intro to Orthopaedics Flashcards
What are the main 4 stressors of the musculoskeletal system?
TRAUMA - sports injuries, road traffic accidents, overuse
INFECTION - bone and joint
ALTERED METABOLISM - age related, disease related OA/RA
NEUROLOGICAL - muscle spasticity, muscle paralysis
Which joints can be replaced?
- upper limb = shoulder/elbow/wrist/hand
- lower limb = hip/knee/ankle
- spine = disc displacements
What are some indications for replacement?
- degenerative disease (OA)
- inflammatory disease (RA)
- trauma (fracture of neck of femur/neck of humerus)
- tumour
- vascular disease (avascular necrosis)
- previously failed/worn out replacements
What is the mechanism of action of cemented hip replacements?
- femoral stem and acetabulum cemented into place
- bone and cement lock together to make insertion last
- cement is a filler between bone and implant
In what cases is a cemented hip replacement used for?
- obese patients
- dysplastic hips
- Osteoporosis
What are the benefits of a cemented hip replacement?
- less chance of intra-operative fracture
- weight bear immediately
- better prognosis in age 65 and over
What is the disadvantage of a cement hip replacement?
- high chance of fat embolism and aseptic loosening
What is the mechanism of an uncemented hip replacement?
- rough surface covered with porous membrane with hydroxyapatite covering
Who is uncemented hip replacements for?
- younger and more active patients
What are the benefits of uncemented hip replacement?
- less chance of aseptic loosening
- lower incidence of fat embolism
- more popular
What is the disadvantage of uncemented hip replacement
- 4-6 weeks of non weight bearing
- more expensive
What are the other ways of doing hip replacements?
- hybrid = cemented stem and cementless cup
- reverse hybrid = cementless stem and cemented cup
What are the old materials used in replacements?
- Metal on polyethene
- fragments = immune reaction
What are the new materials used in replacements?
Least to most wearable
- ceramic on ceramic
- metal on metal
- ceramic in cross-linked polyethylene
- oxinium in cross linked polyethylene
When is spinal decompression surgery done?
- spinal stenosis
- damaged IV disc
- fractured vertebrae
- tumours
What is spinal fusion?
- when 2 or more vertebrae are joined together with section of bone
- stabilise and strengthen vertebral column
What are some examples of soft tissue orthopaedics?
- tendon repair
- tendon transfer
- tendon lengthening
- ligament repair
- ligament replacement
- free muscle transfer
What is an example of a tendon transfer in the lower limb?
- tibialis posterior to tibialis anterior when loss of dorsiflexors
- detach distal attachment point, pull out and feed through anterior side
What is an example of a tendon transfer in the upper limb?
- more complicated than lower limb as more complicated movements in upper limb
What are the requirements of donor muscles in upper limb tendon transfer?
- under conscious voluntary control
- expendable
- adequate tendon length
- innervated
What muscle transfer can be done for radial nerve palsy to fix wrist extension?
- pronator teres to extensor carpi radialis brevis
What muscle transfer can be done for radial nerve palsy to fix MCP extension?
- flexor carpi ulnaris to extensor digitorum
What muscle transfer can be done for radial nerve palsy to fix thumb extension?
- plantaris to extensor pollicis longus
When is tendon lengthening done?
- for Achilles
- when plantar flexors are under tension so patient only able to walk on toes
- open achilles tendon and lengthen
When would a ligament replacement be done?
ACL reconstruction
in free muscle transfer what muscles can be used?
- gracilis
- rectus femoris
- any muscle that is expendable and relatively superficial
What can the gracilis be used for in free muscle transfer?
- deltoid reconstruction
- elbow flexion/extension
- finger flexion/extension
Why may fracture healing be delayed?
- failure to consolidate within 1.5x normal expected time
When may there be mal-union in fracture healing?
- misalignment of proximal and distal fragments
- leads to biomechanical deformity = rotation, angulation, shortening, translation
When may there be non-union in fracture healing?
- failure to consolidate within x2 normal expected time
- atrophic/hypertrophic
- depends on blood supply/degree of stability
What are 2 methods of reconstructive orthopaedics?
- osteotomy (re-alignment)
- distraction (bone lengthening procedure) (use external fixator)
What do bone grafts allow?
- osteogenesis (formation/development of new bone cells contained in graft)
- osteoconduction
- osteoinduction
- osteopromotion
What is osteoconduction?
- physical effect by which matrix of graft forms scaffold favouring outside cells to penetrate graft and form new bone
What is osteoinduction?
- chemical processes: molecules contained in the graft convert neighbouring cells into osteoblasts
What is osteopromotion?
- when grafted material enhances osteoinduction
What are the types of bone grafts?
Human Bone -> autografts and allografts
Bone substitutes -> xenografts and alloplast
