The knee joint takes much wear and tear and is easily injured in a number of ways. In most cases, physical therapy and other medical interventions prevent permanent damage. However, if the knee joint sustains irreparable damage--usually from sports injuries or arthritis--physicians may consider partial or total knee replacement surgery. DePuy Orthopaedics, Inc., owned by Johnson & Johnson, offers three options for knee replacement: the Sigma® High Performance Partial Knee, the Sigma® Rotating Platform Knee and Sigma® Fixed-Bearing Knee.
Sigma® High Performance Partial Knee
According to the American Association of Orthopaedic Surgeons, the Sigma® High Performance Partial Knee replaces the medial, lateral and patellofemoral compartments while offering low wear and a high degree of flexion. This partial knee replacement allows for deep knee flexion, as well as the movement required for kneeling, squatting or sitting cross-legged. DePuy Orthopaedics claims patients may experience less pain and move more naturally if this option is used.
Sigma® Rotating Platform Knee
The Sigma® Rotating Platform Knee manufactured by DePuy is designed to bend and rotate, allowing for more natural movement while offering less implant wear when compared to traditional knee replacement. The manufacturer says these implants mimic the natural movement of the knee joint. A study published in "Clinical Orthopaedics and Related Research" indicates that more than 97 percent of such knee implants are still in use after 20 years.
Sigma® Fixed-Bearing Knee
Physicians prefer DePuy's Sigma® Fixed-Bearing Knee replacement implant, using it in most knee replacement surgeries in the United States. The design reduces wear by distributing pressure evenly throughout the joint. An article published in "The Journal of Arthroplasty" states that 99.6 percent of those with this type of knee implant still had the implant five years after surgery.
