This question is asked by many patients and may be applied to many joints such as ankles, hands, and elbows for the weeks following the initial injury or surgical intervention.
Edema is the physiological response to a chemical imbalance within the cells and tissues of the body. This chemical imbalance may be caused by a mechanical stress put on the tissue (twisted ankle or surgical intervention to the tissue) or a pathological process going on within the body (infection, gout, etc). Swelling is the term we use to describe the abnormal enlargement or protuberance we visualize as the result of edema or excessive fluid within a body cavity or joint region.
The above question references swelling as a result of mechanical stress. In fact, this patient had a total knee replacement which involves significant mechanical stress to the entire knee complex. If you don’t believe me check out this video on total knee replacement:
While the healing process of the injured tissue may have occurred and the weakened tissue is back to full tensile strength, there still may be swelling which is activity dependent. The typical scenario reported by the patient is that my knee is normal size in the morning and then by end of day it is swollen, painful, and tight to the degree where I am limping again. As frustrating as this may be for the patient, it is normal to go through this sequence of no swelling in the morning and swelling to the point of functional deficits by the end of the day. How is this possible? Shouldn’t the swelling go away and stay away? The answer to that is no. It is not that easy and the recovery period from any injury is always longer than you think it should be.
When an injury occurs, various tissues are mechanically stressed and thus weakened. Let’s take the total knee replacement noted above. The initial insult to the tissue starts when the skin and soft tissue is intruded with the incision and separation of tissue and muscle to expose the actual knee joint. The bone is mechanically stressed with a drill, saw, and hammer as noted in the video and the end result is major tissue disruption with subsequent swelling, which can become problematic if not controlled with ice, elevation, compression, and muscle activation.
As noted in a previous blog, (E is for elevation), elevating just 3 tablespoons of fluid within the knee joint will inhibit the quadriceps muscle from contracting at a normal intensity and without good quad strength all functional tasks involving weight bearing are difficult. Following any mechanical injury or surgical intervention there is swelling and subsequent muscular weakness and stiffness within the joint involved. Even if the cellular structure of the tissue has healed, the patient may still have a muscular strength loss and the muscles do not absorb gravitational forces efficiently or propel the body through space with power.
Your body is like a car and the muscles are the shock absorbers in that luxury car. If you have weak muscles, your body does not move efficiently and thus more stress is put on the tissues, which then results in swelling. To regain strength, you must push your intensity of exercise and everyday activity, yet there will be a transitional period of time when you don’t have enough strength to tolerate all those stresses and guess what, that is when the body responds with swelling.
You need to keep pushing your activity every day and you will reach that threshold when you have the strength to tolerate all the stresses of exercise and then your swelling will resolve. Keep moving and controlling your swelling with ice. You will make it through that phase when you keep pushing into the yellow zone of the traffic light. Your knee (or any other joint) will return to a normal appearance but it takes time and hard work to push through that discomfort/swelling phase. When you are in question about your swelling and exercise intensity, ask your physical therapist for advice.
If it doesn’t challenge you, it won’t change you!