Question

Problem Statement: Your 15‐year‐old cousin, a sports enthusiast, has been diagnosed with juvenile
idiopathic arthritis. Unfortunately, your cousin did not respond to medication or physical therapy. The
doctor has suggested a total knee replacement. As a biomedical engineer, your cousin has asked you
what type of implant would be best given their age and lifestyle.

Instructions: Deliver a report to inform your cousin on their options. Your report should consist of three
sections: a description of the most likely problems with a total joint replacement in this case, a survey of
the options on the market including which materials are used

Answer 1

Juvenile idiopathic arthritis(JIA) is chronic inflammation commonly occurs in early childhood. Recently, biological therapies are used in JIA at the early stage as same as rheumatoid arthritis, due to retain joint cartilage. However, some of young patients have painful knee problems requiring knee replacement.

Total joint replacement can often dramatically reduce pain and improve motion, mobility and function. It is usually reserved as the final option for joints that are so severely damaged, painful and stiff that they interfere with the child’s functioning and quality of life. The most commonly replaced joint due to JIA is the hip, followed by the knee; rarely is the ankle, elbow or shoulder replaced.

This surgery involves removing a damaged joint and replacing it with an artificial joint made of metal, ceramics and/or plastics. The metals used in artificial knees are alloys of cobalt-chromium and titanium. The bearing portion of the joint is made of a high-grade, wear-resistant plastic. The metal-plastic bearing combination is the most common type used  in knee replacement implants worldwide.