Patello Femoral Dysfunction
Patellofemoral syndrome Anatomy
Patello femoral problems originate under the knee cap. The knee cap (patella) is a small bone in the front of the knee. It glides up and down a groove in the thigh bone (femur) as the knee bends and straightens. The patella has a smooth coating (articular cartilage) on its underside which allows it to slide easily in this groove.
The groove in the femur is called the femoral groove and it is also coated with articular cartilage. The patellar tendon is a thick, rope like structure that connects the bottom of the patella to the top of the large shinbone (tibia). The powerful muscles on the front of the thigh, the quadriceps muscles, straighten the knee by pulling at the patellar tendon via the patella. One of the quadriceps muscles, the vastus medialis, pulls the patella inward (medially).
Another quadriceps muscle, the vastus lateralis, pulls the patella outward (laterally). There are also smaller rope like structures (ligaments) on the inner (medial) and outer (lateral) sides of the patella. These small ligaments work with the quadriceps muscles to help keep the patella in the centre of the femoral groove. Frictional stress between the knee cap and the femoral groove causes inflammation leading to patellofemoral syndrome.
Poor biomechanics, is the major cause of patellofemoral injury. The most common mechanical problem is over pronation. Over pronation increasing frictional stress under the patella causing inflammation. This occurs because the patella is not running smoothly within the femoral groove at the angle at the knee (called the Q angle) is increased.
This is far more common in women runners as due to the hip anatomy of a female athlete, they have an increased Q angle to begin with. Read more->
Tight muscles groups are another leading cause of patellofemoral injury. If posterior groups such as calf muscles and hamstrings are tight extra stress is placed on the knee as it does not fully extend through the gait cycle. Constant knee flexion leads to injury.
Weak muscle groups do not provide the stability required around the knee joint and can lead to patellofemoral syndrome.
Worn footwear is also a major contributory factor. If the shoe is not doing its job of providing both stability and shock absorbency then ground reaction force will be transferred to the knee increasing the chances of patellofemoral problems occurring. See our running shoe guide.
Other causes of patellofemoral injury include;
Increasing activity levels.
Increased hill work.
Pain under and around your kneecap.
The pain can get worse when you’re active or when you sit for a long time.
Pain can occur in only one or both knees.
Pain is often noted when climbing or descending stairs.
Mild swelling may be noted around the knee.
The knee cap area may feel warm to the touch.
The athlete may feel the knee cap ‘grating’ during extension or flexion of the knee.
Remember that virtually all patellofemoral problems occur at the contact phase of gait (when the foot hits the ground) due to increased biomechanical stress at this point.
Golden rule- Don’t ignore the problem, it won’t go away
The way we function biomechanically is predominantly controlled by genetics, its hereditary (runs in the family). The way you function is set and cannot be cured. What you can do however is control lower limb biomechanics by altering foot position during the contact phase of gait. This can be achieved by wearing a good shoe (see our shoe guide) with orthotics (foot beds), knee strengthening and knee support.
1. Check your footwear
Are your running shoes worn and in need of replacing? If so change them. The chances of patellofemoral injury is greatly increased both with the higher impact forces and loss of stability caused by a worn shoe. For more advice on running trainers our running shoe advice page is worth reading. Read more->
Below are a selection of trainers that are ideal for athletes.
Trainers for a neutral or under pronating foot type
Trainers for over pronators
2. rectify Poor biomechanics with orthotics
The way your foot strikes the ground and the forces that are placed on it can have a direct effect on biomechanics causing patellofemoral injury and can also delaying healing times. Check our biomechanics page for detailed information. Read more->
3. Knee strengthening
The single best exercise to improve the strength of the muscles around the knee is eccentric loading. This is usually done none weight bearing, however the use of a wobbleboard is an excellent way to strengthen muscles around the knee, foot and ankle in a controlled gentle manner. Whilst our clinicians have found it a brilliant way to strengthen muscles around the knee, traditionally a wobbleboard was used to help balance (proprioception). Proprioception is the nerve connection from the brain to the foot. This is often damaged/ disrupted after injury and can increase the chances of injury from recurring. It can also significantly delay recovery.
Use of a wobbleboard therefore has a dual benefit in the treatment of patellofemoral injury.
4. Knee support
Consider purchasing a knee brace . This device provides extra stability to the knee when playing sports. The material also causes localised vasodilation (opening of the blood vessels) increasing circulation to the area. This is vital as all ligaments have a notoriously poor blood supply. Increasing circulation to the ligaments can reduce the chance of injury. Extra stability will also reduce the chances of irritation and damage to the knee.
patellofemoral injury prevention checklist summary
- Rectify Biomechanics if necessary
- Check Running shoes
- Knee strengthening
- Knee support
Returning to Activity
The goal of rehabilitation is to return you to your sport or activity as soon as is safely possible. If you return too soon you may worsen your patellofemoral injury, which could lead to permanent damage. Everyone recovers from patellofemoral syndrome at a different rate. Returning to your activity is determined by how soon your meniscus recovers, not by how many days or weeks it has been since your meniscus injury occurred
You may safely return to your sport or activity when, starting from the top of the list and progressing to the end, each of the following is true:
You have full range of motion in the injured leg compared to the uninjured leg.
You have full strength of the injured leg compared to the uninjured leg.
You can jog straight ahead without patellofemoral pain.
You can sprint straight ahead without patellofemoral pain.
You can do 45-degree cuts, first at half-speed, then at full-speed.
You can do 20-yard figures-of-eight, first at half-speed, then at full-speed.
You can do 90-degree cuts, first at half-speed, then at full-speed.
You can do 10-yard figures-of-eight, first at half-speed, then at full-speed.
You can jump on both legs without pain and you can jump on the injured leg without pain.