Postmarketing Study for Determine Performance of the SIGMA HP® PARTIAL KNEE SYSTEM

• Survivorship (revision) [ Time Frame: 3 years ] [ Designated as safety issue: Yes ]
  Kaplan Meier Survival analysis at 3 years (based on revision of the femoral or tibial components)
  
  

• Survivorship [ Time Frame: 1, 2, 5 and 10 years ] [ Designated as safety issue: Yes ]
  Survival analyses at each post-operative assessment.
  
  
• Knee Society Score [ Time Frame: 1, 2, 5 and 10 years ] [ Designated as safety issue: No ]
  Mean change from baseline (pre-op) to each post-operative assessment
  
  
• KOOS [ Time Frame: 1, 2, 5 and 10 years ] [ Designated as safety issue: No ]
  Mean change from baseline (pre-op) to each post-operative assessment.
  
  
• HAAS [ Time Frame: 1, 2, 5 and 10 years ] [ Designated as safety issue: No ]
  Mean change from baseline (pre-op) to each post-operative assessment.
  
  
• Kujala Score [ Time Frame: 1, 2, 5 and 10 years ] [ Designated as safety issue: No ]
  Mean change from baseline (pre-op) to each post-operative assessment.
  
  
• Oxford Knee Score [ Time Frame: 1, 2, 5 and 10 years ] [ Designated as safety issue: No ]
  Mean change from baseline (pre-op) to each post-operative assessment.
  
  
• EQ-5D [ Time Frame: 1, 2, 5 and 10 years ] [ Designated as safety issue: No ]
  Mean change from baseline (pre-op) to each post-operative assessment.
  
  
• Radiographic Analysis [ Time Frame: 1, 2, 5 and 10 years ] [ Designated as safety issue: Yes ]
  Change from 6 week post-operative assessment at all post-operative timepoints to identify the number of implants that are 'at risk'.
  
  

The purpose of this study is to collect more information about a particular type of joint replacement for people with degenerative diseases of the knee such as osteoarthritis. This type of knee replacement is called the Sigma HP® Partial Knee System and it is made by a company called DePuy International. Orthopaedic surgeons have been using this type of knee replacement for about two years. The aim of this study is to measure how this particular type of knee replacement performs over a ten year period.

Osteoarthritis (OA) is the most common form of arthritis and can affect any joint in the body. It occurs due to some type of trauma to the joint, a repeated injury to the joint, or simply due to ageing and 'wearing' of cartilage which covers and cushions the inside of a joint.

There are a number of different ways to treat OA and other degenerative diseases of the knee but commonly people have all or part of their knee joint replaced with artificial parts. The knee is made up of three compartments and arthritis can affect any number of these compartments. The Sigma HP® Partial Knee System allows a surgeon to replace only the compartments that are affected by the arthritis rather than replacing all the compartments which is what would happen in a total knee replacement. Replacing only the damaged areas maintains more of your natural knee and we think this means that more of the knee's natural movement and function can be restored. The surgery for a partial knee replacement is less invasive than for a total knee replacement and this should mean there is potential for a faster recovery.