Patellar resurfacing Flashcards
What are the mechanical functions of the patella?
Provides better leverage for the patellar tendon - lowers joint reaction force - so component wear and loading are reduced
What are the rough magnitudes of the reaction force of the patella?
4 to 5 times body weight
Why might the anterior part of the femoral component be grooved in the frontal plane?
To better accommodate the patella and to encourage patellar tracking
What is the replacement patellar bearing surface made from?
HDP
How does the shape of the contact surface of the patella affect wear rate?
Conforming shapes contoured to match the femur wear less than convex (non-conforming) shapes
Why has wear been shown to be worst in metal backed patellae?
Because the HDP is insufficiently thick to distribute the loads and is therefore prone to higher contact streses than the less rigid all-HDP component
How did resurfaced patellae compare with non-resurfaced compare in a recent bilateral study?
Resurfaced = less pain Resurfaced = knee stronger in flexion for demanding activities (such as stair climbing)
Why might it be necessary to make the patella thinner?
To achieve closure of the surgical wound
In what condition is it preferable to replace all joitn surfaces>
Rheumatoid arthritis
