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| − | {{toplink
| + | #REDIRECT[[:Category:Joints - Developmental Pathology]] |
| − | |backcolour =CDE472
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| − | |linkpage =Musculoskeletal System - Pathology
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| − | |linktext =Musculoskeletal System
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| − | |maplink = Musculoskeletal System (Content Map) - Pathology
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| − | |pagetype =Pathology
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| − | |sublink1=Joints - Pathology
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| − | |subtext1=JOINTS
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| − | }}
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| − | <br>
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| − | ===Hip dysplasia===
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| − | *Mainly large and giant dog breeds, especially with stocky conformations
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| − | *Seen in cattle - Herefords
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| − | *Subluxation of hip joint due to maldevelopment
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| − | *Not present at bith
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| − | *Inherited + environmental factor involvement (nutrition, exercise)
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| − | *Pelvic muscles are behind the bone development in rapidly growing dogs -> lack of restraint of the joint -> excess movement before acetabulum is fully mature
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| − | *Usually develops within first 6 months of life
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| − | *Varying degrees of severity
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| − | *Pathogenesis:
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| − | **Joint laxity / acetabular dysplasia
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| − | **-> Flattened femoral head +/- mild or severe periarticular [[Musculoskeletal terminology|osteophyte]] formation
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| − | **-> Thickening of femoral head + degeneration of [[Joints - normal#Articular cartilage|articular cartilage]]
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| − | **[[Musculoskeletal terminology|Eburnation]]
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| − | *Predisposes to [[Joints - degenerative#Degenerative joint disease (DJD)|DJD]]
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| − | *Round ligament of femoral head may rupture -> luxation
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| − | ===Elbow dysplasia===
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| − | * = '''Ununited anconeal process'''
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| − | *In dogs, especially German Shepherd Dogs, St. Bernards, Labradors
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| − | *Occurs during first few years of life
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| − | *Failure of anconeal centre of ossification to unite with the ulna
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| − | **Normally, they unite between 4-6 months of life
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| − | *May partially or totally separate from each other
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| − | *Intra-articular irritation -> [[Joints - degenerative#Degenerative joint disease (DJD)|DJD]] with [[Musculoskeletal terminology|osteophyte]] formation within the joint
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| − | ===Osteochondrosis===
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| − | [[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>]]
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| − | [[Image:Osteochondrosis dissecans.jpg|right|thumb|100px|<small><center>Osteochondrosis dissecans (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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| − | *Defect in cartilage growth (i.e. '''dyschondroplasia''')
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| − | *In growing animals: large breeds of dogs (4-8 months), pigs (5-7 months) and horses (weeks - 2 years)
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| − | *Involves both the [[Bones - normal#Physis (Growth plate)|growth plate]] and the immature [[Joints - normal#Articular cartilage|joint cartilage]]
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| − | *Multifactorial:
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| − | **Trauma
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| − | **Genetic
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| − | **Rapid growth
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| − | **Ischaemia
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| − | **Nutritional
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| − | *Essentially idiopathic
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| − | *Failure of [[Bones - normal#Bone development|endochondral ossification]]
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| − | *Lesions bilateral in 70% of cases but lameness often unilateral, sometimes no clinical signs
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| − | *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
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| − | Different manifestations include:
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| − | *'''1. ''Osteochondrosis dissecans''''' (OCD):
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| − | **Retained cartilage cores
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| − | ***White, wedge-shaped areas of retained cartilage in the metaphysis
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| − | ***Clefts -> separation of cartilage from bone -> flaps or free '''joint mice'''
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| − | ***May interfere with joint function
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| − | **Lysis → bone cysts
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| − | **Focal disruption of [[Bones - normal#Bone development|endochondral ossification]]
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| − | **-> Angular limb deformities and [[Joints - degenerative#Degenerative joint disease (DJD)|degenerative joint disease]]
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| − | **May be present together with '''synovitis'''
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| − | **Predilection sites:
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| − | ***<u>In dogs:</u>
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| − | ****Proximal humerus
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| − | ****Lateral femoral condyle
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| − | ****Coronoid process of ulna
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| − | ***<u>In pigs:</u>
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| − | ****Humeral and medial femoral condyles
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| − | ****Anconeal process of elbow
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| − | ***<u>In horses:</u>
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| − | ***Medial femoral condyle
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| − | ***Distal tibia
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| − | **''Osteochondrosis dissecans'' in dogs:
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| − | ***Grossly:
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| − | ****Lesion in central part of the caudal aspect of developing ossification centre in humeral head
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| − | ***Histologcally:
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| − | ****Lesion filled with [[General Pathology - Chronic Inflammation#Granulation tissue|granulation tissue]] (fibroplasia)
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| − | ****Surrounding thickened bone spicules
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| − | ****Cap of thickened [[Joints - normal#Articular cartilage|articular cartilage]] over the defect
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| − | ****-> May fragment - joint mice
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| − | ****Calcified cartilage fragments may be in the posterior pocket of joint capsule
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| − | *****May grow through synovial fluid nourishment
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| − | *'''2. Epiphysiolysis'''
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| − | **Not associated with retention of cartilage
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| − | **Separation of epiphysis from the metaphysis
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| − | **Likely to be due to trauma to degenerated [[Bones - normal#Physis (Growth plate)|growth plate]]
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| − | **Possibly the basis of ununited anconeal process and ununited coronoid process in dogs
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| − | ===Arthrogryposis===
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| − | *Persistent congenital flexure of a joint in conjunction with muscle contraction
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| − | *Caused by:
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| − | **Inactivity or paralysis in utero
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| − | **Spinal dysraphism
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| − | **Intrauterine viral infections
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| − | **Toxic plants (poison hemlock, lupine)
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| − | **Cause persitent contraction of uterus -> fetal compression
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| − | *Arthrogryposis and [[Oral Cavity - Cavity & Gingiva#Cleft Palate|palatoschisis]] in Charolais cattle
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| − | ===[[Bones Developmental - Pathology#Angular limb deformity|Angular limb deformity]]===
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