That pesky patella. For something that is so important to human beings and their ability to ambulate, it sure is part of a delicate mechanism.
The patella (or kneecap) is basically the junction point between the femur (thighbone) and tibia (shinbone), and is held in alignment by a complex system of ligaments and tendons. Cartilage and bursae (fluid-filled sacs) help the knee move smoothly and keep bone from rubbing on bone.
There are two sets of ligaments around the knee joint that help keep everything in alignment. The ACL and PCL prevent the femur from sliding backward or forward on the tibia, which reduces the risk of hyperextension. The MCL and LCL prevent the femur from sliding side to side on the tibia. Both sets of ligaments work to help stabilize and support the knee joint. The better the alignment, the happier your knee will be.
So getting back to the issue at hand. What is Runner’s Knee?
Patellofemoral Pain Syndrome (Runner’s Knee) is pretty ubiquitous – it has become a bit of a catch-all term for knee pain in runners. But PFPS is characterized by an achy pain underneath the kneecap – kind of in the center of your knee. According to Dr. Thomas C. Michaud, ‘A classic sign that you have this injury is that your kneecap aches when you sit for long periods, and the pain goes away when you straighten your leg.’
The root cause of PFPS is tough to pinpoint, but sports medicine professionals suggest that the origin of the misalignment that leads to PFPS is actually at the femur, not at the knee.
Think of the patella as being the stable part of the equation. If the femur is unstable and over-rotates into the patella, it can lead to inflammation in the soft tissues around the kneecap – particularly the articular cartilage underneath the patella. Inflammation gives way to pain and discomfort. So Runner’s Knee is rarely caused by the knee itself.
What causes over-rotation of the femur?
Like most running injuries, we have the usual suspects to blame. Here’s the most prominent:
Hip weakness in particular is an aggravating cause of PFPS. Ideally, your pelvis and hips stay in a level, aligned state when you run. But most of us have some sort of imbalance and weakness through the pelvic area, which impacts the body’s ability to self-stabilize. From Competitor Running:
“In runners whose hip stabilizers are weak, the thigh tends to rotate internally as the foot comes in contact with the ground. This is a compensatory movement that is performed unconsciously to enable other muscles to take up the slack of stabilizing the pelvis. But the slack is not entirely picked up by these other muscles, and consequently the pelvis tilts laterally toward the ground on the side of the unsupported leg. The thigh tilts with it, like a falling tower, while the lower leg remains upright, pinching the knee between them.”
Exercises to build functional hip strength are a way to combat PFPS and make sure it never returns. Some great strength moves you can do in your own living room include lunges, single-leg deadlifts, leg lifts, and our personal favorite, resistance band lateral walks.
To do these, place a resistance band about halfway up your calves. Get into a squat position, with your feet below your hips. Step out to the right, resisting the tension placed on your left side. Move your left leg in, returning to your starting squat position. Take 5-10 steps on each side, and make sure you feel the burn! Go slow and focus on good form.
Information for this post was adapted from ‘Injury-Free Running’ by Dr. Thomas C. Michaud & ‘Running Strong’ by Dr. Jordan Metzl