SA Ortho - Hip Dysplasia Flashcards
Hip joint development
Normal hips at birth - femoral head & neck are cartilaginous and under go endochondral ossification
Hip joint congruence/stability
Stability is dependent on periarticular soft tissue that surrounds joint, critical stage in development
Disparity in development
Bony part of joint
Soft tissue (muscles, ligs, JC)
Hip joint injury progression
Laxity/instability
Poor joint congruence
Subluxation
Abnormal hip development
Hip joint damage
Abnormal forces applied lead to …
Damaged cartilage surface, abnormal growth direction, reduced surface area
Progressive degeneration of CHD
Periarticular osteophyte formation
Deformation of cartilaginous femoral head/acetabulum
Structural & biochemical changes in cartilage
Factors for CHD development
Genetic
Nutrition influence
Environmental
Genetic factors of CHD
Complex/poly genetic
Heritability 20-60%
Genetic influences of CHD
Bony /soft tissue anatomy
Joint biomechanics
Growth rate
Joint fluid production/quality
Connective tissue quality
Hormone production
Nutritional influences
High plane of nutritional affects growth rate
Rapid bone growth & weight gain
Over-loads soft tissue support
Increased frequency & severity of HD
Dietary electrolyte balance w CHD
Low anion gap (Na, K, Cl) = less subluxation
Excessive synovial fluid may increase joint laxity
Vitamin d
Over dose of Vitamin D caused increased calcium/decreased remolding
Trauma to hips
Reduction of activity in predisposed dogs reduced the incidence rate
Acetabular growth plates
Tripartite allows plastic changes to occur in the first 6 months
Bones normally close at 6m
- close at 5m in over fed dogs
- close at 7m in restricted diet dogs
Signalment for CHD
Large fast growing breeds (GS, restrictive, Rotties)
Rare in small dogs/cats
Clin signs
Lameness
Abnormal gait
NWB lameness
Low exercise, v ROM, muscle atrophy
Physical exam findings
Laxity and pain
Pain in hip
-appearance of crepitus
- decreased ROM
Ortolani signs
Sub lux
Abduction
Reduction
(Sedation)
Radiographic views
Ventraldorsal with limbs pulled out and turned inwards, pressing heads into acetabular space and exposing the femoral head for viewing
PennHIP - distraction Index
DI = d/r
Proper placement / displacement
Anything closer to 1 is bad
What does the pennHIP DI measure
Presence of degenerative OA
Congruence (% covered)
What factors influences scores on pennHIP DI
Breeds
Conservative CHD management
NSAIDS, Rehab, weight management, holistic
Surgical CHD management - disease modifying procedures
Juvenile pubic symphyiodesis (JPS)
Double/triple pelvic osteotomy
