There's much interest and debate around this topic. The materials used in a total knee replacement (TKR) are designed to give the implant movement like a normal joint. The implant is usually made of sturdy materials such as stainless steel, alloys of cobalt and chrome, and titanium. Plastic liners may be part of the implant. These are durable and wear resistant.
Orthopedic surgeons, engineers, and other scientists are working together to improve the surgery and implant materials. Right now these materials are not made to withstand the stresses of running, heavy physical work, or contact sports. Engaging in these types of activities after TKR may lead to damage or early wear of the implant. The estimated lifespan of a knee implant is 10 to 15 years.
Impact sports like running are not usually advised. No-impact or low-impact sports are acceptable. Be sure to tell your doctor your interests in activities. Sometimes the type of implant used can make a difference. Find out what to expect. Your implant last the longest if you follow your doctor's advice.