Chapter 89 - OCD Flashcards
What does “osteochondritis dissecans” mean?
Inflammation of bone and cartilage resulting in loose fragments.
What condition is most commonly associated with osteochondrosis in horses?
Developmental orthopedic disease (DOD).
What does the term “osteochondrosis” refer to?
A disorder of bone development in growing horses.
What is the primary characteristic of “osteochondritis dissecans”?
Cartilaginous or osteochondral separation.
What does “OC latens” represent?
Focal chondronecrosis in the growth cartilage.
What does “OC manifesta” indicate?
Impaired endochondral ossification and cartilage retention.
What does “OC dissecans” describe?
Cleft formation in necrotic cartilage.
What are examples of JOCC?
OCD, cuboidal bone disease, and other immature skeletal failures.
What term includes disorders related to immature joints or growth plates?
Juvenile osteochondral conditions (JOCC).
What is “endochondral ossification”?
The process of bone development from cartilage.
At what stage does endochondral ossification begin?
Fetal stage.
What is Wolff’s law?
Bone remodels in response to biomechanical load.
Where does longitudinal growth of long bones occur?
At growth plates or physe
What is the typical presentation of an OC patient?
A yearling with joint effusion, usually without lameness.
Which breed shows a high prevalence of OC in the tarsocrural joint?
Warmbloods and Standardbreds.
Which advanced imaging modalities outperform radiography?
Computed tomography (CT) and magnetic resonance imaging (MRI).
What is the role of radiography in diagnosing OC?
It’s the gold standard for detecting OC lesions.
Which joint commonly shows evidence of OC on radiographs?
The tarsocrural or femoropatellar joint.
What joints are most affected by OC in horses?
Tarsocrural, femoropatellar, and MCP/MTP joints.
What is a limitation of radiography for OC?
It may miss lesions limited to cartilage or subtle bone changes.
What joints are most often affected bilaterally by OC?
Tarsocrural and femoropatellar joints.
What is a predilection site for OC in the tarsocrural joint?
Distal intermediate ridge of the tibia.
What is the common location of OC in the shoulder joint?
The glenoid and humeral head.
Where are OC lesions commonly found in the femoropatellar joint?
Lateral trochlear ridge of the femur.
Are POFs part of OC?
No, they are traumatic in origin.
What do POFs indicate histologically?
More osteoarthritis than osteochondrosis.
What biomarker profile difference exists between OC and traumatic joint injuries?
OC has an increase in C2C, while traumatic injuries have increased CPII.
Can young foals show lameness with OC?
Yes, especially with large lesions in the femoropatellar joints.
What role does genetic predisposition play in OC?
Racing Thoroughbreds.
What makes diagnosing OC in very young animals challenging?
The lack of mineralization in subchondral bone.
Can OC lesions regress in young animals?
Yes, they can regress during early juvenile phases.
What is the primary period for the development of OC?
During active endochondral ossification in growing animals.
At what age do tarsocrural lesions typically resolve?
By 5 months, though some persist.
When do femoropatellar lesions commonly stabilize?
Around 8 months of age.
What was a unique finding in Lusitano foals regarding OC?
More lesions at 1 month of age in the femoropatellar joint.
Can minor OC lesions resolve after 12 months?
Yes, up to 24 months in some cases.
What is the “age of no return” for lesion resolution in most joints?
Generally set at 12 months.
What enzyme’s level change reflects cartilage metabolism in young animals?
Matrix metalloproteinase-3 (MMP-3).
Why does the healing of cartilage lesions decrease with age?
Due to reduced metabolic and repair capacity.
What is the prevalence of OC in Dutch Warmblood yearlings?
Around 67.5%.
hat prevalence rate is typical in Dutch Warmbloods at age 3?
Approximately 30%.
What was OC prevalence in South German Coldbloods?
61.7%.
What is the OC prevalence in Thoroughbred yearlings?
23%.
How does OC prevalence vary in Thoroughbred studies using repository radiographs?
Lower than in clinical records, likely due to preselection.
Are Warmblood horses more susceptible to OC than Thoroughbreds?
Yes, they generally have a higher prevalence of OC.
How often is OC found in ponies?
Rarely, with low prevalence.zad
What is a potential primary cause in OC pathogenesis?
Damage to cartilage canal vessels.
How might feral horses’ OC prevalence differ from that in managed horses?
Lower, possibly due to different management and breeding.
What does OC latens refer to?
Clinically silent, early lesions in OC development.
How might genetics play a role in OC pathogenesis?
Certain genes related to vascularization are linked to OC susceptibility.
How does chondrocyte activity change in long-existing OC lesions?
Metabolic rate decreases, indicating possible exhaustion.
How does collagen VI distribution differ in OC lesions compared to normal tissue?
Collagen VI distribution is different in OC lesions compared to normal tissue.
What post-translational modifications were observed in early OC lesions?
Differences in post-translational modifications of collagen type II were demonstrated in samples from early lesions.
What gene showed strong mRNA expression near OC lesions?
TGF-ß mRNA showed strong expression in chondrocyte clusters surrounding OC lesions.
What were the changes in collagen expression in osteochondrotic cartilage?
OC cartilage showed increased expression of collagen types I, II, III, and X, and MMP-13, ADAMTS-4, and TIMP-1, while TIMP-2 and TIMP-3 decreased.
Was MMP-16 significantly altered in osteochondrotic cartilage?
What was demonstrated regarding cathepsin B activity in OC?
A strong increase in cathepsin B activity was observed in chondrocyte clonal clusters in OC.
What was the effect of copper supplementation on cathepsin B?
Copper supplementation confirmed the increase in cathepsin B activity in OC
How did OC tissues differ in proteoglycan content?
OC tissues produced significantly less GAGs, and there was increased activity of gelatinases (MMP-2 and MMP-9).
What role did IGF-1 play in osteochondrotic tissue?
IGF-1 was upregulated in osteochondrotic tissue, likely related to the repair response.
How did OC severity correlate with biomarkers at 11 months of age?
OC severity correlated negatively with osteocalcin and collagen degradation markers and positively with anabolic markers.
What correlation was found in biomarker research regarding osteocalcin?
A strong correlation was found between serum osteocalcin levels and OC severity in foals.
What signaling pathways are known to regulate cartilage differentiation?
Wnt/β-catenin, Ihh/PTHrP, and retinoid signaling pathways.
What evidence supports the role of the Wnt/β-catenin pathway in OC?
Significant changes in expression of Wnt signaling components were found in OC cartilage.
What inhibitors were upregulated in OC lesions?
A Wnt signaling inhibitor, sclerostin, was strongly upregulated in OC lesions.
How does diet influence OC according to the text?
High-energy diets characterized by easily digestible carbohydrates influence OC significantly.
What mitochondrial changes have been observed in OC cartilage?
Abnormal mitochondria have been observed in the deep zone of OC cartilage.
What factors determine the osteochondrotic phenotype?
Genetic components and environmental factors.
What is heritability in the context of OC?
Heritability estimates how much variation in a trait is due to genetic variation.
Which joint showed the highest heritability for OC?
The tarsocrural joint, with an average heritability of around 0.30.
How does breed affect OC susceptibility?
Many identified quantitative trait loci (QTL) for OC are breed-specific.
What two major environmental influences affect OC?
Loading (biomechanical factors) and nutritional factors.
How does biomechanical loading influence OC?
It plays a crucial role in conditioning the musculoskeletal system during early juvenile development.
What is the relationship between energy intake and OC?
High energy intake, particularly from carbohydrates, is associated with increased OC risk.
What hormonal response is triggered by high energy intake?
Postprandial hyperinsulinemia, which varies between horses and may affect OC susceptibility.
How do thyroid hormones relate to OC?
Thyroid hormones are involved in chondrocyte differentiation and blood vessel invasion during ossification.
How did copper levels relate to OC incidence in early studies?
Low copper levels in feed were associated with OC, but further studies showed that extremes in copper intake could provoke lesions.
What is the importance of the calcium/phosphorus ratio in bone metabolism?
Severe aberrations in this ratio can lead to various bone disorders, including OC.
What has been concluded about loading as a cause of OC?
Loading is considered an additive factor rather than a sole cause of OC.
How did pasture access affect OC prevalence?
Foals with irregular pasture access or those kept in large plots showed a higher prevalence of OC.
What has been observed in horses on normal diets regarding OC?
OC lesions can also develop in horses on normal diets without insulin metabolism abnormalities.
What are the two main treatment options for OC?
The two main treatment options are conservative management and surgical management.
What does conservative treatment primarily involve?
Conservative treatment mainly consists of rest and controlled exercise.
What medications may be used in conservative treatment?
Systemic NSAIDs and intraarticular medications such as corticosteroids and disease-modifying osteoarthritic drugs may be administered.
In what cases is nonsurgical management theoretically successful?
It can be successful in very young animals or very mild cases of OC.
What size and depth of lesions are likely to heal with conservative treatment?
Lesions less than 2 cm long and less than 5 mm deep without fragmentation are likely to heal.
what recent data suggests about conservative treatment in scapulohumeral joint OC?
Recent data suggests it may be a viable option in mild cases involving the glenoid cavity.
What is the preferred treatment for tarsocrural OC in athletic horses?
Many authors recommend surgical intervention for tarsocrural OC in athletic horses.
What happens during the surgical management of OC?
Loose fragments and cartilage flaps are removed, and the surrounding tissue is débrided.
What is crucial when débriding subchondral bone in young animals?
What percentage of success was found in horses with reattached cartilage flaps?
A 95% success rate was reported in horses with reattached cartilage flaps.
What innovative technique was used in a Thoroughbred filly for osteochondrotic defects?
A sponge impregnated with growth factors and stem cells was used for healing.
What was the outcome of using a multilayered osteochondral scaffold?
The filly showed good performance and improvement in bone contour at follow-up.
What factors influence the prognosis after surgical intervention?
The prognosis varies based on joint involvement, lesion extent, and definition of “favorable outcome.”
What success rate was reported for the femoropatellar joint?
A 64% success rate was reported for this joint in mixed populations.
What percentage of horses treated for tarsocrural OC perform as intended?
About 76% of horses treated for tarsocrural OC were able to perform as intended.
What is the prognosis for shoulder OC?
The prognosis is less favorable, with a reported success rate of only 15% in racehorses.
What types of lesions in the MCP and MTP joints require immediate surgical intervention?
Lesions with fragmentation or loose bodies should be treated surgically to prevent osteoarthritis.
What is the percentage of return to athletic activity reported for proximal sagittal ridge lesions?
A 90% return to athletic activity has been reported for proximal sagittal ridge lesions.
What common surgical treatment method is used for OC?
Arthroscopy is the common surgical treatment method used for OC cases.
What limitations exist in eliminating OC from the equine population?
Current management practices and breeding goals complicate efforts to eliminate OC.
