| Line 6: |
Line 6: |
| | | | |
| | | | |
| − | ===Osteochondrosis=== | + | ===[[Osteochondrosis]]=== |
| − | [[Image:Pig elbow osteochondrosis.jpg|right|thumb|100px|<small><center>Osteochondrosis in pig elbow (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]] | |
| − | [[Image:Osteochondrosis dissecans.jpg|right|thumb|100px|<small><center>Osteochondrosis dissecans (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
| |
| − | | |
| − | *Defect in cartilage growth (i.e. '''dyschondroplasia''')
| |
| − | *In growing animals: large breeds of dogs (4-8 months), pigs (5-7 months) and horses (weeks - 2 years)
| |
| − | *Involves both the [[Bones - Anatomy & Physiology|growth plate]] and the immature [[Joints - Anatomy & Physiology#Articular cartilage|joint cartilage]]
| |
| − | *Multifactorial:
| |
| − | **Trauma
| |
| − | **Genetic
| |
| − | **Rapid growth
| |
| − | **Ischaemia
| |
| − | **Nutritional
| |
| − | *Essentially idiopathic
| |
| − | *Failure of [[Cartilage - Anatomy & Physiology|endochondral ossification]]
| |
| − | *Lesions bilateral in 70% of cases but lameness often unilateral, sometimes no clinical signs
| |
| − | *Some authors consider this condition more generalised, in which case e.g. [[Joints Developmental - Pathology#Elbow dysplasia|ununited anconeal process]] would be part of osteochondrosis syndrome
| |
| − | | |
| − | Different manifestations include:
| |
| − | | |
| − | *'''1. ''Osteochondrosis dissecans''''' (OCD):
| |
| − | **Retained cartilage cores
| |
| − | ***White, wedge-shaped areas of retained cartilage in the metaphysis
| |
| − | ***Clefts -> separation of cartilage from bone -> flaps or free '''joint mice'''
| |
| − | ***May interfere with joint function
| |
| − | **Lysis → bone cysts
| |
| − | **Focal disruption of [[Cartilage - Anatomy & Physiology|endochondral ossification]]
| |
| − | **-> Angular limb deformities and [[Joints Degenerative - Pathology#Degenerative joint disease (DJD)|degenerative joint disease]]
| |
| − | **May be present together with '''synovitis'''
| |
| − | **Predilection sites:
| |
| − | ***<u>In dogs:</u>
| |
| − | ****Proximal humerus
| |
| − | ****Lateral femoral condyle
| |
| − | ****Coronoid process of ulna
| |
| − | ***<u>In pigs:</u>
| |
| − | ****Humeral and medial femoral condyles
| |
| − | ****Anconeal process of elbow
| |
| − | ***<u>In horses:</u>
| |
| − | ***Medial femoral condyle
| |
| − | ***Distal tibia
| |
| − | **''Osteochondrosis dissecans'' in dogs:
| |
| − | ***Grossly:
| |
| − | ****Lesion in central part of the caudal aspect of developing ossification centre in humeral head
| |
| − | ***Histologcally:
| |
| − | ****Lesion filled with [[Granulation Tissue|granulation tissue]] (fibroplasia)
| |
| − | ****Surrounding thickened bone spicules
| |
| − | ****Cap of thickened [[Joints - Anatomy & Physiology#Articular cartilage|articular cartilage]] over the defect
| |
| − | ****-> May fragment - joint mice
| |
| − | ****Calcified cartilage fragments may be in the posterior pocket of joint capsule
| |
| − | *****May grow through synovial fluid nourishment
| |
| − | | |
| − | *'''2. Epiphysiolysis'''
| |
| − | **Not associated with retention of cartilage
| |
| − | **Separation of epiphysis from the metaphysis
| |
| − | **Likely to be due to trauma to degenerated [[Bones - Anatomy & Physiology|growth plate]]
| |
| − | **Possibly the basis of ununited anconeal process and ununited coronoid process in dogs
| |
| − | | |
| − | | |
| − | [[Category:Joints - Developmental Pathology]]
| |
| | | | |
| | | | |