20. Orthopedics (Robson) Flashcards
What are the two types of replacement forms that can be used?
Cemented
Uncemented
What is the problem with cemented replacements?
Artificial
Can break and fracture - damaged and requires replacement
How do uncemented replacements work?
Cells involved with uncemented prosthetics are?
Coated with calcium hydroxyapetite - involves usage of the skeleton’s own bone formed by osteoclasts to fuse the replacement into place
Osteoclasts
What are the problems with uncemented replacements compared to cemented?
Uncemented - more expensive, require more skill in implanting them and require a longer recover period e.g. seven to 10 days before you can walk on it compared to next day with cemented
For whom are cemented replacements better for?
Older patients
Obese patients
Osteoporosis
For whom are uncemented replacements better for?
Younger patients
More active patients
What is the component used in cemented replacements?
Acrylic polymer - PMMA
What is the component used in uncemented replacements?
Calcium hydroxyapetite
What is the hybrid replacement?
This is a replacement that is half cemented and half non-cemented
What different mechanisms can be used to repair IV disc damage
IV disc prosthetic
Spinal fusion
Bone graft
Ground up dead bone
Which is the best out of IV disc prosthetics and spinal fusion and why?
Spinal fusion - cheaper and safer
Very fiddly putting the prosthetic in and this can be dangerous so close to the spinal cord
What is a common joint replacement made in RA?
Small joint replacement e.g. if there is subluxation of the MCP joint with ulnar deviation
What is tendon repair?
Stitching the tendon back together again
What is tendon transfer?
Used in cases of nerve palsy
Take a tendon with it’s muscle and transfer it to a different location - replace the damaged nerve and muscle
Is upper limb or lower limb tendon transfer more complicated and why?
Upper limb because the upper limb is required to do more complicated movements
What is tendon lengthening and when is this used?
Used for those with muscle imbalances e.g. one muscle group bigger and stronger compared to the antagonising ones
Lengthen the tendons of the weaker ones if necessary
What are the two different methods used for ACL reconstruction?
Can use the patella, the patella ligament and the tibia to replace the patella
OR can use the hamstring tendons and plait this and use this as a replacement
What is mal-union of fractures?
There has been a misalignment of the proximal and distal fragments during healing
What is non-union of a fracture?
The two fragments caused by the fracture have failed to fuse to one another and there is a gap between them
Why might non-union occur? x2
Lack of blood supply
Lack of stability of the two fragments
What is osteotomy?
The surgical cutting of a bone to allow for realignment
When is physiotherapy advised after bone grafting?
Before AND after the procedure
Why is physiotherapy advised with bone grafting?
Build up the muscles around the joint to allow the joint to be mobile quicker
Four methods of bone grafting
Osteogenesis
Osteoinduction
Osteoconduction
Osteopromotion
What will be replaced in a hip replacement for OA?
Femoral head AND the acetabulum
What will be replaced in a hip replacement for avascular necrosis of the femoral head?
Just the femoral head
Three parts of a knee prosthesis are?
Tibial component
Femoral component
Patella component
When might a K wire be used for internal fixation?
When fracture healing is quick
When might plates and screws be used for internal fixation?
Long bones and radius and ulnar
When might intra-medullary nails be used for internal fixation?
Long bones
Osteogenesis - bone graft - involves what?
Formation of new bone by cells contained in the graft
Osteoinduction - bone graft - involves what?
Chemical process - molecules are contained in the graft and these convert cells into bone forming osteoblasts
Osteoconduction - bone graft - involves what?
Matrix of the graft forms a scaffold that favours outside cells to penetrate the graft and form new bone
What is an autograft?
Bone is harvested from the same individual
Two sites of autografts for ACL repair are?
Semitendinosus
Semimembranosus
What is arthrodesis?
Surgical fusion of a joint
What is ankylosis?
Spontaneous fusion of a joint
Two reasons to perform arthrodesis?
Pain relief in a severely damaged joint
Stabilisation of a joint which has lost stability
Indication of osteotomy in OA is?
To relieve pain in OA at the hip and the knee
