Changes

Hip dysplasia is a developmental trait characterised by an '''instability of the hip joint'''.  

Hip dysplasia is a developmental trait characterised by an '''instability of the hip joint'''.  

The hip joint laxity is responsible for early clinical signs and joint changes. The abnormal motion of the hip stretches the fibrous joint capsule and ligament connecting the head of the femur to the pelvis, producing '''pain and lameness'''. The acetabulum is '''easily deformed''' by continual movement of the femoral head. '''Micro fractures of the acetabular bone''' may occur, causing further pain and lameness in the immature dog.  The dog’s physiologic response to joint laxity is proliferative '''fibroplasia of the joint capsule''' and formation of '''osteophytes''' on the rim of the acetabulum and the femoral neck. This helps to stabilise the hip joint but results in the chronic signs of '''degenerative joint disease''', which progresses over the lifetime of the dog.

The hip joint laxity is responsible for early clinical signs and joint changes. The abnormal motion of the hip stretches the fibrous joint capsule and ligament connecting the head of the femur to the pelvis, producing '''pain and lameness'''. The acetabulum is '''easily deformed''' by continual movement of the femoral head. '''Micro fractures of the acetabular bone''' may occur, causing further pain and lameness in the immature dog.  The dog’s physiologic response to joint laxity is proliferative '''fibroplasia of the joint capsule''' and formation of '''osteophytes''' on the rim of the acetabulum and the femoral neck. This helps to stabilise the hip joint but results in the chronic signs of [[DJD|'''degenerative joint disease''']], which progresses over the lifetime of the dog.

It primarily affects '''large and giant breed dogs''', but can also occur in smaller dogs and cats.

It primarily affects '''large and giant breed dogs''', but can also occur in smaller dogs and cats.

'''The Ortolani test''' should be performed with the dog under sedation.

'''The Ortolani test''' should be performed with the dog under sedation.

#Dog placed in dorsal recumbency with both femurs verticals

#Dog is placed in dorsal recumbency with both femurs vertical.

#Axial pressure is put on the femurs and the femoral heads will subluxate if hip dysplasia is present.

#Axial pressure is put on the femurs and the femoral heads will subluxate if hip dysplasia is present.

#The limbs are then abducted and a click or pop will be heard and felt as the femoral head returns to the acetabulum: the angle at which this occurs is the angle of reduction.

#The limbs are then abducted and a click or pop will be heard and felt as the femoral head returns to the acetabulum: the angle at which this occurs is the angle of reduction.

There may be evidence of hip subluxation: shallow acetabulum, less than 50-60% of the femoral head inside the dorsal rim of the acetabulum.

There may be evidence of hip subluxation: shallow acetabulum, less than 50-60% of the femoral head inside the dorsal rim of the acetabulum.

Degenerative joint disease may also be evidence: ostephyte proliferation, thickened femoral neck, spurring, flattening of the femoral head, sclerosis of the subchondral bone.

Degenerative joint disease may also be evidence: osteophyte proliferation, thickened femoral neck, spurring, flattening of the femoral head, sclerosis of the subchondral bone.

The hip dysplasia can usually be '''scored''' radiographically by licenced technicians.

The hip dysplasia can usually be '''scored''' radiographically by licenced technicians.

Conservative and surgical options are available.

Conservative and surgical options are available.

Most '''immature animals''' are best treated with conservative and medical management. 75% of dogs respons favourably to this option, and 25% require further treatment or surgery.  

Most '''immature animals''' are best treated with conservative and medical management. 75% of dogs respond favourably to this option, and 25% require further treatment or surgery.  

Conservative treatment involves '''exercise restriction''' and the use of '''NSAIDs''' for pain flare-ups. '''Neutraceuticals''' may be considered.

Conservative treatment involves '''exercise restriction''' and the use of '''[[NSAIDs]]''' for pain flare-ups. '''Neutraceuticals''' may be considered.

A surgical option for immature dogs with joint laxity but no osteoarthritis is: '''triple pelvic osteotomy'''. This involves osteotomies of the ilium, pubis and ischium in order to increase the capture of the femoral head in the acetabulum. This stabilises the hip joint and slows the progress of osteoarthritis.

A surgical option for immature dogs with joint laxity but no osteoarthritis is: '''triple pelvic osteotomy'''. This involves osteotomies of the ilium, pubis and ischium in order to increase the capture of the femoral head in the acetabulum. This stabilises the hip joint and slows the progress of osteoarthritis.

If medical therapy fails to control the pain and lameness, surgery as a salvage procedure may be the only option. Two options exist:

If medical therapy fails to control the pain and lameness, surgery as a salvage procedure may be the only option. Two options exist:

:'''Femoral Head and Neck Excision''': most effective in small and medium-sized dogs

:'''Femoral Head and Neck Excision''': most effective in small and medium-sized dogs

:'''Total Hip Replacement''': only possible in animals heavier than 15-20kg. Many complications and must be performed in a specialist facility.

:'''Total Hip Replacement''': only possible in animals heavier than 15-20kg. Many complications may occur and the surgery must be performed in a specialist facility.

Results following surgey are good to excellent, but owners have to be fully committed to aftercare and physiotherapy.

Results following surgery are good to excellent, but owners have to be fully committed to aftercare and physiotherapy.

{{Learning

{{Learning

Slatter, D. (2002) '''Textbook of small animal surgery''' ''Elsevier Health Sciences''

Slatter, D. (2002) '''Textbook of small animal surgery''' ''Elsevier Health Sciences''

[[Category:Joints - Developmental Pathology]]

[[Category:Joints - Developmental Pathology]]