Difference between revisions of "Joints Developmental - Pathology"

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#REDIRECT[[:Category:Joints - Developmental Pathology]]
 
 
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|linkpage =Musculoskeletal System - Pathology
 
|linktext =Musculoskeletal System
 
|maplink = Musculoskeletal System (Content Map) - Pathology
 
|pagetype =Pathology
 
|sublink1=Joints - Pathology
 
|subtext1=JOINTS
 
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===Hip dysplasia===
 
 
 
*Mainly large and giant dog breeds, especially with stocky conformations
 
*Seen in cattle - Herefords
 
*Subluxation of hip joint due to maldevelopment
 
*Not present at bith
 
*Inherited + environmental factor involvement (nutrition, exercise)
 
*Pelvic muscles are behind the bone development in rapidly growing dogs -> lack of restraint of the joint -> excess movement before acetabulum is fully mature
 
*Usually develops within first 6 months of life
 
*Varying degrees of severity
 
*Pathogenesis:
 
**Joint laxity / acetabular dysplasia
 
**-> Flattened femoral head +/- mild or severe periarticular [[Musculoskeletal Terminology - Pathology|osteophyte]] formation
 
**-> Thickening of femoral head + degeneration of [[Joints - Anatomy & Physiology#Articular cartilage|articular cartilage]]
 
**[[Musculoskeletal Terminology - Pathology|Eburnation]]
 
*Predisposes to [[Joints Degenerative - Pathology#Degenerative joint disease (DJD)|DJD]]
 
*Round ligament of femoral head may rupture -> luxation
 
 
 
 
 
===Elbow dysplasia===
 
 
 
* = '''Ununited anconeal process'''
 
*In dogs, especially German Shepherd Dogs, St. Bernards, Labradors
 
*Occurs during first few years of life
 
*Failure of anconeal centre of ossification to unite with the ulna
 
**Normally, they unite between 4-6 months of life
 
*May partially or totally separate from each other
 
*Intra-articular irritation -> [[Joints Degenerative - Pathology#Degenerative joint disease (DJD)|DJD]] with [[Musculoskeletal Terminology - Pathology|osteophyte]] formation within the joint
 
 
 
 
 
===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 - normal#Physis (Growth plate)|growth plate]] and the immature [[Joints - Anatomy & Physiology#Articular cartilage|joint cartilage]]
 
*Multifactorial:
 
**Trauma
 
**Genetic
 
**Rapid growth
 
**Ischaemia
 
**Nutritional
 
*Essentially idiopathic
 
*Failure of [[Bones and 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 [[Bones and 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 [[Chronic Inflammation - Pathology#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 - normal#Physis (Growth plate)|growth plate]]
 
**Possibly the basis of ununited anconeal process and ununited coronoid process in dogs
 
 
 
===Arthrogryposis===
 
 
 
*Persistent congenital flexure of a joint in conjunction with muscle contraction
 
*Caused by:
 
**Inactivity or paralysis in utero
 
**Spinal dysraphism
 
**Intrauterine viral infections
 
**Toxic plants (poison hemlock, lupine)
 
**Cause persitent contraction of uterus -> fetal compression
 
*Arthrogryposis and [[Cleft Palate|palatoschisis]] in Charolais cattle
 
 
 
 
 
===[[Bones Developmental - Pathology#Angular limb deformity|Angular limb deformity]]===
 

Latest revision as of 14:20, 3 March 2011