Jan
Patellofemoral Syndrome
Pain in the front of the knee that is worse with hill running or long term sitting is likely due to a poorly understood but very common condition. This condition is so poorly understood that experts can’t even agree what to call it. It goes by: Anterior knee pain; Chondromalacia patella; Patellofemoral arthralgia (PFA); Patellofemoral chondromalacia; Patellar misalignment syndrome; Patellofemoral syndrome (PFS); Runner’s knee; and many other names. We’ll call it PFS.
A google search of PFS yielded 150 thousand hits. In fact PFS is so common that it affects 10% of male runners and a woping 50% of female runners at some point in their lives.
PFS pain is felt behind the kneecap or patella. It may feel like a sharp pain or like a dull ache. You may feel popping in your knee when you bend your leg.
The problem is worse with hill work and may be worse with a sudden increase in mileage. Loading a bent knee as in going up or down stairs also hurts. Riding in your big chain ring may make PFS worse. It is particularly painful with prolonged sitting with bent knees, or when getting up after sitting for a long time.
What causes PFS?
Like we said, PFS is poorly understood. But here is the best we have to date:
Normally the kneecap (patella) lives in front of the thigh bone (femur) in a groove that is lined with cartilage, a sensitive material (Figure I).
As the knee bends and straightens, the patella glides up and down in the groove. The muscles that hold the patella in the groove come from the thigh. If those muscles are too weak to hold the patella right in the middle of the groove, the kneecap knocks on the sidewalls of groove. The patella tracks toward the outer (lateral) edge of the femur. This off-kilter path damages the cartilage between the patella and the femur and causes pain.
PFS is more likely to happen in people who have feet that pronate; a wide pelvis; or weak quadriceps (thigh muscles). The problem also occurs in bicyclists with excessive side-to-side knee motion on the downstroke.
What can be done about PFS?
The good news is that surgery is not the cure to this condition. But the bad news is that fixing PFS usually requires lots of rehab and hard work.
Start with the standard cure-alls: cross training and ice. That will be enough for some cases of PFS. The remainder will need a specific quadriceps strengthening, hamstring stretching and general conditioning program to fix any muscle imbalances. The program will be designed to “straighten” the improper tracking pattern of the patella on the femur. A Sports Medicine provider can devise such a program for you.
Motion control shoes, a shoe insert, or even orthotics may be necessary to help the pronator with PFS. A knee brace with a cut out hole for the patella may assist the misalignment problem. Similarly, taping the kneecap into a specific position during workouts may help reduce PFS pain.
In more sever cases, injecting the knee with a viscous lubricant helps reduce the pain from cartilage damage behind the patella. A good Sports Medicine physician can determine whether you are a candidate for this type of treatment.
