Vascular pattern of the developing intertarsal joint in the domestic fowl

The origin and nature of vascular canals in the distal tibiotarsus and proximal tarsometatarsus of the fowl have been described. The vascular pattern was modified at different stages of growth and there were anastomoses between epiphyseal vascular canals in the proximal tarsometatarsus. Such anastomoses are not seen in other bone extremities of the fowl and their presence may be a consequence of the incorporation of tarsal elements in proximal tarsometatarsi. In all the distal tibiotarsi examined, a third epiphyseal ossification centre was present. The pattern of metaphyseal vessels in the distal tibiotarsus and proximal tarsometatarsus was altered in some young chicks. This finding may be the result of abnormal angulation of the intertarsal joint which would result in uneven joint loading.     

Bilateral carpus valgus with cranial bowing of the distal radius in a foal

Bilateral carpus valgus with concomitant outward rotation and cranial bowing of the distal radii was diagnosed in a crossbred foal. The foal was not lame on admission and showed no radiographic evidence of carpal bone abnormalities. Surgery was limited to the most severely affected leg, and consisted of a combination of growth promotion (periosteal transection and stripping) and temporary physeal retardation (transphyseal bridging) procedures. Correction of the valgus deformity was nearly complete in the operated limb and substantial improvement was observed in the cranial bowing and outward rotation in both limbs, five months postoperatively.     

Effect of unilateral weight-bearing on pelvic limb development in broiler fowls: vascular studies

Fifteen broiler fowls which habitually adopted a unilateral weight bearing stance were studied. In the majority of fowls the left pelvic limb was weight bearing and the right limb showed severe angular deformity. Dyschondroplasia occurred most frequently in the load-bearing limb. In the load-bearing limb the majority of lesions were in the femur and proximal tibiotarsus. In the non-load-bearing limb lesions most frequently occurred in the bone extremities of the distal tibiotarsus and proximal tarsometatarsus. Occluded epiphyseal vascular canals occurred in conjunction with physeal thickening at some dyschondroplastic sites. The majority of dyschondroplastic lesions contained elongated penetrating epiphyseal vessels and vessels derived from the perichondrial ring. These vessels were associated with chondrocyte hypertrophy and matrix calcification, which was considered to lead to the repair of the lesions. There was minimal calcification of cartilage at the base of the dyschondroplastic lesions and the underlying metaphyseal vessels were blunt ending. This suggested that a band of abnormal physeal cartilage was acting as a barrier to penetration by the metaphyseal vessels and so preventing subsequent endochondral ossification.     

Spread bow leg syndrome in ostrich (Struthio camelus) chicks aged 2 to 12 weeks

1. The incidence of spread bow leg syndrome and associated pathology in 15 ostrich chicks aged 2, 4, 8 and 12 weeks is reported. Measurements were made of hind limbs: femur plus tibiotarsus; tarsometatarus; phalanx I, digit III; phalanx II, digit III plus phalanx III, digit III; and phalanx IV, digit III. 2. A run was constructed (6 m x 1.7 m) and subdivided into 2 m sections and the time taken to traverse it was recorded. Measurements (cm) were made of the left and right footprints; the number of footprints and average stride length in 0 to 2, 3 to 4 and 5 to 6 m. Speed was calculated using distance run (m) divided by time taken (s). 3. The number of steps was greater in bow leg chicks aged 4 and 8 weeks by comparison with healthy birds. Stride length, however, was smaller in all age groups with bow leg. All speeds in bow leg chicks were lower than those in healthy birds, except for that recorded at 2 m in chicks aged 2 weeks which did not differ markedly. 4. In affected birds, feathers were sparse. Icterus was present. The tarsometatarsus was twisted, with severely inflamed joints, eroded distal ends, thickening of the cartilage and the presence of fibrous material surrounding the ligaments. Muscles in the hind limb were emaciated. 5. The syndrome compromises the ability of chicks to keep up with adults in flocks, and may compromise their ability to escape predation.     

Correction of angular limb deformity in two subspecies of flamingo (Phoenicopterus ruber) utilizing a transphyseal bridging technique.

Three hand-raised American flamingo (Phoenicopterus ruber ruber) chicks and one hand-raised Chilean flamingo (Phoenicopterus ruber chilensis) developed valgus angular limb deformities of the proximal tarsometatarsal bone. All flamingos underwent surgical correction to unequally retard the growth plate using transphyseal bridging. Positive profile pins were placed in the proximal epiphysis and distal to the growth plate in the metaphysis on the convex side of the affected tarsometatarsus. Various banding techniques were used in each flamingo to create tension. Three of the four flamingos responded in 7-14 days with correction or slight overcorrection of the valgus limb deformity. The fourth flamingo's leg deformity did not improve for reasons thought to be related to improper implant placement. Growth plate retardation by transphyseal bridging proved successful in correcting valgus limb deformity of the proximal tarsometatarsus. This technique may be considered as an option for correction of angular limb deformities of the proximal tarsometatarsus in flamingos less than 90-120 days of age.     

Effect of dyschondroplasia on the rate of bone growth in the fowl

A group of Leghorn and a group of broiler chicks were reared from day old. At two weeks old a metallic marker was placed unilaterally in the mid-diaphysis of the femur, tibiotarsus and tarsometatarsus of every chick. After the operation the limbs were radiographed. After a period of growth the birds were killed and the radiographs repeated. Measurements from the radiographs enabled the calculation of the rate of growth at the bone extremities. There were metaphyseal defects indicative of dyschondroplasia present in some of the broiler bone extremities, these bones were considered as a separate group. When the Leghorn and normal broilers were compared there was a significant reduction in the proportion of growth in the proximal tibiotarsus of the broilers. The dyschondroplastic bone extremities in broilers demonstrated a reduction in the proportional growth rate compared with normal extremities.     

Pathology of vitamin D deficiency in growing turkeys

Turkey poults were fed a vitamin D-deficient diet and examined for clinical signs and structural changes of bone and parathyroid glands. Vitamin D-deficient poults developed ricketic changes during days 10 to 14. Control poults (deficient diet plus vitamin D) did not develop rickets. In deficient poults, lengths of proliferating-prehypertrophied zones of growth plates increased significantly in the proximal tibiotarsus but were only slightly elongated in the distal tibiotarsus. Unmineralized hypertrophic chondrocyte zones increased in length rapidly in conjunction with a decrease in the length of mineralized hypertrophic degenerative zones; this occurred more rapidly in proximal than in distal tibiotarsus. Other ricketic changes included decreases in bone ash, total femoral bone ash (calcium, phosphorus, magnesium), bone length, and body weight. Plasma alkaline phosphatase was increased, calcium was normal, and phosphorus was normal or elevated. Parathyroids were hyperplastic and had foci of degeneration. Vitamin D3 metabolites 25OHD3, 1,25(OH)2D3, and 24,25(OH)2D3 were rapidly depleted. Increase in bone ash Ca/P ratios in deficient poults suggests that phosphorus may be selectively released from ricketic bone. Low 25OHD3 and 1,25(OH)2D3 of control poults early in the experiment suggests that 1,400 IU of vitamin D3/kg of feed may not be an adequate level of vitamin D3 for growing turkey poults.     

Periosteal transection of the proximal phalanx in foals with angular limb deformities of the metacarpo/metatarsophalangeal area

Bilateral angular limb deformities of the metacarpo/metatarsophalangeal regions in 2 foals are discussed. Periosteal transection was used to correct the deformity in both foals. In one foal, only the right forelimb was treated because the deformity in the left forelimb did not appear to warrant surgery. Subsequently, an angular limb deformity, which could have been prevented, developed in the left forelimb. A third foal developed a deformity in the proximal phalanx after periosteal transection of the distal third metatarsal bone.     

Vascular pattern of the developing knee joint in the domestic fowl

Laying strain fowls were reared from hatching till 20 weeks old. Birds were killed throughout the growth period and specimens from the distal femur and proximal tibiotarsus prepared for study. The origin and nature of cartilage canals were established in the two bone extremities. The canals follow a pattern of development which was similar in fowls of the same age. Similarities were noted with the vascular patterns reported in other species. The epiphyseal ossification centre of the proximal tibiotarsus formed in an area extensively perfused by cartilage canals. Anastomoses occurred between epiphyseal vascular canals in association with the formation and growth of the epiphyseal ossification centre in the proximal tibiotarsus. Anastomoses between epiphyseal vascular canals did not occur at any other site. The development of the epiphyseal ossification centre in the proximal tibiotarsus suggests that this is a traction epiphysis.     

Comparison of Holding Power of Three Different Pin Designs for External Skeletal Fixation in Avian Bone: A Study in Common Buzzard (Buteo buteo)

Objective— (1) To evaluate resistance to axial extraction of 3 pin designs in avian humerus and tibiotarsus; (2) to assess the effect of pin location within the bone on holding power; and (3) to assess the influence of thread pitch on holding power. Study Design— Resistance of pins to axial extraction was measured immediately after insertion. Animals— Adult common buzzards (Buteo buteo; n=9). Methods— Different pin designs (1 smooth; 2 threaded pins, differing in pitch) were inserted into the proximal and distal metaphysis and the proximal, middle, and distal diaphysis of the humerus and tibiotarsus. Maximum force required for axial extraction of pins was recorded. Results— Smooth pins had the lowest extraction force (P<.05). Pins inserted into the diaphysis (proximal, middle and distal) of the humerus and the distal metaphysis of the tibiotarsus had a greater pullout strength than pins in other locations. Pins with a smaller pitch inserted into the proximal diaphysis and distal metaphysis of the humerus, and the proximal metaphysis of the tibiotarsus had significantly greater holding power than pins with a larger pitch (P<.05). Conclusions— Pins inserted into the diaphysis of humerus and the distal metaphysis of the tibiotarsus are better at resisting extraction. Pins with a smaller pitch possess greater holding power than pins with a larger pitch in avian humerus and tibiotarsus. Clinical Relevance— Consideration should be given to pin location and thread pitch, when choosing external skeletal fixation to repair an avian humeral or tibiotarsal fracture.     

Granulosa thecal cell tumour in a mare causing hypertrophic osteopathy

Hypertrophic osteopathy (HO) is a rare condition in the horse characterised by symmetrical proliferation of connective tissue and subperiosteal bone, along the diaphyses of limb bones. In this case, a 10‐year‐old Irish Draught cross Thoroughbred mare was presented for investigation of weight loss, lethargy and firm swelling of all 4 distal limbs. Radiographs of the distal limbs revealed palisade‐like periosteal new bone formation perpendicular to the cortex of the distal third metacarpal and metatarsal bones, proximal (P1) and mid (P2) phalanges. Rectal examination revealed a mass of approximately 20 x 30 cm in the right caudoventral abdomen. The mare was diagnosed with HO due to a granulosa thecal cell (GTC) tumour. The GTC tumour was removed and the diagnosis confirmed on histological examination. Clinical examination and radiographs of the distal limbs after surgery demonstrated reduction in size of the limb swellings and new bone formation. To the authors' knowledge this is the first report of HO due to a GTC tumour in a mare.     

Patterns of cell proliferation and growth rate in limb bones of the domestic fowl (Gallus domesticus)

The growth rates of each extremity of the tibiotarsus (TibT) and tarsometatarsus (TMT) bones and of a phalangeal bone were measured in Rhode Island red chicks. Histological sections of the growth plates at each of these sites were made for measurements of the thickness of the flattened dividing cell layer and counts of the number of cells between its boundaries. The diameter of the mature chondrocytes in the metaphysis was also measured. The extent of the dividing cell population within the flattened cell layer and the proportion of cells in division were measured from autoradiographs prepared after labelling dividing cells in vitro or in vivo (three birds in each group) with tritiated thymidine. From the results the rate of cell production in the plane of growth at each growth plate was estimated. It varied from about six cells per day at each end of the phalanx to just over 50 cells per day at the proximal end of the TibT and TMT. The duration of the cycle time was estimated to be 13 to 21 hours at the proximal TibT and TMT and distal TibT but considerably longer at the distal TMT and at both ends of the phalanx. Variation in growth rate between extremities of the bones examined was associated largely with variation in the dividing cell populations and the thickness of the flattened cell layer, but it appears that there were also significant differences in cell cycle times between sites. The in vitro and in vivo labelling techniques gave comparable results.     

Effect of Cerclage Wires on Periosteal Bone in Growing Dogs

Three diameters of wire were placed circumferentially around the femora of six 22 week old puppies. The wires were placed over the periosteum on one limb and under the periosteum on the other limb. The effect of the wires on actively growing bone was evaluated 3 and 8 weeks after placement. Diffuse growth of periosteal new bone occurred in immature dog femora in which cerclage were placed under the periosteum. This reaction corresponded with dramatically increased medullary and periosteal microvascularity coupled with histologic active trabecular bone formation. In femora in which wires were placed over the periosteum, even though the placement of the wires should supposedly have been the most detrimental, there were active vessels within the cortex directly under all wires. In both preparations, cerclage wires were becoming encased in the growing cortical bone 8 weeks after placement. Cerclage wires did not devitalize immature bone nor did it restrict adjacent appositional bone growth.     

Experimental rickets in broilers: gross, microscopic, and radiographic lesions. III. Vitamin D deficiency

Day-old broiler chicks were fed a vitamin D-deficient diet for 30 days. Gross, microscopic, and radiographic examinations of the proximal tibiotarsus were done at 2, 3, and 4 weeks of age. In 2-week-old chicks, there was variable lengthening and disorganization of the proliferating-prehypertrophied zone (P-PHZ), resorption of cartilage spicules in the degenerating hypertrophied zone and primary spongiosa, and lengthening of bone spicules in the secondary spongiosa; many bone surfaces were lined with increased osteoid. In 3-week-old chicks, there was a tendency for the P-PHZ to decrease in relative length and for cartilage spicules to increase in length. In 4-week-old chicks, however, there was marked lengthening of the P-PHZ, resorption of cartilage spicules, and replacement of the metaphysis with irregularly oriented islands of woven bone, osteoid, and loose fibrous connective tissue.     

Experimental rickets in broilers: gross, microscopic, and radiographic lesions. II. Calcium deficiency

Day-old broiler chicks were fed a calcium-deficient diet for 30 days. Gross, microscopic, and radiographic examinations of the proximal tibiotarsus were done at 2, 3, and 4 weeks of age. In 2-week-old chicks, the growth-plate proliferating-prehypertrophied zone (P-PHZ) was variably lengthened and disorganized, cartilage columns of the degenerating hypertrophied zone and metaphyseal primary spongiosa were shortened, and bone spicules of the secondary spongiosa were bordered by increased osteoid. In 3-week-old chicks, lesions were either similar or more pronounced, with the additional finding of metaphyseal peritrabecular fibrosis. In 4-week-old chicks, the P-PHZ decreased in relative length, osteoid seams and fibrous connective tissue were less prominent, and tibial dyschondroplasia-like lesions were present. Results demonstrated that dietary calcium deficiency produced rachitic lesions, that the lesions were very different from those of phosphorus deficiency or calcium excess, and that the lesions were variable over time.     

Case report: Hypertrophic osteopathy in roe deer (Capreolus capreolus)

This report describes a case of hypertrophic osteopathy in an approximately three years old male roe deer (Capreolus capreolus). The hunter reported that the animal was apparently healthy and showed no signs of movement imparities. At dissection, a combination of a lung abscess with bony swellings at the distal parts of the limbs was observed. Further investigation revealed that the bony swellings were caused by a severe periosteal hyperosteosis at the diaphyses of the digital phalanges, metacarpal and metatarsal bones. The periosteal new bone was characterized by the formation of coralliform osteophytes, typically seen in cases of hypertrophic osteopathy. As usual in animals with hypertrophic osteopathy, the pathological changes in this roe deer developed secondary to a intrathoracic lesion (lung abscess).     

Metacarpal and metatarsal fractures in dairy cattle: 33 cases (1979-1985)

Metacarpal (22) and metatarsal (11) fractures in 33 dairy cattle were treated by application of short or full limb casts. Twelve fractures involved the distal physis (6 closed, 6 open) and 21 fractures were nonphyseal (17 closed, 4 open). All physeal fractures were noncomminuted and 11/12 were classified as Salter-Harris type II. Eleven (52%) of nonphyseal fractures were comminuted. Closed fractures were reduced and a cast was applied after manual restraint, sedation with xylazine (along with use of ropes), or general anesthesia. Open fractures were best treated with the cow under general anesthesia. These fractures were carefully debrided, lavaged, and reduced, and a cast was applied. Antibiotics and analgesics were given parenterally. All cattle were restricted to a box stall during fracture healing. Fracture healing generally was rapid and uncomplicated. No closed fracture perforated the skin. Fracture healing was characterized radiographically by extensive circumferential periosteal new bone growth, closure of the distal physis, and preservation of articulations adjacent to the fracture site. Follow-up ranged from 6 to 78 months (mean, 32 months). Thirty of 33 (91%) cattle survived for a long period. All cows with closed (23) and 7 of 10 (70%) with open fractures survived. Three cows were euthanatized; 2 developed severe osteomyelitis and one fractured her metatarsus above a short cast. All 30 surviving cattle were considered by their owners not lame on the previously injured limb, with no noticeable angulation, bowing, or shortening. No deleterious effects on milk production were detected.     

Late-onset fracture-associated osteosarcoma in a cat

An 18-year-old male, castrated Domestic Shorthaired cat was presented with the complaint of acute severe lameness of the left pelvic limb. There was no history of trauma, apart from a distal physeal left femoral fracture that had been repaired 17 years previously. Radiology revealed a displaced distal metaphyseal femoral fracture with marked areas of bone lysis and periosteal proliferations. A pathological fracture due to a bone neoplasia was suspected. An amputation with coxofemoral disarticulation was performed. Histopathology confirmed the tentative diagnosis of appendicular osteo-sarcoma. No postoperative complications were encountered and the cat made a full recovery. This case shows an unusual presentation of a late-onset fracture-associated feline osteosarcoma.     

Systemic injection of FGF-2 stimulates endocortical bone modelling in SAMP6, a murine model of low turnover osteopenia.

The effects of systemically administered fibroblast growth factor-2 (FGF-2) at doses of 0.1 and 0.3 mg/kg/day for 7 days were investigated 5-week-old male SAMP6 mice, a model of low turnover osteopenia. The bone histomorphometry in the distal epiphyseal growth plate of the femur showed that 0.3 mg/kg/day of FGF-2 decreased the longitudinal growth rate and cartilage cell production rate and increased the growth plate width. Growth plate chondrocytes showed the features of defective endochondral ossification at the same dosage level. In the distal one third of the femur, the marrow trabecular area, endocortical mineral apposition rate and/or bone formation rate were increased in both the SAMP6 mice given 0.1 and 0.3 mg of FGF-2/kg/day. In this region, the endocortical osteoblasts were hypertrophied with some layers of overlying proliferated fibroblastic mesenchymal cells. The presence of small foci of bone formation within the layers of these mesenchymal cells indicates their osteogenic potential. On the other hand, the periosteal bone formation rate in the mid-shaft of the femur was depressed in the 0.3 mg/kg/day group. These results suggest that systemically administered FGF-2 may have the possibility to increase the peak bone mass in SAMP6 by stimulating the osteoprogenitor cells to proliferate and differentiate into osteoblasts and enhancing endocortical bone modelling. The higher dose of FGF-2, however, inhibited both endochondral and periosteal bone formation.     

Distal metacarpal sequestration in a bison.

A 2-year-old 400-kg female American bison was admitted for evaluation and treatment of an open fracture of the right metacarpal bones 3 and 4. Radiography revealed osteolysis of the distal metaphysis and epiphysis, with extensive bony callus formation along the dorsoproximal and proximomedial aspects extending distally to the proximomedial aspect of the proximal phalanx. Evidence of periosteal or bony proliferation at the fracture site or along the distal segment of the third and fourth metacarpal bones was not visible, suggesting that the distal fracture fragment was becoming a sequestrum. Treatment consisted of soft tissue debridement and placement of the limb in a full-limb cast. The cast was changed every 4 weeks until the sequestrum was removed and the bone healed. It is rare for the distal half of a long bone to sequester following fracture. Additionally, it is remarkable that the sequestrum served as a buttress, which prevented collapse of the bone until the sequestrum was replaced by functional bony callus.