Patella Pain in Runners
Knee problems seem to be increasing in incidence in the population in general. This is possibly the result of increased exposure to injury through increased activity and risk taking behaviors, and perhaps more importantly, improvements in diagnostic skills of treating practitioners, especially orthopedic surgeons. Although one of the stated goals of managed care is the limitation of costs of care by limiting access to specialists, this runs counter to the trend of enhanced diagnosis. It stands to reason that a specialist who treats knees for a living, will have a superior ability to recognize and differentiate various knee problems relative to the general orthopedist who sees a variety of problems involving all parts of the musculoskeletal system, or especially relative to a primary care provider who has more limited orthopedic training and may see only a few orthopedic problems in an average day.
This concept is important with regard to patella pain. The cookie-sized, kneecap can produce pain for a multitude of reasons. These include wear and tear, and overuse of the surface cartilage (chondromalacia), and malalignment and instability of the patella within the saddle-shaped groove on the end of the thigh bone (femoral trochlea). Quadriceps muscle weakness or lack of development, and tendinitis of the attaching quadriceps and patella tendons above and below the patella,can also cause pain in front of the knee. Congenital problems, such as a two-part (bipartite) patella, and internal abnormalities, such as synovial folds (plicae) can also produce pain in front of the knee. It is very easy to call all patella pain: "patellofemoral syndrome", and make little or no effort to get at the very root of the problem. Although the initial treatment for much of these problems may be similar, ultimate treatment for those that do not respond to initial interventions, and prognosis, can be vastly different. Furthermore, efficient treatment is of course, dependent upon efficient diagnosis.
Apart from the contributors noted above, probably the most common cause of patella pain in runners is overuse, generically: "too much, too soon, too fast." Increases in speed or hill running, running the same direction on a circular track, or on the same side of a cambered road, all may contribute. Running downhill places great stress on the patella and its cartilage, as well as the tendons attached above and below the bone. This is because of the quadriceps develops tension as the knee flexes with each step, in order to decelerate the body. This mechanism is analogous to letting a fish run out on a taut line, while keeping tension on the line. The muscle is contracting while stretching out, or lengthening; called "eccentric" contraction. This is usually associated with much muscle soreness afterward. The more typical pattern of muscle work is shortening with tension: "concentric contraction".
Reasonable things to try as initial interventions include avoidance of hills, quad stretches, anti-inflammatory medications and ice, and use of a knee sleeve. Regarding quad strengthening exercises, although they are usually of great benefit to those dealing with patella pain, how they are done can make or break the outcome. Doing knee extension type strengthening, i.e.- pushing off with the front of the shin, applies substantial loads to the retropatellar surface, which can actually make the pain and underlying problem worse. Safer means of strengthening all have in common the use of the sole of the foot for application of force to the leg, so-called "closed-chain" exercises, such as cycling, stair climbing, rowing machines, leg press, etc. These types of exercises result in less force behind the patella, and hence, typically less pain.
Most patella problems respond, in time to conservative measures. Occasionally however, surgery may be required to restore performance to the knee extensor mechanism. In this situation, it is imperative to know exactly and precisely the cause of the problem, as procedures for malalignment, instability, chondromalacia, plica, etc., are very different. It is rare to operate for chronic tendinitis, but sometimes no options exist other than abandoning running.
Happy and healthy running! Dan Wnorowski, M.D.