Extra- and intra-articular synovial chondromatosis and malignant transformation to chondrosarcoma.

Intra- and extra-articular primary synovial chondromatosis (SC) was observed in a five-year-old, entire male German Shepherd. Thousands of small cartilaginous nodules were removed from the stifle joint as well as from several adjacent muscles. Diagnosis of SC was established based on clinical, radiographic and biopsy results. The owner declined to have a new surgery performed for complete nodule removal and partial synovectomy. Nine months after the initial presentation, a proximal pathological intra- articular tibial fracture was observed and malignant transformation to chondrosarcoma was diagnosed after limb amputation. No metastasis was observed after 1.5 years of follow-up.

The stepped hybrid plate for carpal panarthrodesis - Part I: relationship between plate and bone surfaces.

In the 1990s, the AO (Arbeitsgemeinschaft für Osteosynthesefragen) Hand Study Group developed several anatomically bent plates (standard and short) for wrist panarthrodesis in humans. However, only straight plates have been used for carpal panarthrodesis (CP) in animals to date. The primary purpose of this study was to determine if precontoured plates are more anatomical for CP in dogs. Measurement of several of the bones that are implicated in CP, as well as the relationship between their surfaces and the surface of a straight plate, were performed in a radiographic and computed tomographic cadaveric study. Axial and transverse measurements taken at different levels of the metacarpal bones 2, 3 and 4 were also included. The second objective of this study was to develop a more anatomical CP plate according to the results obtained. The measurements and images obtained in this study show that, as in human orthopaedics, bent or stepped plates are more anatomically correct than straight plates for CP in dogs.

The stepped hybrid plate for carpal panarthrodesis - Part II: a multicentre study of 52 arthrodeses.

Fifty-two carpal panarthrodeses (CP) were carried out in 44 dogs (eight bilateral), in a multicentre study using a single (n = 47) or double (n = 5) stepped hybrid CP plate. Of these 44 cases, 39 were between 20-55 kg in bodyweight , 26 were males , and the carpometacarpal was the most common joint involved. Falling and other impact trauma were the most common aetiology. Pain of unknown origin, carpal luxation, chronic accessory carpal bone fracture, distal comminuted intra-articular radial fracture, bone tumour, degenerative joint disease, canine erosive idiopathic polyarthritis, avascular necrosis of the radial carpal bone and fractures of several metacarpal bones were some of the pathologies reported. Fracture of the third metacarpal bone during screw insertion was the only intrasurgical complication. Malpositioning of the plate or screws and over-tightened screws were technical errors observed in seven of the procedures. The radial carpal bone was not fixed with a screw in two cases due to bone deformity. Concurrent plate breakage and bending in the same patient operated on bilaterally was observed during the follow-up period, which represented a major complication rate of 3.8% for all procedures. Minor complications were: low grade infection, lick granuloma, digit hyperextension, screw loosening or failure, incomplete fusion of some joints and a fracture of the third metacarpal bone at the distal screw hole of the plate; which represented a rate of 44.2% on all procedures. Complete carpal healing was observed radiographically in 94.2% of all procedures. Limb function was excellent to good, and all of the owners, except for one, were satisfied with the procedure.

Simultaneous bilateral contracture of the infraspinatus muscle.

A case of bilateral fibrotic contracture of the infraspinatus muscles in a five-year-old Belgian Shepherd dog is described. The dog was presented with progressive forelimb lameness with postural and gait abnormalities three months after an episode of overexertion. When walking, the lower part of both forelimbs swung in a lateral arc causing a circumduction movement and in the standing position, the dog showed elbow adduction with external rotation of the distal part of both front limbs. Orthopaedic examination revealed bilateral atrophy of both infraspinatus and supraspinatus muscles and restriction in the range of motion of both shoulders, especially when attempting abduction and flexion. No specific findings were observed in the shoulder or elbow radiographs but hyperechogenic areas were evident in the ultrasonographic examination of both infraspinatus muscles. A diagnosis of fibrotic contracture of both infraspinatus muscles was established and bilateral tenectomy of the insertion tendons of the infraspinatus muscles was performed. Complete recovery of the animal was achieved after the surgery, which was confirmed in a long-term follow-up (10 months). In conclusion, physical examination and ultrasonography allowed a proper diagnosis of the condition, and tenectomy of the infraspinatus muscles resulted in a complete recovery of the patient even with bilateral involvement.

Beta-tricalcium phosphate as a synthetic cancellous bone graft in veterinary orthopaedics: a retrospective study of 13 clinical cases.

The clinical use of beta-tricalcium phosphate (beta-TCP) as a synthetic cancellous bone graft in veterinary orthopaedics is herein reported. The retrospective study was based on 13 clinical cases belonging to 11 dogs and one cat. The weights of the dogs ranged from 3.4 to 48 kg. One female cat weighing 3.5 kg completed the study. The clinical cases were six arthrodeses (four carpal, two tarsal), one hypertrophic non-union (femur), one atrophic non-union (metacarpal bones) and five long-bone fractures (two femurs, one tibia, two radii) possessing subcritical-sized bone defects. The beta-TCP used in this study was presented as irregular interconnected- porous granules and was placed in the bone defects after mixing it with fresh blood. Bone healing was achieved at between eight and 12 weeks in all clinical cases except for the case of the chronic atrophic nonunion in which only one of the four metacarpal bones healed. In the 12 successful cases, the bone defect grafted with beta-TCP showed a radiological bone ingrowth of 100% (10 cases), 90% (one case) and 75% (one case). The complete lack of tissue adverse effects in our series, and the good defect healing, allows us to hypothesise that beta-TCP can be successfully used as a synthetic bone graft in bone defects with good local biological conditions and where osteoconduction is especially needed for assuring a structural scaffold for new-bone ingrowth. When, in addition to osteoconduction, osteoinduction and osteogenesis are necessary for defect healing, the fresh cancellous bone graft remains the gold standard in veterinary orthopaedics.

Interlocking nail treatment of long-bone fractures in cats: 33 cases (1995-2004).

A retrospective study between 1995 and 2004 of fracture repair in cats (n = 46) using interlocking nails (ILN) was made. Only the cases in which clinical and radiographic examination of bone healing were available are included. Five humeral and twenty eight femoral fractures were reviewed. Multiple-hole interlocking nails (MH-ILN) were used in 22 fractures, with the four-hole model (FH-ILN) in the remaining cases. In three of the cases, the FH-ILN was transformed to a three-hole model by cutting the nail between the two most distal holes. The average length of humeral ILN was 78.8 mm, and the femoral ILN was 97.2 mm. Static fixation was performed in 27 cases, with dynamic fixation in the remaining. The medullary canal filling was 100% in both radiographic views in 16 cases. Intra-operative complications were encountered in two cases. A total number of 76 screws were inserted, with 5.26% of them being malpositioned. Malunion, in a deformed femur, and partial unscrewing of one screw were the only radiographic complications observed at the time of follow-up. The clinical outcome, as well as fracture healing, were excellent in all of the cases. The results of this study indicate that the 4.0 and 5.0 mm MH-ILN and FH-ILN can be used to repair simple or comminuted humeral and femoral fractures in cats.

Management of leishmanial osteolytic lesions in a hypothyroid dog by partial tarsal arthrodesis.

A five-year-old male boxer, previously diagnosed with leishmaniasis and hypothyroidism, had gradually become unable to bear weight on its left hindlimb. Physical examination revealed a left popliteal lymphadenopathy, mild crepitus, and severe swelling of the left tarsal joint, a radiographic examination of which revealed severe bone destruction of the talus and a periosteal reaction of the calcaneus. Laboratory findings and serological tests suggested an active leishmanial infection, and a Leishmania species was identified by direct cytology of a sample from the osteolytic area and by indirect immunohistochemistry of a bone biopsy. The dog's condition improved when it was treated with meglumine antimonate and allopurinol. Because of the large osteolytic area and the increased use of the affected leg, a partial tarsal arthrodesis was performed to prevent a fracture. Five months after the surgery, the osteolytic area had healed completely and the calcaneus periosteal reaction had disappeared.

Back-scattered electron imaging of a non-vertebral case of hypervitaminosis A in a cat.

We describe a clinical case of hypervitaminosis A in a cat. The main lesions were bony fusions of both the hip and stifle joints, without spinal involvement. A post-mortem study using back-scattered scanning electron microscopy (BEI-SEM) revealed that exostoses had formed around the joints without articular surface involvement. The more recently formed areas of bony proliferation were composed mainly of chondroid tissue surrounded by different degrees of woven bone. As the bony reaction occurred, remodelling of the trabeculae was observed which lead to progressive substitution of chondroid tissue by woven bone surrounded by apposition of lamellar bone. No traces of calcified cartilage were observed in any of the bone sections evaluated.

Early experience with the use of an interlocking nail for the repair of canine femoral shaft fractures.

Static locked nailing was used to repair fractures of the femoral diaphysis in 15 dogs. The implant consists of a 5, 6, or 7 mm diameter stainless steel rod made up of two parts: the body of the nail, in which there are 13 threaded holes, and a piece without holes that contains a slot for anchoring the jig. Good limb function was obtained after less than 3 weeks in 12 dogs and these dogs remained sound throughout the study. Radiographic examination revealed fracture healing in 11 of the dogs, between 8 and 16 weeks after surgery. One dog was not returned for follow-up evaluation until 22 weeks after surgery; complete healing was apparent from radiographic examination. The remaining three dogs had to have additional operations, one because of lameness caused by excessive length of the distal screws, one because of a nonunion, and the third because of a sequestrum. Fracture healing in these dogs was observed at 18, 21, and 24 weeks respectively. Loosening of one screw and angulation of the bone occurred in one dog. These complications had no adverse effects on clinical outcome.