Total hip replacement Flashcards
What is hip dysplasia characterised by?
Hip laxity and or instability
developmental disease of the hip
At what age does hip laxity develop?
4-5months
What environmental factors influence hip laxity?
size of dog, rate of growth, diet and exercise
What clinical conditions can arise due to hip laxity?
inflammation
microfractures (acetubular rim)
Pain
Thickening of the joint capsule
Remodelling via erosion of the cranial and caudal borders acetabulum
Round teres ligament stretched or ruptured
femoral head flattened
When do skeletal changes occur in the dog with hip laxity?
During growth in the first year of life
What does hip laxity present with?
Bunny hopping frequent sitting Lateral sway of the spine exercise intolerance clicking of the hips difficulty rising pelvic limb lameness/stiffness
What will a dog with hip laxity experience during an orthopaedic examination?
Pain on abduction and hip extension
Audible click
instability
Muscle atrophy (biceps femoris and gluteals
What investigations are carried out when assessing hip laxity?
radiography (orthogonal views, ventraldorsal extended and lateral)
Quantify the degree of laxity via radiography
Ortoloni test (not useful in dogs that are older)
Identification secondary arthritis
Ultrasound
What may conservative management include for the hip dysplasia dog?
Restricted diet
short lead walks
NSAIDS
introduce hydrotherapy
Why is it important to try conservative treatment first in the young dog with hip dysplasia?
Joint may stabilise with time by fibrosis and bone remodelling
What are the aims of treatment in hip dysplasia?
Minimise pain and swelling
improve limb function
reduce the progression of osteoarthritis
How is a decision made as to whether surgical or medical management should be tried in hip dysplasia?
Dogs age presence of arthritis dogs behaviour potential use severity of clinical signs
What two types of surgical treatment can a hip dysplasia dog undergo?
Prophylactic procedures
Salvage procedures
What prophylactic procedures can a dog undergo for hip dysplasia?
Triple pelvic osteotomy
Juvenile pubic symphysiodesis
What is involved in a juvenile pubic symphysiodesis?
Fusion of the pubis symphysis growth plate
improves hip congruence
only suitable young dogs no signs of secondary arthritis
increased femoral head coverage
What is involved in a triple pelvis osteotomy?
Increase the dorsal coverage of the femoral head
Moderate hip laxity angle of reduction less than 35 degrees
no OA between 4 and 8 months of age
Pelvis is cut in two or three places and the acetabulum is freed
What are the salvage procedures that can be preformed in the hip dysplasia dog?
femoral head and neck excision
Total hip replacement
What is involved in a femoral head and neck excision?
Femoral head and neck are removed allowing for psuedoathrosis to form
(smaller dogs do better)
Younger dogs with severe laxity or older dogs
Preserve soft tissue leaving articular bone surface
What is the postoperative management of Femoral head and neck excision?
Encourage exercise as soon as sutures are removed to achieve mobile pseudoarthrosis
initiate physiotherapy 2-3days after surgery
What are the two methods of completing a total hip replacement?
Bone cement implant
Non-cemented systems (new)
who are the ideal candidates for THR?
chronically painful arthritic hips no concurrent ortho or neuro issue Conservative management tried and failed not overweight no other concurrent problems
When should a THR be preformed in young dogs with severe hip laxity?
9 months of age once their growth plates have fused.
How long should be left between bilateral hip surgeries?
6-8weeks
what are the indications for THR?
advanced coxofemoral osteoarthritis
What are the advantages and disadvantages of a cemented THR?
90-95% success rate
Once in place difficult to remove
Bone must be prepared, pulsatile lavage (remove cancellous bone), plug to pressurise cement, cement gun centralizers
What are the advantages and disadvantages of non cemented THR?
Recent development size of implant must be correct, dependant on a tight fit Quicker procedure revision surgery easier ingrowth of bone can occur
What are the complications of THR?
infection implant failure luxation osteomyelitis aseptic loosening femoral fractures subsidence sciatic neuropraxia cement granuloma
What discharge instructions would you write for a THR?
Exercise severly restricted minimal lead walks 6 weeks Avoid play and slippery floors Re-examined at the end of 6 weeks Gradual return to exercies
