Sx Diseases of the Hip Objectives Flashcards
What is the definition of hip dysplasia?
Abnormal development of the coxofemoral joint resulting in
hip laxity
What factors contribute to the expression of hip dysplasia?
Etiology is multifactorial (genetic and non-genetic necessary)
Genetic component = polygenic and epigenetic (gene expression not DNA)
Environmental component = decreased pelvic muscle mass (Greyhound, GSD), rapid weight gain, and/or high dietary energy, Ca/Vit D
What is the typical presenting signalment of hip dysplasia?
Large breed dogs, male OR female (equal sex distribution!)
biphasic age presentation (5-12 months, or old animals)
What are the physical exam and historical findings associated with hip dysplasia in a young dog? In an old dog?
Young dog- hip laxity palpable (can subluxate femoral head), + ortolani sign
Old dog- chronic/recurring signs, decreased ROM in extension, crepitus, NO palpable laxity
- Exercise intolerance*
- Bunny hopping* gait at trot
- Difficulty rising/stiff after rest*
- Reluctant* to climb stairs or jump
Sits “to the side” = avoiding hip flexion = SPECIFIC to hip dysplasia
What gait abnormality is associated with hip dysplasia?
Bunny Hopping!
(instead of alternating back legs, transfers weight to the spine)
What is the ortolani sign? How is it elicited?
Palpable/audible clunk heard
when pushing stifle proximally while abducting stifle
Why is the ortolani sign absent in older animals with hip dysplasia?
Due to remodeling in a chronic process
which radiographic view is considered diagnostic for hip dysplasia?
Hip EXTENDED view with internal rotation of distal limbs
How do you judge proper positioning on a hip extended radiograph
for hip dysplasia diagnosis?
To ensure straight view of pelvis, obturator foramen should be same size
(alien eyes)
What is Morgan’s line on a radiograph?
Represents a caudal curvilinear early osteophyte
and is a well-defined linear density between femoral head and
greater trochanter
DO NOT confuse with a “puppy line”- which is self-limiting, not significant, but is indistinct and at a similar location
What are the typical radiographic findings of hip dysplasia?
Early: Morgan’s line
Later: Increased joint space, less than 50% acetabular coverage, femoral neck thickening or coxa valga, femoral head flattening or sclerosis
A change in the angle or shape between the femur and femoral neck
as an adapted response to abnormal stresses is known as
Coxa Valga
T/F:
expression of hip dysplasia can be very different in littermates
TRUE
What are the two most common methods of screening for hip dysplasia?
OFA: Cannot certify hip dysplasia before 2 years!
Single VD pelvis view- underestimates subluxation
PennHip: Distraction under anesthesia and measurement (distraction index)
Does not change after 16 weeks!
Estimate of probability of OA only, not clinical signs
DI < 0.3 is ideal (lower the better=less laxity)
What is the “ideal” value for acetabular coverage?
For distraction index?
>50% acetabular coverage is ideal (means no hip dysplasia)
<0.3 DI (means no hip laxity)
What are medical/conservative treatment options for hip dysplasia?
Anything used to treat arthritis works
Puppy: Decrease Ca/Vit D/Energy intake in diet
Adult: Weight management is the most important!
Exercise moderation
Physical therapy
NSAIDs
What are surgical treatment options for hip dysplasia?
-
Corrective Procedures:
- To reverse laxity
- JPS (Juvenile Pubic Symphodesis)
- TPO (Triple Pelvic Osteotomy)
- To reverse laxity
-
Salvage Procedures
- To preserve function
- FHO (Femoral Head Ostectomy)
- THR (Total Hip Replacement)
- To preserve function
In regards to corrective procedures for hip dysplasia, what are the
indications for JPS and TPO?
JPS: If less than 20 weeks old and
risk is high according to PennHIP at 16 weeks
TPO: if clinical signs of hip dysplasia are present, positive ortolani sign, angle of reduction is < 30°, and there is no rad evidence of DJD or remodeling
In regards to corrective procedures for hip dysplasia, how do JPS and TPO help fix the mechanics of hip dysplasia?
JPS: Fuses pubic symphasis which tethers growth of pelvis at midline and rolls the acetabulum ventrally to catch the femoral head
TPO: Osteotomy of the pubis, ischium, and ilium and fixation of ilium with angled plate rolls the acetabulum dorsally to catch the hip (preventing subluxation)
In regards to corrective procedures for hip dysplasia, what is the prognosis for future problems associated with hip dysplasia for JPS and TPO?
JPS: Reduces incidence of OA
TPO: DJD is usually progressive, but long term function excellent
In regards to salvage procedures for hip dysplasia, what are the
indications for THR and FHO?
THR: For large, active dogs after have exhausted other options
FHO: Smaller patients, and first line for salvage
Do both AFTER skeletal maturity (7 - 8 months of age)
In regards to salvage procedures for hip dysplasia, what are the
differences between THR and FHO?
THR: entire hip joint replaced with prosthesis
FHO: removal of entire head and neck of femur
Both have near normal function after sx
In regards to salvage procedures for hip dysplasia, what are the
post- op recommendations for FHO?
IMMEDIATE post-op limb use is essential!
ROM and PT exercises encouraged!
What are treatment options for hip dysplasia based on?
CLINICAL signs (not rad signs!)
Why should medical management of hip dysplasia
precede sx treatment?
Sx treatment is very risky. Even though the prognosis is great, complications are CATASTROPHIC, so if you can use meds, do that.
What is the most common etiology of coxofemoral luxation?
trauma
What is the most commonly luxated joint?
coxofemoral luxation!
What is the difference between craniodorsal and caudolateral luxation?
Craniodorsal: leg held in relaxed extension, stifle externally rotated with foot beneath body, affected leg is shorter, pain/crepitus on manipulation
Caudolateral: leg held abducted and flexed, stifle internally rotated,
affected leg is longer
What type of coxofemoral luxation is most common and why?
Craniodorsal most common (>90% of luxations)
due to the pull of the gluteal muscles
How is hip luxation diagnosed?
VD and Lateral rads
When is closed reduction NOT indicated for coxofemoral hip luxation?
Contraindications = dysplastic hip, and/or presence of a fracture
What maneuvers are required for closed reduction of
a coxofemoral hip luxation?
Grasp tarsus, externally rotate limb
Bring femoral head DISTAL to acetabulum
Internally rotate limb after femoral head clears acetabulum
What type of coaptation is required for caudoventral coxofemoral luxation?
Apply Hobbles at level of stifle
in order to prevent abduction of limb
What type of coaptation is required for craniodorsal coxofemoral luxation?
Ehmer sling in order to achieve abduction and internal rotation
to push femoral head away from damaged craniodorsal joint capsule
What is anatomically happening in craniodorsal vs. caudoventral
hip luxation?
Caudoventral: Femoral head trapped ventral to ischium and the greater trochanter is recessed medially/difficult to palpate
Craniodorsal: Greater trochanter is displaced dorsally
What are the indications for open reduction of the coxofemoral joint?
Pelvic/acetabular fracture
Femoral fracture
Hip dysplasia
Unstable closed reduction
Reccurrence after closed reduction
What are the objectives for open reduction of the coxofemoral joint?
Reconstruct joint capsule and adjacent soft tissues
or
Maintain reduction temporarily with implant until soft tissues heal
What are the three most commonly used procedures for correcting coxofemoral luxation?
Capsulorrhapy (closing joint capsule with heavy gauge suture- insufficient alone)
Prosthetic capsule (drill hole across femoral neck, screw in acetabulum, suture in figure 8 through tunnel and around screws)
Toggle pin/rod (Prosthetic capital ligament, suture “toggle” attached to pin placed through acetabulum, suture through femoral neck, secure to lateral femur)
What are the salvage procedures that can be used in treating coxofemoral luxation?
FHO and THR
(I think salvage is indicated if you screw up the open reduction sx)
What is the prognosis for coxofemoral luxation?
Better prognosis with open reduction, but expect DJD over time regardless
of corrective procedure (this DJD is clinically insignificant though)
What is the likelihood of recurrence for closed vs. open reduction
of a coxofemoral luxation?
Closed = 50% recur
Open = 10 - 20% recur
Aseptic necrosis of the femoral head is a condition known as
Legg-Perthes Disease
What is the pathophysiology of Legg-Perthes Disease?
Ischemia to femoral head causes necrosis resulting in
epiphysis collapse with loading then fragmentation of the articular surface
Revascularization leads to new bone but with malunion of fractured femoral head
What is the typical signalment of Legg-Perthes Disease?
Cats and SMALL/TOY breed dogs
4 - 11 months old
What breeds are predisposed to Legg-Perthes Disease?
Mini Poodles and Westies predisposed
___% of cases of Legg-Perthes Disease is bilateral
15%
What do you see on Hx and PE for animals with Legg-Perthes Disease?
Signs of hip pain that is slow, progressive = necrosis
If pain acute, non-weightbearing = pathologic fracture
Chronic remodeling feels like hip dysplasia (mm atrophy, crepitus, decreased ROM)
How is Legg-Perthes Disease diagnosed?
Radiographs!
Early: Radiopacity of lateral femoral head, focal bony lysis = moth eaten/ apple core sign
Later: Flattening/mottling of femoral head, collapse/thickening of neck
If have the clinical signs, but rads normal, repeat in 1 month (rad changes take time)
What are the tx recommendations for Legg-Perthes Disease?
SURGERY is only option (med tx unhelpful)
FHO or THR
BUT *no need to delay procedure past skeletal maturity*
Post-op: Weight management, NSAIDs, and PT recommended
What is the prognosis for Legg-Perthes Disease?
GOOD (but warn owner about 15% rate of contralateral dz)
