Technique Geek: Physiotherapy treatments for Anterior Knee Pain/PFPS

Current evidence would support the use of physiotherapy interventions to reduce pain associated with Patellofemoral Pain Syndrome (PFPS), although there is limited evidence to support one type of intervention over another. What does seem clear however is that when rehabilitation is individually tailored to address specific deficits the outcomes appear improved (Crossley et al 2001).

Common treatments include:

Taping

Made fashionable by Jenny McConell in the 1980’s taping has proved to be an effective means of providing pain relief in PFPS. The theory for the improvement in symptoms was traditionally an alteration in the position of the patella itself. This theory has however been shown to be incorrect following fMRI studies which showed no change in the position of the patella following application of the tape. The reason behind its success must therefore be non-mechanical. Current theories suggest an alteration in the afferent feedback through proprioceptive and sensory pathways. This may lead to an increase in motor unit synchronization, that is decreased in people with PFPS (Mellor & Hodges 2005), and therefore muscular control, as well as a ‘pain-gating’ effect, which may in turn lead to a decrease in muscle inhibition causing further improvement in motor activation.

Kinesio-taping

tape-for-patello-femoral-pain

This taping technique has become fashionable in recent years, as we all witnessed at the Olympics this year. The elasticity of the tape allows patterning along the lines of the anatomy. It also provides further evidence that the effects of the tape are not to alter joint position, rather to create neuro-physiological effects, which cause the improved outcomes. A further advantage of this form of taping is the breathability of the material, allowing it to remain in-situ for weeks if necessary.

Strengthening

The Quadriceps are the largest, and strongest, muscle group in the body and have been shown to be weakened during chronic knee conditions. Maintenance of Quads strength is vital due to their critical involvement in maintaining normal biomechanics. The lateral structures of the knee are naturally tighter than the medial Quads musculature. Therefore the muscle must provide sufficient force to counter-balance the lateral structures and maintain the patella within the femoral groove in which it naturally resides. Altered positioning can cause stress upon soft-tissue around the patella, as well as the subchondral bone which have both been shown to be likely sources of the pain felt in PFPS.

As part of the Quads rehabilitation physiotherapists may attempt to improve the relative timing of the medial (Vastus Medial Obliquus – VMO) and lateral (Vastus Lateralis) Quadriceps. There has been research that has pointed to an alteration in the relative contraction timings, which in turn affects biomechanics (Chester et al 2008).

Strengthening may also involve the Hamstrings and the hip rotators, which have an effect of lower limb biomechanics, depending on the specific requirements of the patient.

Mobilisations

Mobilisations may be used as a mechanism to decrease the discomfort felt around the knee. Much in the same way as the tape provides improved muscle function, mobilisations may decrease pain leading to decreased muscle inhibition and improved function (Moss et al 2007). While this effect may only be temporary it does allow a window of opportunity during which strengthening and rehabilitative work can be carried out, which in turn can provide longer-term effects.

Orthotics

While bespoke orthotics are the business of Podiatrists, physiotherapists may provide generic orthotics if required. Again the idea is that the lower limb biomechanics are preferably altered leading to decreased stress upon the painful structures at the anterior knee. Not everyone will benefit from orthotics however, as highlighted by a recent study that found no added benefit to orthotics when added to physiotherapy treatment in the short-term (Collins et al 2009).

Stretching

As discussed previously the lateral structures of the knee are tighter than the medial structures, which may cause an unwanted lateral pull of the patella if a muscle imbalance is present. Likewise tightening of the Quads may cause an alteration in patella position, this time superiorly, that may need to be addressed through manual and home stretches. Equipment such as Foam Rollers may be used to further aid home stretching regimes.

References:

Chester R, O’Smith T, Sweeting D, Dixon J, Wood S, Song F. The relative timing of VMO and VL in the aetiology of anterior knee pain: a systematic review and meta-analysis. BMC Musculoskeletal Disorders 2008;9:64

Collins N, Crossley K, Beller E, Darnell R, McPoil T, Vicenzino B. Foot orthoses and physiotherapy in the treatment of patellofemoral pain syndrome: randomised clinical trial. British Journal of Sports Medicine 2009;43:169-171

Crossley K, Bennell K, Green S, McConnell J. A systematic revoew of physical interventions for patellofemoral pain syndrome. Clinical Journal of Sports Medicine 2001;11:103-110

McConnell J. The management of chondromalacia patellae: a long term solution. The Australian Journal of Physiotherapy 1986;32(4):215-223

Mellor R, Hodges P. Motor unit synchronization is reduced in anterior knee pain. The Journal of Pain 2005;6(8):550-558

Moss P, Sluka K, Wright A. The initial effects of knee joint mobilization on osteoarthritis hyperalgesia. Manual Therapy 2007;12:109-118

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