Hip

Question 1

What are the surgical disorders of the hip?

Answer 1

Hip dysplasia
Coxofemoral luxation
Leg-calve perthesis disease

Question 2

What is the pathogenesis of hip dysplasia ?

Answer 2

Abnormal development of coxofemoral joint resulting in joint laxity
— laxity leads to malarticulation and DJD

Associated with disparity of growth of muscle mass vs skeletal structures
—affected dogs have rapid skeletal growth and delayed muscle growth

Bony changes occur because of lack of congruity between femoral head and acetabulum

Question 3

What is the signalment with hip dysplasia?

Answer 3

Large breed

Juveniles present with joint laxity
Mature patients present with DJD and osteoarthritis

Question 4

What is a common history seen in animals with hip dysplasia ?

Answer 4

Exercise intolerance

Difficulty rising
Intermittent/continual lameness
Sits funny/ falls to the side

Bunny hops
Takes stairs with both legs together

Slow, chronic onset

Question 5

What do you see in the early phase of hip dysplasia during an orthopedic exam?

Answer 5

Early phase — lame, pain on extension of hip joints

Bunny hopping, straight stifles, throw weight forward, head and neck extended, narrow base rear, wide Base front

Muscle atrophy and reluctant to rise

Question 6

What do you see during an orthopedic exam in late phase hip dysplasia?

Answer 6

Restricted extension, muscle atrophy, pain on extension, crepitus

Question 7

What is the Ortolani sign?

Answer 7

Dog is in dorsal recumbency with femurs at 90 degree angle to table

Subluxation femoral head dorsally by pressure on stifle joint (adduct slightly)

Maintain pressure white slowly abduct stifle

Palpating (and hearing) head return to acetabulum = positive Ortolani sign

The greater the angle of reduction, the greater the degree of joint laxity

Question 8

The pain associated with hip dysplasia in a juvenile is caused by?

Answer 8

Exposure of pain receptors in subchondral bone and joint capsule

In older dogs, pain is secondary to osteoarthritis

Question 9

What radiographic changes are see in hip dysplasia?

Answer 9

Early stage - increased joint space, flattened acetabulum, coxa valga, osteophyte

Late stage - above +DJD

Question 10

What is your DDX for hip dysplasia?

Answer 10

Neurological
Orthopedic

L-S instability
Herniated disc
Myelopathy
Bilateral CCL

Question 11

T/F: medical managment is always the first line treatment in hip dysplasia

Answer 11

True

Question 12

How can you medically manage a dog with hip dysplasia ?

Answer 12

Reduce food intake — keep dog lean (low fat and protein)

Managed exercise
Swimming and controlled long slow leash walks

Alleviate pain (passive and active exercises and NSAIDS)

Maintain strength and joint motion

Question 13

You have a 15week old puppy with hip dysplaia. What surgical intervention would be appropriate ?

Answer 13

Juvenile pubic symphysiodiesis (JPS)

— alters growth of pelvis and degree of ventroversion of acetabulum

Question 14

What surgical management for hip dysplasia is appropriate in a 6month dogs without radiographic evidence of DJD?

Answer 14

Triple pelvic osteotomy

—> osteotomy of pubis, ischium, and ileum

Ileum is then fixed with an angled TPO plate to achieve axial rotation of the acetabulum

Question 15

In what cases in triple pelvic osteotomy provide the most favorable prognosis?

Answer 15

Stress radiographic evidence of subluxation

Minimal to no DJD

Angle of reduction <30degrees and angle of subluxation <10degrees

Solid distinctive reduction of femoral heal (positive Ortolani sign)

Question 16

What are surgical procedures for hip dysplasia that can be done in mature dogs?

Answer 16

Total hip replacement

Femoral head and neck ostectomy

Question 17

T/F: total hip replacement for hip dysplaia is only done as a salvage procedure after non-response to medical managment

Answer 17

True

Question 18

What are the two types of total hip replacement?

Answer 18

Cemented and cementless prosthesis

Question 19

T/F: large and active dogs have better function with total hip replacement than with FHO

Answer 19

True

Question 20

What are complications to THR?

Answer 20

Dislocation PO

Infection

Loosening —cemented
Failure of ingrowth —cementless

Femur fracture

Question 21

What is a femoral head and neck ostectomy?

Answer 21

Removal of the head and neck of femur with saw or osteotome

Pesudoarthrosis is formed using gluteal muscles and tendons to support weight

Question 22

What is the approach to the hip joint when doing a FHO?

Answer 22

Craniolateral

Question 23

What is the prognosis for surgical correction of hip ?

Answer 23

TPO- long term function good to excellent
— progressive degenerative changes

THR - excellent to normal function unless complication

FHO- smaller patients have better results

Question 24

What is the most commonly luxated joint in dog and cat

Answer 24

Coxofemoral

Question 25

What is the cause of coxofemoral luxations?

Answer 25

Motor vehicle accidents Associated with contralateral pelvic or long bone fracture Associated with thoracic injury Silent trauma — eg fell down stairs

Question 26

T/F: coxofemoral luxation causes an acute, unilateral weight bearing lameness

Answer 26

False Acute unilateral NONweightbaring lameness

Question 27

What are your DDX for coxofemoral luxation?

Answer 27

Fracture of femoral head or neck Slipped capital physis or avulsion fracture Fracture of acetabulum Hip dysplasia and degenerative joint disease (DJD)

Question 28

What are the 3 stabilizers of the hip joint?

Answer 28

Ligament of head of femur Joint capsule Dorsal acetablular rim

Question 29

What muscles attach to the greater trochanter of the femur, which requires a tension band when repairing with osteotomy

Answer 29

Middle and deep gluteals

Question 30

T/F: most coxofemoral luxations are in the craniodorsal direction

Answer 30

True

Question 31

This this consisted with a (craniodorsal or caduoventral) coxofemoral luxation? ``` Non-weight bearing lameness Greater trochanter difficult to palpate Hold leg out and flexed Stifle internally rotated Affected limb longer on extension ```

Answer 31

Caudoventral luxation

Question 32

This this consisted with a (craniodorsal or caduoventral) coxofemoral luxation? Affected leg held in relaxed extension with foot beneath the body and stifle externally rotated Affected leg is shorter on extension of hip Pain and crepitus on palpation

Answer 32

Craniodorsal

Question 33

T/F: Ehmer slings should be used to stabilize reduced caudoventral coxofemeral luxation

Answer 33

True Place in hobbles

Question 34

T/F: Ehmer sling should be used to stabilize a reduced craniodorsal coxofemeral luxation

Answer 34

True | 7-10days post reduction

Question 35

How do you do a closed reduction of a craniodorsal coxofemoral luxation?

Answer 35

Grap tarsus and externally rotate the limb Apply distal traction to bring head of femur below the acetabular rim When head clears acetablulum, internally rotate limb Place thumb of opposite hand on ventral rim acetabulum and index finger on trochanter Apply pressure while putting joint through ROM to clear out debris from joint

Question 36

When is open reduction indicated for coxofemoral luxation?

Answer 36

Avulsion of fovea capitis Closed reduction unsuccessful Unable to maintain closed reduction

Question 37

What are the two possible approaches to open reduction of coxofemoral luxation?

Answer 37

Cranial -lateral Dorsal approach by osteotomy of greater trochanter

Question 38

What are the types of repair can you do on coxofemoral luxations

Answer 38

Reconstructions — capsulorrhahy —translocation of greater trochanter Prosthetic implant — prosthetic capsule made of suture —toggle pin (only procedure that does not required coaptation) Total hip replacement Femoral head and neck osteotomy

Question 39

How s a prosthetic capsule made?

Answer 39

Hole drilled transversely across neck of femur Bone screws and washers are inserted into dorsal acetabulum Non absorbable suture material is placed through hole and around screws in figure 8 pattern

Question 40

How is a toggle pin/rod made?

Answer 40

Toggle with non-absorbable suture attached into acetabular fossa Suture material is drawn through tunnel drilled in femoral neck Suture is secured on lateral side of femur

Question 41

What is the prognosis for closed and open coxofemoral luxation reductions?

Answer 41

Closed - 50% Lower with dysplasia or previous trauma Open - 85-50% with good to excellent limb function

Question 42

What is legg-perthes disease?

Answer 42

Aseptic necrosis of the femoral head

Question 43

Possible causes of legg-perthes disease?

Answer 43

Hereditary | Infraction of femoral head

Question 44

Pathogenesis of legg-perthes disease?

Answer 44

Blood supply to femoral head is occluded Aseptic necrosis of subchondral bone followed by cartilage collapse Incongruity resulting in DJD and lameness

Question 45

Signalment associated with legg-perthes disease?

Answer 45

Young (prior to capital physis closure) Toy and small breed 6-7months

Question 46

Diagnosis of legg-perthes disease?

Answer 46

Pain on manipulation of hip Chronic — muscle atrophy and creptius, decreased ROM Rads —deformity of femoral head —shortening and thickening of femoral neck —foci of bone opacity in epiphysis

Question 47

Treatment for legg-perthes disease?

Answer 47

Femoral head and neck excision Surgery as early as possible Need pain management and physical therapy Prognosis - good