Runner’s knee or patellofemoral pain syndrome (PFPS) is an overuse disorder that presents as pain around and under the kneecap. After doing research for many hours, my conclusion is that there is no agreement on the definition and classification of this condition, as you can read in Patellofemoral pain syndrome by Collado H et al. , and that’s why the definition I give you is quite short ( it is the only thing all we health professionals are clear about regarding this injury). This is a fairly recent study Patellofemoral pain syndrome by Petersen W et al., which gives us some more information.
Although health professionals frequently make the diagnosis of PFPS, no one really knows what the etiology or the factors responsible for causing this injury are exactly. Once again, there are different theories, but no one knows which one is the best one. The most widely accepted theory suggests that this injury is a result of excessive joint stress due to abnormal movement of the kneecap or, in other words and as Management of patellofemoral pain syndrome by Dixit S et al. shows, runner’s knee is caused by imbalances in the forces controlling kneecap tracking during knee flexion and extension.
Let’s analyse the name of this injury, “PFPS”:
Patella: in other words, kneecap. It is a circular-triangular bone which covers and protects the anterior surface of the knee joint.
Femoral: refers to the femur or thigh bone.
Pain: explanation is not needed.
Syndrome: it is the association of signs and symptoms of a condition, the cause of which can be known or not. The reality is that syndrome means nothing to me, as it doesn´t clarify anything.
Runner’s knee or Patellofemoral pain syndrome, also called anterior knee pain syndrome or patellofemoral syndrome, is the most common knee pain. It particularly affects runners, cyclists, hikers, teenagers and/ or anyone who sits for long hours a day (that´s why it is sometimes called moviegoer´s knee or theatre sign).
Runners are by far the most commonly affected, PFPS being the most common knee injury in runners (that´s why it is called runner´s knee). Chondromalacia patellae ( irritation of the cartilage underside of the kneecap) and patellofemoral tracking syndrome are other names used for this condition, but many professionals think that it is wrong, as these might be different conditions.
This can be a really annoying injury, as sometimes treatment might not be effective. Sometimes your knee hurts, but we can’t find anything wrong with your knee, it seems to be healthy. Although, it is not like that in the majority of cases.
The signs and symptoms of runner’s knee are:
- Pain usually under or around the kneecap.
- Pain usually increases slowly, it doesn´t appear suddenly. It often starts for the first time while going uphill.
- Pain is generally worse when bending your knee: climbing stairs or hills (but may be painful descending as well), squatting, lunging, running and doing deep knee flexion.
- Pain becomes worse when you get up after sitting with knees bent, along with stiffness.
- Tends to affect active people especially those who also sit at a desk for long periods. For example, a long-distance runner working in an office.
- It may occur in one or both knees.
- It is usually intermittent, the pain tends to come and go but it will become continuous when your injury worsens (for instance, if you are a runner and you don’t rest).
- You might present with weakness and tightness in the surrounding muscles.
- Some health professionals talk about crepitus (grinding sound) associated with knee movement, but it is not known whether this would be another injury in that case.
Notice that ITB syndrome is sometimes called runner’s knee. You can call it ITB syndrome if you like, but be clear that this and PFPS are different injuries. Symptoms and signs of ITB syndrome are different, for instance you will feel pain on the outside of your knee, and a bit under your knee joint.
I am pretty sure that you could add something to this post. Leave a comment.
If you have any questions, do not hesitate to contact me on The Physical Therapy, Physiotherapy Clinic in Southampton, and I will be happy to help you.