One bit of confusion I run across regularly is how much walking to do after a total knee replacement. The answer to the question is actually fairly complicated because it has to do with a combination of a couple of variables, but one of those variables is of the utmost importance.
That variable is swelling. Controlling swelling is key when it comes to rehabbing a knee replacement. If you can control the swelling, then you can recover must faster. So what causes swelling after a total knee? Well, I am glad you asked. The answer is joint irritation, which is caused by weight bearing. I am not talking about being overweight, but the mechanical loading that comes from gravity plus your body weight on the “new” knee, especially in the first several weeks after surgery. In Biomechanics, we call this concept the Ground Reaction Force, which is the compression force that is concentrated on a weight bearing joint during the impact when your heel strikes the ground. So when we say “weight bearing”, that means standing and walking. Weight-bearing on a knee replacement within the first 12 weeks tends to produce swelling. The body produces swelling and inflammation when the newly formed tissue is stressed repeatedly under the load of our body weight plus gravity and ground impact. However, after a total knee replacement one of the most important things to do is walk, thus the dilemma. You have to get walking, not only for the strength in your knee, but also for the function of your body including other muscles, the digestive system, the cardiovascular system (i.e. to avoid blood clots) and your heart and lungs. So remember, it is very important to get walking right after your knee replacement, but you do want to strike the right balance and not do too much!
I do occasionally see clients who have not progressed their walking like they should and they tend to have a set of problems that include weakness and lack of knee extension. However, the opposite problem is actually more common. I mostly see patients that have progressed their walking far too quickly. When that happens, they come in with a knee that is excessively more swollen than it needs to be, so much more that the swelling limits their bending range of motion and ironically making it harder to walk.
So what is the solution? The solution is to have a balanced attack. You need to figure out how much walking might be too much and how much walking might be to little. Also, having a regulated walking schedule and tracking how your body feels after activity can help you find that balance. Remember that just because your knee feels “ok” right after walking doesn’t mean that it will be “ok” in the next 12-24 hours. The body usually takes some time to produce the response to the irritation. I have seen it take as long as 72 hours, so just because after your walking activity you feel fine, may not mean you’re in the clear. The best advice is to wait 12-24 hours after the possible irritating event to see if you are actually in the clear. My suggestion, if you do have any questions about how much walking to do after total knee replacement and your struggling with swelling limiting your ROM, then you may be doing too much walking. Be sure to ask an experienced physical therapist to help you “problem solve” your dilemma if that is the case.