A blog by runners. For runners.

A new theory to runner’s knee

The knee is the most common area of the body to be injured among runners. Females are 2.2 times more likely to develop patellofemoral joint dysfunction (runner’s knee) than males. The etiology of this problem has been attributed to abnormal patellar tracking. Treatments for this problem have been patellar taping and bracing, strengthening the vastus medialis oblique, and patellar mobilizations.

A new theory that has developed over the last few years is one of the possible causes of patellofemoral pain is due to abnormal hip mechanics.

Anatomy and mechanics

Think of the body as a chain and when one link is off it affects the others, especially above and below the dysfunctional segment. The femur (thigh bone) has the hip joint at the top and the knee joint at the bottom. The patella (knee cap) sits on top of the knee joint attached to the quadriceps and the patellar tendon, which is attached to the tibia. There are many muscles that make up the hip and the thigh, but I want to focus on the muscles that have been found to be weak in people with patellofemoral joint dysfunction. Those muscle include the hip extensors, abductors and external rotators . When those muscles are weak people lose the ability to control their femur from adducting (moving inwards) and internally rotating during dynamic (running) and static (squatting) activities. That will affect the patellofemoral mechanics and can cause knee pain. Watch yourself perform a single leg squat in a mirror, focus on what your knee looks like. It should minimally move inwards as you squat down. If you notice moderate to significant movement inwards then you probably have some hip and trunk weakness.

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Clinical implications

This new information has really changed how I’ve treated “runner’s knee” over the past few years. In the past I would focus on taping the patella and strengthening the patients VMO, which did have some positive results. In the last few years I’ve really emphasized on strengthening the hip extensors, abductors and external rotators in non weight bearing and weight bearing activities and have had a lot more success. I also have focused on form and making sure that the knee is controlled in all weight bearing activities. Flexibility is also important when controlling the hip. I find that a lot of my patients are not only weak in the hip, but are also tight in some of the muscles. It is also important to work on pelvic and trunk stability (lower abdominals, transverse abdominis, obliques, mulifidi, erector spinae) secondary to excessive trunk motions may negatively affect the knee.

Treatment

Just because you run does not excuse you from strengthening and stretching exercises. There may be other mechanical issues besides muscle weakness and tightness and I would recommend having a professional evaluation. Here are a few basic strengthening and stretching exercises to help prevent and treat knee pain. Again, if you do have knee pain you can work with a physical therapist to have a more customized exercise program developed for you.

Side lying hip abduction

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Lie on your side on the floor, slightly roll your top hip forward and extend your hip back. Slightly turn your foot out and slowly raise your leg up focusing on the gluts doing the work. You should minimally feel it in your thighs, if you down extend the hip back a little more. This exercise should be pretty fatiguing. 2-3 sets of 10

Prone bent knee lifts

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Lie on your stomach and bend one knee to 90 degrees and slowly raise the thigh up without using the low back. 2-3 sets of 10

Single leg bridge

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Lie on your back and with one knee bent and one leg straight slowly raise your buttocks and the straight leg up keeping your hips level. 2-3 sets of 10.

Pretzel stretch

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On all fours, cross one leg underneath you and straighten the opposite leg. Next, lean onto the side with the leg that is bent underneath you. Hold 20 seconds, 4 times on each side.

Hip adductor stretch

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Sitting up straight or with your back against the wall bend your knees having your feet touch and slowly push your knees down. Hold 20 seconds, 4 times on each side.

Hip hike

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Stand on a 6 inch step with one leg hanging off the step, keep the knee straight, and raise the unsupported leg keeping the knee straight. 2-3 sets of 10.

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Written by Meredith Franczyk, PT, MPT: Meredith has over ten years of experience and is currently working in outpatient orthopaedics at lakeshore physical therapy. Over this time, she has developed specialities in general orthopaedics, manual therapy, and sports rehabilitation. Meredith has specific interests in sports related injuries. She takes a keen interest in new methods and advancements in physical therapy practice and has taken multiple continuing education courses to improve her skills and enhance her knowledge. If you have any questions or are looking for physical therapy please contact her at Lakeshore Physical Therapy.