The Forgotten Joint, Part 1

The patellofemoral joint (PFJ), or the knee cap joint, is often referred to as the "forgotten joint" of the kneeespecially as it relates to a patient's "awareness" of the joint in everyday life.

Where is it?
When we talk about “knee joint”, we refer to the femoral-tibial joint. As the name indicates, it is the joint formed by femur and tibia which are the two long bones in our thigh and leg respectively. However, PFJ is situated right in front of the true knee joint. It is formed by the patella (knee cap) and the lower end of the femur. If you run your fingers down the front of your thigh, the first hard and bony structure you hit is the upper edge of the patella.

Misconception
Most people think whenever there is pain in the knee area, it comes from the true knee joint (femoral-tibial joint). Some people even worry it may lead to total knee replacement. The injury of PFJ is very common, especially among the athletes and people with alignment issues, but people are not aware of it. PFJ is usually involved before the true knee joint. That means most of the time people may have pain in the knee area but their true knee joints are fine. Furthermore, total knee replacement replaces the true knee joint and leaves the PFJ untouched. In fact, the surgeon will try hard to preserve the PFJ as much as they can. In another word, if the pain is from the PFJ, you will still have the pain after the total knee replacement.

How do I know the pain is from PFJ?
It is a good question. It is something that all therapists should know in order to provide treatment accordingly. In fact, the approach and the emphasis in the treatment of PFJ and the true knee joint are quite different. It is a big topic and I will talk about it in great detail in next month's blog. Stay tuned.

Read The Forgotten Joint, Part 2

Peggy Hau, PT, MscPT is a licensed physical therapist at Mettler Center. Experiencing knee pain? Ask an Expert. Knee pain is best evaluated by a physical therapist who can detect functional problems and make the best possible recommendation for treatment. Call 217-398-9800 to schedule a free 30-minute consultation with a physical therapist or request an appointment online.