The knee is one of the largest and most complex of the body’s joints and is susceptible to many sources of pain. Knees can sustain acute injuries or be worn down chronically due to age and wear-and-tear. When treating knee pain, it is important to understand the source.
Once the more common sources of knee pain—meniscus tears, ACL sprains and osteoarthritis, for example—are ruled out, it is up to an orthopedist to look to the lesser known causes of knee pain.
Patellofemoral pain syndrome (PFPS), also known as runner’s knee or jumper’s knee, is one such source. Because it affects cartilage, PFPS is often confused by the lay population with osteoarthritis, but there are key differences. Let’s look at what PFPS is, what it isn’t and what to do about it.
What PFPS Is—and Isn’t
It is important to note that PFPS is more of a general, umbrella term for a number of possible conditions, rather than a condition itself. The term patellofemoral pain syndrome is often used interchangeably with chondromalacia, which is the wearing away of the cartilage on the underside of the kneecap. Chondromalacia is one possible cause of PFPS, but there are others.
The Kneecap and the Trochlear Groove
What we think of as the knee joint is a meeting of three bones: the shinbone (tibia), the thigh bone (femur) and the kneecap (patella). The first clue as to what PFPS is can be found in the name: It is a problem having to do with the patella and the femur, so it is going to cause pain around the front of the knee joint.
The knee, like the elbow, is a hinge joint, with two bones connected by muscles, tendons, ligaments and cartilage. This is different from ball-and-socket joints such as the hip, where the end of one bone fits into a socket in the other. Unlike the elbow, however, the knee has a third bone—the patella—to protect the other two.
In a healthy knee, the patella moves up and down within a depression at the end of the femur called the trochlear groove. One of the main causes of PFPS is when the kneecap is off kilter from the trochlear groove, which can cause chondromalacia.
This misalignment can be due to an injury that knocked the kneecap out of place, but is frequently due to muscle tightness or weakness. A number of muscles attach on or near the knee, including the calf muscles, hamstrings and quadriceps. If one of these muscles is particularly tight, or weak compared to the rest of the muscles, the forces at play can pull the kneecap out of alignment with the trochlear groove.
Overuse is another common cause of PFPS. The condition is referred to as runner’s knee and jumper’s knee for a reason. High-impact activities such as running, basketball or track and field can cause tendons and ligaments to weaken or tighten, or can cause muscle imbalances (especially if the athlete is not on a proper strength and conditioning regimen), all of which can change the forces on the knee and pull the patella out of alignment.
Luckily for those with pain in the front of the knee, PFPS is frequently treated without surgery. The first thing you should do when you notice anterior (front) knee pain is follow the RICE protocol. RICE stands for:
RICE is a standard protocol for minor (non-emergency) athletic injuries and designed to control pain, swelling and inflammation. It means:
- First, stop whatever activity is causing pain
- Ice the affected area for about 20 minutes at a time, a few times a day
- Use a wrap or a brace to compress the area
- Elevate the painful part above the heart
Next, it is important to see a medical professional to get a proper diagnosis. Because the main symptom is knee pain, PFPS can mimic a large number of painful knee conditions, some of which will benefit from a surgical approach to treatment. Your doctor will need to rule out possible causes of pain such as meniscus tears, ACL sprains and fractures.
The next step, assuming a confirmed diagnosis of PFPS, is a physical therapy or strength and conditioning program. The goal of these programs is to correct any muscle weakness or tightness that is contributing to the misalignment of the knee cap.
Finally, if conservative measures have not alleviated your knee pain, surgical treatment may be the right option for you. Depending upon the exact cause of your PFPS, surgery can take one of a number of forms, including:
- Debridement—cleaning out damaged or diseased tissue
- Tendon release—dividing a tendon to decrease the pressure it is putting on the kneecap
- Tibial tubercle transfer—surgical realignment of the kneecap
If you are experiencing pain in the front of your knee, request an appointment with me or another sports medicine specialist at Summit Medical Group Orthopedics. We will be able to diagnose the cause of your knee pain and develop a treatment plan that’s right for you and your circumstances.