b) What is the case of the athletes pain and how has it results in eleveated mac

Question

b) What is the case of the athletes pain and how has it results in eleveated macrophage activity

c)How might the hip implant the runnre receieved been modified to avoin this problem given his active lifestyle ?

(25 pts) A marathon runner receives a co-cr hip implant with a non-crosslinked polyethylene cup liner, goes through the necessary physical therapy, and after clearing it with his doctor begins to run again. During the first few months the runner feels great and is able to train the but after about a year starts to complain about localized pain and "tenderness" in replaced hip joint. After visiting the doctor, the runner is told he has high macrophage activity surrounding the hip replacement yet no signs of infection a. (15 pts) Describe the cascade of events immediately following placement of the hip implant resulting in the most common final resolution for orthopaedic implants. Include specific cell types and list 5 of at least 10 steps in this process.

Explanation / Answer

a. Co-Cr alloys are commonly used to make artificial joints like knee and hip joints because they are corrosion resistant and chemically inert. This minimizes the possibility of irritation and allergic reaction.

Due to the wear of orthopedic implants metal particulates are released which give stimulus for tumor genesis. The steps involved in Implant associated tumor genesis are:

1. Cell and foreign body reaction

2. Capsule formation (fibrous)

3. Preneoplastic cells contact the implant surface

4. Preneoplastic cell maturation and proliferation

5. Tumor formation

b. The athletic activities put patient at risk of traumatic injuries after hip prosthesis. Since sports involve lot of motion therefore the patient is at the risk of dislocation or periprosthetic fractures.

Even the better technology decreases the wear of the implants there continues to be wear in every THA or Total Hip Arthoplasty. With historical polyethylene metal on polyethylene articulations it generates about 500000 particles of sub-micron size. These particles activate macrophages. The activated macrophages release and recruit interleukin-1 and prostaglandinE and tumor necrosis factor. These chemicals are inflammatory and can cause osteolysis around the implants. Therefore the increased patient activity can increase the polyethylene wear.

c. Hip replacement surgery is the means to reduce pain caused by osteoarthritis. After hip replacement the runners can continue with their sport after a period of rest and rehabilitation. The American college of Sports Medicine suggests that only experienced runners should undertake their sport after hip replacement and not the beginners.

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