Disorders of the tarsus in the dog. I

Treatment of Medial Instability of the Carpometacarpal and Tarsometatarsal Joints Using the Isolock® System in Two Dogs

This case report describes a novel procedure using the Isolock Intrauma® implant system for treating medial instability of the carpometacarpal and tarsometatarsal joints, as demonstrated in in two dogs. A 9-year-old spayed female Spanish greyhound presented with a non-weight-bearing right hindlimb following a trauma. The clinical and radiological findings confirmed medial tarsometatarsal instability consistent with valgus deviation of the tarsus and the opening of the joint line on the medial aspect from the first to the third tarsometatarsal joints. A 4-year-old female Drahthaar presented with a non-weight-bearing left forelimb, swelling of the carpus and valgus instability. Radiological examination revealed a widening of the spaces between the intermedioradial carpal bone, second carpal bone and metacarpal bone II, confirming the medial carpometacarpal instability. In both cases, the Isolock system, an implant including ultra-high-molecular-weight polyethylene suture (UHMWPE), was used to reinforce the medial joint structures. Minor short-term complications were observed, such as swelling of the tarsal surgical site and hyperextension of the carpus, but these resolved spontaneously. No lameness or major complications were reported five months postoperatively. Carpometacarpal and tarsometatarsal instabilities are rare diseases in dogs as compared to subluxations of the other joints of the carpus and tarsus. There are no previous reports regarding the use of a UHMPWE implant for the treatment of these rare joint injuries, though the present case report suggests the validity and efficacy of the Isolock Intrauma® implant for restoring carpal and tarsal stability and preserving joint mobility.

Description and outcome of prosthetic ligament placement for stabilization of medial or dorsomedial tarsometatarsal joint luxation in dogs and cats: 16 cases (2004-2017)

OBJECTIVE

To describe prosthetic ligament placement for reduction and stabilization of medial or dorsomedial tarsometatarsal joint luxation in dogs and cats and to report complications and postoperative outcomes for patients that underwent that procedure.

ANIMALS

14 dogs and 2 cats with medial or dorsomedial tarsometatarsal joint luxation.

PROCEDURES

The electronic database of a referral surgery practice was searched to identify records of dogs and cats with tarsometatarsal joint luxation that underwent prosthetic ligament placement between January 2004 and March 2017. For each study subject, information extracted from the medical record included signalment, a description of the tarsometatarsal joint injury, durations of anesthesia and surgery, and intraoperative and postoperative care and complications. Radiographic images were also reviewed. The long-term outcome for study subjects was assessed by administration of a standardized questionnaire to owners.

RESULTS

Prosthetic ligament placement successfully stabilized the luxated tarsometatarsal joint in all 16 patients. Six patients developed minor postoperative complications, which included bandage-associated dermatitis or ulceration (n = 5) and orthopedic wire failure (1). No major or catastrophic complications were reported. All 13 owners who completed the questionnaire perceived that the described technique resulted in satisfactory long-term function for their pets.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that prosthetic ligament placement was a technically simple procedure that achieved satisfactory long-term stabilization of the tarsometatarsal joint in small animal patients with medial or dorsomedial luxation of the joint. Prosthetic ligament placement may be an alternative to arthrodesis for tarsometatarsal joint stabilization in appropriate patients.

Osteochondrosis dissecans of the tarsus in Labrador Retrievers: Clinical signs, radiological data and force plate gait evaluation after surgical treatment

Objectives: To report the outcome of unilateral surgery, by a plantaromedial approach, in 15 Labrador Retrievers with osteochondrosis dissecans (OCD) of the medial trochlear ridge of the talus. To evaluate the influence on outcome of age at surgery, bilateral involvement, periarticular soft tissue increase (PSI), osteophyte size (OS), decrease of range of joint motion and follow-up. To assess the extent of tarsal hyperextension in the standing dog.

Methods: A retrospective clinical and radiographic study was conducted and the posttreatment gait was analysed using a force plate. Ground reaction force (GRF) data were compared with data derived from 24 healthy Labrador Retrievers (control group).

Results: Six dogs had an excellent or good clinical result. Significant differences were found between the patients and the control group for many GRF data. Propulsive and vertical forces significantly decreased in the operated limb and increased in the contralateral pelvic and ipsilateral or both thoracic limbs. The lameness was significantly correlated to the OS postoperatively, the range-of-motion, the PSI, the length of the follow-up period, and the vertical ground force. No hyperextension in stance was recorded.

Clinical significance: Although most dogs improved, the prognosis remains guarded. This seems to be independent of age, bilateral involvement, or preoperative OS in these dogs. No relation between medial talar OCD and tarsal hyperextension in stance was found in these dogs.

Central tarsal bone fracture in a cat

Fracture of the central tarsal bone is an uncommon injury in dogs and occurs predominantly in racing Greyhounds. To the authors' knowledge, this type of fracture has not been described previously in cats. This case report describes a five-year-old Domestic Shorthair cat referred to the Centro Veterinario Luni Mare because of lameness, swelling and signs of pain in the right hindlimb caused by trauma. Clinical examination and diagnostic imaging revealed a right central tarsal bone fracture. Open reduction and internal fixation with a 2.0 mm position screw and two 0.8 mm Kirschner wires were carried out. The last follow-up examination three years postoperatively found the cat in good health with normal range of motion and function, and no signs of lameness in the right hindlimb.

Canine tarsal architecture as revealed by high-resolution computed tomography

Central tarsal bone (CTB) fractures are well documented and are a subject of increasing importance in human, equine and canine athletes although the mechanism of these fractures in dogs is not fully understood and an extrapolation from human medicine may not be accurate. This study reports the use of high-resolution computed tomography (CT) of 91 tarsal joints from 47 dogs to generate a more detailed in situ anatomical description of the CTB architecture in order to obtain a better understanding of the pathogenesis of CTB fractures in this species. The dogs studied represented a wide range of ages, breeds and levels of habitual physical activity and the angles of the tarsal joints studied ranged between maximal flexion (16.4°) and maximal extension (159.1°). Regardless of tarsal angle, the CTB articulated with the calcaneus exclusively at the level of its plantar process (PPCTB) in all dogs. The PPCTB presented two distinct parts in all dogs, a head and a neck. The calcaneus tended to rely on the PPCTB neck during flexion and on the PPCTB head during extension. This study describes new tarsal elements for the first time, including the calcaneal articular process, the fourth tarsal bone plantar articular process and the talar plantar prominence of the CTB. Based on calcaneo-PPCTB architecture, it is postulated that the PPCTB is a keystone structure and that at least some of CTB fractures in dogs could either commence at or are induced at this level due to the impingement forces exercised by the calcaneus.

Third tarsal bone fractures in the greyhound

OBJECTIVE

To describe the signalment, morphology, response to treatment and prognosis of third tarsal bone fractures in the racing greyhound.

METHODS

All third tarsal bone fractures seen by the author over a ten year period were included in the study. Diagnosis was by radiography. Treatments were reconstruction with a lag screw, fragment removal, centrodistal joint arthrodesis or conservative management.

RESULTS

Twenty-three cases were included in the study of which 16 cases were recent and seven cases chronic fractures. The chronic cases had been rested from between three and six months before an examination for recurrent lameness. There were five concomitant second tarsal bone fractures. Partial dorsal collapse was present in four cases. Thirteen dogs had lag screw fixation; three were lost to follow-up, seven returned to racing and three, all with partial tarsal collapse, failed to return to racing. Two dogs that had a centrodistal joint arthrodesis and one dog treated by rest alone raced again. Two dogs that had fragment removal failed to return to racing.

CLINICAL SIGNIFICANCE

Veterinary examination of greyhounds with third tarsal bone fractures is often not sought at the time of the initial injury due to the benign presenting signs. Recurrence of lameness after rest is common. The prognosis for a successful return to racing would appear to be good following fragment fixation in both acute and chronic cases without dorsal tarsal collapse. Centrodistal joint arthrodesis may encourage bone union. The prognosis for conconservatively treated cases is guarded. Fragment removal is not recommended as a treatment.

Fractures of the central tarsal bone in eight racing greyhounds

The case records of eight greyhounds that had undergone a surgical repair of either a type III or type IV fractured central tarsal bone were reviewed. In some cases difficulties were encountered which resulted in less than ideal fixation methods being used, but the fractures healed satisfactorily by intertarsal ankylosis and were radiographically complete after four to six months. For a successful outcome it was not necessary to preserve functional intertarsal joints by interfragmentary reconstruction and compression. The absence of dorsal slab fixation, poor dorsal screw positioning, or loss of the dorsal fragment, had no influence on the results. It took from six months to one year for the dogs to return to racing.