04 Feb Runner’s Knee (Patellofemoral Pain Syndrome)
Patellofemoral Pain Syndrome (PFPS) is the most common type of kneecap pain. A hallmark is discomfort on stair usage, running, or arising from a squat. Pain also occurs during yard work and circuit exercise. The cause(s) of PFPS is variable; sometimes debatable. The crux of the issue is some combination of overuse, harmful individual practices, and biomechanical factors.
Overuse refers to repetitive or frequent activity that stresses the knees. Among many examples are running, squats, lunges, leg presses, lawn mowing, stair usage, dancing, tennis, and walks on hills. Pain often resolves with simple activity modification.
Examples of harmful individual practices are improper technique, improper footwear; and sudden changes in activity frequency, intensity, or duration. Your doctor might recommend certain shoewear and/or the use of shoe inserts. A discussion about your training routine will be vital.
Biomechanical factors include muscle weakness, lack of flexibility, decreased range of motion, uneven leg lengths, ankles that roll in too much, and flat feet. Another factor is abnormal kneecap movement. In a healthy knee, both the patella and its groove (the trochlea) are lined in healthy, smooth, protective cartilage. Whenever one bends or straightens the knee, the patella vertically slides in its groove on the femur (or “thigh bone”). In many patients with PFPS, the patella does not slide in a normal pattern. This “mal-tracking” can result from a combination of different factors. For example, weakness of the buttock/hip muscles, abdominals, or the quadriceps (a group of thigh muscles which attach to the knee cap) are common contributors. Muscle tightness and flat or pronated feet have also been associated with this condition. Moreover, lower body neuro-muscular coordination is often abnormal. Mal-tracking can gradually wear down the healthy cartilage of the knee (chondromalacia) eventually causing pain. Swelling can also occur.
PFPS typically resolves with rest from painful activity, physician-guided home rehabilitation, formal physical therapy, footwear modifications, knee braces, medication, physician-guided weight loss, and evaluation of your training program. In cases which do not respond to these measures, your doctor might discuss other treatment options with you such as injection therapy. Typically this condition does not require surgery. One exception might be severe chondromalacia.
Chondromalacia Patellae is a condition that is associated with PFPS. This term literally means softening of the protective chondral (“articular” or “joint”) surface behind the knee cap. The terms chondromalacia and PFPS are often used interchangeably. This is misleading as chondromalacia does not account for all cases of patellofemoral pain. Chondromalacia is typically attributed to patella mal-tracking. It is unclear as to whether chondromalacia leads to early arthritis. Not surprisingly, the initial treatment is the same as that for PFPS as it is focused on relief of pain and swelling chiefly via optimization of knee biomechanics.
Patients with severe chondromalacia might derive only limited symptom relief from typical treatments. In these cases, the physician might offer an injection (viscosupplementation) or surgical intervention. Viscosupplementation entails injection of liquid material containing hyaluronic acid (HA) into a joint. HA is a component of one’s natural joint fluid which helps to absorb shock and to control friction. The benefits of viscosupplementation have been documented in patients with knee osteoarthritis. Viscosupplementation is occasionally used for symptoms of significant chondromalacia, though the benefits of doing so are not as well documented. Many folks note significant symptom relief of variable duration. Another treatment is Platelet Rich Plasma (PRP). PRP is obtained from blood drawn from your body. It contains elements that can stimulate soft tissue healing. Candidates for this treatment may need a few rounds of PRP injection to achieve results. Some folks with persistent symptoms are candidates for surgery. The type of surgery performed will depend on one’s demographics, health status, anatomic alignment, and the presence of any arthritis in the knee.
If you have knee pain or swelling then check with your doctor before resuming exercise. X-rays might be taken to look at the bones. Less often, an MRI is ordered to check the cartilage and soft tissues. Your doctor can help you identify the cause of your problem and develop a plan to safely return to your desired activities.