Comparison of exposure of the radius afforded by the craniomedial and craniolateral open surgical approaches in dog cadavers.

Management of antebrachial fractures in dogs typically involves open reduction and bone plate stabilisation of the radius performed using either a craniomedial approach (CMA) or craniolateral approach (CLA). The aim of this cadaveric study was to compare radial exposure afforded via the craniomedial and craniolateral approaches, without and with releasing the abductor digiti I longus (ADIL) muscle. The CMA and CLA were performed on alternate paired cadaver forelimbs with the subsequent release (CMA) or elevation (CLA) of the ADIL muscle (n = 12). The percent area of exposure was calculated in defined longitudinal radial segments (LRSs) and hemi-circumferential radial segments (HRSs) using digitally uploaded images. A non-parametric rank sum test was used for statistical analysis (p < 0.05). While both the CMA and CLA provided sufficient exposure for radial cranial plate placement in the mid-to-distal diaphyseal region (50-80% LRSs), the CMA afforded greater exposure to the distal metaphysis (80-90% LRS). The CLA was advantageous in exposing the proximal diaphysis (20-50% LRSs) and distal epiphysis (90-100% LRS). Exposure of the distal diaphyseal, metaphyseal, and epiphyseal regions (80-100% LRSs) was impeded by the ADIL muscle. A tenotomy of the tendon of insertion of the ADIL muscle increased exposure afforded by the CMA in the distal metaphyseal and epiphyseal regions. The exposure afforded by the CLA in the distal diaphyseal and metaphyseal regions was significantly improved by elevating the origin of the ADIL muscle. The results of this study provide useful clinical information when surgeons are deciding which approach to use for cranial radial plating.

Antebrachiometacarpal arthrodesis in five dogs.

CASE REPORTS: Five dogs (4 with severe carpal contracture, 1 with a chronically infected carpal joint) underwent antebrachiometacarpal arthrodesis. Excision of all carpal bones, except the accessory carpal bone, was done, either because of persistent infection or to allow the manus to be arthrodesed in a functional position. All five dogs developed varying degrees of soft tissue swelling of the surgical site following surgery. All five arthrodeses achieved complete osseous union within 4-67 weeks. The immediate postoperative distal radiometacarpal frontal plane angulation ranged from 1° to 19° (mean ± SD: 7 ± 8°). The immediate postoperative distal radiometacarpal sagittal plane angulation ranged from 6° to 26° (mean ± SD: 17 ± 9°). Plate coverage of the secured metacarpal bone(s) ranged from 75% to 87% (mean ± SD: 80 ± 4%). Infection necessitated plate removal in four dogs, 3-17 (mean ± SD: 8 ± 6) months following surgery and 0-15 (mean ± SD: 5 ± 7) weeks following radiographic documentation of complete osseous union. CONCLUSION: Despite one dog having marked elbow incongruency and degenerative joint disease and one dog having an ipsilateral radial nerve deficit, all five dogs improved and had acceptable limb function at the time of the final evaluation, which ranged from 25 to 296 (mean ± SD: 99 ± 111) weeks following surgery.

Retrospective evaluation of the efficacy of minimally invasive, fluoroscopic-assisted reduction and stabilisation of unicondylar humeral fractures.

OBJECTIVE: This study evaluated the proficiency in executing closed, fluoroscopic-assisted reduction of unicondylar humeral fractures. The following were hypothesised: experienced surgeons would be highly successful in performing closed reduction; body weight, time to surgery and surgeon experience would influence the reduction method; and the reduction method would not affect technical aspects of the repair. METHODS: All unicondylar humeral fractures stabilised between January 2007 and January 2017 were reviewed. Signalment and time to surgery, experience of the attending surgeon, and the initial and definitive reduction methods were recorded. Initial and subsequent postoperative radiographs were used to assess fracture reduction, implant placement and complications. Univariate polychotomous logistic regressions, Fisher's exact test, Kruskal-Wallis rank sums non-parametric test or equivalence tests were used to compare parameters evaluated based on the approach employed (P < 0.05 significant). RESULTS: A total of 36 dogs with 37 fractures were identified (median weight: 5.4 kg; median time to surgery: 3 days). Of these, 11 of 15 attempted closed reductions were successful. Successful closed reductions had shorter times to surgery than limited open or open reductions (P = 0.009). Age, weight and surgeon experience did not influence the definitive reduction method. Technical aspects of reduction and stabilisation were similar among the reduction methods. Surgery times were shorter for closed reductions (P = 0.034). Of the fractures, 75% healed without complications and 85% had excellent long-term function. CONCLUSION: The results suggested that closed, fluoroscopic-assisted reduction is a proficient (73% successful) and efficient (shorter surgery times with comparable technical results compared with other limited open and open reduction) means of stabilising acute unicondylar humeral fractures.

Intraoperative use of a transarticular circular fixator construct to facilitate reduction and stabilisation of a proximal tibial physeal fracture in a dog.

CASE REPORT: A 4-month-old female intact American Pit Bull Terrier was presented for right pelvic limb lameness 1 day after the dog had been hit by an all-terrain vehicle. Orthogonal radiographs of the right stifle revealed a Salter-Harris type IV fracture through the proximal tibial physis extending caudodistally through the proximal tibial metaphysis. The distal tibia was markedly displaced cranially, laterally and proximally, resulting in complete overriding of the fracture segments. An open approach was made in order to facilitate direct reduction, but the fracture could not be sufficiently distracted and the epiphyseal segment remained fixed caudal to the remainder of the tibia. Concerns regarding possible iatrogenic trauma to the epiphysis prompted the use of a transarticular circular fixator construct to distract the fracture segments to facilitate reduction. Distraction that facilitated reduction was performed using three TrueLok Rapid Quick Adjust Struts that were positioned between the two ring components. The struts also allowed for multiplanar adjustment of alignment, which allowed the fracture to be maintained in anatomic reduction as divergent interfragmentary Kirschner wires were placed. Radiographic union was confirmed 19 days after surgery. CONCLUSION/CLINICAL SIGNIFICANCE: Transient intraoperative application of a circular construct incorporating the TrueLok components facilitated accurate fracture reduction without inflicting further iatrogenic trauma to the epiphysis, after traditional direct reduction techniques proved ineffective, and afforded a successful clinical outcome in the dog reported here.

Genetic Association of MMP10, MMP14, and MMP16 with Dental Caries.

Matrix metalloproteinases (MMPs), which degrade extracellular proteins as part of a variety of physiological processes, and their inhibitors have been implicated in the dental caries process. Here we investigated 28 genetic variants spanning the MMP10, MMP14, and MMP16 genes to detect association with dental caries experience in 13 age- and race-stratified (n = 3,587) samples from 6 parent studies. Analyses were performed separately for each sample, and results were combined across samples by meta-analysis. Two SNPs (rs2046315 and rs10429371) upstream of MMP16 were significantly associated with caries in an individual sample of white adults and via meta-analysis across 8 adult samples after gene-wise adjustment for multiple comparisons. Noteworthy is SNP rs2046315 (p = 8.14 × 10-8) association with caries in white adults. This SNP was originally nominated in a genome-wide-association study (GWAS) of dental caries in a sample of white adults and yielded associations in a subsequent GWAS of surface level caries in white adults as well. Therefore, in our study, we were able to recapture the association between rs2046315 and dental caries in white adults. Although we did not strengthen evidence that MMPs 10, 14, and 16 influence caries risk, MMP16 is still a likely candidate gene to pursue.

Plate failure by bending following tibial fracture stabilisation in 10 cats.

OBJECTIVE: To describe the clinical findings and management of tibial fractures in cats in which osteosynthesis failed due to plate bending. METHODS: Case records and radiographs of cat tibial fracture repairs from five referral centres were reviewed for signalment and to assess incidence of plate failure by bending. Cats that sustained plate bending following plate or plate-rod fixation were reviewed for fracture configuration, repair method, initial postoperative and postfailure tibial alignment, revision treatment and outcome. RESULTS: The incidence of plate bending in cat fractures managed with plate and plate-rod fixation in the four referral centres where the overall number could be established was 13% (8/60). In the 10 cats in which plates bent, initial fractures were generally oblique or spiral with mild comminution and located in the middle or distal third of the tibia. Mean time to implant failure was 24 days (range 2 to 56 days). Mean tibial valgus angle increased from 12·9° to 30·9° following bending of the plate. Short-term outcome following revision surgery using orthogonal plating or stacked medial plates was favourable with improvement in tibial valgus in all five fractures with follow-up data. CLINICAL SIGNIFICANCE: Plate bending following tibial fracture stabilisation in these 10 cats resulted in tibial valgus deformation. Consideration of plate and/or intramedullary rod selection and application should be given to avoid a plate strain environment that exceeds the yield point of the plate.

Retrospective evaluation of the efficacy of isolating bacteria from synovial fluid in dogs with suspected septic arthritis.

OBJECTIVE: To evaluate the efficacy of synovial fluid culture in obtaining the causative organism from dogs with suspected septic arthritis. METHODS: In this retrospective evaluation, synovial fluid cytology and microbiology submissions from dogs with suspected septic arthritis from March 2007 to August 2011 were reviewed. Synovial fluid cytology consistent with joint sepsis was identified. Cultures of synovial fluid from dogs with clinical histories and abnormalities consistent with septic arthritis were used to evaluate the efficacy of bacterial isolation. RESULTS: In total, 36 dogs met the inclusion criteria. Initial aerobic cultures of joint fluid yielded bacterial growth in 44% of these dogs. All anaerobic cultures were negative. In 19% of the dogs with positive cultures, antibiotics had been administered prior to arthrocentesis compared with 10% of dogs with negative cultures. There was no association between culture efficacy and the administration of antimicrobial treatment prior to synovial fluid culture or recent surgery involving the affected joint (P=0.637 and P=0.106, respectively). CONCLUSION: Culture of synovial fluid from dogs with suspected septic arthritis has a low yield, necessitating a more effective means of identifying bacteria from suspected septic joints in dogs.

Comparison of synovial fluid culture and 16S rRNA PCR in dogs with suspected septic arthritis.

OBJECTIVE: To prospectively compare the sensitivity and specificity of 16S rRNA PCR with culture for identifying the causative organism in synovial fluid obtained from dogs with suspected septic arthritis. METHODS: Synovial fluid cytology, PCR analysis and aerobic, anaerobic and Mycoplasma culture of samples from the affected joints of 18 dogs presenting with suspected septic arthritis were performed. Synovial fluid samples from the corresponding contralateral joints of 7 dogs were also analysed as negative controls. RESULTS: There was no significant difference between the sensitivity of bacterial detection via culture (63.2%) versus PCR (73.7%) of synovial fluid (P=0.728) or between culture and combined PCR and culture (89.5%) of synovial fluid (P=0.124). The specificity of PCR (42.9%) was significantly lower than culture specificity (100%) (P=0.07). CONCLUSION: Although 16S PCR may hold potential as an ancillary diagnostic test for identifying the causative organism in dogs with septic arthritis, our study failed to demonstrate improved accuracy compared with traditional synovial fluid culture.

Corrective osteotomy for procurvatum deformity caused by distal femoral physeal fracture malunion stabilised with String-of-Pearls locking plates: results in two dogs and a review of the literature.

BACKGROUND: This report describes the treatment of severe procurvatum because of distal femoral physeal fracture malunion in two skeletally immature dogs. CASE REPORTS: Both dogs presented with severe right hindlimb lameness and markedly reduced stifle extension at less than 5 months of age. Severe distal femoral procurvatum and mild-to-moderate femoral shortening secondary to distal femoral physeal fracture malunion were evident on radiographs. The sagittal plane deformities were addressed with a caudal opening-wedge osteotomy in one dog and cranial closing wedge ostectomy in the other dog. String-of-Pearls locking plates were used to stabilise the osteotomies. Functional stifle extension range of motion and femoral length were improved post surgery in both dogs. Explantation of the plates was required in both dogs because of local soft tissue irritation. Both dogs had excellent outcomes based on subjective and objective measures (pressure sensitive walkway, force platform analysis) when assessed at skeletal maturity. CONCLUSIONS: Corrective osteotomy stabilised with String-of-Pearls locking plates is a viable treatment option for improving limb function in dogs with severe procurvatum deformities caused by distal femoral physeal fracture malunion.

Hinged circular fixator construct for correction of congenital metatarsal deformity in a foal.

A five-week-old American Quarter Horse colt was presented for evaluation of a left hindlimb deformity and lameness. Radiographs of the left hindlimb revealed a varus deformity with recurvatum originating in the mid-diaphysis of the third metatarsal bone. Surgical correction was undertaken by performing an osteotomy through the centre of rotation of angulation located within the mid-diaphysis of the third metatarsal bone, and a four-ring hinged circular external fixator construct was applied. Distraction of the osteotomy site was performed over an 11 day period. Notable complications included failure of a fixation pin, infection of the surgical site, and temporary laxity of the supporting tendons and ligaments of the contralateral metatarsophalangeal joint. The fixator was maintained until there was sufficient bone formation to allow frame removal, 152 days after the initial surgery. Use of a hinged circular construct allowed for partial correction of the deformity with resultant lengthening and resolution of the lameness in this colt.

In vivo femorotibial subluxation during weight-bearing and clinical outcome following tibial tuberosity advancement for cranial cruciate ligament insufficiency in dogs.

Ex vivo studies have been used extensively to investigate the mechanisms of tibial osteotomies but few have explored femorotibial alignment in vivo. The aim of this study was to assess femorotibial joint alignment under static weight-bearing conditions (and subsequent outcome) in dogs treated for cranial cruciate ligament (CrCL) insufficiency with tibial tuberosity advancement (TTA). Twenty-five dogs (30 stifles) with CrCL insufficiency treated by TTA were included. The distance from the origin to insertion of the CrCL (CrCLd) was measured on non-weight-bearing immediate post-operative radiographs and weight-bearing follow-up radiographs. CrCLd values were compared using a paired t test. The relationship between change in CrCLd (ΔCrCLd) and post-operative patellar tendon angle according to the common tangent method (PTACT) was assessed using Pearson's correlation. Outcome was assessed with an owner-completed questionnaire, and peak vertical force (PVF) and vertical impulse (VI) as percentages of bodyweight (BW). Following TTA, 21/30 stifles were persistently subluxated at a follow-up of 18 ± 14 months (mean ± SD). Follow-up weight-bearing CrCLd was greater (P<0.001) than post-operative non-weight-bearing CrCLd, with a mean ΔCrCLd of 5.8 ± 3.4mm (16 ± 10%). Post-operative PTACT was 89 ± 3° and did not correlate with ΔCrCLd (r=0.002, P=0.994). Mean PVF and VI were 65 ± 10% BW and 9±2% BW, respectively. All owners felt TTA provided improvement in lameness. The results indicated that TTA does not normalize sagittal plane femorotibial stability during standing at a PTACT of 90°, but most dogs return to good limb function regardless of femorotibial alignment.

Use of hinged circular fixator constructs for the correction of crural deformities in three dogs.

BACKGROUND: Hinged circular external skeletal fixator constructs are used to perform sequential correction of angular limb deformities, often with resultant limb segment lengthening, via distraction osteogenesis. Although there are several reports describing the use of these constructs for correction of antebrachial deformities in dogs, there is little information regarding their use on other limb segments. This report describes the use of hinged circular fixator constructs for the correction of acquired crural deformities in three skeletally immature dogs. CASE REPORTS: Two dogs had purely frontal plane deformities (one valgus, one varus) and the third dog had frontal (valgus) and sagittal (recurvatum) components to its deformity. At the time of long-term evaluation, frontal plane angulation relative to the contralateral limb improved from 40° to 22° of valgus, 30° to 5° of valgus, and 20° to 1° of varus in the three individual dogs. Tibial length discrepancies of 12% and 22% that were initially present in two dogs were improved to 6% and 10%, respectively, of the contralateral tibial length at the time of final evaluation; both dogs had compensatory growth of the ipsilateral femur and all dogs had an excellent functional outcome. CONCLUSION: These cases illustrate the value of using hinged circular fixator constructs for correction of crural angular deformities, particularly when length discrepancies of the tibia are present.

A review of extra-articular prosthetic stabilization of the cranial cruciate ligament-deficient stifle.

Extra-articular prosthetic stabilization techniques have been used as a method of stabilization of the cranial cruciate ligament (CrCL)-deficient stifle for decades. During extra-articular prosthetic stabilization, the prosthesis is anchored to the femur and tibia, and tensioned in the attempt to resolve femorotibial instability. The position of the anchor points of the prosthesis is crucial for restoring a normal range of joint motion and mitigating alterations in prosthesis tension during motion. Recently developed techniques offer several innovations with potential advantages such as bone-to-bone fixation, prosthetic materials with better mechanical properties, and improved isometry of the anchor points. Whether these innovations provide clinically superior results to the traditional techniques such as lateral circumfabellar-tibial suture techniques has yet to be determined.

Use of an interlocking nail-hybrid fixator construct for distal femoral deformity correction in three dogs.

Our purpose was to report the use of an interlocking nail-hybrid external fixator construct to correct distal femoral deformities in three dogs. Radiographs, computed tomography and a three-dimensional model were used to plan the surgical procedure. A femoral osteotomy or ostectomy was performed at the level of the centre of rotation of angulation in all three dogs. Angular and rotational deformities were corrected acutely. Distraction osteogenesis was performed to lengthen each femur postoperatively. All three dogs had additional anatomic abnormalities of the affected hindlimb complicating the correction of the distal femoral deformity. While the interlocking nail-hybrid fixator construct allowed for stable distraction of the femur, all three dogs developed complications during the postoperative convalescent period, and each had some degree of residual lameness. Lengthening the femur following acute deformity correction is problematic and additional experimental and clinical studies are warranted to decrease postoperative morbidity and improve functional results.

Stabilisation of metacarpal or metatarsal fractures in three dogs, using circular external skeletal fixation.

CASE HISTORY: Three dogs that presented with multiple metacarpal or metatarsal fractures, between January 2004 and November 2008. CLINICAL FINDINGS: Case 1 had sustained closed fractures of metacarpal bones II-V, resulting in a valgus angulation of the manus. Case 2 had 2-week-old open, infected, comminuted diaphyseal fractures of metatarsal bones II-IV. Case 3 had sustained open fractures of metacarpal bones II-V, that were initially stabilised with intramedullary Kirschner wires, but had gone to non-union 5 months after the initial surgery. TREATMENT: Circular external skeletal fixation was used in each of the three dogs. In Case 1, the fixator was used to perform a closed reduction, to align the overridden, angulated fractured metacarpus, by distracting the frame. In Case 2, the fixator was applied after a limited open reduction, and was used to provide stable fixation of the comminuted infected fractures while facilitating open wound management. In Case 3, the fixator was applied in buttress fashion, following open debridement and placement of an autogenous cancellous bone graft at the non-union fracture sites. CLINICAL OUTCOME: All three dogs developed drainage tracts from the fixator wire. There was minimal associated lameness or pain in two of the dogs, but Case 3 developed a transient lameness ascribed to infection associated with the wire tracts, which resolved following administration of antibiotics. Inflammation of wire tracts resulted in the fixator being removed prior to radiological evidence of union of all fractures in each dog, and the mean time from surgery to removal of the frame was 12 (range 7-24) weeks. None of the dogs had residual lameness or discomfort associated with the fractures at the time of long-term evaluation, which ranged from 10-45 months following surgery. CLINICAL RELEVANCE: These three cases illustrate the utility of circular external skeletal fixation for the stabilisation of complicated fractures of the metacarpus and metatarsus. The fixators were applied without inducing substantial iatrogenic trauma, and the small-diameter fixation wires provided effective stability of the short metacarpal and metatarsal fracture segments, allowing the fractures to heal. Although complications associated with wire tracts should be anticipated, circular external skeletal fixation should be considered as a viable method for managing complex fractures of the metacarpus and metacarpus in dogs.

Minimally invasive plate osteosynthesis: applications and techniques in dogs and cats.

Bone plating has been used as a method of fracture management for many years. Recently, a trend toward the use of fracture fixation techniques which preserve the local fracture environment, known as biological osteosynthesis, has evolved. This trend has resulted in the development of a less traumatic method of bone plating referred to as minimally invasive plate osteosynthesis (MIPO), or percutaneous plating. During MIPO fracture stabilisation, plates are inserted through short incisions and a communicating epiperiosteal tunnel. Typically, bone plates applied in this fashion have a bridging function. Promising outcomes have been reported in human patients undergoing MIPO fracture stabilisation, and limited reports of the use of this technique in dogs and cats have yielded positive results as well. Careful case selection, pre-operative planning, and appropriate instrumentation are necessary when performing the technique. Rapid time to union, low complication rates and good return to function have been noted in human patients. Additional research is needed to define selection criteria and outline the definitive benefits of MIPO in dogs and cats.

Dicondylar humeral fracture stabilisation in a dog using a transilial rod and external fixation.

Repair of a Salter-Harris type IV dicondylar humeral fracture was performed on a 15-week-old pitbull terrier. Interfragmentary compression of the intracondylar component of the fracture was achieved with a transilial rod and locking nuts (Trans-ilial Rod; IMEX Veterinary, Inc.). The transilial rod was articulated with a modified type I external fixator which functioned as adjunctive stabilisation for the supracondylar component of the fracture. Fracture healing was confirmed radiographically five weeks following surgery. The dog had no appreciable lameness when examined 12 months after fracture repair.

Bilateral correction of metatarsal rotation in a dog using circular external skeletal fixation.

An 8-month-old castrated male Saint Bernard was evaluated for bilateral hind limb lameness. Lameness was ascribed to bilateral metatarsal rotational abnormalities on the basis of the physical examination and radiographic evaluations. Staged, bilateral deformity correction and tarsometatarsal arthrodeses were performed using circular external skeletal fixators. The dog's gait improved following surgery and the fixators were removed 3 (left hind paw) and 4 (right hind paw) months following surgery. Twenty months after the initial surgery, the owner reported that the dog was walking well without apparent lameness. Previous reports suggest that metatarsal rotation is untreatable; however, our results suggest that surgical correction of this deformity can substantially improve limb function in dogs affected with metatarsal rotation.

Treating pedal shortening in a dog by metatarsal distraction osteogenesis.

A five-month-old, male German shepherd dog was presented with a left hindlimb deformity. Wearing a cast for a prolonged period to treat left metatarsal fractures at eight weeks of age had resulted in physeal closure of the calcaneus, metatarsals and phalanges. Hyperextension of the phalanges and ulceration of the plantar skin proximal to the main tarsal pad were seen. The left foot was 40 mm shorter than the right. At seven months of age, a modified circular external skeletal fixator (CESF) was used to perform distraction osteogenesis of the metatarsal bones for 28 days. The CESF apparatus was removed after eight weeks when there was radiographic consolidation of regenerate bone. At follow-up evaluations four and 12 months after surgery, the phalangeal hyperextension and plantar skin ulceration had resolved. No lameness was detected.