What is it?
Patellofemoral pain (PFP) is generally described as pain felt at the front of the knee or around the knee cap and is one of the most frequently diagnosed knee conditions in primary care (GP), orthopaedics and sports medicine settings.
Recovery from this condition is thought to be poor with estimates that more than 50% with the condition will report symptoms up to 5 years following diagnosis (Lack et al, 2018)
- PFP is more likely to affect people who are physical active especially those who regularly undertake activities that load the knee joint (squatting, climbing, running).
- The annual prevalence in the general population if 22.7%
- Women are 2 times more likely to have PFP than men- 13% of women between 18-35 have PFP
- 7.2% of general adolescent population have PFP
- 6.4- 29.3% of elite athletes have PFP (Smith et al, 2018)
What causes PFP?
There are many complex factors that cause PFP. However, it is thought that altered biomechanics that lead to altered patella tracking or positioning can cause an increase in the joint pressures (Powers et al, 2017) and negatively affect the tissue homeostasis (Dye, 2005).
Biomechanics
Some altered movements are thought to over load the knee joint in day to day functional activities such as squatting, climbing stairs or running. This leads to mal-tracking or incorrect alignment of the patella (knee cap) which eventually increases the stress at this joint causing a loss of tissue balance which ultimately can lead to irritation of pain receptors and inflammation in the bone surface and surrounding soft tissues.
Muscle weakness around the pelvis, hip and knee as well as some specific muscle tightness causes this mal- tracking.
- The pelvis drops on the opposite side putting increased tension on the outside of the leg and pulling the knee cap outwards.
- The hip collapse inwards and the knee caps rolls inwards.
- The Thigh muscles are weak which mean that there is poor support for the knee and knee cap.
- The foot rolls in too much causing the shin and knee to roll inwards.
Tissue homeostasis
Either doing too much or too little can alter the balance within the tissue and cause PFP. Over loading suddenly or repeatedly can cause tissue to become inflamed and pain receptors to fire off. It is often the case that people who do too much too soon are at greater risk of developing knee pain.
On the other hand, those who do no exercise or activity have reduced capacity for exercise or function and are also likely to easily irritate these joints.
What can you do about it?
The honest answer……See a physio!
During a full assessment a Physiotherapist will be able look at your biomechanics focusing on your pelvis and leg/ foot. It is also useful to assess the strength of the muscles in your legs and around your core and to determine if you also have any additional muscle tightness or tension that is also causing mal tracking of the knee and knee cap.
Once you have been assessed you will be given some specific strengthening exercises that focus on weakness at your pelvis, hip or leg, and possibly some stretches to help to reduce any areas of tightens or tension that are adding to the mal tracking. You may even need some insoles for your shoes to improve your foot position and therefore change the mal tracking at your knee.
Education is also a vital component in the treatment of this condition so various factors will be explained to you;
Load management
Managing how much and how quickly you load your joints is very important. A physiotherapist can give you a progressive exercise programme that slowly builds up over time (whether this is a day to day activity or a specific type of exercise).
There is evidence that shows a sharp increase in the number of patients with PFP following rapid increases in how much exercise they do. The number of people developing PFP during basic military training has been reported to be as high as 32% (Van Tiggelen et al, 2009) whilst in a couch to 5k programme it can be up to 17% (Thijs, Y, 2008)
Fear of movement
Whilst it is very common for people suffering form PFP to be fearful of some movements that aggravate their pain such as climbing the stairs, running and jumping, studies show that a reduction in fear of movement leads to reduction in the level of pain experienced (Domenech et al, 2014). A physiotherapist can advise you on ways to gradually return to normal activities so as to build up your tolerance of those activities that have caused pain over a period of time. This may be part of your exercise routine and will focus on the specific activities that cause you problems.
Knee crepitus
Knee crepitus or noisy knee is also very common in people who complain of PFP. However recent research shows that noisy knees are not an indicator that you will have more pain or problems with your knee cap. In fact a study by Robertson et al (2017) investigated 250 people who had no complaints of PFP and found that 99% had knee crepitus!
So don’t panic if you have noisy knees… you can still treat your knee pain and exercise pain free as long as you follow the advice given to you by your Physiotherapist.
What can you try at home?
Here are a few stretches that I regularly advise the people in local run groups to try if they are starting to experience pain in their knees. These should be done daily and without pain.
Stretching exercises to loosen off tight muscles and joints
- Glut stretch- Lie on your back (about a foot from the wall) with your legs straight and feet up the wall. Place the right foot onto the left knee and let the right knee drop out. Slide the left foot down the wall until you feel a stretch into your bottom cheek. Repeat on the other side
- Quad stretch- Lie on your stomach and keep your legs together and knees close. Take the heel to the bottom and use your hand to add to the stretch. Use a cord around the ankle if you cannot comfortably hold onto the foot. Repeat on the other side.
- Calf stretch- Stand with the toes of the front foot up to the wall and the other leg extended behind. Make sue that the back foot is straight. Bend the front knee towards the wall. Repeat on the other side
- Back stretch- Lie on your back with your arms outstretched. Place the right knee over the left and roll the knees to the left side (keeping your shoulders down on the floor as much as possible). Repeat on the other side.
Strengthening exercises- to improve biomechanics and joint positioning, and to support the knee joint
- One Leg Stand- Stand and hold a steady balance for up to 1 minute. You can progress this exercise by adding mini knee bends keeping the knee in line with the foot and controlled.
- Squat- Keep feet hip width and squat down with control, keeping the knees in line with the feet (don’t let the knees come over the toes).
- Wall slide- Stand with your back against the wall and the feet hip width and about a foot away from the wall. Slowly bend the knees and slide down the wall (don’t let the knees come over the toes)
- Bridge- Lie on your back with the feet hip with and knees bent. Tilt the pelvis/ tail bone under and lift the spine slowly off the floor (one spinal level at a time). Lift and hold this position by squeezing your glut muscles.
However, if you continue to feel pain or discomfort, or your symptoms worsen, then get in touch and book a full Physiotherapy assessment!
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0161 759 3917
References
Domenech J., Sanchis- Alfonso V., Espejo B. (2014) Changes in catastrophizing and kinesiophobia are predictive of changes in disability and pain after treatment in patients with anterior knee pain. Knee Surgery Sports Traumatology Arthroscopy, 22(10), pp. 2295- 2300.
Dye, SF (2005) The pathophysiology of patellofemoral pain: a tissue homeostasis perspective. Clinical Orthopaedics and Related Research. 436. pp.100-110.
Powers C.M., Witvrouw E., Davis I.S., Crossley KM (2017) Evidence based framework for a pathomechanical model of patellofemoral pain. British Journal of Sports Medicine. 51(24). pp. 1713-1723
Robertson C.J., Hurley M., Jones F. (2017) Peoples belief about the meaning of crepitus in patellofemoral pain and the impact of these beliefs on their behaviour: a qualitative study. Musculoskeletal Science and Practice. 28. pp. 59-64.
Smith B.E., Selfe J., Thacker D., Hendrick P., Bateman M. (2018) Incidence and prevalence of PFP: a systematic review and meta- analysis. PLoS One. 13(1).
Thijs Y., De Clercq D., Roosen P., Witrouw E. (2008) Gait related intrinsic risk factors for PFP in novice recreational runners. British Journal of Sports Medicine. 42(6). pp. 466-471.
Van Tiggelen D., Cowan S., Coorrevits P. (2009) Delayed vastus medialis obliquus to lateral onset timing contributes to the development of PFP in previously healthy men. The American Journal of Sports Medicine. 37(6). pp. 1099-1105.
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