Long-term outcomes after arthroscopic treatment of dogs affected by osteochondrosis dissecans of the humeral trochlea, with or without medial coronoid disease: 23 cases (2012-2020).

The objective of this study was to report long-term clinical and radiographic outcomes following arthroscopic reparative treatment - flap removal, curettage, and osteostixis of subchondral bone - in dogs with humeral trochlea osteochondritis dissecans (OCD). Dogs were included in this retrospective multicenter case series if they had a computed tomography diagnostic of humeral trochlear OCD, with or without medial coronoid disease, that was treated by arthroscopic reparative technique, and a detailed follow-up at least 6 mo postoperatively. The latter included a clinical examination, assessment of lameness, measurement of the brachial circumference and elbow amplitude, International Elbow Working Group (IEWG) radiographic score, owner-completed canine brief pain inventory (CBPI) score, and visual analogue scale (VAS) rating. A generalized linear model and tests for symmetry and marginal homogeneity were used to compare data. Twenty-three dogs (30 affected elbows) were included. Long-term (median: 22 mo; range: 6 to 98 mo) postoperative lameness, CBPI, VAS, joint distension, and pain scores were significantly improved compared with the preoperative values. Long-term postoperative range of motion and brachial circumference did not reveal any significant difference between OCD-affected and unaffected elbows. Long-term IEWG scores were similar to preoperative values in 56% of elbows and had progressed by 1 grade in 44%. Long-term complications included persistent Grade-1 lameness and occurred in 23% of dogs. Long-term outcomes based on lameness and CBPI scores were considered excellent in 67% of dogs, good in 27%, and intermediate in 6%. Arthroscopic treatment is thus a suitable surgical procedure for OCD of the humeral trochlea in dogs and provides good long-term results.

Cette étude rapporte les résultats cliniques et radiographiques à long terme après un traitement arthroscopique chez des chiens atteints d'ostéochondrite disséquante (OCD) de la trochlée humérale. Les chiens inclus ont reçu un diagnostic d'OCD de la trochlée humérale par tomographie, un traitement réparateur par arthroscopie et un suivi post-opératoire d'au moins 6 mois. Ce dernier comprenant un examen clinique et orthopédique, la mesure de la circonférence brachiale et de l'amplitude du coude, le score radiographique de l'International Elbow Working Group (IEWG), le score Canine Brief Pain Inventory (CBPI) et l'échelle visuelle analogique (EVA). Un modèle linéaire généralisé et des tests de symétrie et d'homogénéité marginale ont permis de comparer les données. Vingt-trois chiens (30 coudes affectés) ont été inclus. Les scores postopératoires à long terme (médiane, 22 mois), de boiterie, de CBPI, d'EVA, de distension articulaire et de douleur étaient significativement améliorés. L'amplitude de mouvement et la circonférence brachiale postopératoires à long terme entre les coudes affectés et non affectés n'ont pas révélé de différence significative. Les scores IEWG à long terme étaient similaires aux valeurs préopératoires dans 56 % des coudes et avaient progressé d'un grade dans 44 %. Les résultats à long terme basés sur la boiterie et les scores CBPI ont été considérés comme excellents chez 67 % des chiens, bons chez 27 % et intermédiaires chez 6 %. Le traitement arthroscopique est donc une procédure chirurgicale appropriée pour l'OCD de la trochlée humérale chez le chien et donne de bons résultats à long terme.(Traduit par les auteurs).

Detection of fragment migration into the biceps tendon sheath originating from a humeral osteochondrosis lesion - A case report and review of the literature.

The purpose of this report is to demonstrate that radiographic evaluation of the canine shoulder joint alone is not sensitive enough to detect migrated osteochondral fragments within the biceps tendon sheath, as a sequela to osteochondrosis dissecans of the caudal humeral head. A 6-months-old, male, 35 kg Hovawart was referred due to chronic intermittent lameness on the left forelimb. Survey radiographs revealed a semilunar radiolucency surrounded by a moderately sclerotic rim at the caudal aspect of the left humeral head, referred to as osteochondrosis dissecans. However, only computed tomography combined with ultrasonography could clearly confirm a dislodged osteochondral fragment within the left biceps tendon sheath and a consequent tenosynovitis. Arthroscopic treatment on the clinically affected left forelimb followed by an additional approach over the left biceps tendon sheath to remove the migrated fragment resulted in a complete remission of the lameness until the last follow-up one year after surgery. In our opinion, computed tomography should be applied in the medical work up of canine shoulder osteochondrosis (OC) as standard. Combined with ultrasonography, it can further aid in complete evaluation of the shoulder joint and reliable exclusion of displaced osteochondral fragments, which might also be missed during arthroscopy when located too far distally.

Angular limb deformities due to distal radial physeal osteochondrosis in farmed deer stags in New Zealand.

CASE HISTORY: Three different farms reported cases of angular limb deformities (ALD) in rising 2-year-old velvet, mostly red deer (Cervus elaphus), stags with the earliest recorded cases occurring in 2010. Farm 1 reported a prevalence of 10-35%, farm 2, 5-11.5%, and farm 3, 2-5%. Farms 1, 2, and 3 are located in South Canterbury, northern Southland, and the Waikato, respectively. CLINICAL FINDINGS: Affected animals developed ALD, with predominantly varus forelimb (bowed) deformities. On all farms serum calcium and phosphorus concentrations in affected animals were normal. Serum and liver copper concentrations were variable across the period of the study and between farms. Although some measurements were below the reference ranges, there was no evidence for a statistical association with the prevalence of abnormalities. PATHOLOGICAL FINDINGS: The distal radius from 25 affected and four control red and red-wapiti (Cervus canadensis) cross deer from Farm 1 in 2010/2011, two affected red deer from Farm 2 in 2016, and one affected red deer from Farm 3 in 2021, were examined. The most consistent lesions were present in the distal radial physis, most commonly the lateral edge. There was mild-to-severe segmental thickening of the physis and, in some animals, physeal cartilage was duplicated with both sections of physis varying in thickness. Microscopically, in severely affected animals there was massive segmental thickening of physeal cartilage which often contained large cystic cavities. The cartilage matrix was eosinophilic and showed a loss of metachromatic staining with toluidine blue. In less severe cases, necrotic physeal vessels were present, consistent with vascular failure. In more chronic cases, there was duplication of the physis, the two layers being separated by a combination of normal trabecular bone and dense fibrous connective tissue. DIAGNOSIS: Physeal osteochondrosis. CLINICAL RELEVANCE: Osteochondrosis has a multifactorial aetiology and we propose that an increased requirement for nutrients for velvet production and increased weight-bearing stress (behaviour and rapid weight gain) may lead to progression of osteochondrosis and ALD in these deer. The involvement of periods of copper deficiency is unclear at this time.

Long-term outcome of dogs treated by surgical debridement of proximal humeral osteochondrosis.

OBJECTIVE: To evaluate long-term clinical outcomes of dogs surgically treated for proximal humeral osteochondrosis (OC). STUDY DESIGN: Cross-sectional study. SAMPLE POPULATION: Twenty dogs (n = 26 shoulders). METHODS: Dogs treated with surgical debridement of proximal humeral OC lesions >12 months prior were enrolled. Orthopedic examination (including limb circumference and shoulder goniometry), kinetic gait analysis, shoulder radiographs, shoulder computed tomography (CT), and shoulder arthroscopy were performed. All owners completed a dog mobility questionnaire. RESULTS: Brachial circumference (P = .003) and maximum shoulder extension (P = .013) were decreased and maximum shoulder flexion (P = .008) was increased (ie less flexion) in the OC limb versus the contralateral limb in unilaterally affected dogs. There were no differences in peak vertical force and vertical impulse between affected and unaffected limbs. Dogs demonstrated a 4.4% decrease in load distributed to the operated limb. Osteoarthritis was present in all shoulders treated for OC lesions. The degree of osteoarthritis in OC-affected shoulders was increased compared to the contralateral limb as evaluated on CT (P = .005) and radiography (P = .0001) in unilaterally affected cases. Moderate-to-severe synovitis was seen in all OC-affected joints. Arthroscopically, all lesions were noted to have patchy, incomplete cartilaginous infilling. Median of aggregate Liverpool Osteoarthritis in Dogs (LOAD) scores was 6. CONCLUSION: All dogs exhibited ipsilateral muscle atrophy and progressive osteoarthritis, with most dogs exhibiting subtle lameness on the subjective gait examination. Despite this, owner-perceived mobility was satisfactory. CLINICAL SIGNIFICANCE: Progression of joint disease over time should be expected; however, the abnormalities detected on examination appear to be of questionable clinical relevance.

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.

Microstructural features of subchondral radiolucent lesions in the medial femoral condyle of juvenile Thoroughbreds: A microcomputed tomography and histological analysis.

BACKGROUND: The aetiology of equine medial femoral condyle (MFC) subchondral bone radiolucencies (SR) is unknown. OBJECTIVES: Characterise the microstructural structural features of MFC SR in juvenile Thoroughbreds with microcomputed tomography (µCT) and histology. STUDY DESIGN: Cross-sectional post-mortem study. METHODS: Distal femurs were collected at post-mortem. Conventional tomodensitometry was employed to scout for MFCs with and without SR lesions (SR+ and SR-, respectively). Group 1 were CT MFC SR+ and Group 2 age-matched SR- controls. Both underwent µCT and histological analysis. Group 3 CT MFC SR- foals, <6 months, were selected to search for chondronecrosis. Histological sections, processed from the lesion (Group 1) and a corresponding site in Groups 2 and 3, were assessed for chondronecrosis, fibrin, fibroplasia and osteochondral separation. Group 3 sections were surveyed for chondronecrosis alone. RESULTS: A total of 178 femurs from 89 Thoroughbreds were harvested. Of these horses 19.1% (95% CI: 10.9%-27.3%) were CT MFC SR+ (17/23; 7.46 ± 4.36 months) and met the inclusion criteria for Group 1. Group 2 included 30 CT MFC SR- specimens (5.00 ± 2.73 months) and Group 3 had 44 CT MFC SR- s (2.68 ± 1.74 months). SR were located axially in foals <7 months of age, and centrally thereafter. All SRs had areas of thickened cartilage on histology and separation at the osteochondral junction containing fibrin (acute event) and fibroplasia (chronicity) in 73.9% (17/23; 95% CI: 56%-91.9%). In Group 1 specimens, chondronecrosis was present in 82.6% (19/23; 95% CI: 67.1%-98.1%) but four MFC SR+ had no evidence of chondronecrosis. Chondronecrosis was not detected in the Group 3 foal MFCs. MAIN LIMITATIONS: No longitudinal follow-up. CONCLUSIONS: The absence of chondronecrosis, pathognomic of osteochondrosis, in four MFC SR+s and in all of the CT MFC SR- foals suggests that osteochondrosis is not the cause, or the only cause, of these lesions and favours trauma as an alternate aetiological hypothesis.

Radiographic diagnosis and surgical management for successful outcomes for osteochondrosis in Japanese Black calves.

Osteochondrosis (OC) is not well recognized in cattle. Japanese Black (JB) cattle are valued for their beef and studies regarding OC are scarce. Hence, the aim of this study was to retrospectively discuss clinical and radiographical findings, diagnosis and treatment options for OC in JB cattle for successful outcomes. Medical records of 11 calves affected with OC were reviewed, retrospectively. Clinical and radiographic findings, treatment and outcomes and postmortem examination findings were analyzed. All calves had lameness. Stifle (4/14) and tarsal (4/14) were the most affected joints. Subchondral bone lucencies were observed in all joints (14/14) and accompanied with sclerosis (10/14). Radiographic grading was performed in calves. Calves were treated surgically (8/11) or conservatively (1/11). Surgically treated calves were auctioned (5/8). Postmortem examination was performed (2/11). Gross findings revealed ulcerative lesion at articular surface. Histopathologically, cartilage layer was defected at lesion. Inflammation (2/2) and granulation tissue (1/2) was also observed. In conclusion, OC in JB cattle can be diagnosed on the basis of radiography with history and clinical signs in clinical setting. Surgery should be performed in mild cases for successful outcomes. A modified radiographic grading criteria for clinical cases may hold potential in evaluating prognosis and outcomes.

Influence of osteochondrosis on the longevity and racing performance of standardbred trotters and pacers.

OBJECTIVE: To determine the influence of clinical osteochondrosis (OC) on the short-term (2, 3, and 4-year-old) and long-term racing performance and longevity of standardbred racehorses. STUDY DESIGN: Retrospective case-control study. SAMPLE POPULATION: Standardbred racehorses from a single breeding farm born between 2009 and 2017 that survived to racing age (n = 2711). Three hundred eighty-two (14%) horses were OC-affected (829 lesions confirmed arthroscopically during surgical treatment), and 2329 (86%) horses were nonaffected. METHODS: Racing performance data were obtained from an online database and evaluated with multiple linear regression models. RESULTS: Trotters were more likely than pacers to be affected by OC (odds ratio [OR] = 1.4, 95% CI = 1.1-1.9, P = .006). Compared with nonaffected horses, long-term OC-affected horses had 8.8 fewer starts (95% CI = -14.4 to -3.2, P = .002), 1.0 fewer wins (95% CI = -1.9 to -0.1, P = .030), and 3.8 fewer total number of first through third place finishes (95% CI = -6.2 to -1.4, P < .0001). Nonaffected horses had longer careers compared with OC-affected horses, racing 0.32 years longer (95% CI = -0.52 to -0.12, P = .002). Osteochondrosis had no impact on short-term racing performance. Horses with lesions at the distal intermediate ridge of the tibia or lateral trochlear ridge of the talus had decreased performance compared with horses without these lesions. CONCLUSION: Pacers were less likely than trotters to be affected by OC. Affected horses had fewer starts and shorter careers, despite early surgical intervention. CLINICAL SIGNIFICANCE: Osteochondrosis decreases long-term racing performance in racing standardbreds.

Bisphosphonate use in the horse: what is good and what is not?

BACKGROUND: Bisphosphonates (BPs) are a family of molecules characterized by two key properties: their ability to bind strongly to bone mineral and their inhibitory effects on mature osteoclasts and thus bone resorption. Chemically two groups of BPs are recognized, non-nitrogen-containing and nitrogen-containing BPs. Non-nitrogen-containing BPs incorporate into the energy pathways of the osteoclast, resulting in disrupted cellular energy metabolism leading to cytotoxic effects and osteoclast apoptosis. Nitrogen-containing BPs primarily inhibit cholesterol biosynthesis resulting in the disruption of intracellular signaling, and other cellular processes in the osteoclast. BODY: BPs also exert a wide range of physiologic activities beyond merely the inhibition of bone resorption. Indeed, the breadth of reported activities include inhibition of cancer cell metastases, proliferation and apoptosis in vitro. In addition, the inhibition of angiogenesis, matrix metalloproteinase activity, altered cytokine and growth factor expression, and reductions in pain have been reported. In humans, clinical BP use has transformed the treatment of both post-menopausal osteoporosis and metastatic breast and prostate cancer. However, BP use has also resulted in significant adverse events including acute-phase reactions, esophagitis, gastritis, and an association with very infrequent atypical femoral fractures (AFF) and osteonecrosis of the jaw (ONJ). CONCLUSION: Despite the well-characterized health benefits of BP use in humans, little is known regarding the effects of BPs in the horse. In the equine setting, only non-nitrogen-containing BPs are FDA-approved primarily for the treatment of navicular syndrome. The focus here is to discuss the current understanding of the strengths and weaknesses of BPs in equine veterinary medicine and highlight the future utility of these potentially highly beneficial drugs.

Arthroscopic Management of Osteochondrosis of the Glenoid Cavity in a Dog.

A 5 mo old English setter dog was presented with mild left forelimb lameness. Physical examination revealed pain upon shoulder palpation and extension. Mediolateral radiographs of both shoulders showed a subchondral bone defect in the mid-portion of the glenoid cavity. Computed tomography arthrography and arthroscopy revealed a cartilage flap, suggesting osteochondritis dissecans of the glenoid cavity. Subchondral bone cysts of the glenoid cavity and incomplete fusion of the supraglenoid tubercle were also observed. Arthroscopic removal of the fragment led to a favorable outcome.

Surgical Management of Osteochondrosis in Foals.

Osteochondrosis is common in young, athletic horses. Some lesions respond to conservative therapy. Surgical management is the mainstay of treatment. Arthroscopic debridement is useful in the femoropatellar joint, tarsocrural joint, fetlock joint, and shoulder joint. Debridement is associated with good outcomes, except in the shoulder joint. Osteochondrosis lesions in the elbow may be difficult to access arthroscopically, thereby transosseous debridement. Surgical management of subchondral cystic lesions of the medial femoral condyle consists of debridement, debridement with grafting, transcondylar screws, and intralesional corticosteroid injection. Surgical management is indicated with lameness and persistent effusion, and in many horses intended for athletic use.

Prevalence of humeral head osteochondrosis in the Greater Swiss Mountain dog and the Border Collie in Switzerland.

INTRODUCTION: Osteochondrosis (OC) is common in large-breed dogs. According to the breeding guidelines of the Swiss kennel clubs, the shoulder joints are included in the radiographic screening for joint diseases in the Greater Swiss Mountain dog (GSMD) and the Border Collie (BC) since 1993 and 2003, respectively. The aim of this study was to estimate the overall prevalence of humeral head OC in these 2 breeds in Switzerland based on the data of the Swiss National Dysplasia Committees. All radiographs were re-evaluated to assess single radiographic changes. From 1993 and 2003, accordingly, until 2013, the overall prevalence was 14% for the GSMD and 8% for the BC, respectively. Affected joints showed a focally reduced opacity or a flattened/indented contour of the caudal section of the humeral head. Articular flaps were only seen occasionally. Degenerative joint disease was significantly more common in OC affected joints (GSMD: 32%; BC: 20%) than in joints without OC. The present study is the first report on the prevalence of humeral head OC in a large cohort of GSMD and the BC over a long study period. In comparison to other breeds, the herein reported prevalences are in the mid to upper range. Results of the present study should alert veterinarians to the disease in these breeds and may serve as a starting point for further epidemiological and genetic studies.

INTRODUCTION: L'ostéochondrose (OC) est fréquente chez les chiens de grande race. Conformément aux prescriptions d'élevage des clubs cynologiques suisses, l'articulation de l'épaule est incluse dans le dépistage radiologique des affections articulaires chez le Grand bouvier suisse (GBS) et le Border Collie (BC) et ceci depuis 1993 respectivement 2003. Le but de la présente étude était d'estimer la prévalence de l'OC de la tête humérale chez ces deux races en Suisse, sur la base des données des commissions nationales suisses de dysplasie. Toutes les radiographies ont été réévaluées pour repérer des altérations radiologiques isolées. Depuis 1993 respectivement 2003 jusqu'en 2013, la prévalence était de 14% chez le GBC et de 8% chez le BC. Les articulations affectées montraient une opacité localement réduite ou un contour aplati/ dentelé de la partie caudale de la tête humérale. Des souris articulaires n'étaient constatées qu'occasionnellement. Les affections articulaires dégénératives étaient significativement plus fréquentes sur les articulations affectées d'OC que sur les autres (GBS: 32%; BC: 20%). La présente étude rapporte pour la première fois la prévalence de l'OC de la tête humérale sur une large cohorte de GBS et de BC sur une longue période. En comparaison avec d'autres races, les prévalences constatées se situent entre la moyenne et le niveau supérieur. Les résultats de cette étude doivent alerter les vétérinaires au sujet de cette affection chez ces races et peut server de pont de départ pour de futures recherches épidémiologiques et génétiques.

Preliminary report on osteochondrosis in cattle in the north-western parts of South Africa.

The north-western part of South Africa, in particular, is well known for mineral imbalances. Aphosphorosis, resulting in rickets and osteomalacia, received a lot of attention at the turn of the nineteenth century (1882-1912). This was followed in 1997 by research on Vryburg hepatosis, another area-specific mineral imbalance-related disease in young calves reared on manganese-rich soil derived from the weathering of dolomitic (carbonate) rock formations. In 1982, a totally new syndrome (osteochondrosis) manifested in, amongst others, areas in South Africa where aphosphorosis was rife. Osteochondrosis was also identified in the south-western parts of Namibia as well as southern Botswana and other areas in South Africa. Osteochondrosis has a multifactorial aetiology and this study focused on the role of minerals, particularly phosphorus, in the development of the disease. A significant improvement in the clinical signs in experimental animals and a reduction of osteochondrosis occurred on farms where animals received bioavailable trace minerals and phosphorus as part of a balanced lick. An increase in the occurrence of the disease on farms during severe drought conditions in 2012-2013 prompted researchers to investigate the possible role of chronic metabolic acidosis in the pathogenesis of the disease.

Impact of feeding and housing on the development of osteochondrosis in foals-A longitudinal study.

Osteochondrosis dissecans (OCD) is a developmental orthopedic disease caused by a failure of the endochondral ossification in epiphyseal plates and joint cartilage. This trouble may induce the presence of osteochondral fragments in the articulation, fissures or subchondral bone cysts in the growth cartilage. Occurrence of osteochondrosis is influenced by a complex interaction of different factors. Among these, the effect of the housing and the feeding of the foals during their first months of life, have been described as risk factors for the development of osteochondrosis. The aim of this study was to investigate the evolution of OCD lesions with a longitudinal study in 204 young foals from 6 to 18 months in comparison to the type of feeding and the type of housing conditions. These factors and OCD status were obtained by a questionnaire and radiological examination, respectively. This allowed dividing the foals into four groups according to the initial OCD status and the evolution of the condition. As a result, we found that foals fed with concentrates show a higher probability to develop OCD lesions (p=0.06), while foals not receiving concentrates, had a higher probability to heal from existing OCD lesions (p=0.001). This study supports the theory that management factors such as feeding or housing may influence the evolution of the osteochondrosis disease.

OSTEOCHONDROSIS IN THE DISTAL FEMURS OF AN ADULT RETICULATED GIRAFFE (GIRAFFA CAMELOPARDALIS RETICULATA): MACROSCOPIC, RADIOLOGIC, AND HISTOLOGIC FINDINGS.

An adult male reticulated giraffe (Giraffa camelopardalis reticulata) was presented for postmortem examination. During radiologic examination of the hindlimbs, osseous cyst-like lesions were detected in both medial femoral condyles. These lesions were subsequently examined macroscopically and histologically. The gross appearance suggested a diagnosis of bilateral osteochondrosis that was confirmed with histopathologic examination. This finding has not previously been reported in giraffes. Macroscopic visualization of the major limb joints, including the femorotibial joints, is therefore encouraged in future postmortem examinations of giraffes (Giraffa camelopardalis), and further assessment of clinical significance is required.

Osteochondrosis Can Lead to Formation of Pseudocysts and True Cysts in the Subchondral Bone of Horses.

Osteochondrosis arises as a result of focal failure of the blood supply to growth cartilage. The current aim was to examine the pathogenesis of pseudocysts and true cysts in subchondral bone following failure of the blood supply to the articular-epiphyseal cartilage complex in horses. Cases were recruited based on identification of lesions (n = 17) that were considered likely to progress to or to represent pseudocysts or true cysts in epiphyseal bone in histological sections and included 10 horses ranging in age from 48 days to 5 years old. Cases comprised 3 warmbloods, 3 Standardbreds, 1 Quarter horse and 1 Arabian with spontaneous lesions and 2 Fjord ponies with experimentally induced lesions. Seven lesions consisted of areas of ischemic chondronecrosis and were compatible with pseudocysts. Two lesions were located at intermediate depth in epiphyseal growth cartilage, 2 lesions were located in the ossification front, 2 lesions were located in epiphyseal bone and 1 lesion was located in the metaphyseal growth plate (physis). Ten lesions contained dilated blood vessels and were compatible with true cysts. In 2 lesions the dilated blood vessels were located within the lumina of failed cartilage canals. In the 8 remaining lesions areas of ischemic chondronecrosis were associated with granulation tissue in the subjacent bone and dilated vessels were located within this granulation tissue. Failure of the blood supply and ischemic chondronecrosis can lead to formation of pseudocysts or dilatation of blood vessels and formation of true cysts in the epiphyseal bone of horses.

Diagnostic sensitivity of radiography, ultrasonography, and magnetic resonance imaging for detecting shoulder osteochondrosis/osteochondritis dissecans in dogs.

Radiography, magnetic resonance imaging (MRI), and ultrasonography are commonly used for diagnosis of shoulder osteochondrosis and osteochondritis dissecans (OC/OCD) in dogs, however there is a lack of published information on the relative diagnostic sensitivities of these modalities. The purpose of this prospective study was to compare diagnostic sensitivities of these modalities for detecting shoulder OC/OCD in a group of dogs, using arthroscopy as the reference standard. Inclusion criteria were history and clinical findings consistent with osteochondrosis and/or osteochondritis dissecans involving at least one shoulder. With informed client consent, both shoulders for all included dogs were examined using standardized radiography, ultrasonography, MRI, and arthroscopy protocols. One of three veterinary surgeons recorded clinical and arthroscopic findings without knowledge of diagnostic imaging findings. One of two veterinary radiologists recorded diagnostic imaging findings without knowledge of clinical and arthroscopic findings. Eighteen client-owned dogs (n = 36 shoulders) met inclusion criteria. Diagnostic sensitivity, specificity, and accuracy (correct classification rate) values for detecting presence or absence of shoulder osteochondrosis/osteochondritis dissecans were as follows: radiography (88.5%, 90%, 88.9%), ultrasonography (92%, 60%, 82.6%), and MRI (96%, 88.9%, 94.4%). Odds of a correct diagnosis for MRI were 3.2 times more than ultrasonography and two times more than radiography. For MRI detection of lesions, the sagittal T2 or PD-FAT SAT sequences were considered to be most helpful. For radiographic detection of lesions, the additional supinated-mediolateral and pronated-mediolateral projections were considered to be most helpful. Findings from the current study support more evidence-based diagnostic imaging recommendations for dogs with clinically suspected shoulder osteochondrosis or osteochondritis dissecans.

Arthroscopic assessment of osteochondrosis of the medial humeral condyle treated with debridement and sliding humeral osteotomy.

OBJECTIVE: To document the progression of disease after an unloading procedure when combined with arthroscopic debridement to treat osteochondrosis (OC) lesions affecting the medial humeral condyle in juvenile dogs without medial compartment disease. STUDY DESIGN: Retrospective case series. ANIMALS: Dogs with medial humeral condyle OC (n = 6). METHODS: Dogs with medial humeral condyle OC (9 elbows) were treated by arthroscopic debridement of the OC lesion and sliding humeral osteotomy (SHO). Outcomes were assessed by radiography (n = 9), 2nd-look arthroscopy (9) and clinical examination including lameness assessment (9) at 18-28 months after surgery. RESULTS: Seven elbows had marked progression of pathology affecting the medial compartment, 5 elbows developed subsequent fragmentation of the medial coronoid process of the ulna [FMCP], 2 elbows had fibrocartilaginous infill of the humeral defect without development of coronoid pathology. CONCLUSION: This limited case series suggests that medial compartment disease develops despite unloading of the medial compartment using a distal diaphyseal SHO in juvenile dogs with OC.