Lecture 5: Surgery of the hip (Exam 1) Flashcards
List some sx tx of the hip
- Triple pelvic Osteotomy (TPO)
- Double pelvic osteotomy (DPO)
- Femoral Head & neck excision (FHO)
- Total hip replacement (THR)
- Juvenile pubic symphysiodesis (JPS)
What occurs in a triple or douple pelvic osteotomy (TPO or DPO)
- Position of osteotomies for completion of TPO
- Stabilization w/ bone plate
- There is atual rotation & lateralization of the hemi pelvis
- There is axial rotation & lateralization of the hemipelvis
- A DPO Does not have a ischial cut but a TPO does
What does this radiograph show
- Post FHO
- Complete removal of the femoral neck
What is this
Cemented canine THR implant
What is this
Cementless canine THR implant
What is this
Kyon THR
What is done in a juvenile pubic symphsiodesis
- Expose the pubic sympysis w/ a ventral midline incision over the pubis
- The spatucal is set @ 40 Watts
- Place the electrode on the symphysis ~ 10 seconds
- Repeat Q2 to 3 mm along the symphysis
What is coxofemoral (CF)/ hip luxation
Traumatic displacement of the femoral head from the acetabulum
What causes coxofemoral luxation
- Craniodorsal displacement of the femoral head from the acetabulum (most due to trauma like a mortor vehicle accidents)
- Ventrocaudal displacements where the femoral head may lodge w/in the obturator foramen (may be b/c of fx of the greater trochanter) are much less frequent
Discribe what happens to the round ligament of the femoral head in a coxofemoral luxation
- Always fails completely
- May be an interstitial rupture
- Or avulsion of the ligament from the fovea capitis
What happens to the fibrous joint capsule during a coxofemoral luxation
- Is completely torn for dislocation of the femoral head
- Tear in the joint capsule may be small rent through which trhe femoral head protrudes or there is complete fraying of the capsule
Why is a coxofemoral luxation treated as quickly as possible
- Prevents continued damage of soft tissue surrounding the hip joint & degeneration of articular cartilage
- Early reduction = return of the nutrient sourcew for articular cartilage
Where does the articular cartliage gets its nutrients from
- From synovial fluid
- Pumpoed into the matrix during normal articular movement
T/F: up to half of px have a major injury in addition to CF luxation
True
Why is a PE performed before induction of ax & tx of lux hip
To ID concurrent trauma
What is this image showing & describe the position of the paw
- Carriage of the limb in a px w/ craniodorsal CF lux
- Position of the paw is beneath the body & there is external rotation of the stifle
Describe the Thumb test
- Thumb is in the space caudal to the greater trochenter & the femur is rotated externally
- If the CF joint is intact the greater trochanter displaces the thumb (A & B)
- If the CF Joint is luxated then the greater trochanter rolls over the thumb (C & D)
What is a way to Dx a CF lux
Position of the greater trochanter is related to the ilial crest & tuber ischii
What should be eval in radiographs
- Avulsion of the fovea capitis
- Associated hip joint fractures
- Degenerative changes secondary to hip dysplasia
What is the prognosis when there is a spontaneous luxation secondary to hip dysplasia
Poor prognosis
What are the DDx of CF lux
- Acute subluxation or luxation hip joint secondary to hip dysplasia
- Femoral capital physeal fracture
- Femoral neck fracture
- Acetabular fracture
What is the medical management of a CF lux
- Closed reduction (no surgical approach; tried first unliess evidence of hip dysplasia or fracture)
- Open reduction (open surgical manipulation)
T/F: There is no need for ax during a closed reduction
False; ax is given for a closed reduction
What are the steps of a closed freduction for a craniodorsal lux
- Grasp near the tarsus w/ one hand & place the other hand under the limb against the body wall to provide resistance (A)
- Externally rotate the limb & pull caudally to position the femoral head over the acetabulum (B)
- When the femoral head is lateral to the acetabulum internally rotate the limb to seat the femoral head in the acetabulum (C)
Describe what is done during a closed hip reduction
- Px is anesthetized & placed in lateral recumbency w/ the limb elevated
- A rope or towel is placed in the inguinal area & pulled dorsally
- Provide contertraction by grasping the distal portion of the limb & pulling in the opposite direction
- Distraction allows the contracted tissues to strecth
- Use maintained distraction to allow the femoral head to align w/ the acetabulum
- One hand is on the greater trochanter & the other hand is distal on the stifle or hock (reduced by externally rotating the limb & applying firm & consistent distraction)
- Once the femoral head is over the acetabulum the limb is internally rotated w/ the hand on the greater trochanter pushing caudally & slightly abducted
- Firm press is applied to the greater trochanter (this motion allows femoral head to “toggle” over the cranial lip of the acetabulum into norm position)
What is done in a closed hip reduction once the hip is reduced
- Firm pressure is applied to the greater trochanter w/ vigorous ROM of the hip
- Helps displace the soft tissues & reduces hematoma formation in the acetabulum
How is a hip reduction assessed
- Palpation of landmarks (ilial crest, tuber ischii, & greater trochanter)
- Measure width of space btw/ the greater trochanter & tuber ischii
- Restoration of limb length
- Compare to the contralateral hip during assessment
What is this
Ehmer sling
When is an ehmer sling used
- Used to prevent pelvic wt bearing
- Post hip reduction or acetabular fxs
What are the steps of a closed reduction of caudoventral lux
- The px is in lateral recumbency, the limb is held perpendicular to the spine, & the limb is grasped near the tarsal joint w/ one hand & the other is used to stabilize the body (A)
- Place traction on the limb while simultaneously abducting the leg to pull the femoral head beyond the medial rim of the acetabulum (B)
- Once the femoral head clears the acetabular rim place lateral pressure medial to the hip joint (positions the femoral head lateral to the acetabulum) & push proximally & allow the femoral head to fall into the acetabulum (C)
What is another way to do a closed reduction of a caudoventral lux
Place in hobbles @ the tarsus or stifle for ~ 7 D
When is a capsular reconstruction sx tech performed
- Use if the joint capsule is salvageable rare
- In most cases the capsule can’t be securely closed & additional stability is needed
How long does the hip need to be stable for the capsule to heal
3 to 4 W
What are some other reconstructive procedures
- Synthetic capsular reconstruction w/ suture & bone screws or suture anchors
- Toggle pin placement
- Additional stability is gained by translocation of the greater trochanter
Why is a hohmann retractor placed w/in or just caudal to the acetabulum
- To lever the femur caudally
- Improves visualization of the acetabulum
What can excess traction from the hohmann retractor lead to
Sciatic neuropraxia
What is req for reconstruction of the joint capsule as the sole means of stabilization
- Dorsal joing capsule is ID
- Normal conformation of the hip joint
Describe a capsulorrhapy
- Stabilization of the capsule
- Intrerrupted sutures to appose the joint capsule
Describe how a prosthetic capsule is placed
- Placement of bone screws in dorsolateral acetabulum
- Swuture passed from screws through predrilled tunnel in dorsal femoral neck & tightened
- Suture prevents craniodorsal reluxation
- Can use suture anchors
How is stabilization w/ toggle pin suture placed (“toggle rod fixation”)
- Drill a hole centered through the femoral neck (A)
- Then through the acetabular fossa (B)
- Attach multiple strands of nonabsorbable suture to the toggle pins (can use K wire & toggle rod ava)
- Pass the toggle pin/rod thru the hole in the actabular foss & pull to the set pin/bar (C)
- Pass the sutures thru the hole drilled in the femoral neck to reduce the hip & secure the sutures (D)
How is stabilization by translocating the greater trochanter done
- Prepare site distal & slightly caudal to norm anatomic position
- Stabilize the greater trochanter in position w/ small pins & orthopedic wire (tension band)
Where is tension band wire placed & what is its mechanical principle
- Wire exerts force that counters force of muscle contraction
- Compresses the fracture surface
What is done during post op
- Ehmer sling to assit hip reduction early in post op (removed in 4 to 7 days)
- Once the sling is removed begin very controlled physical rehab exercises
- Cage confinement is adeq for dogs w/ stable hips
What is the success rate of maintining reduction & regaining good/excellent limb fxn w/ closed reduction
~ 50%
What px have a poor prognosis
Px w/ poor conformation of the hip joint (secondary to hip dysplasia or prev trauma)
What should always be attemepted in px w/ hip luxation
Closed reduction
What is the success rating for maintaining reduction w/ good/excellent limb function w/ opend reduction
~ 85 to 90%
Describe legg-perthes dx
- Noninflammatory aseptic necrosis of the femoral head
- Occurs in young px before closure of the capital femoral physis
- Also known as avascular necrosis of the femoral head
What is used to manage legg-perthes dx
- Femoral head & neck excision (FHO)
- Total hip replacement (THR)
