WHAT IS A SORE JOINT?
When a joint is injured in sports or other activities, some of the supportive soft tissues are usually damaged. This results in localized swelling due to the direct tissue damage, and also because there is an increase in the production of joint fluid.
The cartilage itself is not a source of pain, but due to the soft tissue inflammation, numerous inflammatory chemical mediators are released into the joint fluid. Because some of these chemical mediators destroy articular cartilage matrix components, the cartilage recognizes this and responds by regulating or making more matrix components.
Typically, if some combination of rest, bandaging for soft tissue support, and administration of select medications to limit inflammation is initiated, the swelling and soreness are usually short lived.
With more serious injuries, or insufficient rest between episodes of injury, there is a persistent presence of excessive joint fluid, all containing more destructful chemical mediators. If the situation persists, the rate of cartilage matrix destruction becomes greater than the ability of the body to replace it, and cartilage loss can ensue.
Microscopic View of Normal Cartilage Matrix
Microscopic View of Cartilage with Partially Depleted Matrix
In chronic cases, articular cartilage can soften and completely disappear from certain areas of the joint, leading to painful and debilitating ‘bone on bone’ situations.
By understanding how a joint works and what happens to it when it’s injured, we can put together effective plans for both preventing and treating the problems of joint soreness. The goal for treating an injured or sore joint, whether in a human athlete or their animal counterparts, should be to relieve discomfort and inflammation, but to also preserve the long term integrity of the articular cartilage.