Ultrasonographic assessment of equine metacarpal cartilage thickness is more accurate than computed tomographic arthrography

Articular cartilage can be directly imaged using ultrasonography. The fetlock is a common site of osteochondrosis, with the sagittal ridge of the third metacarpal bone most commonly affected. In osteochondrosis, cartilage thickening may be an initial finding. This postmortem study investigated the ability of ultrasonography to accurately measure the dorsodistal articular cartilage of the third metacarpal bone in young horses, compared to computed tomographic arthrography (CTA) and histological measurements. A total of 33 metacarpophalangeal joints from 18 horses between the ages of 12 days and 10 months old were imaged ultrasonographically and with CTA and sectioned and measured using histology. Imaging measurements were made by two observers. Despite overall weak agreement between ultrasonography and histology, the best agreement was at the distal aspect of the sagittal ridge of the third metacarpal bone. Interobserver agreement at this site was also moderate. CTA showed poor agreement overall with histology. Cartilage thickness decreased with age on ultrasonography, CTA, and histology. In conclusion, ultrasonography is a more accurate imaging modality than CTA in the assessment of cartilage in young horses.

Environmental factors of equine osteochondrosis and fetlock osteochondral fragments: A scoping review - Part 1

Various environmental and genetic risk factors are linked to the pathogenesis of equine osteochondrosis and osteochondral fragments in the fetlock joint. Therefore, a scoping review was conducted to describe current evidence linking genetic factors and environmental factors of these osteochondral disorders. This article constitutes the first part of this scoping review and focuses on environmental factors, with the second part addressing genetic factors. To identify potentially relevant papers online bibliographical databases PubMed and Web of Science were utilised, supplemented with articles listed on the OMIA website (OMIA:000750-9796). After entry collection, removing duplicates, screening titles, abstracts, and full-text documents for eligibility, and manually searching reference lists of the remaining articles, a total of 212 studies was identified for this scoping review. First, an overview of the current understanding of the etiopathogenesis of equine osteochondrosis and osteochondral fragments in the fetlock joint is given. Subsequently, the article delves into the environmental factors associated with the prevalence of these disorders, which are categorized into foetal programming, biomechanical trauma and exercise, growth, anatomic conformation, nutrition, weaning, hormonal factors, bacterial infection, sex, date of birth, and other environmental factors. In conclusion, future research should adopt a multidisciplinary approach, emphasizing longitudinal studies and precise phenotype definitions. This strategy will help elucidate the complex relationships between environmental factors and OC, DOF, and POF, considering the dynamic nature, varying phenotypes, and scarcity of research in some domains of these osteochondral disorders. This approach will be crucial in developing effective management strategies aimed at improving equine orthopaedic health.

Nineteen years of radiographic screening: Impact of sepsis and evolution of osteochondrosis dissecans prevalence in Walloon sport horses born between 2004 and 2022

Osteochondrosis dissecans is a particularly common developmental orthopaedic disorder in equines. Among its causes, the hereditary component is no longer a matter of debate, and, for several decades, the various studbooks for sport horses have been selecting stallions in order to limit the prevalence of this condition in the population. However, to our knowledge, no study has evaluated changes in the prevalence of osteochondrosis dissecans over time through longitudinal monitoring of a population of sport horses. The study presented here is part of a large screening programme for developmental orthopaedic pathologies in Wallonia (Belgium) and assessed the presence of these lesions over a period of 19 years in the Walloon sport horse population according to constant and standardised sampling and diagnostic criteria. The effects of breeding conditions and infection in foals were also assessed by means of questionnaires. The results showed no significant change in the prevalence of osteochondrosis dissecans in a population of 1099 individuals born between 2004 and 2022. Furthermore, individuals who had suffered from sepsis during their growing period were very significantly predisposed (p < 0.001) to the development of osteochondrosis dissecans compared to a control group, with respectively 14/21 (67%) and 103/364 (28%) of individuals affected. This study suggests that the selection programmes applied to the population studied are not sufficiently strong or adapted to reduce the prevalence of osteochondrosis dissecans in the population over a period of 19 years. Moreover, this study confirms that foals with sepsis and concurrent osteochondrosis dissecans lesions should not necessarily be excluded from breeding programmes on this basis.

Methodological approaches to assessing the genetic predisposition of osteochondrosis of the tarsocrural joint in the Pura Raza Española horses

Osteochondrosis (OC) is a developmental orthopaedic disease of significant concern in numerous sport horse breeds, with significant international relevance. Using digital radiographs, we assessed the occurrence of hock (tarsocrural joint) OC in 3 048 Pura Raza Española (PRE) horses which took part in a morpho-functional test, in three specific locations in the tarsus limbs: the Distal Intermediate Ridge of the Tibia (DIRT), the lateral trochlear ridges of the talus (LTT), and the medial trochlear ridges of the talus (MTT). An incidence rate of 13.3% was found for hock OC in the analysed sample, with the highest incidence rate observed in DIRT (10.0%) and the lowest in MTT (0.2%). Estimates of genetic predisposition to hock OC were carried out using three genetic approaches: 1a) a binomial threshold model based on the presence or absence of OC, 1b) a multinomial threshold model, on a scale from 0 (absence) to 3 (maximum), and 2) a linear model. The effects considered in the models included sex, genetic origin and stud class. All the analyses were based on the Bayesian inference methodology, using the THRGIBBS3F90 software. The binomial threshold model yielded the most suitable results, with an estimated heritability for Overall hock OC of 0.71 ± 0.055 on the underlying scale (0.53 on the observed scale), ranging in different locations from 0.48 ± 0.087 (LTT) to 0.66 ± 0.063 (DIRT) on the underlying scale (0.10 and 0.38 on the observed scale, respectively). The highest significative genetic correlation was observed between Overall and DIRT (0.97) for approach 1a, and the lowest significant genetic correlation was between Overall and LTT (0.49), for approach 2. This study contributes valuable insights into the genetic predisposition towards, as well as for the potential for selective breeding against, hock OC in PRE horses, and provides a basis for future research and breeding programmes aimed at minimising the occurrence of hock OC and promoting the overall health of this breed.

Osteochondrosis in the central and third tarsal bones of young horses

Recently, the central and third tarsal bones of 23 equine fetuses and foals were examined using micro-computed tomography. Radiological changes, including incomplete ossification and focal ossification defects interpreted as osteochondrosis, were detected in 16 of 23 cases. The geometry of the osteochondrosis defects suggested they were the result of vascular failure, but this requires histological confirmation. The study aim was to examine central and third tarsal bones from the 16 cases and to describe the tissues present, cartilage canals, and lesions, including suspected osteochondrosis lesions. Cases included 9 males and 7 females from 0 to 150 days of age, comprising 11 Icelandic horses, 2 standardbred horses, 2 warmblood riding horses, and 1 coldblooded trotting horse. Until 4 days of age, all aspects of the bones were covered by growth cartilage, but from 105 days, the dorsal and plantar aspects were covered by fibrous tissue undergoing intramembranous ossification. Cartilage canal vessels gradually decreased but were present in most cases up to 122 days and were absent in the next available case at 150 days. Radiological osteochondrosis defects were confirmed in histological sections from 3 cases and consisted of necrotic vessels surrounded by ischemic chondronecrosis (articular osteochondrosis) and areas of retained, morphologically viable hypertrophic chondrocytes (physeal osteochondrosis). The central and third tarsal bones formed by both endochondral and intramembranous ossification. The blood supply to the growth cartilage of the central and third tarsal bones regressed between 122 and 150 days of age. Radiological osteochondrosis defects represented vascular failure, with chondrocyte necrosis and retention, or a combination of articular and physeal osteochondrosis.

Shapes of cervical articular process joints and association with histological evidence of osteochondrosis in Warmblood foals: A post-mortem study

BACKGROUND

Osteochondrosis dissecans (OCD) of articular process joints (APJs) is involved in cervical vertebral compressive myelopathy (CVM). Biomechanical forces, important in development of OCD, depend on joint conformation. Oval and flat APJ surfaces are considered normal.

OBJECTIVES

To identify and grade gross shape variation of cervical and cranial thoracic APJ surfaces and determine association with histological evidence of osteochondrosis.

STUDY DESIGN

Case series.

METHODS

Eight hundred and four cervical and cranial thoracic APJ surfaces of 30 foals were evaluated for shape(s) and grades, and were correlated with osteochondrosis.

RESULTS

Three top view shapes (oval, pointed, elongated) and seven lateral view shapes (flat, convex, concave, stepped, bevelled, folded edge, raised edge) were regularly encountered. The oval top view shape was most common. Flat and bevelled were the most common lateral view shapes. General shape grade of caudal articular surfaces was significantly higher than of cranial surfaces. The combinations of an oval top view shape and the lateral view shapes folded edge, concave, or flat with additional raised edge and/or folded edge (flat +), were more likely to have OC than oval with convex, bevelled or flat lateral view shapes (normal vs. oval and folded, odds ratio [OR] 2.49 [95% confidence intervals (CIs) 1.13-5.67]; normal vs. oval and flat +, OR 2.77 [95% CI 1.15-6.85]; oval and convex vs. oval and folded, OR 3.20 [95% CI 1.35-8.20]; oval and convex vs. oval and flat +, OR 3.56 [95% CI 1.43-9.54]; oval and bevelled vs. oval and concave, OR 2.02 [95% CI 1.14-3.60]; oval and bevelled vs. oval and folded, OR 3.50 [95% CI 1.91-6.60]; oval and bevelled vs. oval and flat +, OR 3.90 [95% CI 2.00-7.70]).

MAIN LIMITATIONS

Most foals (21/30) were less than 1 month old. Lack of observer reliability scores for shape and shape grade.

CONCLUSION

APJs shape might contribute to CVM by increased likelihood to have OC.

Visualizing neutrophil extracellular traps in septic equine synovial and peritoneal fluid samples using immunofluorescence microscopy

Septic synovitis and peritonitis are routinely diagnosed in horses based on clinical examination findings and laboratory assessment of synoviocentesis and abdominocentesis samples, respectively. Diagnosis is difficult in some cases because of an overlap in laboratory results for septic and non-septic inflammation. Neutrophil extracellular trap (NET) formation is part of the innate immune response against pathogens. Identifying and quantifying NETs, which have not been explored in clinical samples from horses with septic synovitis and peritonitis, to our knowledge, may be helpful in detecting infectious processes. Our main objective was to determine whether NETs could be visualized in septic equine synovial and peritoneal fluid cytology samples using immunofluorescence with antibodies against citrullinated histone H3 (Cit-H3) and myeloperoxidase (MPO). We analyzed 9 synovial and 4 peritoneal fluid samples. NET percentages were quantified using a simple counting technique, which is suitable for high-quality, well-preserved, and stained cytospin smears. NETs were evident in all septic samples and were absent in a non-septic sample; NETs were better visualized with Cit-H3 than with MPO immunolabeling. Overall, we believe that there is the potential for NETs and associated markers to be used to investigate and understand septic inflammation in horses.

Evaluation of the appearance of osteochondrosis lesions by two radiographic examinations in sport horses aged from 12 to 36 months

Osteochondrosis is a developmental orthopedic disease characterized by a defect of enchondral ossification. This pathological condition develops and evolves during growth and is influenced by various factors, in particular genetic and environmental. However, little research has been conducted on the dynamic of this condition in horses after the age of 12 months. The retrospective study presented here investigates changes in osteochondrosis lesions through two standardized radiographic examinations carried out on young Walloon sport horses after one year of age (mean age at first and second examination was 407 (±41) and 680 (±117) days respectively). Each examination, analyzed independently by three veterinarians, included latero-medial views of the fetlocks, hocks, stifles, plantarolateral-dorsomedial hocks view and additional radiograph if the operator deemed it necessary. Each joint site was graded as healthy, osteochondrosis (OC) or osteochondrosis dissecans (OCD) affected. A group of 58 horses was studied, among them 20 presented one or more osteochondrosis lesions for a total of 36 lesions present during at least one examination. In this population, 4 animals (6.9%) presented osteochondrosis during only one examination (2 at the first examination and 2 at the second one). Moreover, it was possible to demonstrate the appearance, disappearance and more generally the evolution of 9/36 lesions (25%) within the different joints. The results of the study suggest that, although substantial main limitations, osteochondrosis lesions can evolve after the age of 12 months in sport horses. Knowing this is useful in helping to decide the appropriate radiographic diagnosis timing and management.

"Cross-talk" between gut microbiome dysbiosis and osteoarthritis progression: a systematic review

Objectives

The aim of this systematic review was to summarize the available literature on gut microbiome (GMB) and osteoarthritis (OA), analyze the correlation between GMB and OA, and explore potential underlying mechanisms.

Methods

A systematic search of the PubMed, Embase, Cochrane, and Web of Science with the keywords "Gut Microbiome" and "Osteoarthritis" was conducted to identify the human and animal studies exploring the association between GMB and OA. The retrieval time range was from the database inception to July 31, 2022. Studies reported the other arthritic diseases without OA, reviews, and studies focused on the microbiome in other parts of the body with OA, such as oral or skin, were excluded. The included studies were mainly reviewed for GMB composition, OA severity, inflammatory factors, and intestinal permeability.

Results

There were 31 studies published met the inclusion criteria and were analyzed, including 10 human studies and 21 animal studies. Human and animal studies have reached a consistent conclusion that GMB dysbiosis could aggravate OA. In addition, several studies have found that alterations of GMB composition can increase intestinal permeability and serum levels of inflammatory factors, while regulating GMB can alleviate the changes. Owing to the susceptibility of GMB to internal and external environments, genetics, and geography, the included studies were not consistent in GMB composition analysis.

Conclusion

There is a lack of high-quality studies evaluating the effects of GMB on OA. Available evidence indicated that GMB dysbiosis aggravated OA through activating the immune response and subsequent induction of inflammation. Future studies should focus on more prospective, cohort studies combined with multi-omics to further clarify the correlation.

Maternal allogeneic cancellous bone graft for the treatment of osteitis along the physeal scar of the proximal metatarsus in a foal

OBJECTIVE

To describe the treatment and outcome of a foal with a fresh allogenic cancellous bone graft after surgical debridement of a traumatic septic osteitis.

ANIMAL

A neonatal Quarter Horse foal.

STUDY DESIGN

Case report.

METHODS

The foal sustained a traumatic laceration exposing the proximal third metatarsal bone. One week after surgical debridement and closure, radiographic signs of septic osteitis were noted along the physeal scar. The lesion was debrided, and antimicrobial therapy was implemented. The infection resolved but left a large defect in the metaphysis and epiphysis. Grafting was indicated to avoid pathologic fractures of the plantar and proximal cortices. Due to a discrepancy between defect size and the bone stock of the foal, an allogeneic cancellous bone graft was harvested from the dam's tuber coxae and used to fill the foal's defect.

RESULTS

No adverse reactions to the graft were noted. After 1 month, the wound had healed. Radiographic examination was consistent with graft incorporation in the bone structure. The foal was sound at a walk and trot when examined at 6, 12, and 21 months. The bone's contour was even and its structure homogeneously radio dense. The surgical site of the mare healed without complications.

CONCLUSION

Fresh allogenic cancellous bone grafting resulted in the healing of a large traumatic-septic bone defect in a foal, with an excellent functional and cosmetic outcome. For future use, compatibility testing should be considered prior to allogeneic bone grafting.

A method for labelling lesions for machine learning and some new observations on osteochondrosis in computed tomographic scans of four pig joints

Background

Osteochondrosis is a major cause of leg weakness in pigs. Selection against osteochondrosis is currently based on manual scoring of computed tomographic (CT) scans for the presence of osteochondrosis manifesta lesions. It would be advantageous if osteochondrosis could be diagnosed automatically, through artificial intelligence methods using machine learning. The aim of this study was to describe a method for labelling articular osteochondrosis lesions in CT scans of four pig joints to guide development of future machine learning algorithms, and to report new observations made during the labelling process. The shoulder, elbow, stifle and hock joints were evaluated in CT scans of 201 pigs.

Results

Six thousand two hundred fifty osteochondrosis manifesta and cyst-like lesions were labelled in 201 pigs representing a total volume of 211,721.83 mm³. The per-joint prevalence of osteochondrosis ranged from 64.7% in the hock to 100% in the stifle joint. The lowest number of lesions was found in the hock joint at 208 lesions, and the highest number of lesions was found in the stifle joint at 4306 lesions. The mean volume per lesion ranged from 26.21 mm³ in the shoulder to 42.06 mm³ in the elbow joint. Pigs with the highest number of lesions had small lesions, whereas pigs with few lesions frequently had large lesions, that have the potential to become clinically significant. In the stifle joint, lesion number had a moderate negative correlation with mean lesion volume at r = − 0.54, p < 0.001.

Conclusions

The described labelling method is an important step towards developing a machine learning algorithm that will enable automated diagnosis of osteochondrosis manifesta and cyst-like lesions. Both lesion number and volume should be considered during breeding selection. The apparent inverse relationship between lesion number and volume warrants further investigation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03426-x.

Osteochondrosis and other lesions in all intervertebral, articular process and rib joints from occiput to sacrum in pigs with poor back conformation, and relationship to juvenile kyphosis

Background

Computed tomography (CT) is used to evaluate body composition and limb osteochondrosis in selection of breeding boars. Pigs also develop heritably predisposed abnormal curvature of the spine including juvenile kyphosis. It has been suggested that osteochondrosis-like changes cause vertebral wedging and kyphosis, both of which are identifiable by CT. The aim of the current study was to examine the spine from occiput to sacrum to map changes and evaluate relationships, especially whether osteochondrosis caused juvenile kyphosis, in which case CT could be used in selection against it. Whole-body CT scans were collected retrospectively from 37 Landrace or Duroc boars with poor back conformation scores. Spine curvature and vertebral shape were evaluated, and all inter-vertebral, articular process and rib joints from the occiput to the sacrum were assessed for osteochondrosis and other lesions.

Results

Twenty-seven of the 37 (73%) pigs had normal spine curvature, whereas 10/37 (27%) pigs had abnormal curvature and all of them had wedge vertebrae. The 37 pigs had 875 focal lesions in articular process and rib joints, 98.5% of which represented stages of osteochondrosis. Five of the 37 pigs had focal lesions in other parts of vertebrae, mainly consisting of vertebral body osteochondrosis. The 10 pigs with abnormal curvature had 21 wedge vertebrae, comprising 10 vertebrae without focal lesions, six ventral wedge vertebrae with ventral osteochondrosis lesions and five dorsal wedge vertebrae with lesions in the neuro-central synchondrosis, articular process or rib joints.

Conclusions

Computed tomography was suited for identification of wedge vertebrae, and kyphosis was due to ventral wedge vertebrae compatible with heritably predisposed vertebral body osteochondrosis. Articular process and rib joint osteochondrosis may represent incidental findings in wedge vertebrae. The role of the neuro-central synchondrosis in the pathogenesis of vertebral wedging warrants further investigation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-03091-6.

Osteochondral necrosis of the femoral condyles in Thoroughbred foals: eight cases (2008–2018)

OBJECTIVE

To describe clinical, imaging, gross, and histopathological abnormalities associated with osteochondral necrosis of the femoral condyles in foals and identify features suggestive of a common pathogenesis.

ANIMALS

8 Thoroughbred foals euthanized with a presumptive diagnosis of necrosis of the femoral condyles.

PROCEDURES

Postmortem CT was performed on all distal femoral epiphyseal samples. The articular epiphyseal cartilage complex (AECC) of affected distal femurs was examined grossly and histologically, focusing on lesions of interest identified on CT images.

RESULTS

7 foals were between 9 and 23 days old at the time of euthanasia; 1 foal was 85 days old. Concurrent illness (neonatal maladjustment syndrome, neonatal isoerythrolysis, or infection such as enteritis and omphalitis) was diagnosed in 7 foals. The characteristic antemortem radiographic and postmortem CT finding was a crescent-shaped osteochondral flap displaced from the affected medial femoral condyle. Synovial fluid cytology from affected joints was either within normal limits or consistent with mild inflammation. Histologically, all lesions were characterized by osteochondral necrosis and detachment of the AECC. In 6 foals, polymorphonuclear cells were found within growth cartilage canals, representing septic cartilage canals.

CLINICAL RELEVANCE

Osteochondral necrosis was interpreted to be secondary to bacterial colonization of the distal femoral AECC, evidenced by septic cartilage canals identified in 6 of 8 foals. This uncommon condition was previously thought to arise from an ischemic event, but the disease process was not well understood. An improved understanding of the pathogenesis of osteochondral necrosis is the first step in formulating more successful preventative and treatment strategies.

Radiological, vascular osteochondrosis occurs in the distal tarsus, and may cause osteoarthritis

BACKGROUND

Osteochondrosis occurs due to failure of the blood supply to growth cartilage. Osteochondrosis lesions have been identified in small tarsal bones and suggested to cause distal tarsal osteoarthritis; however, it has not been determined whether distal tarsal osteochondrosis lesions were the result of vascular failure.

OBJECTIVES

To perform post-mortem arterial perfusion and micro-computed tomography (CT) of the central (CTB) and third tarsal bones (TIII) of fetuses and foals up to 5 months old, to describe tarsal development and any lesions detected.

STUDY DESIGN

Descriptive, nonconsecutive case series.

METHODS

Twenty-three animals that died or were euthanased from 228 days of gestation to 5 months old were collected, comprising two fetuses and nine foals of miscellaneous breeds and 12 Icelandic Horse foals, a breed with high prevalence of distal tarsal osteoarthritis. One hindlimb from each foal was perfused arterially with barium, and the CTB and TIII were examined with micro-CT.

RESULTS

Perfusion yielded partial information from 41% of the animals. The CTB and TIII were supplied by nutrient arteries and perichondrial vessels with vertical, transverse and circumferential configurations. Fourteen of the 23 (61%) animals had focal defects in the ossification front, that is, radiological osteochondrosis. The majority of lesions matched the configuration and development of vertical vessels. Additionally, full-thickness, cylindrical defects matched transverse vessels, and the long axes of some dorsal lesions matched circumferential vessels.

MAIN LIMITATIONS

Lack of histological validation.

CONCLUSIONS

Post-mortem perfusion was poor for examination of the blood supply to the growth cartilage of the CTB and TIII. Radiological osteochondrosis lesions were compatible with vascular failure because they were focal, and because lesion geometry matched vessel configuration. The relationship between osteochondrosis and distal tarsal osteoarthritis warrants further investigation.

Factors associated with survival and racing performance of 114 Thoroughbred foals with septic arthritis compared with maternal siblings (2009-2015)

BACKGROUND

There is little consensus on factors associated with survival in foals with septic arthritis and limited data on long-term racing performance of Thoroughbred foals treated for septic arthritis. A more thorough understanding of short- and long-term outcome is necessary to help inform owners, and subsequently guide treatment.

OBJECTIVES

To investigate factors associated with survival, and to analyse racing performance of foals with septic arthritis compared with their maternal siblings.

STUDY DESIGN

Retrospective cohort and a case-control study.

METHODS

Veterinary clinical records of Thoroughbred foals ≤180 days old that underwent arthroscopic, cannulae or through-and-through needle lavage for the treatment of septic arthritis between 2009 and 2015 were reviewed. Data included signalment, and clinicopathological information. The dam's foaling records were reviewed and the lifetime racing records were obtained for affected foals and two of their maternal siblings. Logistic regression analysis was used to determine factors associated with survival to discharge or racing. Comparisons between treated foals and their maternal siblings were made.

RESULTS

Ninety (78%) of 115 foals diagnosed with septic arthritis were discharged alive. Foals <26 days old at the time of admission were five times less likely (P = .003) and foals with concurrent multisystemic disease were six times less likely (P = .02) to be discharged alive. Sixty (67%) foals discharged alive started in ≥1 race, and there was no difference in the proportion of foals that started in a race or racing performance between foals treated for septic arthritis and their maternal siblings.

MAIN LIMITATIONS

Retrospective study design, limited number of foals with multiple joint involvement and failure to accurately record duration of clinical signs.

CONCLUSIONS

Foals treated for septic arthritis at the Scone Equine Hospital, New South Wales, Australia had a good prognosis for survival, and for this cohort, foals that survived to discharge had a similar ability to race as their maternal siblings.

Development of the blood supply to the growth cartilage of the medial femoral condyle of foals

BACKGROUND

Growth cartilage is found in the articular-epiphyseal cartilage complex (AECC) and the physis. It has a temporary blood supply organised as end arteries. Vascular failure is associated with osteochondrosis, but infection can also obstruct vessels. The location of bacteria was recently compared to arterial perfusion, and the results indicated that they were located in the distal tips of AECC end arteries. Systematic perfusion studies were not available for comparison to the infected physes. Further studies may improve our understanding of infections and other pathologies.

OBJECTIVES

To describe development of the blood supply to the growth cartilage of the medial femoral condyle in fetuses and foals from 228 days of gestation to 62 days old.

STUDY DESIGN

Ex vivo arterial perfusion study.

METHODS

The left medial femoral condyle of 10 Norwegian Fjord Pony fetuses and foals (228 days of gestation to 62 days old) and one Norwegian-Swedish Coldblooded Trotter foal (10 days old) was arterially perfused with barium and underwent micro-computed tomography, qualitative and quantitative description of vessels.

RESULTS

In the fetus, the physis was supplied by metaphyseal-origin arteries. In 1-10 day-old foals, the physis was supplied by a mixture of metaphyseal- and epiphyseal-origin arteries, and from 15 days of age by epiphyseal-origin arteries only. The number of vessels increased before it decreased in both the AECC and the physis postnatally. Vessels in the cartilage showed a monopodial branching pattern, whereas vessels in epiphyseal and metaphyseal bone showed both monopodial and dichotomous branching.

MAIN LIMITATIONS

Foals with confirmed pathologies were not examined.

CONCLUSIONS

The blood supply to growth cartilage changed with age, including the physeal supply that changed from metaphyseal- to epiphyseal-origin arteries. The number of vessels increased before it decreased postnatally, and two different branching patterns were observed. These results may improve our understanding of growth cartilage vascular failure and osteomyelitis.

Cervical articular process joint osteochondrosis in Warmblood foals

BACKGROUND

In Warmblood horses, degenerative joint disease is involved in cervical malformation and malarticulation (CVM). The degree of contribution of articular process joint (APJ) osteochondrosis (OC) is not clear.

OBJECTIVES

(a) To explore the presence of predilection sites for APJ OC in cervical and cranial thoracic vertebral columns of Warmblood foals and (b) to examine the correlation of such a site with the predilection site of CVM.

STUDY DESIGN

Case series.

METHODS

Seven hundred APJ facets of C2 to T2 of 29 foals (11 months gestation to 12 months [median age 7 days; range 365 days; 95% confidence interval [95% CI] 2-47 days]) were examined for OC and prevalence between joints, and the predilection site for CVM and the cranial cervical vertebral column were evaluated.

RESULTS

About 20.6% of facets revealed OC. There was no predilection site. Prevalence decreased with age up to 1 year (odds ratio [OR] 0.997; (95% CI 0.975-0.998)) but not up to 5 months. Severity increased with age in all age ranges (up to 1 year OR 1.023; 95% CI 1.005-1.049; >1-5 months, OR 1.203; 95% CI 1.014e+00-1.921; up to 1 month, OR 1.114; 95% CI 1.041-1.228). Highest prevalence was in cranial facets of the cervical and cervical-thoracic joints and in caudal facets of the thoracic joint up to 1 year and up to 1 month (OR 0.364; 95% CI 0.170-0.745, OR 0.434; 95% CI: 0.235-0.782, OR 7.665; 95% CI: 1.615-66.553 and OR 0.400; 95% CI 0.170-0.880, OR 0.351; 95% CI 0.172-0.700, OR 5.317; 95% CI 1.098-44.344 respectively).

MAIN LIMITATIONS

Two-thirds of the foals were less than 1 month of age.

CONCLUSIONS

Articular process joint OC in Warmblood foals is common and is not more prevalent at CVM predilection sites, suggesting that abnormalities of enchondral ossification may not be major contributors to CVM.

Computed tomographic development of physeal osteochondrosis in pigs

BACKGROUND

Articular osteochondrosis follows a dynamic development pattern. Lesions arise, in incidence peaks compatible with failure of cartilage canal vessels during incorporation into bone, and can also resolve. Lesions that resolve before examination at a single time point will constitute false-negative diagnoses. The aim of the study was to identify physeal osteochondrosis lesions in pigs and monitor their development by computed tomography (CT), to determine if they follow a similar dynamic development pattern to articular osteochondrosis.

RESULTS

Thirteen physes were evaluated bilaterally in up to eight biweekly CT scans from 18 male Landrace pigs age 70-180 days (total: 112 scans), generating 2912 scores. There were 1754 (60%) lesion-negative scores and 1158 (40%) lesion-positive scores. Positive scores comprised 138 lesions present at the start and 235 lesions that developed during the study, from 4 to 32 lesions per physis (median: 15 lesions). There were 1-2 peaks in the incidence curves for 12/13 examined physes, the exception being the proximal humerus. Positive scores also included 785 times that lesions persisted, from 1.3-4.8 examination intervals per lesion (median: 2.8 intervals). Negative scores included 190 times that lesions resolved, from 19 to 100% of lesions per physis (median: 65%). Lesions resolved by filling with bone from marginal sclerosis and reparative ossification centres. In the distal scapula and distal fibula, perichondrial new bone formation occurred that led to permanent enlargement of physeal regions. Angular limb deformity was not identified in any pig.

CONCLUSIONS

Physeal osteochondrosis followed a similar dynamic development pattern to articular osteochondrosis. There were peaks in the incidence curves, compatible with failure of vessels during incorporation into bone. In some physes, osteochondrosis led to permanent enlargement, potentially relevant for decubital ulcers. The relationship between physeal osteochondrosis and angular limb deformity must be examined further in pigs over 6 months old in future.

Imaging of osteochondrosis

Osteochondrosis is an abnormality of the epiphyses or epiphyseal equivalents (round bones and apophyses) during later stages of endochondral ossification. This process of abnormal endochondral ossification can occur at various locations throughout the body. The pathogenesis of osteochondrosis is under active investigation. In humans, the process of abnormal endochondral ossification has been attributed to a combination of vascular insult and trauma. Although the proposed etiology of osteochondrosis varies based on body part affected, the overall process is defined by necrosis, revascularization and repair. As such, common radiologic findings include those of osseous destruction and associated inflammation. The purpose of this review is to discuss the current understanding of osteochondroses as a disease entity and explore imaging features of osteochondroses throughout the body.

Cartilage-gut-microbiome axis: a new paradigm for novel therapeutic opportunities in osteoarthritis

DNA of gut microbiota can be found in synovium of osteoarthritis and rheumatoid arthritis. This finding could result from the translocation of still alive bacteria from gut to joints through blood, since the diversified dormant microbiota of healthy human blood can be transiently resuscitated in vitro. The recent finding of gut microbiome in human cartilage, which differed between osteoarthritis and controls, suggests that a similar trafficking of dead or alive bacteria from gut microbiota physiologically occurs between gut and epiphysial bone marrow. Subchondral microbiota could enhance cartilage healing and transform components of deep cartilage matrix in metabolites with immunosuppressive properties. The differences of microbiome observed between hip and knee cartilage, either in osteoarthritis or controls, might be the counterpart of subtle differences in chondrocyte metabolism, themselves in line with differences in DNA methylation according to joints. Although bacteria theoretically cannot reach chondrocytes from the surface of intact cartilage, some bacteria enter the vascular channels of the epiphysial growth cartilage in young animals, whereas others can infect chondrocytes in vitro. In osteoarthritis, the early osteochondral plate angiogenesis may further enhance the ability of microbiota to locate close to the deeper layers of cartilage, and this might lead to focal dysbiosis, low-grade inflammation, cartilage degradation, epigenetic changes in chondrocytes and worsening of osteoarthritis. More studies on cartilage across different ethnic groups, weights, and according to age, are needed, to confirm the silent presence of gut microbiota close to human cartilage and better understand its physiologic and pathogenic significance.

Osteochondrosis in the Distal Femoral Physis of Pigs Starts With Vascular Failure

Articular osteochondrosis (OC) arises due to vascular failure and ischemic chondronecrosis. The aim of the study was to describe the histological and computed tomographic (CT) characteristics of changes in the distal femoral physis of pigs, to determine if they represented OC lesions and if the pathogenesis was the same as for articular OC. The material included 19 male Landrace pigs bred for predisposition to OC. One or 2 pigs were euthanized and CT-scanned at 2-week intervals from 82 to 180 days of age. Material from 10 pigs was available for histological validation. The CT scans revealed 31 lesions confirmed in 3 planes and 1 additional macroscopically visible lesion confirmed in 2 CT planes. Twelve of the lesions were histologically validated. All lesions were compatible with OC. Cartilage canal and eosinophilic streak morphological changes corresponded to failure of end arteries coursing from the epiphysis, toward the metaphysis. The location of lesions was compatible with failure at the point of vessel incorporation into bone. Vascular failure was associated with retention of viable hypertrophic chondrocytes and delayed ossification but not cartilage necrosis. Lesion width ranged from 1.1% to 45.6% of the physis. Several lesions were expected to resolve due to small size and evidence of CT-identifiable, reparative ossification. Angular limb deformity was not detected in any pig. The pathogenesis of physeal OC started with vascular failure that was morphologically identical to articular OC. The heritable predisposition may therefore be the same. The association between lesions and limb deformity should be studied further in older pigs in future.

Prevalence of osteochondral lesions in the fetlock and hock joints of Standardbred horses that survived bacterial infection before 6 months of age

BACKGROUND

Young Standardbred horses frequently develop fragments in joints. Some fragments represent osteochondrosis; others are considered developmental, but it is uncertain whether they result from preceding osteochondrosis. Osteochondrosis occurs as a consequence of failure of the cartilage canal blood supply and ischaemic chondronecrosis. In heritably predisposed foals, failure was associated with incorporation of vessels into bone. However, bacterial vascular failure was also recently documented in foals suffering spontaneous infections, proving that bacteria can cause osteochondral lesions in foals up to 150 days old. The aim was to determine prevalence of fetlock and hock lesions at screening age in Standardbred horses that survived infections before 6 months of age, and compare this to prevalence reported in the literature.

METHODS

The material consisted of 28 Standardbred horses; 17 males and 11 females that presented and were diagnosed clinically with bacterial infections from 1 to 150 days of age (average: 41.3 days). A screening set of 8 radiographic projections was available from all 28 horses at 7-85 months of age (average: 23.6 months). Lesion prevalence was compared to three previously reported Standardbred cohorts.

RESULTS

Osteochondral lesions were detected in one or more joints of 19/28 horses (67.9%); in the fetlock joint of 14/28 horses (50%) and the hock joint of 11/28 horses (39.3%). These prevalences were ≥ 2 x higher than the corresponding prevalences in the comparison cohorts, and statistically significantly so in 5:6 comparisons (p-values from < 0.00001 to 0.01). In the sepsis cohort, there were an average of 2.3 affected joints and 2.5 lesions per affected horse, whereas there in the one comparable literature cohort were an average of 1.5 affected joints and 1.7 lesions per affected horse.

CONCLUSIONS

Standardbred horses that survived bacterial infections before 6 months of age had more osteochondral lesions than literature comparison cohorts at screening age. The implication was that some of the lesions in this group were caused by bacteria. It may become necessary to develop methods for differentiating between acquired, septic and aseptic, heritably predisposed lesions.

Juvenile osteochondritis dissecans of the knee is a result of failure of the blood supply to growth cartilage and osteochondrosis

OBJECTIVE

Juvenile osteochondritis dissecans (JOCD) is similar to osteochondrosis dissecans (OCD) in animals, which is the result of failure of the cartilage canal blood supply, ischemic chondronecrosis and delayed ossification, or osteochondrosis. The aim of the current study was to determine if osteochondrosis lesions occur at predilection sites for JOCD in children.

METHOD

Computed tomographic (CT) scans of 23 knees (13 right, 10 left) from 13 children (9 male, 4 female; 1 month to 11 years old) were evaluated for lesions consisting of focal, sharply demarcated, uniformly hypodense defects in the ossification front. Histological validation was performed in 11 lesions from eight femurs.

RESULTS

Thirty-two lesions consisting of focal, uniformly hypodense defects in the ossification front were identified in the CT scans of 14 human femurs (7 left, 7 right; male, 7-11 years old). Defects corresponded to areas of ischemic chondronecrosis in sections from all 11 histologically validated lesions. Intra-cartilaginous secondary responses comprising proliferation of adjacent chondrocytes and vessels were detected in six and two lesions, whereas intra-osseous responses including accumulation of chondroclasts and formation of granulation tissue occurred in 10 and six lesions, respectively. One CT cyst-like lesion contained both a pseudocyst and a true cyst in histological sections.

CONCLUSION

Changes identical to osteochondrosis in animals were detected at predilection sites for JOCD in children, and confirmed to represent failure of the cartilage canal blood supply and ischemic chondronecrosis in histological sections.