Lecture Osteoarthritis and Lower Extremity Athroplasty Flashcards
what is osteoarthritis?
generally progressive loss of articular cartilage accompanied by attempted repair of articular cartilage, remodelling, and sclerosis of subchondral bone, and in many instances the formation of subchondral bone cysts and marginal osteophytes
- attributed to both inflammatory and biomechanical factors
difference btw primary and secondary OA
prevalence of OA in men and women
incidence of OA in men and women
describe the pathology of OA
- lecture slides 8-12 review
what are the ROM and capsular patterns that are seen with OA patients?
OA knee: SOME evidence of Cyriax’s “capsular” pattern, NEITHER group significantly restricted ROM vs. “norms”
OA hip: NO evidence of Cyriax’s “capsular” pattern, BOTH groups significantly restricted ROM vs. “norms”
*People don’t necessarily need to have less rom to be classified as OA!
what are the signs and symptoms of OA?
–joint pain
–restriction of motion (capsular vs. bony)
–crepitus with motion
–joint effusions (fluid shift test)
–deformity (severe oa)
explain the progression of OA
Typically slow, over many years
–Occasionally rapid
May spontaneously stabilize or even improve
–partial restoration of the articular surface
–decrease in symptoms
describe articular cartilage
Diarhtrodial joint – what you think of when you hear joint – very moveable
Aneural = cant be source of pain, avascular = cant get nutrition well and therefore heals slower/hard to heal
what is articular cartalage composed of?
*composed of: Cells, Extracellular Matrix, Water – very important
what are chondrocytes?
–Formation and maintenance of articular cartilage
–Respond to environmental stimuli
- Physiological
- Mechanical
–Loading & hydrostatic pressure
describe the extracelular components of cartalage
it is bi-phasic: Fluid phase (Water), Solid phase (Extra-cellular matrix)
- see slides 21-25
describe compressive loading in articular cartilage
describe effect of cartilage when unloaded
describe effect of cartilage when loaded
1.Stress Shielding
–≤95% of compressive load is borne by FLUID phase
–decrease stress on solid matrix
2.Flow-dependent viscoelastic behaviour
–Hydrodynamic drag force is rate-dependent
–Forces on solid matrix vary with rate of loading
describe additional stresses on articular cartilage
- Articular cartilage = good s=with compression not with tensile stresses!
describe the cycle of tissue damage in OA
1) initial injury to collagen matrix (increased permeability and loss of tensile strength)
2) limited repair (avascular and chondrocytes)
3) chondral repair tissue
*slides 35-37
explain the importance of joint loading for OA and type of loading
–High loading rates (impact loading) → OA
–Low loading rates (even at high loads) → no OA
- Ie a squat
- Distance running = usually not bad
describe effect of immobilization on cartilage
describe how articular contact forces affect the presentation of OA
- slides 42-44
describe for Patients undergoing a 2nd total joint replacement of a hip or knee due to OA or RA where the second replacement is more likely to be
–RA: 2nd joint “random”
–OA: Non-random - most likely to be on same joint, contralateral side OR different joint, contralteral side
* see sldie 45
describe the Biomechanical gait analysis in lower limb OA
- peak medial load (varus) before surgery which is still present after surgery
- contralateral>ipsilateral
what are the specific recomendations for people with OA?
Minimum ≥150 min/wk of moderate-intensity PA
~250 to 300 min/wk (approximately 2000 kcal/wk)
describe semented vs cementless athroplasty
- Rough surface allows bone to grow into it to hold it in better
acrylic cement
–Generally allows immediate WBAT
cementless
–Porous surface (for bone in-growth) vs. non-porous
–Trend – younger, more active patients (bc will be sturdier than other and they are more likely to be more mobile after)
–May require a period of PWB or NWB
what is not preserved after arthroplasty?
- screwhome mechanism
name the 2 surgical approaches for hip athroplasty
- Anterolateral surgical approach (less common)
- Posterolateral surgical approach
describe the anterolateral surgical approach
describe the posterolateral surgical approach - contraindications? - for how long? - what ligaments are cut?
–no osteotomy of the greater trochanter (abductor function is not compromised)
–Complication – higher post-op dislocation rate (but still very uncommon)
name some of the tissues involved with a posterolateral approach
describe the knee athroplasty surgical approach
describe surgical approach for ankle athroplasty
- Contraindications to movement based on surgical report
- Most nwb for period of time
describe what the prehabilitation process entails
Comprehensive exercise program
- muscle strength, power & endurance
- cardiorespiratory fitness
- flexibility
- +/- balance training (for LE surgery)
Instructions for
- Transfers
- Use of supportive devices / walking aids
- Stair training
- Dislocation precautions (hip)
- Preparation for hospital discharge (OT home visit, etc.)
post-op contraindications for hip
post-op contraindications for knee
- note that machines used for ROM, but need active muscle contraction to prevent DVT
post-op contraindications for ankle
knee antroplasty post-op day 1-2
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knee antroplasty post-op day 3-7
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knee antroplasty post-op weeks 1-6
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knee athroplasty post-op day 1-5
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knee athroplasty post-op day 6-14
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knee athroplasty post-op weeks 2-3
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knee athroplasty post-op weeks 3-8
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