Knee Pain

There are few sporting injuries that equally trouble the athlete and the couch-potato. Patello femoral syndrome, also known as Theatre goer’s knee, is the name given to the pain that develops behind the knee cap. This condition can cause the knee to become stiff and sore during the course of watching a movie. You can easily spot a person with Theatre goer’s knee because they try to sit in the aisle seat with their sore leg held straight.  Theatre goer’s knee is usually sore when walking down stairs.

Stand now on one foot with your knee straight.  See how easily you can move your knee cap from side to side with your hand. This is because the natural architecture of the knee locks the knee into a stable position so that no effort by your thigh (quadriceps) muscle is necessary to keep your knee in that position. Now, bend your knee slightly forward by say 10°. You will notice that your thigh muscle quickly contracts and the knee cap cannot be moved from side to side at all. This is because there is an estimated one and a quarter times body weight compressing the knee cap against the groove at end of the femur. You will be horrified to learn that when you go down to a deep crouch and then stand up, because of the angles involved, there is up to eight times your body weight holding your knee cap against the femur. Even when sitting in the theatre without any weight on your feet you will find that it is not at all possible to move your knee cap from side to side because it is held in place by the enormous passive tension of the thigh muscle.

Patella femoral syndrome (PFS) arises if there is an irritation of the cartilage at the back of the knee cap. If the knee cap is not gliding properly in the groove at the end of the femur there can be increased pressure against the back of the knee cap from this groove of the femur.  Now, stand once again on one foot and allow your foot to roll in so the arch flattens and then allow your foot to roll out. You will notice that as the foot moves, the leg will also rotate in and out. This then changes the line of pull of the thigh muscles that supply the knee which can alter the tracking of the knee cap along the groove at the end of the femur.

Whilst it is important to strengthen the muscles of the thigh that control the movements of the knee, it is also important to control the movement of the foot for this will help limit some of the internal rotation (torque) of the knee that can cause the pain of PFS. At the Brunswick Foot Clinic our podiatrists will advise you about the suite of necessary exercises to strengthen the muscles that control the knee. Our podiatrists will also teach you how to recognise the ideal features of a shoe that will help to control the motion of your feet that may be contributing to this painful condition. It is sometimes also necessary to strap the knee cap to alter the direction of pull of the muscles of the thigh on the knee cap. If necessary, our podiatrists will assess your suitability for orthotic therapy. So the next time you have knee pain, it is often wise to think more about the movement of your feet.

Chris Wheeler       
Accredited Podiatrist