding used for eventing. In addition to the radiographically evident partitioned navicular bones, magnetic resonance imaging (MRI) also detected other concurrent abnormalities occurring within the foot that have not been described before in other cases of navicular bone partition. MRI not only revealed soft tissue lesions of the podotrochlear apparatus, but also allowed for more detailed characterisation of the recently diagnosed osseous navicular bone pathology. CONCLUSION: Knowledge of these additional changes influenced prognostication in this case and provides an explanation for why this condition usually results in such a poor prognosis for the return to previous levels of performance in athletic patients.

Arthroscopy of the Dorsal and Plantar Pouches of the Tarsocrural Joint for the Treatment of Osteochondritis Dissecans in the Horse: Clinical Features and Follow-Up.

OBJECTIVE: To describe the clinical details and pathology within the dorsal and plantar pouches of the tarsocrural joint of a population of horses that underwent arthroscopic surgery for tarsocrural osteochondritis dissecans (OCD). STUDY DESIGN: Retrospective cohort study. ANIMALS: Horses referred for arthroscopic treatment of tarsocrural OCD between 2005 and 2013 (102 horses; 144 joints). METHODS: Case records of all horses that had tarsocrural arthroscopy for OCD at Rossdales Equine Hospital, Newmarket, United Kingdom were included. Cases from 3 ECVS Diplomates were included, 1 of whom routinely examined 70 plantar pouches concurrently with routine dorsal pouch investigation. A structured questionnaire was used to obtain follow-up data alongside examination of racing records where appropriate. Descriptive data and 95% CI were calculated. RESULTS: Of the 70 joints that had both dorsal and plantar pouches examined, there was cartilage erosion/degeneration in 22 dorsal pouches (31.4%), cartilage wear lines in 32 plantar pouches (45.7%), and fragments were removed at the time of surgery from 7 plantar pouches (10.0%). Of the plantar pouches with wear lines, 18 (25.7%) had no evidence of cartilage abnormalities (separate from the OCD lesion) within the dorsal pouch. From the 102 horses with available follow-up, 34 horses (66.7%) achieved their intended use postsurgery. CONCLUSION: Routine plantar pouch investigation is warranted in cases of tarsocrural OCD to provide further information on the health of the joint and allows for removal of fragments from the plantar pouch that may not have been identified by routine diagnostic radiography.

Congenital foot deformation alters the topographic organization in the primate somatosensory system.

Limbs may fail to grow properly during fetal development, but the extent to which such growth alters the nervous system has not been extensively explored. Here we describe the organization of the somatosensory system in a 6-year-old monkey (Macaca radiata) born with a deformed left foot in comparison to the results from a normal monkey (Macaca fascicularis). Toes 1, 3, and 5 were missing, but the proximal parts of toes 2 and 4 were present. We used anatomical tracers to characterize the patterns of peripheral input to the spinal cord and brainstem, as well as between thalamus and cortex. We also determined the somatotopic organization of primary somatosensory area 3b of both hemispheres using multiunit electrophysiological recording. Tracers were subcutaneously injected into matching locations of each foot to reveal their representations within the lumbar spinal cord, and the gracile nucleus (GrN) of the brainstem. Tracers injected into the representations of the toes and plantar pads of cortical area 3b labeled neurons in the ventroposterior lateral nucleus (VPL) of the thalamus. Contrary to the orderly arrangement of the foot representation throughout the lemniscal pathway in the normal monkey, the plantar representation of the deformed foot was significantly expanded and intruded into the expected representations of toes in the spinal cord, GrN, VPL, and area 3b. We also observed abnormal representation of the intact foot in the ipsilateral spinal cord and contralateral area 3b. Thus, congenital malformation influences the somatotopic representation of the deformed as well as the intact foot.

Surgical correction of angular and torsional metatarsal deformity with cylindrical osteotomy and locking compression plates in a calf.

OBJECTIVE: To report successful surgical correction of concurrent angular and torsional metatarsal deformities in a calf using a cylindrical osteotomy and locking compression plate (LCP) technology. STUDY DESIGN: Case report. ANIMALS: A 10-week-old composite bull calf. METHODS: Using Paley's principles of angular limb deformity correction, a cylindrical osteotomy was performed to concurrently correct varus deformity and external torsion of the metatarsus. The limb was aligned and stabilized using two 3.5 mm broad LCP with locking head screws. RESULTS: The calf was immediately weight bearing after surgery and did not experience any postoperative complications. Follow-up radiographs 5 months postoperatively revealed complete osteotomy healing and remodeling. The limb was in good alignment, the calf was fully weight bearing, and client satisfaction was very high. Telephone follow-up with the owner 16 months after surgery revealed continued full use of the operated limb and the bull was being used in a pasture breeding program. CONCLUSIONS: Cylindrical osteotomy with LCP stabilization can provide a favorable outcome in angular and torsional metatarsal deformity correction in cattle.

Congenital digital aplasia in a free-ranging group of silvery marmosets, Mico argentatus.

Congenital aplasia of the hallux (big toe) was observed in seven adult and infant members of a free-ranging group of silvery marmosets (Mico argentatus) in the Alter do Chão savannah of central Amazonia. Apparently heritable, the condition was more common in males (80%) than females (50%) but was found in no other members of the population. Animals with the condition presented normal behaviour.

Correction of rotational deformity of the pes with external skeletal fixation in four dogs.

OBJECTIVE: To report unilateral correction and initial stabilization with external skeletal fixation (ESF) of metatarsal rotation in 4 immature Bernese Mountain Dogs. STUDY DESIGN: Case series. ANIMALS: Bernese Mountain Dogs (n=4). METHODS: The limb deformity, including degree and origin of the deformity at the level of the proximal intertarsal joint and involvement of the central tarsal bone, was characterized by clinical and radiographic assessment. Unilateral surgical correction of the most severely affected limb was performed by disrupting the ligaments and debriding the articular cartilage of the proximal intertarsal joint to allow for derotation of the deformity and arthrodesis of the proximal intertarsal joint stabilized with either circular or linear ESF. RESULTS: Initial metatarsal rotation of the corrected limbs ranged from 60 degrees to 80 degrees of external rotation (mean, 72.5 degrees). Three limb corrections were stabilized with circular ESF and 1 with a biplanar linear ESF. Implants were removed at the time of radiographic bony union (range, 7-10 weeks; mean, 8.6 weeks). Residual deformity was minimal, ranging from 6 degrees to 15 degrees (mean, 11 degrees). Two minor complications (loosening of 1 pin, serous drainage from 1 pin) resolved with treatment. CONCLUSION: Correction of rotational deformity of the pes with intertarsal arthrodesis yielded an excellent clinical outcome, with only a mild residual deformity. CLINICAL RELEVANCE: Rotational metatarsal deformities can have a significant impact on gait, ambulation, and appearance. Correction of these deformities and stabilization with ESF and intratarsal arthrodesis can yield an excellent functional outcome, with improved gait and ambulation.

Ectrodactyly in a West Highland white terrier.

A case of monomelic forelimb ectrodactyly (lobster-claw deformity) in a West Highland white terrier is reported. Clinical and radiographic findings are described. The dog was treated with a soft tissue reconstruction of the cleft. It later developed a slight varus-type deformity at the carpus but remained sound with occasional bouts of mild lameness following vigorous exercise. To the author's knowledge, this is the first reported case of canine ectrodactyly treated by simple cleft reconstruction, and only the second report of ectrodactyly in this breed.

Foot management in the foal and weanling.

Foot management and hoof care of foals, weanlings, and yearlings tends to be considered a specialist job. Many farriers and veterinary surgeons have little exposure to young and growing stock. Nevertheless, a variety of angular and flexural limb deformities can benefit from simple podiatry techniques, which can be performed provided that a few basic rules are followed. The combined skills of the farrier and veterinary surgeon offer many young horses with angular or flexural limb deformities a chance of a future athletic career.

Distraction osteogenesis for treatment of premature physeal closure and shortening of the third and fourth metatarsals of a dog.

A 4-month-old Siberian husky was presented for a history of lameness of the left hind limb. Physical and radiographic examination revealed a 1-cm shortening of metatarsals III and IV, with subsequent hyperextension of the digits on the left hind paw. A circular external skeletal fixator was used to accomplish distraction osteogenesis in both metatarsals over a period of 15 days. Treatment was successful in restoring appropriate length of the metatarsals and in resolution of the lameness. At 6 and 12 months after surgery, the owner reported that the dog was ambulating normally and had no complications related to the surgery.

Clinical and pathological findings in two Mauritian pink pigeons (Columba mayeri).

Two Mauritian pink pigeons (Columba mayeri) from a captive breeding programme, with locomotor disorders were examined clinically and post mortem. One bird was unable to fly owing to a permanent luxation of the left elbow. The other bird had an inclined foot caused by a medial curvature and outward rotation of the tarsometatarsal bone, a deformity similar to the previously recorded 'inclined feet' in birds bred in Mauritius.

A lobster claw abnormality in the common marmoset (Callithrix jacchus).

A congenital abnormality of the digits, similar to the 'lobster claw' deformity of humans, was observed in 8 common marmosets. The condition varied in severity and in effect on the animals; it appeared to be due to a single autosomal recessive trait.

Three congenital anomalies of domestic fowl.

Of 35,000 necropsies performed on domestic poultry, three cases of anomalies were recorded. The anomalies observed were duplicate polydactyly, accessory hepatic lobe, and reduplication of caeca.