Fractures of the central tarsal bone in eight racing greyhounds

Characteristics, surgical treatment, and outcomes of injuries involving the tarsus in greyhounds

Objective

The first objective of this study was to describe the type of tarsal injuries sustained, surgery performed, and postoperative complications in greyhounds presenting to a single veterinary hospital. An additional objective of the study was to determine the surgical site infection (SSI) and explantation rate, and if any variables were associated with an increased risk of SSI and/or explantation.

Animals

116 greyhounds receiving surgical intervention for a tarsal injury.

Proceures

Medical records from a single veterinary referral hospital were reviewed retrospectively. Data retrieved included signalment, details regarding the injury, surgical intervention, concurrent castration, surgical/anesthesia times, postoperative management, time to healing, and postoperative complications. In cases that underwent explantation, cause, time from initial surgery, and risk factors were evaluated.

Results

The most frequently diagnosed tarsal injuries were fracture of the central tarsal bone (CTB; 57.8%), calcaneal fracture (56.9%) and proximal intertarsal subluxation (34.5%). The most common injury combination was a CTB fracture with a calcaneal fracture (31.9%). In total 115 (99.1%) survived to discharge. Of these, 46 (40.0%) were diagnosed with an SSI and 59 (51.3%) underwent explantation. The most common indication for explantation was SSI. Concurrent medial and lateral surgical approaches was found to be associated with an increased likelihood of SSI and explantation.

Clinical relevance

Practitioners performing surgical intervention for tarsal injuries in greyhounds should be aware of the high SSI rate and likelihood that explantation will be required. This risk is elevated for injuries requiring a bilateral surgical approach.

Usefulness of Imaging Techniques in the Diagnosis of Selected Injuries and Lesions of the Canine Tarsus. A Review

Simple Summary

Tarsal joint lesions are uncommon in dogs but may lead to serious health problems. The most common diseases involving the tarsal joint are osteochondrosis, fractures and injuries of the Achilles tendon. The basis for the diagnosis of lesions in the tarsus is a thorough orthopedic examination, sometimes performed under sedation. Imaging modalities such as radiography, ultrasonography, magnetic resonance imaging or computed tomography can facilitate the detection and assessment of lesions in the canine tarsal joint. The aim of this paper is to characterize and compare the usefulness of imaging techniques available in veterinary medicine for the diagnosis and evaluation of lesions and injuries affecting the tarsal joint in dogs.

Abstract

Tarsus lesions are not common in dogs, but they can cause serious health problem. They can lead to permanent changes in the joint and, in dogs involved in canine sports, to exclusion from training. The most common diseases and injuries involving the tarsal joint are osteochondrosis, fractures and ruptures of the Achilles tendon. These conditions can be diagnosed primarily through accurate orthopedic examination, but even this may be insufficient for performing a proper diagnosis. Imaging modalities such as radiography, ultrasonography, magnetic resonance imaging or computed tomography can facilitate the detection and assessment of lesions in the canine tarsal joint. This review paper briefly presents some characteristics of the above-mentioned imaging techniques, offering a comparison of their utility in the diagnosis of lesions and injuries involving the canine tarsus.

Medial Bone Plating for Management of Type V Central Tarsal Bone Fractures in Six Dogs

OBJECTIVE

 The aim of this study was to report the surgical technique and outcomes of dogs with type V central tarsal bone (CTB) fractures stabilized with a bone plate applied to the medial aspect of the tarsus and metatarsus.

STUDY DESIGN

 This study was a retrospective review of dogs with type V CTB fractures diagnosed with computed tomography and stabilized using a medial bone plate. Follow-up included clinical examination and radiography 8 to 10 weeks postoperatively and/or a long-term owner questionnaire.

RESULTS

 Six dogs were identified. All fractures occurred during exercise without external trauma and all dogs had additional tarsal fractures. Five dogs returned for clinical follow-up; all had no or mild lameness and evidence of fracture healing on radiography. A suspected surgical site infection occurred in one dog and resolved with medical management. Suspected contact between the plate and medial malleolus in one dog, and loosening of a talar screw in another, were identified, though not treated. Five owners completed the questionnaire, a median of 88 months postoperatively. No further complications were reported, limb function was reportedly acceptable, and all owners were very satisfied with the surgery.

CONCLUSION

 Medial bone plate stabilization of highly comminuted CTB fractures resulted in evidence of fracture healing, and a low incidence of complications in six non-racing dogs.

Injuries involving the central tarsal bone in nonracing dogs: Short-term outcomes and prognostic factors

OBJECTIVE

To describe traumatic injuries involving the central tarsal bone (Tc) in nonracing dogs.

STUDY DESIGN

Retrospective multicenter study.

ANIMALS

Thirty-two client-owned dogs.

METHODS

Medical records from January 2010 to December 2016 were searched for dogs with Tc injury. Fracture classification, concurrent tarsal fractures, treatment, and perioperative management were tested for association with postoperative complications and short-term outcome. Outcome measures consisted of the latest lameness score reported in the record.

RESULTS

The most common injuries consisted of type V fractures (22) and luxation of the Tc (8). Other injuries included 1 case each of type III and type IV fractures. Twenty-two concurrent fractures involved other tarsal bones. Complications were diagnosed in 18 (62.1%) dogs, consisting of 13 minor, 4 major, and 1 catastrophic complication. Lameness at final follow-up (median 7 weeks) in 28 dogs was scored as 0 of 5 in 14 (50.0%) dogs, 1 of 5 in 7 (25.0%) dogs, 2 of 5 in 4 (14.3%) dogs, 4 of 5 in 1 (3.5%) dogs, and 5 of 5 in 2 (7.1%) dogs. Major complications were associated with the presence of multiple tarsal fractures (risk ratio [RR] 3.94, 95% CI 0.80-19.37, P = .13), specifically when the calcaneus was involved (RR 5.78, 95% CI 1.53-21.88, P = .05).

CONCLUSION

The most common diagnosis in this population of nonracing dogs consisted of type V Tc fractures. Fractures affecting other tarsal bones were common and were associated with a higher risk of major complications, especially those affecting the calcaneus.

CLINICAL SIGNIFICANCE

Short-term outcomes seem favorable in nonracing dogs with isolated Tc fractures, but dogs with concomitant tarsal fractures are predisposed to major complications.

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.

A novel method for defining the Greyhound talocrural joint axis of rotation for hinged transarticular external skeletal fixation

In order to apply hinged transarticular external skeletal fixation for stabilization of the injured canine tarsal joint, knowledge of the three-dimensional (3D) location and orientation of the transverse axis is necessary. This method of immobilization may be used as a primary or adjunctive method of stabilisation for a large number of traumatic conditions. Using pin-mounted markers in the cadaveric Greyhound crus and talus, a closed-form solution of absolute orientation was used to identify, on radiographs, the lateral and medial locations of the transverse axis by tracking the 3D excursions of the markers during flexion and extension. A line was drawn across the dorsal aspect of the calcaneus from the most dorsal point on the distal articular surface(proximal intertarsal joint: PIJ) to the most dorsal point on its proximal articulation with the body of the talus, and the location of the centre of rotation was expressed in terms of the length of that line. In seven Greyhound tarsal joints, the medial end of the axis was located 73 ± 10% proximal to the PIJ and 11 ± 7% dorsal to the line. The lateral end was 73 ± 9% proximal tothe PIJ and -2 ± 3% plantar to the line.

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.

Bone volume and regional density of the central tarsal bone detected using computed tomography in a cross-sectional study of adult racing greyhounds

AIMS

To determine whether left-to-right asymmetry of the central tarsal bone (CTB) of racing greyhounds was detectable using computed tomography (CT) in live dogs; to quantify the asymmetry in terms of average bone volume, volumetric bone mineral density (vBMD), and dorsal cortical shape, and to determine if age, gender, bodyweight, number of starts or history of tarsal injury were significant covariates.

METHODS

One trainer supplied 11 male and seven female, unrelated, skeletally mature, actively racing greyhounds, including dogs with a history of tarsal injury diagnosed by the trainer and/or track veterinarian (n=8), and dogs without a history of tarsal injury (n=10). Using CT, standardised parameters of the CTB were measured including volume and average vBMD of the left and right CTB, vBMD of regions within the CTB, and bone shape.

RESULTS

There was no difference in the volumes of the left and right CTB and no association with number of racing starts. Volume of CTB in dogs with a history of tarsal injury was greater than in dogs with no history of injury (p<0.001). Mean vBMD of the right was greater than the left CTB (p=0.004), and was independent of history of injury, gender, bodyweight, and number of starts. Males with a history of injury weighed more than those with no history of injury (p=0.004). The region of greatest difference in vBMD between right and left limbs was the centrodorsomedial aspect of the CTB. Middle plantar ligament enthesiopathies and fractures of tarsal bones other than the central tarsal bone were identified in dogs with and without a history of tarsal injury.

CONCLUSIONS

Significant left-to-right asymmetry of the CTB in racing greyhounds was detected using CT. Contrary to previous suggestions, the asymmetry was not associated with the number of racing starts. We propose that the majority of the adaptive modelling of the CTB occurred rapidly following the onset of counter-clockwise training, with little further modelling throughout the racing career of the dog, however further investigation is warranted.

CLINICAL RELEVANCE

This study described a technique using CT for imaging the CTB in live dogs, which opens the way for a longitudinal study of bone modelling of the CTB in response to training and racing in a counter-clockwise direction.

Long-term outcomes after partial tarsal arthrodesis in working farm dogs in New Zealand

AIM

To report the long-term outcome (return to work and owner satisfaction) for working farm dogs in New Zealand after partial tarsal arthrodesis for proximal intertarsal and/or tarsometatarsal tarsal joint injury.

METHODS

Working farm dogs that underwent partial tarsal arthrodesis were identified by diagnosis and breed code via a search of the medical records of Massey University Veterinary Teaching Hospital (MUVTH) and Veterinary Specialist Orthopaedic Services (VetSOS). Fourteen dogs fulfilled the selection criteria and were all actively in work on farms at the time of injury. Data from case files were analysed, and the ability of the dog to work after surgery and owners' satisfaction were assessed using a questionnaire sent to owners at a median follow-up interval of 57 months.

RESULTS

Following partial tarsal arthrodesis, 7/14 (50%) dogs could perform normal work duties required while 4/14 (29%) dogs could perform most of the duties they had undertaken before injury, though some allowance had to be made for reduced performance. Thirteen owners were satisfied or very satisfied with the outcome of surgery and 12/14 thought the financial investment required for the surgery was worthwhile. Of the three dogs that did not return to work, infection requiring implant removal (one dog) and less than optimal post-operative limb alignment (two dogs) were assessed to contribute to the poor outcome. Two other dogs that required implant removal due to infection did successfully return to work.

CONCLUSIONS

In this limited cases series, partial tarsal arthrodesis in working dogs had a good prognosis for return to work. Any conclusion regarding the benefit of a particular surgical technique requires a prospective evaluation with a larger number of animals. It is important to minimise the risk of infection and optimally align the tarsus to avoid a poor outcome.

CLINICAL RELEVANCE

New Zealand veterinarians can now provide more accurate prognostic information to owners whose working dogs suffer tarsal trauma requiring partial arthrodesis.

Observer variation in the evaluation and classification of severe central tarsal bone fractures in racing Greyhounds

OBJECTIVES

To determine observer agreement on radiographic evaluation of central tarsal bone (CTB) fractures and compare this with evaluation of the same fractures using computed tomography (CT).

METHODS

Radiographs and CT scans were obtained of the right tarsi from limbs of Greyhounds euthanatized after sustaining severe CTB fracture during racing. Four observers described and classified each fracture. Inter- and intra-observer agreements were calculated.

RESULTS

Inter-observer agreement was higher for assessment of fractures using CT. Several fractures assessed by radiography were misclassified as a less severe type. Intra-observer agreement for assessment and classification of CTB fractures via radiography versus CT was variable. Overall agreement among all four observers was higher for CT than radiography. Additionally, when identifying fractures of the adjacent tarsal bones, observer agreement was higher for CT than radiography.

CLINICAL SIGNIFICANCE

Computed tomography improved observer ability to correctly evaluate CTB fracture and detect the degree of displacement and extent of any comminution. Identification of fractures of adjacent tarsal bones was also improved when tarsi were assessed using CT. These data suggest that treatment decisions based solely on radiographic assessment of CTB fractures may not produce the expected outcome.

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.

Central tarsal bone fracture in the border collie

Fracture of the plantar process of the central tarsal bone together with a dorsomedial displacement of the body of the bone was seen in six border collies. All injuries occurred during free exercise, with no extrinsic trauma. Three dogs had concomitant tarsal fractures. Primary treatment was by lag screwing the central tarsal bone to the fourth tarsal bone. All cases eventually made an excellent recovery. The superficial radiographic appearance was of a luxation of the bone as reported in a previous series, but appraisal of the radiographs showed evidence of fracture in all cases. A cadaver study to assess the mechanism of luxation showed that it is unlikely to occur naturally.

Centrodistal joint lameness in dogs

Lameness attributable to pathology of the centrodistal joint was investigated in five racing greyhounds, five Border collies and two other dogs. Diagnosis was made by the induction of pain from rotationally stressing the medial aspect of the tarsus, and by the exclusion of tarsal fractures and instabilities. Radiographic changes included plantar ligament entheslopathy and centrodistal joint osteophytosis. In many of the cases, the lameness was poorly responsive to rest and non-steroidal anti-inflammatory drugs. One dog was managed conservatively and became sound. In 10 of 11 cases, surgical promotion of centrodistal ankylosis was associated with a return to soundness.

Dorsal tarsal instability in three racing greyhounds

Rupture of the dorsal ligaments of the tarsus in the greyhound is a rare racing injury. This case report describes dorsal tarsal instability in three greyhounds. A stumble and somersault were observed in two cases and were thought to have caused the injury. Previous reports advocate partial intertarsal arthrodesis as the preferred treatment for dorsal instability of the proximal intertarsal joint, but not all dogs returned to successful racing. In these three cases, stability was restored by the insertion of a wire tension band anchored to two bone screws, allowing the development of periarticular fibrosis. The dogs raced again with no loss of form.