ARTIFICIAL KNEES Veronica Frattaroli November 29, 2011

WHAT DOES AN ARTIFICIAL KNEE ENTAIL?  Usually 3-4 parts:  A cap for the femur  A cap for the tibia  A plastic spacer  Sometimes a back for the patella

KNEE REPLACEMENT  Two types of knee replacement:  Total knee replacement: more commonly used and for more severe damage  Partial knee replacement: still in research but is sometimes used for less severe damage

USES  Used to fix many conditions and diseases:  Osteoarthritis  Rheumatoid arthritis  Avascular necrosis  Malalignment of the knee joint (knock-knees or bowlegs)

TOTAL KNEE REPLACEMENT  Advantages:  Lasts up to 20 years  Good relief of previous pain  Good range of motion (0-120°)  Disadvantages:  Stiffness  Pain  Loss of motion

PARTIAL KNEE REPLACEMENT  Advantages:  Sometimes an outpatient procedure  Can possibly stand with assistance within 2 hours of surgery  Disadvantages:  Not as widely used

PROCEDURE  Vertical incision along the knee  Distal femur is shaped, using a customized device, to properly align the bone to the leg’s original angles  Proximal tibia is also shaped, using a similar device as the femur, to align the bone correctly  If the patella is severely damaged, the undersurface is removed  Metal caps are attached to the appropriate bone using an epoxy cement  Then a plastic spacer is placed on top of the metal cap of the tibia, made of polyethylene (can be replaced to prolong joint life)

PROCEDURE CONT.

RISKS  Blood clots  Infection in the surgical wound or in the joint  Nerve injury  Problems with wound healing  Lack of good range of motion  Dislocation of patella  Fracture of the patella  Instability in the joint

FUTURE  Advances in diagnosis and management of osteoarthritis  Advances in robotics  Less invasive surgery

REFERENCES  "Knee Replacement Surgery." WebMD Arthritis and Joint Pain Center: Symptoms, Causes, Tests, and Treatments. Ed. Anne C. Poinier Web. 26 Nov  What Is Knee Replacement?" EhealthMD. Ed. Guy Slowik. EhealthMD, 28 June Web. 27 Nov  "Total Knee Replacement." Meniscus Transplant and Biologic Knee Replacement to Avoid Knee Replacement by San Francisco Knee Specialist Kevin Stone MD. The Stone Clinic, Web. 27 Nov