The term “runner’s knee” is an umbrella term used to describe pain around the front of the knee or under the kneecap. This is known amongst health professionals as “patellofemoral pain syndrome”.
The patellofemoral joint is the space between the kneecap and the thigh bone. As you bend and extend your knee, your kneecap glides along the groove in the front of the thigh bone. Fluid and other structures that sit between the kneecap and the thigh bone prevent friction between the two surfaces. Patellofemoral pain syndrome can be caused from a direct trauma to the kneecap itself, but is much more commonly a result of several other factors, such as:
- Overuse or overload of this joint from an increase in training load
- Structural or mechanical abnormalities (e.g. alignment or running technique)
- Overpronation of the foot
- Muscle dysfunction and weakness around the thigh, hip or ankle
Let’s just talk about a few of these factors.
The alignment of the kneecap is quite an important factor to consider when treating patellofemoral pain syndrome. When the patella is aligned differently, it may glide more on one side and cause increased pressure on that part of the joint, contributing to pain and irritation. The orientation and alignment of the patella is different from patient-to-patient and can often be different between knees in the same patient! This can be for a number of reasons. Firstly, weakness of the inside quad muscle (VMO) causes the patella to track OUTWARDS, which can cause overuse of the outer aspect of the patello-femoral joint. Similarly, the iliotibial band (ITB) can also cause the patella to track outwards. The ITB is a connective tissue structure that runs along the outside of the thigh and crosses over the knee joint. Sometimes there can be tightness in the muscles that attach into the ITB, which can cause the ITB to become tightened and pull the kneecap outwards.
Overpronation of the foot
When we walk and run, there is a normal amount of “flattening” that happens through the arch of the foot. Some individuals’ feet flatten more in stance than others – too much flattening can cause the shin bone to rotate inwards, which upsets the normal mechanisms at the patellofemoral joint. In this case, it might be appropriate to look at orthotics and/or strength exercises for the foot and ankle.
Dysfunction of the hip/thigh musculature
Imbalances and weakness around the hip musculature including the glutes, hip flexors, hamstrings and deep hip stabilising muscles can cause inefficient biomechanics and change the loading on the knee joint. Here at Gold Coast Sports and Spinal Physio, we use the KangaTech dynamometry system (see the “Our Services” tab) to screen for imbalances in muscle strength that can contribute to pain and dysfunction.
It is important to know that there are a number of other possible causes of anterior knee pain, including:
- Chondromalacia patellae
- Patellar tendinopathy
- Osteoarthritis of the knee
All of these conditions are quite complex and can also be influenced by dysfunction around the hip, foot or ankle. It is important to get an accurate diagnosis and determine the contributing factors in order to manage your knee pain correctly and achieve the best outcome.