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The interaction of hip and foot biomechanics in the presentation and management of patellofemoral pain
  1. Simon Lack1,2
  1. 1Department of Sports and Exercise Medicine, William Harvey Research Institute, School of Medicine and Dentistry, Queen Mary University, London, UK
  2. 2Pure Sports Medicine, London, UK
  1. Correspondence to Dr Simon Lack, Department of Sports and Exercise Medicine, Mile End Hospital, London E1 4DG, UK; s.lack{at}qmul.ac.uk

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What did I do?

My thesis, consisting of six independent studies, investigated whether the interaction of hip and foot biomechanics better explains patellofemoral pain (PFP) presentation and management and could be used to inform feasibility studies delivering biomechancially tailored interventions for individuals with this recalcitrant condition.

Why did I do it?

PFP remains one of the most common conditions within sports medicine, orthopaedic and general practice settings.1 Long-term treatment outcomes are poor and emerging evidence indicates PFP may be on a continuum with patellofemoral osteoarthritis.2 Delivering tailored interventions, directed at the hip and foot, that reflected mine and others clinical practice has been proposed as an approach that improves patient outcome.3 To achieve patient-specific intervention, a greater understanding of effective treatments and the mechanisms of these effects was required.

How did I do it?

I conducted two systematic reviews with meta-analysis to (Study 1) identify predictors of conservative management outcomes and (Study 2) explore the effects and mechanisms of proximal rehabilitation interventions.4 5 A reliability study (Study 3) tested a battery of clinical measures (including strength dynamometry, joint range of motion, foot posture and lower limb function) designed to identify biomechanical deficits common in individuals with PFP (figure 1). Participants from the private and public health sectors in London were used for the subsequent three studies. I completed an observational study (Study 4) of individuals with PFP investigating possible biomechanical mechanisms of effect for in-shoe foot orthoses (figure 2).6 Using multichannel electromyography, in a casecontrol study design (Study 5), I examined the muscle activity of the hip region during common rehabilitation exercises. A randomised feasibility trial (Study 6) implemented a tailored intervention to determine rates of recruitment, retention and adverse effects.

Figure 1

Demonstrating the application of clinical measures, including using the iPhone inclinometer for ankle dorsiflexion, hip rotation range and 1st metatarsal phalangeal joint extension, and handheld dynamometry for assessment of hip extension strength.

Figure 2

Testing within the human performance laboratory using motion capture and electromyography during a step-up task.

What did I find?

Outcome predictors for conservative management are currently at a derivation stage of development. Within clinically reasoned paradigms, predictors of treatment outcome supported the implementation of a specified treatment approach. It was concluded, however, that within a complex heterogeneous PFP group, single predictors might be insufficiently sensitive to identify individuals likely to experience a positive outcome following a specific conservative intervention. This conclusion provided the rationale for developing a reliable battery of clinical tests to further inform this tailored approach to conservative management. Fourteen clinical measures showed good intra-rater reliability and inter-rater reliability for the assessment of lower limb biomechanics. Proximal rehabilitation, using both open and closed kinetic chain exercises directed at the hip and quadriceps, was found to be effective at reducing pain and improving function. The review identified a limited understanding for the mechanism of effect for exercise interventions, which provided rationale for an investigation into the activation pattern exhibited during proximal rehabilitation exercise in those with PFP. Gluteal muscle electromyographic activity was comparable between symptomatic and asymptomatic individuals and showed exercises that preferentially activated the gluteal muscles. Tailoring interventions using biomechanical characteristics, within a randomised trial, was found to be feasible for recruitment and retention.

What is the most important clinical impact/practical application?

  • Interventions directed proximal and distal to the patellofemoral joint are effective in the management of PFP.

  • Indicators of treatment success are at a derivation stage. Adopted within reasoned paradigms, clinicians should consider

    • patellar taping for those with greater usual pain

    • foot orthoses for older and exercise for younger individuals

    • foot orthoses for patients with greater forefoot valgus and rearfoot eversion magnitude peak.

  • Proximal rehabilitation, in combination with quadriceps exercise, should be encouraged in the management of PFP.

  • Proximal exercises, including slow side bridge clam, slow four-point fire hydrant and fast standing fire hydrant (figure 3), produce desired neuromusclar activation patterns.

Figures 3

Multi-channel electromyography collection of hip muscle activation during the completion of rehabilitation exercise in individuals with patellofemoral pain.

Acknowledgments

The support of my PhD supervisors Dr Dylan Morrissey and Dr Christian Barton is acknowledged and was very much appreciated throughout the completion of my PhD

References

View Abstract

Footnotes

  • Twitter @simonthephysio

  • Funding This work was supported by the Private Physiotherapy Education Fund (PPEF) grant number A1 and A2.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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