Patellofemoral Pain Syndrome - 'Runner's Knee'

One of the most common conditions treated by Physiotherapists, Patellofemoral Pain Syndrome  β€“ also known as Runners knee, Chondromalacia Patellae or quite simply anterior knee pain. 

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What is the Patellofemoral Joint?   

Looking at the knee, the thigh bone (femur) and leg bone (tibia) meet to form the tibiofemoral joint. The kneecap (patella) sits in front of these two bones, specifically in a groove (trochlear) on the thigh bone. The kneecap glides in this groove every time you bend and straighten your knee. This connection is called the patellofemoral joint (where the kneecap and thigh bone meet).

 Courtesy: http://orthoinfo.aaos.org/

Courtesy: http://orthoinfo.aaos.org/

What is Patellofemoral Pain Syndrome (PFPS)?

An issue at the Patellofemoral joint where the patella (kneecap) does not track properly in the trochlear (groove). This causes irritation of the articular cartilage under the kneecap and structures in the area. PFPS can be caused by extrinsic factors (such as training load) or intrinsic factors (body mechanics, posture, muscle strength and flexibility). You are at more risk of developing PFPS if you have:

  • Femoral internal rotation (thigh bone rotating inwards), tibial external rotation (lower leg bone rotating outwards, out toeing) or knee valgus (AKA knock-kneed). 
  • Flat Feet
  • Abnormal patella positioning.
  • Knee hyperextension.
  • Tight muscles on the outside of your thighs or hips – specifically the ITB and TFL muscles, as well as the Rectus Femoris (Quad), hamstrings and calfs.  
  • Weakness of the inner quad muscles (VMO muscle); and gluteal muscles.

*Note the last two points cause imbalance at the kneecap. With the tight outer muscles pulling the kneecap outwards, and the weak inner quad muscles not working to hold the knee cap in position = kneecap out of line = poor tracking within the groove. 

 If the Vastus Lateralis (VL) and Iliotibial band (ITB) is tight, and the Vastus Medialis Obliquus (VMO) is weak, the kneecap will be pulled slightly outwards. Therefore, it won't track in it's groove optimally.  Courtesy:  www.aafp.org

If the Vastus Lateralis (VL) and Iliotibial band (ITB) is tight, and the Vastus Medialis Obliquus (VMO) is weak, the kneecap will be pulled slightly outwards. Therefore, it won't track in it's groove optimally.

Courtesy: www.aafp.org

How does it present?

  • Ache pain at the front of the knee – around or behind the kneecap, this ache is often hard to localise. This pain can also be sharp in nature with certain activities.
  • Gradual onset of pain, usually due to an increased or unaccustomed load – this could be increasing your running distance/speed, stair climbing, hill walking, squatting. All of which place more load on the patella-femoral joint.

*Note: PFPS can also caused by acute trauma to the kneecap, or present months after an acute injury at the knee. 

  • Pain is aggravated by activities involving repetitive or prolonged knee bending (for example running, squatting, cycling or sitting for extended periods of time). This is because when the knee is bent the contact between your kneecap and thigh bone increases.
  • Mild swelling of the knee can be evident after activity, and some clients may describe a grinding/grating sensation or noise – this is known as crepitus.

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What can I do about it?

  • Take a rest from high impact/load activities (such as running, jumping, squatting). Instead switch it for something lower load – such as swimming or Pilates.
  • Avoid sitting for long periods of time – if you are an office worker or drive for extended periods, then have breaks every 30 mins to get up and move.
  • Speak to your pharmacist about a short-course of anti-inflammatories.
  • Ice your knee after activity – for 15 minutes. This can ease the pain and reduce any inflammation.
  • If you have been prescribed custom orthotics – wear them! If they are very uncomfortable, or old – then it may be time for a podiatry review.
  • Go see a Physio!

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What can a Physio do?

  • Strengthen VMO (inner quads) and gluteal muscles – especially gluteus medius, to restore balance at the kneecap. This can be given to you via home exercises, or done in the Pilates Studio.
  • Release tight muscles that may be contributing – via massage, dry needling, stretching or self-releases with a trigger ball or foam roller.
  • Taping for temporary relief.
  • Offer advice on what to do and what to avoid – specifically with your training load or activities, and pain reduction advice (ice, medications).
  • Make suggestions as to whether change of footwear, or orthotics may be an appropriate measure – depending on the client’s individual foot type. If necessary a referral to a Podiatrist can be given.

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What’s the prognosis?

  • It’s good news! With effective Physiotherapy treatment and a rehabilitation program, around 80% of clients will have no pain within 6 weeks.
  • Surgery is not recommended, or relevant in most cases. This would only become a consideration if no relief was found after 3 months of rehabilitation, and then the Physiotherapist would refer to a Sports Physician for further review.
  • If you leave it untreated, PFPS can make you more susceptible to developing patellofemoral osteoarthritis. So speak to your Physio sooner rather than later. 

Written by Courtney Kranz, Physiotherapist and Pilates Practitioner at Embody Physiotherapy + Pilates.

References:

1. Brukner P & Khan K, CLINICAL SPORTS MEDICINE, 4th Edn, McGraw-Hill Australia. North Ryde, NSW.

2. Peters, J. S. J., & Tyson, N. L. (2013). PROXIMAL EXERCISES ARE EFFECTIVE IN TREATING PATELLOFEMORAL PAIN SYNDROME: A SYSTEMATIC REVIEW. International Journal of Sports Physical Therapy8(5), 689–700

3. Karlsson J; Thomee, R; Sward, L. (1996). ELEVEN YEAR FOLLOW-UP OF PATELLO-FEMORAL PAIN SYNDROME. Clin J Sport Med, 6(1), 22-26.

4. Kannus, P., & Niittymaki, S. (1994). WHICH FACTORS PREDICT OUTCOME IN THE NON-OPERATIVE TREATMENT OF PATELLOFEMORAL PAIN SYNDROME? A PROSPECTIVE FOLLOW-UP STUDY. Med Sci Sports Exerc, 26(3), 289-296.

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