My husband is concerned with a clicking noise on the outside of my right knee. I have recently noticed pain accompanies the clicking and snapping when I go for long walks. What could this be?

There can be several reasons for the clicking noise in your knee. Commonly, a tendon or a thickened part of the knee joint capsule can slide over a prominent bone. The thickened area of your joint capsules are known as plica. A plica, with irritation, can become inflamed and enlarged to the size of a crayon. The enlarged plica can produce an audible snap as it passes over the femur bone when the knee is moved. The iliotibial band is a wide tendon that crosses the knee joint line on the outer aspect of the knee. Symptoms of pain and snapping can develop in runners related to this tendon, especially if they are running on a lot of incline or hilly terrain. A clicking sensation is also felt by individuals who have knee caps (patellae) in the wrong position. The patella slides into a groove in the femur as the knee moves from an extended position to flexion. If there is a tilt or a slight shift in the patella position as it engages the groove to slide over the femur, a snap or clicking sensation can occur. The incorrect alignment between the femoral groove and the patella can eventually wear down the cartilage surfaces. Another source of the symptoms which you have described can come from a meniscus cartilage tear. The meniscus cartilage is a shock-absorbing cartilage in the knee different from the cartilage directly applied to the bones of the knee joint. The meniscus cartilage is subjected to high twisting stresses. Tears in the meniscus cartilage can occur over time or with an acute injury. Symptoms of clicking and snapping associated with pain in the knee should be evaluated. A problem in its early stages can often be corrected before significant damage or injury is allowed to progress.