Knee Replacement Flashcards
What are the different types of knee replacement
Unicompartmental
Unconstrained bicompartmental
Constrained bicompartmental
What is a unicompartmental knee replacement
Involves replacement of the medial or lateral tibiofemoral compartment only
Usually used for OA
Not suitable for patients with RA
What is an unconstrained bicompartmental knee replacement
The articular surfaces of the knee are replaced by anatomically similar prostheses.
The femoral component is metallic
The prosthetic tibial plateau is made of polyethylene
It is the most common form of total knee replacement
What is a constrained bicompartmental knee replacement
Marked bone loss and severe instability require the insertion of a prosthesis with a fixed hinge
When are constrained bicompartmental knee replacements performed
Mainly used following wide resection of bone for cancer surgery (eg. osteosarcoma around the knee)
What are the major disadvantages of constrained bicompartmental knee replacement
They are more prone to loosening or erosion of surrounding bone - due to lack of rotation causing severe shear stress on the femur and tibia
Revision of these knee replacements is difficult because of the amount of bone loss
What are some contra-indications to knee joint replacement
Knee sepsis
Poor knee extensor function
Significant arterial disease
Why would a patient get a total knee replacement as opposed to a unicompartmental knee replacement
Arthritis in two or all three of the compartments
In unicompartmental knee replacements, which compartment is most likely to be replaced
Medial compartment
