Patellofemoral Knee Pain

Sore knees are a very common affliction. Although dramatic high speed injuries seem very common when watching sport on TV, in reality, the most common knee issues simply creep up on us gradually.

In modern times, our adult legs no longer run from wild animals, climb trees or walk miles for water. As a result, some of the crucial muscles that control our leg movement patterns become lazy. This means that the loads placed on our knee caps are often not ideal.

Even the slightest biomechanical fault with they way our kneecaps move can develop into a painful problem with enough repetition. Think of how many times your knees bend and straighten everyday!

Most people with kneecap issues have a combination of biomechanical (alignment) and impact volume issues. Once this type of knee pain sets in, it can be very stubborn to settle. The contributing factors are often very easy to correct, however, so avoidance is the path of least resistance!

 

Anatomy Made Easy

The main part of our knee joint is made up of our femur (thigh bone) and the tibia (shin bone). Sitting on the front of the main knee joint is the patella, or knee cap. The patella is a small, round, floating disc, which is fully incorporated into the patellar tendon. This large tendon is the culmination of the quadricep muscle.

The patella exists to distribute the force of the powerful quad muscle over our bending knee. If the patella didn’t exist, the patellar tendon would wear away on the underlying bones very quickly. With the patella in place, the knee can bend and straighten, again and again, with the tendon happily safe from excessive wear.

The underside of the patella has a longitudinal ridge, and the femur underneath it has a longitudinal groove. The patella slides up and down on the femur as our knee bends and straightens, and the ridge slides beautifully in the groove – like a train on a track (or perhaps more accurately, a monorail).

 

What Goes Wrong

For the train (patella) to stay beautifully on the track (groove in the femur), the quad muscle must pull the patella evenly and in the right direction. If the pull of the quad muscle is uneven, or the upward pull is in a slightly deviated direction, there is trouble at the station.

The quad muscle in our thigh is made up of 4 parts: one towards the inside of our thigh, two parts on top of each other in the centre, and one towards the outside of our thigh. Unfortunately, the inside part (which we refer to as ‘VMO’ due to a ridiculously long latin name) has a tendency to be lazy. Things like prior knee injury, poor leg alignment and poor fitness, can all result in a lazy VMO. This means that, when the quad pulls on the patella, the pull from the outer part of the quad is stronger than from the lazy inner ‘VMO’ part of the quad. This is not good news for the train, which grinds on its tracks as it is pulled slightly towards one side.

This causes pain, generated from the undersurface of the patella, due to it rubbing where it is not supposed to.

Alignment is another factor that contributes to poor patella function. Try this: Stand up, and do a small squat, keeping your back straight and your heels on the ground – it’s really just a small knee bend. Freeze in the bent knee position. Now have a look down: is the space between your knees smaller, the same or greater than the space between your feet?

Your knees SHOULD be the same distance apart as your feet. If you draw a line straight down to the ground from the middle of your patella, it should fall in line with your middle toe. In this position, the quad is pulling vertically up towards your hip in a straight line, creating ideal tracking for your patella.

In many people, however, the knees fall closer than the feet in this ‘mini squat’ position. This means that the quad pulls on a slightly outwards angle towards the hip, creating grinding of the train on the track.

In reality, VMO weakness and poor knee alignment usually co-exist, so a number of factors plot against the patellar tracking, creating pain.

Some people never realize that they have poor leg alignment and poor VMO strength until they push their knees to do more than they are accustomed to. The start or increase of a running program, a new Boot Camp or a change to a more physical job can all be triggers for the onset of patella pain. The more rapid these changes are made, the more likely it is that patellar pain will develop.

 

Take Action Before You Break

The following exercises will help you to prevent the development of patellofemoral pain in your knees.

The first exercise listed below is to get your VMO working better – it is harder than it looks! Follow the instructions carefully, as rotating the leg very slightly outwards when you do the leg raise is very important.

Next, improve your alignment – notice when your knees are dropping in towards each other when they shouldn’t. Perform the other suggested exercise in front of a mirror, and get used to what it feels like to have your knees bending in the right position – over the toes. Sometimes it helps to think of lifting the arches of your feet, or of holding a beach ball between your knees.

A word of warning – don’t OVER correct. The solution is NOT to simply stand on the very outside edges of your feet and jam your knees out! Your still need all of your toes on the floor! Don’t create NEW problems while trying to fix existing ones!

 

Injury Proof Toolkit:

1) Change Your Environment

  • Ensure your running shoes are not more than 6 months old, and have been fitted by a reputable sports shoe store

 

2) Change Your Habits

  • If you are starting from scratch, start gradually – this is different for everyone, but as a rule of thumb make your first few sessions about 70-80% of your max capacity.
  • Increase the impact activity by no more than 10% volume each session
  • Perform the new or increasing impact activity on alternate, not consecutive days, at least for the first 4 to 6 weeks

 

3) Add These Exercises

If you do these exercises as suggested, every day, over 4 to 6 weeks, you should make a considerable improvement in your knee health. After this timeframe, they can be dropped to 1 to 3 times a week for maintenance.

 

STRAIGHT LEG RAISE

1. Lie on your back – you may prop on your elbows

2. Rotate the leg very slightly outwards

3. Squeeze the quad and lift the leg up straight, about half a meter off the bed/ floor

4. Lower the leg nearly to the bed/floor

5. Perform 10 repetitions each leg

LUNGE

1. Stand tall, feet hip width apart

2. Lunge forward on 1 leg, keeping the knee lined up over the toes

3. Straighten knee back

4. Perform 10 repetitions each leg