Running in the 21st Century (Part 3) : Anterior Knee Pain

The knee is a hugely important joint during locomotion. It absorbs the force sustained at foot contact with the ground, and controls weight transfer as our body moves forward over the leg to push-off through the toes. It is no surprise then that so many runners will experience knee pain during their training for an event such as this year’s City to Surf.
As I mentioned in our last blog, roughly 30% of all distance runners completing more than 40km/week will experience an injury in the next 12 months. A third of these involve the knee. Often this knee pain arises due to a loss of our control and stability on one leg, causing us to put too much stress on the anterior structures of the knee over time. Two structures associated with the knee tend to be associated with knee pain – – anteriorly (the patellofemoral joint) and laterally (the iliotibial band).

Anterior knee pain (Patellofemoral pain syndrome)

Knee Image

Anterior knee pain has a lot of names. What is now generally known as patellofemoral pain syndrome (PFPS) is also often called chondromalacia patella, so-called “patellar malalignment” and “runner’s knee”. Essentially it refers to a non-specific, generalised ache to the front of the knee, typically brought on during or directly following exercise (in this case running). It often presents in conjunction with other biomechanical issues, and can affect up to 30% of runners in some shape or form. It can be extremely debilitating, and if not managed correctly can completely derail your training and race preparations.
The easiest way to understand PFPS is to think about the anatomy. The patellofemoral joint works as a fulcrum, like a seesaw, across the front of the knee; the kneecap slides forward in a groove on the front of the femur. Because the quadriceps normally acts after heel contact as a brake to prevent the knee bending too quickly, fatigue or weakness of these big muscles will put too much stress onto the patella and its associated structures, subsequently leading to pain. There are also a number of other biomechanical factors that will affect the position of the kneecap; these will change the pattern of stress on the anterior knee and also increase discomfort. Many of these factors are listed below.

Risk factors for patellofemoral pain:

– Weak VMO (medial quadriceps muscle) Weak hip abductors Patella Alta Increased hip adduction A Hypermobile patella (moves too much) Other biomechanical malalignment
– Generalised ligamentous laxity (looseness) Poorly fitted/inappropriate shoes
– Female Previous knee surgery or injury
– Excessive foot pronation Overtraining

Sort it out early!!

Luckily, the good news is that with appropriate physiotherapy and pain management, biomechanics can be significantly improved to reduce knee pain in both the short and long term. After a detailed interview and physical exam, physiotherapy usually involves soft tissue and joint mobilisation techniques to restore pain-free movement, coupled with education and a comprehensive exercise programme to address any biomechanical deficiencies identified during the assessment. Electrical stimulation may also be used with exercises in the clinic help get your quadriceps muscles to fire. As part of your rehab you may require a short period of rest and the use of anti-inflammatory medication to also help reduce pain. But the sooner you act on your knee pain, the less time off training you will likely need.
The other end of the spectrum doesn’t bear thinking about. Longstanding anterior knee pain will over time lead to degenerative changes in the joint due to poor loading, and the subsequent advent of knee osteoarthritis. But if you get it early, many of these degenerative changes will not happen, or will at least be significantly slowed.
See us soon at PhysiCo City Physiotherapy, Hyde Park Medical Centre, Sydney  to get you back out on those roads and trails sooner that you might have thought!