Luxation of the radial carpal bone in four dogs

Four cases of radial carpal bone luxation in dogs seen at Glasgow University Veterinary School in a period of six years are described. Three were border collie types. Two of these were working sheepdogs and the third was an agility triallist. The fourth was a rough collie. All were adult, two were male and two were female. Three cases were of short duration and were managed by open reduction of the luxation and surgical stabilisation of the radial carpal bone. The other was of longer duration and was treated by pancarpal arthrodesis. In all cases the carpus was supported externally for one to two months following surgery. At the time of writing, the progress of only the three working dogs was known. Despite the presence of osteoarthritic changes in the carpi of these dogs, they all became sound and returned to work. A mechanism for the injury based upon the results of cadaver studies is proposed.     

A case of dorso-medial luxation of the radial carpal bone in a dog

Luxation of the radial carpal bone is an uncommon injury in the dog and cat. Previous clinical cases have reported palmaro-medial luxation with injury to the short radial collateral ligament. In this study a case of dorsomedial luxation of the radial carpal bone in a 10-year-old female Gordon Setter is described. A closed reduction of the luxation was performed and a conservative treatment was carried out. Thirteen months after the reduction, the dog had a satisfactory limb function, despite the presence of degenerative joint disease of the carpus. A pathogenic hypothesis for this dorso-medial luxation of the radial carpal bone is proposed reproducing the luxation on canine cadavers.     

Luxation of the superficial digital flexor tendon in a cat

Superficial digital flexor luxation has been described in dogs, horses, and cattle. To the authors' knowledge, it has not been reported in cats. In the case of this report, monofilament nonabsorbable suture material was used to repair a laterally luxating superficial digital flexor tendon in a cat. The repair was similar to that which has been described in dogs. Whereas many etiologies of superficial tendon luxation have been proposed in dogs, trauma was believed to have contributed to the tendon luxation in this cat.     

Surgical repair of radial carpal bone fractures in two racehorses

A 3-year-old Standardbred gelding (Case 1) and a 2-year-old Thoroughbred gelding (Case 2) were referred for surgical evaluation of a left radial carpal bone (RCB) fracture, sustained during training. Clinical findings at the time of initial examination included a palpable effusion within the left middle carpal joint in both horses and marked signs of pain and reduced range of motion on flexion of the affected carpus. In both horses, the RCB fracture was evident on the following radiographic views of the carpus: dorsolateral–palmaromedial oblique (30° off lateromedial) and flexed lateromedial. An additional loose wedge-shaped osteochondral fragment at the proximal articular surface of the RCB could be seen in Case 2. Both horses underwent surgical reduction and repair of the fracture between 1 and 2 days following the initial injury, which consisted of arthroscopic removal of any intra-articular osteochondral fragments, and arthroscopic assisted-interfragmentary compression via a standard dorsomedial and dorsolateral approach to the antebrachiocarpal joint (ACJ) and middle carpal joints (MCJ). The two horses returned to function as racehorses, 6 months (Case 1) and 16 months (Case 2) after surgery. The RCB is a relatively uncommon site for large carpal fractures in horses. The clinical presentation and findings from this report were similar to that of third carpal bone (C3) slab fractures, confirming that surgical repair is indicated in selected cases of RCB fractures.     

Luxation and/or fracture of the first carpal bone in thoroughbred horses and its surgical resolution

A syndrome involving luxation and/or fracture of the first carpal bone is described. Affected horses have a grade 1-3 lameness, which responds to intra-articular anesthesia of the intercarpal joint. Medical treatment has not be successful in relieving lameness, and the treatment of choice is surgical removal of the first carpal bone.     

Diagnostic investigation of an unusually large osseous cyst-like lesion of the radial carpal bone

A 10-year-old Irish Sports Horse presented for intermittent, fluctuating lameness of the left forelimb. Nuclear scintigraphy, radiography and computed tomography identified a large osseous cyst-like lesion (OCLL) occupying approximately 50% of the radial carpal bone with an articular communication to the antebrachiocarpal joint. A transcortical surgical approach was used to curette the lining of the lesion prior to injection with triamcinolone acetonide. This imaging report describes the detailed diagnostic findings of an unusually extensive OCLL in the radial carpal bone.     

Galloping exercise induces regional changes in bone density within the third and radial carpal bones of Thoroughbred horses

This study was performed to test the hypothesis that a localised bone hypertrophy could occur within the subchondral cancellous architecture of the third and radial carpal bones. Using 2 levels of controlled and defined exercise, it was observed that a high intensity treadmill exercise protocol resulted in functional adaptation of the carpal bones. The increase in trabecular thickening and density was seen to be localised to those regions underlying common sites of cartilage degradation, the interface of the thickened trabeculae with the normal architecture in the third carpal bone was coincident with a common site of clinical fractures. The bone changes were determined both qualitatively on examination of slab radiographs and quantified by dual energy x-ray absorptiometry. The findings from this study are relevant to mechanical factors involved in the pathophysiology of joint degeneration. The potential clinical implications of this study are in relation to changes in the type and duration of exercise regimens used in training of equine athletes. The rapid response of bone to mechanical stimulation has implications in the longer term for localised cartilage degradation. Imaging techniques could be developed to monitor these early bone changes in the specific areas identified in this study and thus allow appropriate changes in training intensity to minimise subsequent damage to the articular surface.     

Giant cell tumor of the accessory carpal bone in a dog

A 4-year-old Springer Spaniel was referred because of a 6-week history of progressive left forelimb lameness. A marked pain response was elicited by palpation over the left accessory carpal bone. Radiography revealed a lytic, markedly expansile lesion of the accessory carpal bone. The bone was excised, and pancarpal arthrodesis was performed. Histologic examination of the excised bone revealed giant cell tumor. At 14 months after surgery, the dog was using the limb normally. Radiography of the carpus revealed satisfactory progression of the arthrodesis, and thoracic radiographs were negative for metastases.     

Outcome of lag-screw treatment of incomplete fractures of the frontal plane of the radial facet of the third carpal bone in horses

AIM: To describe outcomes for horses diagnosed with incomplete, non-displaced fractures of the frontal plane of the radial facet (INFR) of the third carpal bone (C3) treated by placement of a lag screw across the fracture under arthroscopic guidance. METHODS: Horses (n=13) diagnosed with INFR and treated between December 1999 and January 2005 using a lag screw placed over the fracture were studied. For each case, five horses matched for sire, age and sex which were not known to have INFR were sought for comparison. Racing performance data were collected from a commercial online database. The racing performance of cases pre- and post-operatively, and of cases and matched horses in the post-operative period was compared. RESULTS: Sixteen INFR were found in the 13 horses. Radiographic evidence of healed fracture lines 2-4 months after surgery was seen in 11/16 (69%) fractures; 11/13 (85%) cases raced again after a median recovery period of 292 (range 149-681) days. Treatment was considered successful in 9/13 (69%) cases, which were still in training or had been retired for reasons other than lameness localised to the middle carpal joint at the end of the study period. Just 6/13 (46%) cases had raced prior to injury. The racing ability pre- and post-operatively of five cases was compared, three (60%) of which performed better post-operatively than they had before. There was no significant difference in racing longevity or ability post-operatively between patients and matched (control) horses. CONCLUSIONS: Post-operatively, there was little difference in the racing performance between horses diagnosed with INFR which had a lag screw placed across the fracture line and horses matched for sire, age and sex which were not known to have INFR. CLINICAL RELEVANCE: Horses which were diagnosed with INFR of C3 and had a lag screw placed across the fracture had a good prognosis for future racing performance.     

Comminuted fracture of the ulnar carpal bone in a Labrador retriever dog

A 4-year-old male Labrador retriever dog was evaluated for acute lameness without weight-bearing in the right forelimb after an 8-meter fall. Radiographs revealed a comminuted fracture of the ulnar carpal bone that required removal of bone fragments. This appears to be the first report of such a condition.     

Fractures of the accessory carpal bone in the horse

The clinical signs and radiographic appearance of 19 cases of fracture of the accessory carpal bone of horses are described. In 17 cases the fractures were in the frontal plane and occurred palmar to the groove on the lateral aspect of the bone. In six cases radiographs taken six months to three years after the fracture occurred showed no evidence of bony union; nevertheless, these and five other horses for which follow-up information was available for up to seven years all became sound, and seven of them returned to competitive activity.     

Arthroscopic removal of a palmar radial osteochondroma causing carpal canal syndrome in a horse.

A 5-year-old Arabian stallion with moderate effusion in the right carpal canal and intermittent lameness in this limb was diagnosed to have an osteochondroma projecting from the distal portion of the radius into the carpal canal. oral phenylbutazone treatment over the next 3 years allowed the stallion to continue its show career. Right forelimb lameness returned at that time, and ultrasonography revealed the osteochondroma impinging on the dorsal surface of the deep digital flexor tendon. The owner elected to have the osteochondroma surgically removed. The horse was anesthetized, and the carpal sheath was distended with balanced polyionic solution. A 4-mm arthroscope was inserted into the carpal sheath, and the osteochondroma projecting into the sheath was identified. The osteochondroma was removed by use of a Ferris-Smith bone rongeur, which was inserted into the carpal sheath through a stab incision over the osteochondroma. The effusion in the carpal sheath and the lameness resolved by 2 months, and the horse was returned to training 4 months after surgery.     

Radial carpal bone fracture in dogs

In a retrospective study, 11 radial carpal bone (RCB) fractures in nine dogs were studied. Chronic lameness was reported in all dogs. Reduced range of motion and soft-tissue swelling of the carpal joints were clinical signs seen most frequently. Three common fracture patterns were identified: oblique fracture with a large medial fragment, sagittal fracture with a small medial fragment, and comminuted fracture. Radial carpal bone sclerosis and carpal osteoarthritis were identified in all dogs. Pancarpal arthrodesis was used to manage 55% of the RCB fractures in this report. Although RCB fracture is not associated with obvious trauma, the fracture mechanism is unknown.     

Aneurysmal bone cyst in a rib of a cat

An aneurysmal bone cyst was identified in the rib of a 3 1/2-year-old domestic shorthair cat. Surgical excision of the cyst, with reconstruction of the thoracic wall, was performed. Though aneurysmal bone cyst is a benign neoplastic condition that may be associated with locally aggressive growth, it does not metastasize. The condition is rare in any species other than human beings, but has been reported in cats, dogs, and horses.     

Giant cell tumour of bone in a cat

A domestic shorthaired cat had a firm, non-painful swelling of the left antebrachium. Radiographs showed an expansile, multiloculated lesion in the radius. The mass gradually enlarged over the following four and a half months and the animal became completely lame. The histological diagnosis was giant cell tumour of bone; this is a rare neoplasm of bone in veterinary patients. Giant cell tumour of bone should be considered in the differential diagnosis of bone lesions having an expansile, multiloculated radiographic appearance.