Because most knee replacements survive 20 years or more, younger patients are more likely to require a second knee procedure later in life. If you're overweight, you're more likely to require more surgery. You do a lot of manual labor. You have an active lifestyle. All of these factors can increase your risk of requiring multiple knee surgeries. The average age of people receiving knee implants is 70. Women tend to need their knees replaced sooner than men do. This is probably because they live longer than men do after losing one of their legs. By 80%, this loss represents a serious health issue for women. Men are typically concerned about losing their ability to father children; women are worried about being unable to walk or engage in other activities without pain. People who smoke are likely to need two knee replacements instead of one. Over time, smoking reduces the amount of oxygen that enters your body's largest reservoir, bone marrow. This makes it harder for your bones to heal themselves after injury. The more times you have surgery on your knee, the more likely you are to suffer from complications such as infection or arthritis. Individuals who play soccer, rugby, or any sport that involves jumping around a field or court are at increased risk of needing multiple knee replacements. Because these sports involve a lot of running and jumping, they can lead to stress fractures in your bones.