Orthopaedics Flashcards
3 parts of the bone
diaphysis (shaft)
metaphysis (neck)
epiphysis (end)
Pain asymbolia
Congenital analgesia
pain is experienced without unpleasantness
inability to feel pain
abnormal gaits?
- trenedelenburg : compensating bending on the opposite side
- antalgic
Antalgic gait?
It is a form of gait abnormality where the stance phase of gait is abnormally shortened relative to the swing phase.
hip replacement, small vs bigger heads?
Small: wears off more slowly
Big: wears off more quickly, gives better range of movement
Complications of a hip replacement?
Infection 1-2%
Blood clot formation 1 in 1000
Stroke
Heart attack
Others such as fracture, damage to the neurovasculature, change in length of the leg
Why fractures in metaphysis heal more quickly?
Bigger cross-sectional area
Better blood supply
Why being intra-articular matters for a fracture?
Most likely cartilage is also damaged
Limits movement at the joint
Needs to be immobilised to try to achieve 1^ bone formation and not secondary
Descriptions of a fracture:
- Side
- Location
- Pattern
- No of fragments
- relation to joint
- relation to skin
- Displacement of the bone
- Proximal, middle, distal 1/3 // shaft, head neck
- transverse, oblique (>30 degrees), spiral (when oblique on 2 plains)
- Multi or simple or segmental
- intra or extra articular
- open or close
- Translation
Shortened
Angulated
Rotated
Management of fracture/dislocation?
Operatively or non-operatively
1. Reduce ( open or close)
- Immobilise
I. Non-surgical
Cast: first backslab to avoid compartment syndrome by build up of pressure (inflam), then plaster cast for chronic use
II. Surgical
- Intramedullary: fixation with intramedullary nail or K wires
- Extramedullary: screws and plate or external fixation (allows treatment of the wound at the same time) - Rehabilitate
Difference between subluxed and dislocated
sublux: partial
dis: complete loss of contact
Non-union risk factors
Patient: Old, smoker, alcoholic
Fracture: Open, multi-fragmented
Treatment: poor reduction
Valgus vs varus
vaLgus: distal bone points Laterally, apex medially
varus: distal bone points medially
secondary vs primary bone healing?
2: Callus formation, relative stability
1: absolute stability (rigid fixation), tunneling resorption
3 important compartments of the knee joint?
Medial femorohumeral joint Lateral femorohumeral joint Femoropatellar joint (skyline view) (pain on walking down the stairs)
–> 1/3 narrowing partial replacement, 2/3 complete
Why infection is important during knee replacement?
if infected, abx cant reach, so has to be taken out
virchow’s triad for blood clots?
- hyper coagulity
- immobility
- injury to vessels
Sesamoid bone in knee?
fabella, within lateral head of gastrocnemius
acts as a lever to increase the power
Treatment of injury to menisci within knee?
made of fibrocartilage, not much blood supply
the middle 2/3 gets no blood, so damage –> disected out
Outside 1/3 small blood supply, fixed with sutures
Gout vs pseudogout x-ray differences?
psuedo :calcified meniscus on knee
gout: tophus on x ray, (most common on big toe)
Why ask for a rosenberg radiograph of knee?
On supine or standing ones cartilage loss/narrowing of joint may not be visible and are only visible when knee is at 45 degress
Avulsion fracture?
bone fragment pulled away by muscle
Normal soft tissue width anterior to cervical vertebrae on a lateral radiograph?
C1 to c3 : 1/3 of vertebral body
C4 to c7: width of vertebral body
bigger than that may be due to bleeding
Difference in growth plate of thumb and and other digits metacarpals?
thumb: proximal plate
others: distal
What features would make an intra-articular fracture require surgical attention? Why?
Step off >2mm
Split >2mm
One part of cartilage gets more loaded: increased weight on one side is not tolerable by the cartilage: risk of arthritis
What are the white lines on the surface of the bone?
Trabeculae: shows the direction of spread of the weight
Which articular surface of calcaneous gets the most pressure?
posterior articular facet
Classifications of the ankle fractures?
Their management?
How else can you describe them?
Webbers A: Distal to syndesmoses (tibia and fibula touching distally)
Webbers B: At the syndesmoses
Webbers C: Above syndesmoses
A no fix
b fix if unstable
c always fix
Bimaleolar, trimaleolar (posteriro side)
2 types of bone?
1. Woven laid down in disorganised manner 2. Lamellar a. cortical: -dense, concentric rings - mostly around diaphysis, little around metaphysis b. cancellous - laid along the stress linse (tabeculae)
Bone cell and matrix types?
Oosteocyte (90%, Ca hoemostasis), oesteoblast and oesteoclast
Matrix:
a. inorganic (60%)
made of Ca
resists compressive load
b. organic (40%)
- type I collagen
- resists extensile force
Bone blood supply
- in children
- in mature bone
- how is everything connected in 2?
- Metaphyseoepipheal system and diaphyseal system separated by growth plate
- a. Nutrient artery:
- Ascending and descending limbs
- high pressure, flow from inside to outside
- supplies the inner 2/3
b. perosteal a
- low pressure, from muscle blood supply
- supplies the outer third
- Volkmanns canal (transverse) , haversian canal (within a concentric ring)
Pereosteum 2 layers?
Outer fibrous Inner vascular (Oesteoblastic activity, helps with bone healing)
Shenton line
is an imaginary line drawn along the inferior border of the superior pubic ramus (superior border of the obturator foramen) and along the inferomedial border of the neck of femur. This line should be continuous and smooth