A mismatch of planning and achieved tibial plateau angle in cranial closing wedge surgery: An in silico and clinical evaluation of 100 cases.

OBJECTIVE: (1) To determine whether Oxley's modified cranial closing wedge osteotomy (CCWO) results in a tibial plateau angle (TPA) of 5° in silico, (2) compare in silico to clinical postoperative TPA and (3) determine the impact of ostectomy distalization in silico. STUDY DESIGN: Cross-sectional retrospective radiographic in silico study. SAMPLE POPULATION: A total of 100 stifle radiographs; 90 dogs (small ≤25 kg = 84; large >25 kg = 16). METHODS: Tibial plateau angles were measured preoperatively (TPAPre ), after in silico planning (TPAPlan ), and postoperatively (TPAPost ). Virtual ostectomies were evaluated for plate fit. Postoperative ostectomy position was measured. Virtual ostectomies were performed 5/7.5/10/15 mm from the patellar tendon insertion in 10 dogs from each preoperative TPA category (≤20°/21-25°/ 26-30°/31-35°/>35°). Comparisons for TPAPre , TPAPost , and TPAPlan were made between small and large dogs, and the outcome to the target 5° between TPA categories and ostectomy positions. RESULTS: Mean ± SD TPAPre was 28.6 ± 6.2° and higher in small than large dogs. Mean TPAPlan was 7.6 ± 2.7°. Plate fit was appropriate in all. In silico, TPAs were greater than 5° except for cases with TPAPre > 35°. Median TPAPost was 5.5° (-4-21) and was higher in small (7°) than large (4.5°) dogs. Postoperative ostectomy position was more distal than Oxley's guidelines. When distalized >7.5 mm in silico, the magnitude of under-correction increased. CONCLUSIONS: Oxley's modified CCWO did not result in TPA of 5° in most cases. Ostectomy distalization exacerbated under-correction. CLINICAL IMPACT: Current guidelines should be modified to achieve 5° TPA postoperatively.

Evaluation of subchondral bone cysts in canine elbows with radiographic osteoarthritis secondary to elbow dysplasia.

OBJECTIVE: To investigate whether subchondral bone cysts (SBCs) were present in dogs with radiographic elbow osteoarthritis (OA) and to investigate their relationship with radiographic OA severity. STUDY DESIGN: Retrospective cross-sectional study. SAMPLE POPULATION: Thirty-eight Labrador retrievers (total of 76 elbows). METHODS: Elbow computed tomography (CT) images of 18 young (≤2 years old) and 20 old (>2 years old) Labrador retrievers, which presented for elbow-associated lameness, were reviewed. Radiographic elbow OA was graded into four groups based on the largest osteophyte size on CT. The presence, number, and maximum diameter of SBCs were determined. RESULTS: Subchondral bone cysts were only identified in elbows with osteophytic new bone formation. The number and size of SBCs were associated with radiographic OA severity (p < .001 and p = .041 respectively). Specifically, the rate at which SBCs were present increased for both moderate and severe OA in comparison with the mild OA (moderate OA RR = 2.46, 95% CI 2.08-2.92, p < .001; severe OA RR = 5.60, 95% CI 4.79-6.55, p < .001). For dogs with severe OA, there was an increased likelihood that their SBCs were larger than SBCs from dogs with mild OA (OR = 1.056, 95% CI 1.012-1.101, p = .012). No SBCs were observed in elbows without radiographic evidence of OA. CONCLUSION: Subchondral bone cysts were identified as a feature of radiographic elbow osteoarthritis in Labrador retrievers, and their number and size were indicative of the presence and severity of radiographic elbow OA. CLINICAL SIGNIFICANCE: Subchondral bone cysts are a potential imaging biomarker for quantitative assessment for canine OA.

CD146 Delineates an Interfascicular Cell Sub-Population in Tendon That Is Recruited during Injury through Its Ligand Laminin-α4.

The interfascicular matrix (IFM) binds tendon fascicles and contains a population of morphologically distinct cells. However, the role of IFM-localised cell populations in tendon repair remains to be determined. The basement membrane protein laminin-α4 also localises to the IFM. Laminin-α4 is a ligand for several cell surface receptors, including CD146, a marker of pericyte and progenitor cells. We used a needle injury model in the rat Achilles tendon to test the hypothesis that the IFM is a niche for CD146+ cells that are mobilised in response to tendon damage. We also aimed to establish how expression patterns of circulating non-coding RNAs alter with tendon injury and identify potential RNA-based markers of tendon disease. The results demonstrate the formation of a focal lesion at the injury site, which increased in size and cellularity for up to 21 days post injury. In healthy tendon, CD146+ cells localised to the IFM, compared with injury, where CD146+ cells migrated towards the lesion at days 4 and 7, and populated the lesion 21 days post injury. This was accompanied by increased laminin-α4, suggesting that laminin-α4 facilitates CD146+ cell recruitment at injury sites. We also identified a panel of circulating microRNAs that are dysregulated with tendon injury. We propose that the IFM cell niche mediates the intrinsic response to injury, whereby an injury stimulus induces CD146+ cell migration. Further work is required to fully characterise CD146+ subpopulations within the IFM and establish their precise roles during tendon healing.

Impact of breed on canine humeral condylar fracture configuration, surgical management, and outcome.

OBJECTIVE: To report the prevalence, configuration, risk factors, fixation methods and outcomes after repair of humeral condylar fractures (HCF) in dogs. STUDY DESIGN: Retrospective nested cohort study. SAMPLE POPULATION: One hundred twelve dogs. METHODS: Medical records of dogs referred between January 2010 and August 2018 were searched for HCF. Demographics, fracture configuration, repair, and complications were obtained from medical records. Radiographs were assessed for fracture reduction, implant positioning, and bone healing. Short-term radiographic and clinical outcomes, and long-term owner-assessed outcome was determined. Associations between these variables were statistically analyzed. RESULTS: Dogs with HCF represented 112 of 43 325 (0.26%, 95% CI 0.22-0.31) referrals. French bulldogs and spaniel breeds were predisposed to HCF (P < .02). French bulldogs were 6.58 times (95% CI 1.62-26.7) more likely than other breeds to have a medial HCF (P = .008). Epicondylar plate fixation was associated with reduced complications compared with lag screws and Kirschner wires (P = .009). Lameness was scored as 1 of 5 (median) in the 85 dogs with initial follow-up (median 6 weeks) after HCF repair. Outcome was considered excellent in 26 of 31 dogs with long-term follow-up (median 36 months). CONCLUSION: French bulldogs and spaniels were predisposed to HCF, and medial HCF were more common in French bulldogs. Epicondylar plate fixation was associated with reduced complications. CLINICAL SIGNIFICANCE: French bulldogs are predisposed to HCF, including medial HCF. Epicondylar plate fixation is recommended over other epicondylar fixation methods to reduce complications.

Detection of maturity and ligament injury using magic angle directional imaging.

PURPOSE: To investigate whether magnetic field-related anisotropies of collagen may be correlated with postmortem findings in animal models. METHODS: Optimized scan planning and new MRI data-processing methods were proposed and analyzed using Monte Carlo simulations. Six caprine and 10 canine knees were scanned at various orientations to the main magnetic field. Image intensities in segmented voxels were used to compute the orientation vectors of the collagen fibers. Vector field and tractography plots were computed. The Alignment Index was defined as a measure of orientation distribution. The knees were subsequently assessed by a specialist orthopedic veterinarian, who gave a pathological diagnosis after having dissected and photographed the joints. RESULTS: Using 50% less scans than reported previously can lead to robust calculation of fiber orientations in the presence of noise, with much higher accuracy. The 6 caprine knees were found to range from very immature (< 3 months) to very mature (> 3 years). Mature specimens exhibited significantly more aligned collagen fibers in their patella tendons compared with the immature ones. In 2 of the 10 canine knees scanned, partial cranial caudal ligament tears were identified from MRI and subsequently confirmed with encouragingly high consistency of tractography, Alignment Index, and dissection results. CONCLUSION: This method can be used to detect injury such as partial ligament tears, and to visualize maturity-related changes in the collagen structure of tendons. It can provide the basis for new, noninvasive diagnostic tools in combination with new scanner configurations that allow less-restricted field orientations.

The in vitro behaviour of canine osteoblasts derived from different bone types.

BACKGROUND: Our understanding of the biology of osteoblasts is important as they underpin bone remodelling, fracture healing and processes such as osseointegration. Osteoblasts isolated from human humeral samples display distinctive biological activity in vitro, which relates to the samples' bone types (subchondral (S), trabecular (T), cortical (C)). Our aim was to isolate primary osteoblast cultures from different bone types from the proximal femur of a clinical population of dogs presented for total hip replacement and compare the behaviour of the osteoblasts derived from different bone types, to identify a preferred bone type for isolation. RESULTS: No differences were found for osteoblast doubling time (median for S = 2.9, T = 3.1 and C = 2.71 days, respectively; p = 0.33), final cell number (median for S = 54,849, T = 49,733, C = 61,390 cells/cm2; p = 0.34) or basal tissue non-specific alkaline phosphatase (TNAP) activity (median for S = 0.02, T = 0.02, C = 0.03 U/min/mg protein; p = 0.81) between bone types after 6 days of culture in basal media. There were no differences in mineralizing TNAP activity (S = 0.02, T = 0.02, C = 0.03 U/min/mg protein, p = 0.84) or in mineralized area (S = 0.05, T = 0.04, C = 0.04%, p = 0.92) among cells from different bone types. CONCLUSIONS: There is no significant difference in mean doubling time, basal or mineralizing TNAP activity or mineralized area in osteoblasts derived from subchondral, cortical, or trabecular bone types from the canine femoral head. However, there appears to be a high level of inter-animal variability in the studied parameters, which was independent of age, body mass, and sex. Trabecular isolate osteoblasts have the least variation of the bone types studied, and therefore should be considered a preferred source for primary osteoblast cultures. The work here provides baselines for canine osteoblast function, which has utility for future comparative studies.

Epidemiology of Cranial Cruciate Ligament Disease Diagnosis in Dogs Attending Primary-Care Veterinary Practices in England.

OBJECTIVE: To estimate the prevalence and risk factors for a diagnosis of cranial cruciate ligament (CCL) disease in dogs and to describe the management of such cases attending primary-care veterinary practices. STUDY DESIGN: Historical cohort with a nested case-control study. SAMPLE POPULATION: Nine hundred and fifty-three dogs diagnosed with CCL disease from 171,522 dogs attending 97 primary-care practices in England. METHODS: Medical records of dogs attending practices participating in the VetCompass project that met selection criteria were assessed. Univariate and multivariate logistic regression methods were used to evaluate association of possible risk factors with diagnosis of CCL disease. RESULTS: The prevalence of CCL disease diagnosis was estimated at 0.56% (95% confidence interval 0.52-0.59). Compared with crossbred dogs, Rottweilers, West Highland White Terriers, Golden Retrievers, Yorkshire Terriers, and Staffordshire Bull Terriers showed increased odds of CCL disease diagnosis while Cocker Spaniels showed reduced odds. Increasing bodyweight within breeds was associated with increased odds of diagnosis. Dogs aged over 3 years had increased odds of diagnosis compared with dogs aged less than 3 years. Neutered females had 2.1 times the odds of diagnosis compared with entire females. Insured dogs had 4 times the odds of diagnosis compared with uninsured dogs. Two-thirds of cases were managed surgically, with insured and heavier dogs more frequently undergoing surgery. Overall, 21% of cases were referred, with referral more frequent in heavier and insured dogs. Referred dogs more frequently had surgery and an osteotomy procedure. CONCLUSION: Breed predispositions and demographic factors associated with diagnosis and case management of CCL disease in dogs identified in this study can be used to help direct future research and management strategies.

Clinical comparison of the hybrid dynamic compression plate and the castless plate for pancarpal arthrodesis in 219 dogs.

OBJECTIVE: To describe and compare a large population of dogs that had pancarpal arthrodesis (PCA) using either a hybrid dynamic compression plate (HDCP) or a CastLess Plate (CLP). STUDY DESIGN: Multicenter, retrospective, cohort study. ANIMALS: Dogs (n = 240; 261 PCA). METHODS: Medical records (2000-2012) from 12 UK orthopedic centers were reviewed for dogs that had PCA to document signalment, diagnosis, arthrodesis method, and complication rates. Follow-up data were used to compare outcome (lameness evaluation and radiographic healing) after use of HDCP and CLP plates. RESULTS: PCA was performed with HDCP in 125 cases, CLP in 105, and by other techniques in 31. Carpal hyperextension injury was the most common diagnosis in HDCP and CLP groups. Surgical site infection (18.3%) was the most common postoperative complication. There was no difference in intra- (11% HDCP, 21% CLP) or postoperative (34% HDCP, 41% CLP) complication rates. Use of external coaptation did not affect postoperative complication rates or outcome. External coaptation related complications occurred in 32% HDCP and 18% CLP (P = .02). At median follow-up, most dogs were classified as having no or mild lameness (73% HDCP, 83% CLP) and there was radiographic healing in 40% HDCP and 46% CLP (P = .8) cases. CONCLUSIONS: CLP and HDCP may both be used successfully to achieve pancarpal arthrodesis. Adjunctive external coaptation does not appear to have a measurable clinical benefit but is associated with morbidity.

Pathological calcification in canine tendon-derived cells is modulated by extracellular ATP.

Tendon calcification is a commonly associated with degenerative tendinopathy of the Achilles tendons in dogs. It is characterised by the formation of calcific deposits and is refractory to treatment, often re-forming after surgical removal. Little is known about its pathogenesis and therefore the aims of this study were to develop an in vitro model of canine tendon calcification and use this model to investigate mechanisms driving calcification. Cells from the canine Achilles tendon were cultured with different calcifying media to establish which conditions were best able to induce specific, cell-mediated calcification. Once optimum calcification conditions had been established, the effect of ATP treatment on calcification was assessed. Results revealed that 2 mM di-sodium phosphate combined with 2 mM calcium chloride provided the optimum calcifying conditions, increasing calcium deposition and expression of osteogenic-related genes similar to those observed in tendon calcification in vivo. ATP treatment inhibited calcification in a dose-dependent manner, reducing calcium deposition and increasing cell viability, while osteogenic-related genes were no longer upregulated. In conclusion, the in vitro model of canine tendon calcification developed in this study provides the ability to study mechanisms driving tendon calcification, demonstrating that ATP plays a role in modulating tendon calcification that should be explored further in future studies.

Risk Factors Associated with Plantar Necrosis following Tarsal Arthrodesis in Dogs.

OBJECTIVES: The aim of this study was to define landmarks of the intermetatarsal channel of the dorsal pedal artery and to assess whether damage to the dorsal pedal artery during metatarsal screw placement in dogs undergoing pan- and partial-tarsal arthrodesis (PanTA/ParTA) could be a mechanism in the development of plantar necrosis. STUDY DESIGN: This study was divided in to two parts: (1) ex-vivo anatomical study: 19 canine cadavers, (2) retrospective clinical study: 39 dogs. Cadaveric dissection documented the mean intermetatarsal channel position. Metatarsal screw position was evaluated on postoperative radiographs of dogs after PanTA or ParTA. Screw position, arthrodesis type and surgical approach were assessed for their impact on complications, including plantar necrosis. RESULTS: The mean proximal and distal extent of the intermetatarsal channel lies between 4.3% ± 1.9 and 22.8% ± 2.9 the length of metatarsal III (MTIII) respectively. The intermetatarsal channel lies within the most proximal 25% of MTIII in 95% of cases. At least one screw risked damaging the mean intermetatarsal channel position in 92% of dogs; 8% of these dogs went on to develop plantar necrosis. The mean screw position did not differ between ParTA cases with or without plantar necrosis (p > 0.05). CONCLUSION: Violation of the intermetatarsal channel is possible during metatarsal screw placement. Care should be taken when placing screws in the proximal 25% of the metatarsals, specifically avoiding exiting dorsally between MTII and MTIII and across the distal region of the intermetatarsal channel, where the perforating metatarsal artery passes interosseously, as damage may contribute to the aetiology of plantar necrosis.

Comparison of three radiographic assessment methods for detecting slipped capital femoral epiphyses in cats: Klein's line, modified Klein's line and the S-sign.

OBJECTIVES: The aim of the present study was to investigate whether diagnostic assessment methods used on radiographs in humans with slipped capital femoral epiphysis (SCFE) can be used in cats. METHODS: The ventrodorsal (VD) extended-leg and VD frog-leg pelvic radiographs of 20 cats with SCFE without fully displaced femoral capital epiphyses (FCE), eight cats with fully displaced FCE and five control cats with normal pelvic anatomy were assessed by five observers on two separate occasions 3 months apart. The Klein's line and modified Klein's line were assessed on each VD extended-leg radiograph, and the S-sign was assessed on each VD extended-leg and VD frog-leg radiograph. RESULTS: Excluding cases of fully displaced FCE, the S-sign on the VD frog-leg radiographs more accurately diagnosed SCFE than the S-sign on the VD extended-leg radiographs and the Klein's line (92.4% vs 88.8% vs 60.6%, respectively), and had the greatest sensitivity (93.9% vs 79.2% vs 30.6%, respectively). The S-sign on the VD extended-leg radiographs had greater specificity than the Klein's line and S-sign on the VD frog-leg radiographs (99.2% vs 97.9% vs 90.9%, respectively). The modified Klein's line detected SCFE in 40.2% of cases that were negative for the Klein's line. CONCLUSIONS AND RELEVANCE: The S-sign in both VD extended-leg and VD frog-leg views successfully detected SCFE in cats and can be used to increase early diagnosis and treatment in cats with SCFE that have only subtle radiographic changes.

A new method for segmentation and analysis of bone callus in rodent fracture models using micro-CT.

Fracture burden has created a need to better understand bone repair processes under different pathophysiological states. Evaluation of structural and material properties of the mineralized callus, which is integral to restoring biomechanical stability is, therefore, vital. Microcomputed tomography (micro-CT) can facilitate noninvasive imaging of fracture repair, however, current methods for callus segmentation are only semiautomated, restricted to defined regions, time/labor intensive, and prone to user variation. Herein, we share a new automatic method for segmenting callus in micro-CT tomograms that will allow for objective, quantitative analysis of the bone fracture microarchitecture. Fractured and nonfractured mouse femurs were scanned and processed by both manual and automated segmentation of fracture callus from cortical bone after which microarchitectural parameters were analyzed. All segmentation and analysis steps were performed using CTAn (Bruker) with automatic segmentation performed using the software's image-processing plugins. Results showed automatic segmentation reliably and consistently segmented callus from cortical bone, demonstrating good agreement with manual methods with low bias: tissue volume (TV): -0.320 mm3 , bone volume (BV): 0.0358 mm3 , and bone volume/tissue volume (BV/TV): -3.52%, and was faster and eliminated user-bias and variation. Method scalability and translatability across rodent models were verified in scans of fractured rat femora showing good agreement with manual methods with low bias: TV: -3.654 mm3 , BV: 0.830 mm3 , and BV/TV: 7.81%. Together, these data validate a new automated method for segmentation of callus and cortical bone in micro-CT tomograms that we share as a fast, reliable, and less user-dependent tool for application to study bone callus in fracture, and potentially elsewhere.

Multiligament stifle injury, a multicenter retrospective study in 26 dogs.

OBJECTIVES: To describe multiligament stifle injury in dogs and report complications and long-term outcomes. METHODS: Medical records of dogs surgically treated for multiligament stifle injury were reviewed from six veterinary hospitals. Long-term follow-up was collected from referring veterinarians. RESULTS: Twenty-six client-owned dogs and 26 stifles were included. Road traffic accidents and limb entrapment were the most common causes of injury. Cranial cruciate and lateral collateral ligament rupture was the most common combination of injury (10 cases). The caudal cruciate ligament was damaged in 12/23 cases but was surgically addressed in only 2 cases. Cranial cruciate ligament rupture was present in all cases and was managed using TPLO (6 cases), extracapsular suture (15 cases) and TTA (2 cases). Postoperative immobilisation with a transarticular external skeletal fixator was used in 4/26 cases. Intraoperative complications were reported in 2/23 cases, short-term complications in 17/25 cases, of which eight were major, and long-term complications in 7/18, of which two were major. Patella luxation was seen in one case and is a previously unreported complication. The overall outcome was excellent in 9/24 cases, good in 5/24 cases, fair in 7/24 cases and poor in 3/24 cases. Follow-up time ranged from 1.5 months to 9 years with the median (IQR) of 9.5 (4.0 to 28.5) months. CONCLUSIONS: Multiligament stifle injury in dogs is associated with a high rate of major complications. The overall outcome was good to excellent in just over half of the dogs.

A biomechanical evaluation of a Hybrid Dynamic Compression Plate and a CastLess Arthrodesis Plate for pancarpal arthrodesis in dogs.

OBJECTIVE: To determine mechanical differences between two plates with different requirements for supplementary casting after pancarpal arthrodesis (PCA): the Veterinary Instrumentation Hybrid Dynamic Compression Plate (HDCP), and the OrthoMed CastLess Arthrodesis Plate (CLP). STUDY DESIGN: In vitro mechanical analysis. SAMPLE POPULATION: HDCP(n = 10), CLP(10). METHODS: Single-cycle load to failure using a materials-testing machine and cyclic loading between 38 and 380 N ± 5% to simulate estimated in vivo loads until failure or 10(6) cycles. RESULTS: Single-cycle to failure: bending stiffness was significantly higher for the HDCP(2269 ± 175 N/mm) than CLP(1754 ± 88 N/mm; P < .001). Bending structural stiffness was higher for the HDCP(3.8 ± 0.3 Nm(2) ) versus CLP(2.9 ± 0.2 Nm(2) ; P= .0022). A difference between the 2 plates for bending strength was not demonstrated; HDCP= 13.9 ± 1.4 Nm, CLP13.2 ± 0.5 Nm (P= .24). Cyclic Loading: no failures occurred with either plate type when plates were cycled to 10(6) cycles. CONCLUSION: There is no mechanical advantage in bending resistance afforded by the CLPover the HDCP. Fatigue failure of either plate during the convalescent period of an estimated 150,000-250,000 cycles is unlikely. Based on the bending performance, there is no evidence to support the use of the CLPover the HDCPfor castless PCA.

Defining the safe corridor for transcondylar screw placement in the feline humeral condyle.

OBJECTIVES: The aim of this study was to develop guidelines for the optimal location of drill entry and exit points for insertion of a transcondylar screw across the feline humeral condyle. METHODS: Multiplanar reconstruction of feline elbow CT scans performed between 2016 and 2021 at one referral institution were reviewed. The optimum medial and lateral epicondylar entry and exit points for transcondylar screw placement were determined. These values were normalised to the humeral condylar diameter (HCD) for each elbow to determine the transcondylar screw placement guidelines. These guidelines were applied to each elbow and tolerance angles were determined in the transverse and frontal plane CT images to determine the safe corridor for screw placement. RESULTS: Twenty elbows from 12 cats were evaluated in this study. The guidelines for transcondylar screw placement were as follows: the medial entry/exit point was 0.38 × HCD cranial and 0.16 × HCD distal to the medial epicondyle, and the lateral entry/exit point was 0.3 × HCD cranial and 0.16 × HCD distal to the lateral epicondyle. Tolerance angles were statistically significantly (P <0.05) larger in both frontal (34.5% larger) and transverse (21.1% larger) planes when drilled from a lateral to medial direction compared with drilling from a medial to lateral direction. CONCLUSIONS AND RELEVANCE: The guidelines determined from this study may aid clinicians in the placement of humeral transcondylar screws in cats. Where possible, drilling from a lateral to medial direction is recommended owing to the higher tolerance angles reducing the likelihood of articular surface damage. Further studies are warranted to determine whether these guidelines are clinically useful and result in the safe insertion of a transcondylar screw in the clinical setting.

Demography, management and outcomes of canine physeal fractures (103 cases).

BACKGROUND: This study is a retrospective review of the demography, management, complications and outcomes of canine physeal fractures. METHODS: Clinical records were reviewed for dogs with appendicular physeal fractures, and descriptive statistical analysis was applied to the data set. RESULTS: One hundred and three fractures were included, of which 68 had follow-up. Fractures of the distal humerus were the most common (n = 57), followed by proximal tibial fractures (n = 16). Outcome was fair for most fractures at all locations, aside from the distal humerus, where most outcomes were good. At radiographic follow-up, most physes were closed at all locations aside from the distal tibia. Implant removal to allow ongoing physeal growth was performed in only 3/18 (17%) fractures, in 15/18 (83%) implant removal related to complications. LIMITATIONS: Only short-term follow-up data were present, and hence it is not possible to give a longer term indication of return to function. CONCLUSIONS: The management and demography of canine physeal fractures have evolved considerably from previous publications. Routine implant removal to allow ongoing growth was not regularly performed at all locations in this cohort.

Traumatic physeal fractures in cats: a review of 36 cases (2010-2020).

OBJECTIVES: The aim of this study was to describe the demography, aetiology, location and classification of physeal fractures in cats, and to describe their management and outcomes. METHODS: Clinical records and radiographs of cats referred for management of physeal fractures were retrospectively reviewed. Fractures of the proximal femoral physis were excluded. Descriptive statistics were used to describe signalment, cause of injury, presence of concurrent injuries, fracture description, treatment modality, complications, follow-up, physeal closure, implant removal and outcome. RESULTS: Thirty-four cats with 36 fractures were included, of which 17 affected the distal femur, 11 the distal tibia and fibula, five the distal radius and ulna, two the proximal tibia and one the distal humerus. Salter-Harris classification was type I in 14, type II in 16, type III in two and type IV in four fractures. Thirty-four fractures were treated with primary fixation, and the most common method was crossed Kirschner wires (24/34 fractures). Complications were observed in 14 fractures, of which 12 were minor. At radiographic follow-up, physeal closure was reported in 23 fractures, of which 15 were considered premature. Implant removal was performed in three fractures. Outcome was good in 28, fair in four and poor in two fractures. CONCLUSIONS AND RELEVANCE: Fracture of the distal femoral physis was the most common physeal fracture seen. Cats presenting with physeal fractures may be skeletally immature or mature with delayed physeal closure. The rate of physeal closure after fracture repair was relatively high but without apparent impact. The frequency of implant removal was very low, indicating that despite having a physeal fracture repair, most cats did not require a second procedure to remove implants. Overall, internal fixation provided a good outcome in most fractures.

Computed Tomographic Features of Non-Lame French Bulldog Elbows.

OBJECTIVE: French Bulldogs are predisposed to humeral condylar fractures. Computed tomography (CT) in English Springer Spaniel elbows has allowed identification of humeral intracondylar fissures (HIF), which can cause lameness and predispose to condylar fractures. This study aimed to evaluate CT characteristics of non-lame French Bulldog elbows, to determine the presence of underlying elbow disease. STUDY DESIGN: Retrospective evaluation of CT images from elbows of non-lame French Bulldogs from scans obtained for soft tissue or neurological evaluation was performed. Images were evaluated for the presence of HIF and other elbow abnormalities: condylar and supracondylar remodelling, humeral condylar sclerosis, elbow incongruency, medial coronoid process disease and elbow osteoarthritis. Descriptive statistics were performed. RESULTS: Computed tomographic scans from 37 dogs (74 elbows) were reviewed. No HIF were identified, although 28/74 elbows had an intracondylar sclerotic band. Medial coronoid process disease was noted in 16/74 elbows, and small osteophytes were present in 21/74 elbows, suggesting a degree of subclinical elbow disease. Widening of the caudolateral aspect of the radial incisure was identified (37/74) as a breed normal. Elbow incongruency was otherwise rare. CONCLUSION: Non-lame French Bulldogs showed a low prevalence of occult elbow disease but a proportion had radial incisure widening. Although humeral intracondylar sclerosis was present in over a third of dogs, no HIF were identified and therefore no clear cause for their increased risk of humeral condylar fracture was identified.

Feline Femoral Fracture Fixation: What are the options?

PRACTICAL RELEVANCE: The femur is the most commonly fractured bone in cats. Femoral fractures usually result from high-velocity trauma such as a road traffic accident or fall from a height and, as such, are associated with a wide variety of concurrent injuries. The initial focus of treatment should always be on assessment and stabilisation of the major body systems. Once any concurrent injuries have been addressed, all femoral fractures need surgical stabilisation, with the notable exception of greenstick fractures in very young cats, which can heal with cage rest alone. A number of different surgical options are available depending on the fracture type, location, equipment, surgeon experience and owner finances. CLINICAL CHALLENGES: Femoral fractures can vary hugely in complexity and the small size of feline bones can limit the choice of implants. Furthermore, cats can present unique challenges in the postoperative period due to their active nature and the limited means to control their exercise level. AUDIENCE: This review is aimed at general and feline-specific practitioners who have some experience of feline orthopaedics, as well as those simply wishing to expand their knowledge. AIMS: The aim of this review is to help clinicians assess, plan and manage feline femoral fractures. It provides an overview of diagnostic imaging and a discussion of a range of suitable surgical options, including the principles of different types of fixation. It also highlights cat-specific issues, approaches and implants pertinent to the management of these cases. EVIDENCE BASE: A number of original articles and textbook chapters covering many aspects of femoral fractures in cats and dogs have been published. Where possible, this review draws on information from key feline research and, where necessary, extrapolates from relevant canine literature. The authors also offer practical guidance based on their own clinical experience.

Moving Beyond the Limits of Detection: The Past, the Present, and the Future of Diagnostic Imaging in Canine Osteoarthritis.

Osteoarthritis (OA) is the most common orthopedic condition in dogs, characterized as the chronic, painful end-point of a synovial joint with limited therapeutic options other than palliative pain control or surgical salvage. Since the 1970s, radiography has been the standard-of-care for the imaging diagnosis of OA, despite its known limitations. As newer technologies have been developed, the limits of detection have lowered, allowing for the identification of earlier stages of OA. Identification of OA at a stage where it is potentially reversible still remains elusive, however, yet there is hope that newer technologies may be able to close this gap. In this article, we review the changes in the imaging of canine OA over the past 50 years and give a speculative view on future innovations which may provide for earlier identification, with the ultimate goal of repositioning the limit of detection to cross the threshold of this potentially reversible disease.