Knee Pain and Knee Arthritis
Knee Osteo arthritis (OA) typically effects the medial (inside) knee and is the most common form of adult OA. The UK NICE guidelines recommend orthoses as part of the conservative management of the condition. Reduction of the pain caused by this debilitating disease and improved mobility is the aim of foot orthoses. Progressive deterioration may result in pain levels and joint function that lead to complete loss of mobility. Knee replacement surgery may be offered for eligible individuals that is not without risk, difficult rehabilitation and considerable cost. Reducing the load to the medial knee may help slow the progress of the disease.
After diagnosis your North East Foot Centre Podiatrist will discuss the measures that can be taken to help you fulfill your lifestyle aims. This can include exercise therpy, custom foot Orthoses, Pain management including acupuncture, footwear choices, referral for X ray and referral for surgical opinion.
A prescription choice for Medial knee OA is custom Podfo device, with a lateral rearfoot post. This approach is backed up by our own research trial where we demonstrated a lateral shift of Centre of Pressure using this kind of Podfo device. To arrive at this prescription we have taken a combined approach using the best evidence available.
What does the evidence say? This tends to come in two forms; foot orthoses with a lateral wedge or variable stiffness shoes. The foot orthoses research is further divided into rearfoot wedging just at the heel, or along the whole length and with or without support at the medial arch.
Why not use just a simple lateral wedge? Whilst this will reduce medial knee load, using just such a wedge can produce discomfort in the ankle. Professor Richard Jones (Jones et al, 2013) found that unsupported and supported medial arch insoles with a lateral wedge had an equal effect on the knee, but the supported type was far more comfortable for the trial subjects.
Podfo medial progressive flex utilises this with a custom fit arch, but crucially, it does not push back excessively in late stance phase and therefore reduce the effect of the wedging.
The progressive flex effect is also alluded too in many of the papers regarding differing stiffness shoes. The comfort concern of using a lateral wedge only can be in part addressed via the use of this type of shoe (Teoh et al.102013). Variable stiffness shoes effectively reduce the loads to medial knee.
Podfo medial progressive flex combines the variable stiffness shoe approach with the benefits of the wedged supportive insole design.
These papers and further discuss the importance of comfort in footwear. This is explored again by Prof. Jones in his groups paper , The Effect of Different Types of Insoles or Shoe Modifications on Medial Loading of the Knee in Persons With Medial Knee Osteoarthritis: A Randomised Trial. In this trial they compared a comfort shoe against barefoot walking and laterally wedged insole conditions. The comfort shoe did not reduce the external knee adduction moment compared to the lateral wedged insoles and barefoot walking, but, they led to a significant reduction in pain.
With this design of Podfo, we are aiming for, comfort, a mechanical effect and a reduction in pain for your patients suffering from medial knee arthritis.
Alshawabka, A. Z. et al. (2014) ‘The use of a lateral wedge insole to reduce knee loading when ascending and descending stairs in medial knee osteoarthritis patients’, Clinical Biomechanics. doi: 10.1016/j.clinbiomech.2014.04.011.
Jenkyn, T. R., Erhart, J. C. and Andriacchi, T. P. (2011) ‘An analysis of the mechanisms for reducing the knee adduction moment during walking using a variable stiffness shoe in subjects with knee osteoarthritis’, Journal of Biomechanics. doi: 10.1016/j.jbiomech.2011.02.013.
Jones, R. K. et al. (2013) ‘The biomechanical effects of a new design of lateral wedge insole on the knee and ankle during walking’, Human Movement Science. Elsevier B.V., 32(4), pp. 596–604. doi: 10.1016/j.humov.2012.12.012.
Jones, R. K. et al. (2015) ‘The effect of different types of insoles or shoe modifications on medial loading of the knee in persons with medial knee osteoarthritis: A randomised trial’, Journal of Orthopaedic Research, 33(11), pp. 1646–1654. doi: 10.1002/jor.22947.
Keonyoung Oh, Chang Keun Jung, Haedo Cho & Juho Jung (2017) Different mechanisms and effects of wedged and dual hardness insoles on foot pronation during human running, Footwear Science, 9:sup1, S93-S94, DOI: 10.1080/19424280.2017.1314357
Penny, P., Geere, J. and Smith, T. O. (2013) ‘A systematic review investigating the efficacy of laterally wedged insoles for medial knee osteoarthritis’, Rheumatology International, 33(10), pp. 2529–2538. doi: 10.1007/s00296-013-2760-x.
Teoh, J. C. et al. (2013) ‘Investigation of the biomechanical effect of variable stiffness shoe on external knee adduction moment in various dynamic exercises’, Journal of Foot and Ankle Research. doi: 10.1186/1757-1146-6-39.