Angular Limb Deformities: Growth Retardation.

Angular limb deformities are common in foals; however, the importance of the deformity and if treatment is required depend on the degree of deformity relative to normal conformation for stage of growth, the breed and discipline expectations, age, and response to conservative therapies. This article addresses the importance of the foal conformation examination to determine which foals need surgical intervention to correct an angular deformity and when. Techniques for surgical growth retardation include the transphyseal staple, screw and wire transphyseal bridge, and transphyseal screw. Appropriate timing for intervention for each location and complications associated with each procedure are discussed.

Angular Limb Deformities: Growth Augmentation.

Angular limb deformities are seen in young foals and are defined as lateral or medial deviations of the limb in the frontal plane distal to a particular joint. Several factors can contribute to the development of an angular limb deformity. Early assessment of the level of ossification of the cuboidal bones is critical to avoid complications long term. Although most deviations self-correct with minimal intervention other than modifications in exercise and hoof trimming, some require surgical intervention in the form of growth acceleration or retardation. This article focuses on growth augmentation techniques, such as hemicircumferential transection and elevation.

Radiographic Recognition of Tarsal Malformation in 8- to 9-Week-Old Bernese Mountain Dogs.

INTRODUCTION: Tarsal malformation is a skeletal malformation of unknown aetiology associated with a variety of morphologic changes to the tarsal and metatarsal bones of the dog. OBJECTIVE: The aim of this study was to determine if early diagnosis and prevalence of tarsal malformation could be obtained at approximately 8 to 9 weeks of age in multiple litters of Bernese Mountain dogs. METHODS: A prospective study of 51 Bernese Mountain dog puppies were evaluated from 12 litters in northern Italy. Dorsoplantar radiographic views of the tarsus were obtained at 60 ± 5 days of age. Tarsal malformation was defined as an abnormal extension of the central tarsal bone on its medial side, or the presence of ectopic bone located medially to the central tarsal bone, talus and second metatarsal bones (proximomedial, distomedial and metatarsal ossification sites respectively). RESULTS: All puppies were found to be clinically normal. Thirty-nine of the 51 puppies showed ossification sites medial to the tarsus as defined. A metatarsal ossification was present in all dogs with either a proximo- or distomedial ossification site. No central tarsal bone extensions were observed. The remainder of the tarsometatarsal joints were normal. CLINICAL SIGNIFICANCE: Tarsal malformation can be identified in the 8- to 9-week-old Bernese Mountain dog. The clinical significance of tarsal malformation remains to be determined, either as an incidental finding or a precursor to the development of other clinically relevant and related issues in the tarsus.

Sex-based comparison of limb segmentation in ostriches aged 14 months with and without tibiotarsal rotation.

The aim of this study was to propose equations to predict changes that occur over time in the angular position of the bones during motion and the angular velocity of the bones in forward motion as a consequence of tibiotarsal rotation (TTR) in ostriches aged 14 months. Twenty-four normal 14-month-old ostriches (12 cocks and 12 hens) and 20 birds with TTR (9 cocks and 11 hens) were used in the study. Daily readings of temperature, relative humidity and rainfall, the lengths of the different segments of the legs and wings, the perpendicular height from the top of the torso to ground level and the length of the erect neck were recorded. Measurements of the degree of valgus deformity in the left foot were made where applicable. TTR hens and cocks were smaller in stature than normal birds. Comparing TTR hens and cocks, the toe, claw, humerus, perpendicular height and angle of rotation were larger in cocks, indicating a larger body in cocks. Hens were more severely affected by TTR. We suggest that the equations used in this study will assist in measuring movement of ostriches and how movement is compromised by overcrowding and TTR. Birds suffering from TTR may experience an increased degree of stress due to movement restrictions in confinement.

Gestation length and racing performance in 115 Thoroughbred foals with incomplete tarsal ossification.

BACKGROUND: Incomplete ossification of the cuboidal bones of the carpus and tarsus in foals has the potential for significant consequences including chronic lameness and decreased athletic ability. OBJECTIVES: To determine if the degree of ossification of the cuboidal bones is associated with gestational length and if the diagnosis of incomplete ossification is a predictor of performance in Thoroughbred racehorses. STUDY DESIGN: Retrospective cohort study. METHODS: The medical records of Thoroughbred foals less than 90 days of age from 1994 to 2011 were examined and records containing tarsal radiographs identified. Radiographs of the tarsus were examined for signs of incomplete ossification and those that were incompletely ossified graded on a scale of 1-4 using a modification of a previously reported index, with Grade 1 being the least ossified and Grade 4 being the most. Gestational length was determined by examining breeding records and foaling dates reported to the Jockey Club. Race records for 2- and 3-year-old affected foals and their maternal siblings were obtained and compared. RESULTS: Foals with Grades 1 and 2 ossification were usually premature (gestation length <325 days), but Grades 3 and 4 were not. Foals with Grades 2 and 3 ossification were significantly less likely to race than their maternal siblings and Grades 1, 2, 3 and 4 foals earned less money. MAIN LIMITATIONS: A larger sample size of foals with Grade 1 ossification would increase the power of the study. Foals radiographed at an older age may have had lower ossification scores if radiographed earlier. CONCLUSIONS: Incomplete ossification, especially Grades 1 and 2, is associated with a short gestation length. Foals with Grades 2 and 3 incomplete ossification were less likely to race and Grades 1, 2 and 3 earned around $30,000 less than their maternal siblings.

Disrupted bone metabolism in contaminant-exposed white storks (Ciconia ciconia) in southwestern Spain.

In 1998, the Aznalcóllar mine tailings dyke in southwestern Spain broke, flooding the Agrio-Guadiamar river system with acid tailings up to the borders of one of the largest breeding colonies of white storks in the western Palearctic, Dehesa de Abajo. Over the following years, a high proportion of nestlings developed leg defects not seen before the spill, prompting this study. Nestlings with deformed legs had significantly lower plasma phosphorous (P) and higher Ca:P ratios than non-deformed cohorts in the first two years, but in the third year, when more, younger birds were studied, plasma P ranged from much higher to much lower in the affected colony compared with reference birds. Coefficients of variation for phosphorous were 19% and 60%, in reference and contaminated colonies, respectively. Storks from the contaminated colony were unable to control P levels and Ca:P ratios within the narrow limits necessary for normal bone development.

Surgical correction of a bilateral congenital tarsal hyperextension deformity in a cat.

CASE DESCRIPTION: An approximately three-month-old, 0.45 kg female Domestic Shorthaired kitten with stiff hyperextended hindlimbs distal to the talo-central joint is reported. Attempts at repositioning of the joints by flexion failed while increased manipulative forces caused signs of pain and vocalization. Orthogonal radiographic views revealed a significant malarticulation of the tarsus. Goniometric measurments revealed a 145° extensor and 95° internal torsional deformity. TREATMENT AND OUTCOME: Pantarsal arthrodesis with a transarticular external fixation system was performed for both limbs in two separate stages. Pre-assembled frames were composed of two 40 mm diameter half rings (on the medial side) and two 40 mm diameter full rings connected with two pre-contoured (125° flexion) rods from proximal to distal. Following transection of the superficial and deep digital flexor tendons, cartilage was removed from the articular surfaces, autologous cancellous bone graft was inserted, and joints were fixed in 125° flexion with pre-contured external frames. The cat commenced weight-bearing bilaterally immediately postoperatively. Frames were removed 32 and 27 days after application. Two months after frame removal, joint fusion was confirmed and full weight-bearing at the walk and run was achieved. CLINICAL RELEVANCE: To our knowledge, this is the first report of surgical correction of a bilateral congenital tarsal hyperextension deformity by pantarsal arthrodesis using a transarticular external fixation system.

Skeletal abnormalities in domestic chicken.

In 14,891 necropsies performed on domestic poultry during January 1976 to October 1977, two cases of skeletal abnormalities were found. One was a tarsometatarsal spur in an adult female chicken, and the other was a crossed-beak associated with microphthalmia.

Scoliosis and tibiotarsal deformities in broiler chickens.

The incidence and degree of scoliosis were investigated in broiler chickens with and without intertarsal deformities associated with slipped gastrocnemius tendons. In both groups, the incidence of scoliosis was similar and there was a significant tendency for scoliosis to be convex on the right side. However, scoliosis was significantly greater in birds with intertarsal deformities, and in a significant proportion of these the joint with a slipped tendon was on the convex side of scoliosis. In birds with deformities, inequalities between right and left tibiotarsi were significantly greater, and tibiotarsi with greater length, narrower condyles and trochleae, and shallower trochlear grooves were significantly more often on the convex side of scoliosis. Significant positive correlations were found between scoliosis and rotational and bending deformities of the distal tibiotarsus on the convex side of scoliosis. These findings suggest a cause-and-effect relationship between scoliosis and tibiotarsal deformities associated with slipped tendons.

Histomorphometry and vitamin D metabolism of valgus-varus deformity in broiler chickens.

Vitamin D metabolite levels and tibiotarsal histomorphometric characteristics were determined in 49-day-old male broilers. Valgus-varus bone deformity was present in 5.2% and tibial dyschondroplasia (TD) in 3% of these broilers, which were raised on floor litter under seemingly normal nutritional, space, and lighting conditions. No significant weight differences were observed between normal and lame broilers. The plasma levels of 25-OH-D were the same in lame and normal broilers. However, 1,25-(OH)2D plasma levels were reduced 28% in broilers with valgus-varus deformities but normal in broilers with TD. Anatomically, there were three different patterns of bone development in the undecalcified mid-diaphyseal sections. The pattern with the least periosteal growth, lowest tetracycline labeling, and smallest marrow cavity was most often seen in valgus-varus deformities. Patterns with greatest periosteal growth, high tetracycline labeling, and larger marrow cavities were more representative of normal broilers. It was hypothesized that defective prostaglandin metabolism reduced 1,25-(OH)2D levels, contributing to the overall reduction in bone formation and bone resorption observed in broilers with valgus-varus bone deformity.

Radiographic, high detail radiographic, microangiographic and histological findings of the distal portion of the tarsus in weanling, young and adult horses.

Clinical radiographic (LM and D35L-P1MO views), high detail radiographic, microangiographic and histological findings of the distal portion of the tarsus of 16 horses (five weanling, four young and six adult), without known clinical histories, were evaluated to determine the sensitivity of clinical radiographs for the detection of abnormalities in the distal tarsus and the prevalence of abnormalities in this population. Clinical radiographic and high detail radiographic abnormalities were observed in at least 30 per cent of the tarsi examined. Statistical agreement between observations from clinical radiographs and corresponding post mortem high detail radiographs was not good for subchondral bone plate irregularities and joint margin changes. Three patterns of sclerosis of the medullary spongiosa were visualised on high detail radiographs: thickening of the subchondral bone plate was seen commonly in the weanling group, whereas arching and bridging patterns were more prevalent in the young and adult groups. Bone production on the dorsal cortex of the central and third tarsal bones did not increase with age. Abnormalities in vascular perfusion and articular cartilage histology were observed in association with subchondral bone plate irregularities and focal regions of osteopenia observed on high detail radiographs.

A lag-screw technique for bridging of the medial aspect of the distal tibial physis in horses.

A lag-screw technique for transphyseal bridging of the medial aspect of the distal tibial physis in foals with tarsal valgus deformities and results of the technique in 11 foals (6 with bilateral tarsal valgus deformities and 5 with unilateral tarsal valgus deformities) are described. Briefly, horses were anesthetized, and a single stab incision was made through the skin to the underlying bone over the most distal aspect of the medial malleolus. A 20-gauge needle was placed in the incision to guide screw placement, and a lag screw was inserted parallel to the medial cortex of the tibia under radiographic guidance. Screws were removed when the tarsal valgus deformity was clinically assessed to have improved by at least 80%. Clinically, all horses had evidence of a tarsal valgus deformity of > 7 degrees prior to surgery. Mean age at the time of lag-screw implanation was 220 days (range, 116 to 364 days). Mean time the implant was in place was 62 days (range, 39 to 89 days). The tarsal valgus deformity resolved in all 11 horses with excellent cosmetic results.

Multiple nonlethal congenital anomalies in a llama.

Whereas numerous congenital anomalies in South American camelids have been reported, multiple anomalies are uncommon. A young llama evaluated for bilateral hind limb lameness was found to have cranially rotated tibial tarsal bones as well as bilateral carpus and tarsus valgus and a ventricular septal defect. These anomalies were likely hereditary, and llamas so affected should not be bred.

Incomplete ossification of the tarsal bones in foals: 22 cases (1988-1996).

OBJECTIVE: To determine outcome for foals with incomplete ossification of the tarsal bones and to determine whether clinical and radiographic abnormalities at the time of initial examination were associated with outcome. DESIGN: Retrospective study. ANIMALS: 22 foals. PROCEDURE: Information on signalment, history, owner's initial complaint, clinical findings, whether tarsus valgus was evident, and radiographic abnormalities was obtained from medical records. Radiographic lesions were classified as type I (i.e., incomplete ossification with < 30% collapse of the affected bones) or type II (incomplete ossification with > 30% collapse and pinching or fragmentation of the affected bones). Follow-up information was obtained via telephone conversations with owners. RESULTS: Foals were between 1 day and 10 months old when first examined. Eleven were premature (i.e., < 320 days of gestation) or were twins. Sixteen had tarsus valgus. Severity of radiographic lesions was associated with outcome; 4 of 6 foals with type-I incomplete ossification of the tarsal bones performed as intended, but only 3 of 16 foals with type-II incomplete ossification of the tarsal bones performed as intended. CLINICAL IMPLICATIONS: For foals with incomplete ossification of the tarsal bones, severity of the radiographic lesions was associated with outcome. Foals with type-II incomplete ossification of the tarsal bones have a guarded prognosis for athletic soundness.

Treatment response and athletic outcome of foals with tarsal valgus deformities: 39 cases (1988-1997).

OBJECTIVE: To evaluate the response to various treatments and long-term outcome of foals with tarsal valgus deformities. DESIGN: Retrospective study. ANIMALS: 39 foals with tarsal valgus deformities. PROCEDURE: Data collected from medical records, included signalment, history, reason for admission, and clinical findings. Radiographic views of the tarsus were evaluated for incomplete ossification of tarsal bones and were classified as normal in appearance, type-I incomplete ossification, or type-II incomplete ossification. Treatment and athletic outcome were documented for each foal. RESULTS: Radiographic assessment revealed that 22 of 39 foals (56%) had concomitant tarsal valgus deformities and incomplete ossification of the tarsal bones. Eight of 19 foals with tarsal valgus deformities that were treated with periosteal stripping responded favorably. Foals < or = 60 days old were significantly more likely to respond to periosteal stripping than older foals. Five of 8 foals with tarsal valgus deformities that were treated with growth plate retardation responded favorably. Eleven of 21 foals with long-term follow-up performed as intended. Compared with foals with type-II incomplete ossification, foals with tarsal bones that had a normal radiographic appearance or type-I incomplete ossification were significantly more likely to perform as intended. CONCLUSIONS AND CLINICAL RELEVANCE: Foals with tarsal valgus deformities should have lateromedial radiographic views of the tarsus obtained to assess the tarsal bones for incomplete ossification, which will affect athletic outcome. Because foals with type-II incomplete ossification of the tarsal bones respond poorly to periosteal stripping alone, treatment by growth-plate retardation is recommended.

Development of a quantitative method for the evaluation of varus-angular bone deformity in chickens.

A quantitative technique was developed to measure the degree of flexion (twisting) and torsion (angulation) of the tibiotarsus bone from chickens affected with varus-angular bone deformity (varus-ABD). A plexiglass device was constructed consisting of X, Y, and Z-axis planes. The Y-axis plane was used to position the tibia in a constant reference position. The distance in millimeters from the (0, 0, 0) coordinate to the (X', 0, 0) coordinate was used to measure medial tibial flexion (TF), and the distance from the (0, 0, 5 cm) coordinate to the (X', 0, 5 cm) coordinate was used to measure lateral TF. The X-axis plane was fitted with a protractor to measure the angle of the proximal head of the tibia as a measure of tibial torsion (TT). The Z-axis plane was used to measure tibial length. Tibias with mild varus-ABD had TF values of greater than 0 but less than or equal to 5 mm, whereas severe varus-ABD tibias had TF values of greater than 5 mm. The TT values ranged from 10 to 60 degrees, with the lower values associated with severe varus-ABD.

Biotin deficiency may alter tibiotarsal bone growth and modeling in broiler chicks.

Forty-eight, day-old male broiler chicks (Hubbard x Hubbard strain) were fed purified diets with two levels of biotin (0 and 400 micrograms/kg) and two levels of linoleate (26.5 and 1.5 g/kg) in a factorially designed experiment to determine the effects of these nutrients on tibiotarsal bone growth and modeling. Chicks fed biotin-deficient diets (0 microgram/kg diet) exhibited varus deformities, footpad dermatitis, shortened tibiotarsi, and significantly higher bone densities and percentage bone ash. Anatomically there were two different bone modeling patterns. The mid-diaphyseal cortex was thickest laterally in chicks fed adequate biotin and thickest medially in biotin-deficient chicks. Periosteal bone appositional and bone formation rates, osteoid perimeter, and osteoid area of perimeter were reduced in tibiotarsi of chicks fed diets deficient in biotin compared with effects in chicks fed adequate biotin. Altered bone modeling patterns and quantitative differences in bone histomorphometry suggest a relationship between the effects of biotin on bone growth and the development of varus limb deformities.

Serum- and bone-mineral status of ostriches with tibiotarsal rotation.

Tibiotarsal rotation in ostrich chicks is a serious problem that accounts for considerable financial loss to ostrich farmers. Serum- and bone-mineral analyses of 20 ostrich chicks with tibiotarsal rotation were compared with serum- and bone-mineral analyses of eight normal ostrich chicks of comparable age, sex and body mass, and raised under identical conditions. The serum-zinc values were significantly higher and the bone-calcium and phosphorus values significantly lower in the affected group than in the group of normal ostrich chicks. The results indicated poor mineralization of bone with subsequent reactive osteoid formation.

Factors on farms in eastern Australia associated with the development of tibiotarsal rotation in ostrich chicks.

OBJECTIVES: To determine the incidence of tibiotarsal rotation (TTR) in ostrich chicks and to identify factors on farms associated with the development of TTR. DESIGN: A cross-sectional study using a personal interview. PROCEDURE: During a single visit to 31 farms, data were collected about a defined cohort of chicks, and about farm-related factors that may be associated with the development of TTR. Farms were categorised for TTR status according to the proportion of the chick cohort that survived to 10 weeks of age without developing TTR. Chick performance was measured using descriptive epidemiological methods and univariable analyses were conducted to identify unconditional associations between TTR status and farm-related factors. RESULTS: Ninety-six of 931 ostrich chicks from 21 (68%) farms developed TTR during the first 10 weeks following hatch. Lower limb deformities were the most common cause of death in chicks between 3 and 10 weeks of age. On seven (23%) study farms, where less than 87% of young chicks survived to 10 weeks without developing this condition, TTR was considered a serious problem. Twelve farm-related factors were associated with farm TTR status, including eight chick-related variables (aspects of nutrition, pen design and management) and four farm-related variables (related to the number of veterinary visits, farm location, number of rainy days and the person most closely involved with chick raising. CONCLUSION: The results confirm a continuing problem of young chick wastage in eastern Australia. TTR was an important cause of mortality in farmed ostrich chicks during the first 10 weeks after hatch. The factors that producers could address to reduce the incidence of TTR include pen design, access to water and nutrition.

[The radiologic image of the normal equine tarsus]. / Etude de l'image radiologique du tarse equin normal.

Normal radiographs of hocks were analyzed for 270 horses (3 views for each hock). They were mainly from young and sound horses. For such animals, the mean number of abnormalities found was 2 to 4.5 for each picture. The mean dimension of certain tarsal bones was measured; geldings had greater bones than mares. An increase of reactions at the origin of the M. interosseus was seen with the age. It was possible to demonstrate that Medichrome films increase the number of discrete abnormalities to be found; this is of particular value for purchase examinations of young horses. The direction of the central beam (angle) is important in order to get symmetrical pictures; a minimal change in this angle can show or hide discrete abnormalities. A description of the normal radiographic anatomy of the equine hock, and its principal variations, is given.