Hip dysplasia

Question 1

Laxity vs dysplasia

Answer 1

Hip dysplasia is a hereditary condition
- Puppies are born with normal hips, they then develop abnormally leading to hip dysplasia

Many dogs will have laxity early in life, but this does not predict dysplastic changes later

Question 2

Risks for hip dysplasia

Answer 2

Diet - weight essentially (overweight will put more load on the joints)

Exercise - exercising young puppies excessively will cause them to have all sorts of joint issues

Question 3

Common breeds that develop hip dysplasia

Answer 3

labradors, GSDs, Rotties, Goldens and (increasingly) cross breeds

Question 4

At what age do signs of hip dysplasia start to show?

Answer 4

Typically 6-7mo but may be older

Question 5

Clinical signs of hip dysplasia

Answer 5

difficulty rising,

abnormal gait,

bunny hopping,

pelvic limb lameness,

clicking/clunking of the hips,

May be sensitive around back end on palpation

Question 6

Possible causes of pelvic limb lameness

Answer 6

Hip dysplasia

Cranial cruciate ligament disease

Patellar luxation

Neurological disease
- IVD disease
- lumbosacral disease
- degenerative myelopathy

Question 7

Signs of hip dysplasia on orthopaedic exam

Answer 7

Asymmetric muscle mass, esp. quads and gluteals

Sensitivity over hind quarters

Pain on hip extension, abduction

Reduced range of motion, crepitus (DJD)

Can’t really detect effusion in the hip

Asymmetric pad wear

Question 8

Typical gait observations for hip dysplasia

Answer 8

Will typically hop up steps, moving both hind limbs together to reduce pain

Shortened, slower stride on affected limb

Lateral sway

Bunny hopping when bilateral

Often (60%) bilaterally affected, may well be asymmetric

Question 9

Differential diagnoses for hip dysplasia

Answer 9

Avascular necrosis of the femoral head (younger, small breed dog)

Fracture (pelvis, proximal femur) (traumatic history)

Luxation (traumatic history)

Psoas injury (soft tissue injury - psoas muscle inserts on greater trochanter) (difficult to distinguish)

Sciatic pathology

Neoplasia (bone or joint)

Sepsis

Question 10

Ortolani test

Answer 10

Dog in dorsal recumbency

Dorsal pressure on the stifle

Abduct to detect reduction

Adduct to detect subluxation

When they have hip dysplasia when you press down it will sub-lux and then clunk into place when abducted

Question 11

Barden hip lift

Answer 11

Dog in lateral recumbency

Proximal femur is palpated

Apply dorsal lift to femur

Then reduce with thumb

Palpable movement indicates laxity

Questionable value

Question 12

Radiographic evaluation of hip dysplasia

Answer 12

General screening x-rays (2 view)

BVA-kennel club or OFA scoring films

Assessment of anatomy and presence/absence of secondary changes

May be supplemented by measures of hip laxity
○ PennHip
○ Controversial in UK due to need for manual restraint
○ requires hip extension so if dog is painful you won’t get good hip x-rays
○ good for looking at femoral neck anatomy

Question 13

Hip subluxation on x-ray

Answer 13

Dorsal acetabular cover

Norberg angle

Distraction index: a measure of passive joint laxity

Question 14

Norberg angle

Answer 14

ideally angle is >105 degrees

Question 15

Distraction index

Answer 15

a measure of passive joint laxity

DI < 0.3 - good prognosis
DI > 0.7 - poor prognosis

Question 16

Goals of therapy for hip dysplasia

Answer 16

Manage pain

Improve range of motion

Improve limb function

Improve muscle mass and strength

Improve activity level

Improve quality of life

Question 17

Conservative treatment options for hip dysplasia

Answer 17

Rest

Diet management

Exercise restriction after rest

Small walks a few times a day rather than one long walk

Rehab

Physiotherapy including hydrotherapy

Medical management

Question 18

Medical management for hip dysplasia

Answer 18

NSAIDs
□ Aspirin
□ Carprofen
□ Robenacoxib
□ Meloxicam

Nutraceuticals

Chondroprotectants - much better early on in the disease process (DMOADs)
□ Hyaluronic acid, PSGAG

Analgesics
□ Paracetamol
□ Tramadol
□ Gabapentin

Question 19

Surgical management of hip dysplasia

Answer 19

Pain reduction

Mechanical realignment

Excision arthroplasty

Joint replacement

Question 20

Pectineal myectomy

Answer 20

For hip dysplasia

Adductor of the hip

Inserts onto the capsule

Theory is that cutting this will reduce tension on the joint capsule (pain relief)

Does nothing to stabilise the hip or change sequelae

Clinical outcomes are very variable and it is not usually recommended

Question 21

Juveline pubic symphiolysis

Answer 21

For hip dysplasia

Cauterise the symphis to stop growth

Question 22

Triple pelvic osteotomy

Answer 22

For hip dysplasia

Reorientation of the pelvis to provide improved dorsal acetabular rim coverage

Was much more popular than it is now

Alternative approaches include DPO (double) and 2.5 DPO

Question 23

Indications for triple pelvic osteotomy

Answer 23

Hip dysplasia but no secondary DJD

Clinically significant lameness and stiffness with attendant hip pain

Ideal candidate is 4-8 months of age, with positive Ortolani sign and clear “clunk” on reduction

Angle reduction / subluxation 25-35° / 5°-10°

Can be done as staged bilateral procedure

Question 24

Procedure of triple pelvic osteotomy

Answer 24

3 cuts to mobilise the acetabular segment

Rotated around its longitudinal axis to increase dorsal rim cover

Ilial osteotomy is repaired with plate & screws

Strict exercise control until fracture planes have healed (4-6 weeks)

Question 25

Outocmes of triple pelvic osteotomy

Answer 25

90% success

Complications can be serious, including screw pull-out or breakage

Procedure is relatively less common than it used to be

Question 26

Intertrochaneteric osteotomy

Answer 26

Reorientation of the proximal femur to improve seating of the head within the acetabulum

Indicated in dogs with coxa valga and high femoral neck angle

Bone wedge is resected and the bone stabilised with plate and screws

Question 27

Ostectomies

Answer 27

Remove diseased bone and joint

Femoral head and neck excision

Question 28

Femoral head and neck excision

Answer 28

Salvage procedure, rarely first choice
□ Removes hip joint, leaving pseudarthrosis
□ Suboptimal ROM, hip stability and weight-bearing (but may not be clinically evident)

Can be used in any dog or cat with end-stage DJD

Straightforward procedure but some steps are critical to success

One of the few surgical procedures where we require early active mobilisation (rehab)

Not pain free after surgery

Active rehab is really important

Question 29

Arthroplasty

Answer 29

Joint replacement

Does well for all cases

Total hip replacement

Question 30

Total hip replacement

Answer 30

Restores hip function and should provide good stability and ROM

Can be used in dogs or cats with end stage DJD or pelvic/femoral neck fractures that cannot be repaired

Complex and expensive procedure, with potentially significant complications

Question 31

Indications of total hip replacement

Answer 31

Coxofemoral arthritis (hip DJD)

Hip dysplasia

Chronic hip dislocation (luxation)

Fractured femoral head

Significant clinical hip dysfunction

Question 32

Clinical outcomes of total hip replacement

Answer 32

Good to excellent outcomes in >90% cases

Major complications include luxation, femoral fracture, aseptic loosening, sepsis

Revision surgery is feasible (but expensive), as is conversion to excision arthroplasty