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Patellofemoral Syndrome and Recovery
Q: I occasionally experience some pain in the front of my knee when running on hilly courses. What is this injury, and how can I prevent it from getting worse?
A: It sounds like you may be describing something known as patellofemoral syndrome or PFS. This is an injury that occurs at the articulation between the patella (kneecap) and the underlying femur. Anatomically, the patella is a diamond-shaped bone which lies in a correspondingly shaped groove in the front of the femur. It is designed to function as a pulley, assisting the quadriceps by providing a mechanical advantage for added strength. Generally speaking, PFS occurs either A) when the patella is pressed against the underlying femur or B) when it tracks unevenly to one side (usually laterally) of the groove. In either case, irritation and abrasion of the underlying patella cartilage can result in inflammation and pain.
To address (1) patella pressure on the femur, you'll want to incorporate a few good quadriceps stretches in your daily routine. Several are pictured, below.
Standing Quad Stretch (Basic Level)
Hold onto a rail, wall or sturdy surface with one hand and grasp ankle or shoe lace with the other. Keep knee pressing down toward floor, and press hip forward to stretch hip flexor and quad. If you have trouble simply getting into this position, your quads are extremely tight.
Assisted Quad Stretch (Advanced Level)
To get into position, place one foot several feet in front of high bench, counter or table (a) and use your hand to lift other leg into position on bench. Gradually sink into standing leg until you feel a good stretch in hip flexor and quadriceps. Hold 20-30 seconds without bouncing. Do not try until you have mastered Basic (above) and no longer feel much stretch. Can also be done kneeling (b) with foot on a ball secured against a wall so it won't roll. To get into position, set ball against wall, lean forward onto one bent knee which will enable you to lift the other foot onto the top of the ball. Intense stretch for hip flexor and quad! You might want to place a towel on the floor so knee cap has some support.
Issue (2), lateral tracking of the patella, might be caused by: 1) weakness of the VMO (addressed elsewhere on our web site); 2) tightness of the iliotibial band (ITB), and 3) improper lower extremity biomechanics. Tightness of the ITB can also cause an excessive lateral pulling of the patella by overwhelming the medial pull of the VMO. Try the following stretch to see if you get some relief:
Standing Iliotibial Band Stretch
To stretch right ITB on the outside of the upper thigh, stand close to a wall and turn sideways so your right hip is closer to the wall. Bring left leg across so it takes most of your weight and support your body with hand against the wall. Press hip into wall until you feel a good stretch from outer knee up to hip. Repeat to the other side. Another way to stretch the ITB is to lie on your side on a firm surface such as a bench, and allow the upper leg to hang over the side while using the lower leg for counter-pressure (imagine turning this picture on its side.)
Of all of the conditions that predispose to lateral tracking of the patella, faulty biomechanics in the lower extremities may be the most consistent as well as the most significant. Check out the wear and tear on your shoes (see running shoes for more on this.) If you have an opportunity, have a qualified professional analyze your gait or running stride -- you may be a candidate for orthotics, or special inserts, to help correct pronation of the foot. If you are female, you may have an excessive Q-angle, or quadriceps angle, which tends to lead to overdeveloped outer quads and underdeveloped inner (again, VMO) quads. Strengthening can help (see below.)
To address the problem of pain, first we'd suggest that you stop doing any activities that seriously aggravate your condition, at least for a week. Try substituting non-weight bearing training such as swimming or partial weightbearing, non-impact (and less range of motion) activities such as elliptical training, cross-country skiing, walking, or biking as you can tolerate them. Ice, knee wraps, taping, and anti-inflammatories might also be helpful.
A useful tip when attempting to assess the severity of the injury and the progress and success of treatment is to monitor two particular symptoms. The first is frequently referred to as "theater symptom". Theater symptom is that complaint of pain after sitting for varying periods of time -- the period of time required to produce this symptom directly relating to the degree of injury. This occurs because the patellofemoral joint is under the highest degree of compression when the knee is bent at a right angle, and the inflamed patellofemoral joint will indeed become symptomatic when the knee is bent for excessive periods of time.
The other symptom frequently reported is pain ascending or descending stairs and hills. This occurs because, again, the patellofemoral joint is under higher levels of compression due to increased quadriceps activity and degree of knee flexion when going up and down stairs and hills. Both of these symptoms can be very useful indicators as to the success of treatment and helpful determinants as to the athlete's ability to return to activity. For more tips on climbing and descending hills safely, check out our article on trekking poles.
As symptoms improve, you'll want to strengthen the VMO by performing: 1) an exercise most frequently referred to as "quad sets", simply tightening the VMO when seated or supine with the knee extended for a period of 7-10 seconds and repeated several times per session and repeated several times per day; 2) an exercise called "wall sits", (left) where the injured athlete actually stands with their back to a wall with 20-30x of knee flexion while squeezing an object such as a volleyball between the knees. The squeezing of the object between the knees is important since this recruits the groin muscles (adductors) which are an attachment point of the VMO. As a result, by recruiting the adductors, the patient is indeed selectively strengthening the VMO relative to the other quadriceps -- the key objective of this exercise; and 3) side or reverse step-ups, when symptoms improve sufficiently to allow completion of it pain-free.
As symptoms subside and normal function through appropriate stretching and strengthening exercises is achieved, conditioning exercise can become more advanced. Gradually re-introduce biking, step-aerobics and/or stairmaster training, with intensity and frequency varied depending on symptoms and comfort. Gradually start back with a walk-run program on flat surfaces only, at a very modest pace. If you can avoid concrete, do so -- training on sand, dirt trails, or treadmills might be the best place to start. Hill training should be the last aspect to include again, since this creates the greatest stress to the knee joint.
For more on this topic, see the answer provided by William R. Olson, DPM, Vice President AAPSM at http://www.aapsm.org/ct0298.html. Article modifications, stretches, strengthening exercises and direct applications provided by Courtenay Schurman.