Orthopaedics Flashcards
Name 6 indications for elective adult joint replacement [6]
- Degenerative disease (e.g. osteoarthritis)
- Inflammatory disease (e.g. rheumatoid arthritis)
- Trauma (e.g. fracture neck of femur / fracture neck of humerus)
- Tumour (metastatic / osteosarcoma)
- Vascular disease (e.g. Avascular necrosis)
- Revision of previously failed / worn out joint replacement
Name three main types of total hip replacement (THR)
Cemented
Hybrid: cemented stem; cementles cup
Uncemented - more expensive but more common
Lots of designs: UK: 2010 at least 123 acetabular cups; 146 stems
Cemented fixations use which material to create fixation? [1]
What is the role of cement in the fixation?
Cemented fixation uses an acrylic polymer: Poly(methyl methacrylate) (PMMA)
Cement simply acts as a filler between the bone and the implant
What physiological response occurs as a result of cement fixation insertion? [1]
Highly exothermic response: can burn tissue
Cemented THR are more suitable for which patients? [3]
Uncemented THR are more suitable for which patients? [1]
Cemented:
* obese patients
* dysplastic hips
* patients with osteoporosis
Uncemented:
* Younger & active patients
Describe the surfarce of uncemented fixation [1]
What complication is more common in uncementated fixation? [1]
Uncemented have rough surface covered with porous or hydroxyapatite covering
Can create intraoperative fractures; hole needed in COME BACK
Whats the difference between how long can weight bear between cemented v uncemented? [2]
Cemented can weight bear immediately
Uncemented: wait 4-6 weeks before weigh bearing
State 5 newbiomaterials used for replacements [5]
Ceramic on ceramic
Metal on metal
Ceramic in cross-linked polyethylene
Oxinium in cross-linked polyethylene
Metal in cross-linked polyethylene
Which type of material causes least infections / best wear rate?
Ceramic on ceramic
Metal on metal
Ceramic in cross-linked polyethylene
Oxinium in cross-linked polyethylene
Metal in cross-linked polyethylene
Ceramic on ceramic
Which of the following has the worst wear / break down?
Ceramic on ceramic
Metal on metal
Ceramic in cross-linked polyethylene
Oxinium in cross-linked polyethylene
Metal in cross-linked polyethylene
Metal on metal
The sockets are colour coded.
What are each of these made from? [3]
The sockets are colour coded.
What are each of these made from? [3]
What is a major problem with THR? [1]
Can wear down
What is this? [1]
Which joint does it replace [1]
Speedspiral: tightly rolled acellular human collagen: encourages fibroblast to move in
Replaces carpometacarpal phalangeal joint
Four reasons why may need spinal decompression surgery? [4]
Spinal stenosis
Damaged IV disc
Fractured vertebrae
Tumours
What is spinal fusion? [1]
Where 2 or more vertebrae are joined together with a section of bone to stabilise and strengthen the vertebral column
What is a spinal bone graft? [1]
fuse together painful or unstable bones in the spine so that they heal into a single, solid bone.
State and describe this process
Vertebroplasty: the injection of bone cement into the vertebral body in order to relieve pain and / or stabilise the fractured vertebra
foot drop x
Tendon transfer upper limb
Describe why may undergo tendon lengthening for the Achilles [1]
What are they two methods? [2]
Plantar flexors are more powerful than dorsiflexors; can get hypertonia of plantar flexors
Surgery can lengthen the achilles:
- Cut a V into the achilles and lengthen
OR
- Cut a Z into achilles and lengthen
What are the two methods for ACL reconstruction?
Patella - ligament - tibia
Hamstring: semitendinous and or gracilis tendons
What is a free muscle transfer? [1]
Take whole muscle (& overlying skin) and place elsewhere in body
Which muscle is commonly used for free muscle transfer? [1]
Expl
Rectus femoris
Place femoral nerve that have detached and link to tibial nerve
What are the three types of poor fracture healing? [3]
Delayed
Malunion
Non-union
Explain the different types of poor fracture healing [3]
Delayed
Failure to consolidate within 1.5x the normal expected time
Malunion:
Misalignment of proximal and distal fragments leading to biomechanical deformity:
* Rotation
* Angulation
* Shortening
* Translation
Non-union
* Failure to consolidate within 2x the normal expected time
Can be Atrophic / Hypertrophic depending on blood supply and degree of stability
What is the difference between atrophic and hypertrophic blood supply in non-union fracture healing? [2]
Hypertrophic – there is a blood supply that causes bone growth on either side of the fracture but if there is adequate insecure fixation the fracture moves and forms a callus that may continually break and reform.
Atrophic – no blood supply
What are osteotomy [1] and distraction osteogenesis? [1]
Distraction osteogenesis (i.e. bone lengthening procedures)
* Progressive correction with use of an external fixator (e.g. Ilizarov technique)
Osteotomy
* Re-alignment osteotomy
Explain the four different types of bone grafts
Osteogenesis
* Formation or development of new bone cells contained in graft
* The cells are the “seeds”
Osteoconduction
* Physical effect by which the matrix of the graft forms a scaffold that favours outside cells to penetrate the graft and form new bone
* The scaffolds are the “trellis”
Osteoinduction
* Chemical process by which molecules contained in the graft convert the neighbouring cells into osteoblast
* Growth factors are the “fertilizer”
Osteopromotion
* When the grafted material enhances osteoinduction
* Trellis and fertilizer, or trellis and seeds
Describe the process of aseptic loosening
Difference between hybrid and reverse hybrid fixations? [2]
Hybrid fixation
Femoral component inserted without cement while acetabular is
Reverse hybrid fixation
Acetabular component inserted with cement while femoral isn’t
Difference between hybrid and reverse hybrid fixations? [2]
Hybrid fixation
Femoral component inserted without cement while acetabular is
Reverse hybrid fixation
Acetabular component inserted with cement while femoral isn’t
Tendon transfer for wrist extension (radial nerve palsy)? [2]
PT (pronator teres) to ECRB (extensor carpi radialis brevis)
Tendon transfer for finger MCP extension? (radial nerve palsy)? [2]
FCU to EDC (extensor digitorum communis)
Tendon transfer for thumb extension? [2]
PL (palmaris longus) to rerouted EPL (extensor pollicis longus)
