Q: What activities can I expect to return to after knee replacement?
A: Most people can successfully return to playing tennis, skiing, riding a bicycle, hiking, elliptical, golf, swimming, and weightlifting but high impact start stop activities on hard surfaces are generally not recommended. The concern with high impact activities after knee replacement is the possibility of wearing out the plastic. The plastics today are far superior to 15 years ago. But particularly in heavy man high-impact activities could lead to premature wear of the plastic resulting in loosening of the implant over 15 to 20 years. This could result in the need for a second surgery that would otherwise have never occurred.
Kneeling is a challenge after a knee replacement. Only about 50% of people can comfortably kneel on the knee after knee replacement. This is in part due to the incision in the front of the knee as well as the hard plastic and hard metal in the knee. Pressure directly on the anterior knee is often uncomfortable. People that need to kneel will usually require special kneepads.
Q: What is the typical course of rehabilitation after knee replacement?
A: Knee replacement is a very uncomfortable surgery particularly in the first 2 weeks. And stiffness as well as some swelling may persist for months. During that time, it is essential to work on range of motion and strengthening. Failure to work on these things despite pain can result in a poor outcome. The typical home activities after knee replacement are walking with a walker for a week or 2 for safety, ankle pumps, knee bending as well as knee extension exercises, straight leg raising, and buttock contractures.
Most people after a knee replacement will require a supervised physical therapy program. That can either be in the presence of a physical therapist in their office or a telerehabilitation program over the Internet. Postoperative rehabilitation is focused on range of motion and progressive strengthening. The typical exercises utilized after knee replacement include pedaling therapy either in a stationary bike or recumbent bike. Weight training is very helpful for strengthening. Balance and sensorimotor training is very important as people have often lost their balance and position sense associated with progressive arthritis over years. The balance and sensory training usually involves twisting, quick change of direction activities, start and stop activities, and working on unstable surfaces. In years past continuous passive motion machines were used after knee replacement; However at least 7 prospective controlled trials have shown no long-term benefit from the use of a continuous passive motion machine after routine total knee replacement.
Q: What are the more common potential complications of knee replacement surgery?
A: Stiffness after knee replacement is a very common frustration. It will often improve over the course of 6 months. The amount of trouble with stiffness is correlated with how many prior surgeries have been done on that knee and how much stiffness there was preoperatively. It is also true that patients who work very hard at rehabilitation will have less stiffness than those that have difficulty working through pain.
A blood clot in the legs can happen after knee replacement, therefore everyone after knee replacement will be on a blood thinner for 2 to 6 weeks depending on their preoperative risk profile. The incidence of blood clots in patients who are on blood thinners is still in the neighborhood of 2%. If there is concern about symptoms of a blood clot an ultrasound is used to establish the diagnosis. If a blood clot is detected the patient will be on blood thinners for months after.
The most disastrous outcome after knee replacement is an infection. There are 2 types of infection. One is a superficial wound infection in the immediate perioperative period which can often be treated with antibiotics. A deep infection in the knee usually necessitates further surgery and longer term antibiotics. This can also result in needing a series of surgeries to get rid of the infection. The incidence of infection is largely correlated with the patient’s risk factors. For example, infection is much more common in diabetes, rheumatoid arthritis, obesity, or any immunocompromised state.