The Foot Orthoses versus Hip eXercises (FOHX) trial for patellofemoral pain: a protocol for a randomized clinical trial to determine if foot mobility is associated with better outcomes from foot orthoses

How Do Hip Exercises Improve Pain in Individuals With Patellofemoral Pain? Secondary Mediation Analysis of Strength and Psychological Factors as Mechanisms

OBJECTIVE

To determine whether the effect of hip exercise on patellofemoral pain is mediated through changes in hip muscle strength or psychological factors.

DESIGN

Secondary mediation analysis of a randomized clinical trial, in which 218 participants with patellofemoral pain were randomly assigned to receive foot orthoses or hip exercises.

METHODS

Pain (Knee injury and Osteoarthritis Outcome Score pain subscale) and number of pain-free squats at 12 weeks were the outcomes for this mediation analysis, as they are pathognomonic of patellofemoral pain. Hip strength dynamometry (abduction, adduction, and external rotation) and psychological characteristics (pain catastrophizing, kinesiophobia, and anxiety) measured at 6 weeks were considered as potential mediators. We used mediation analysis to decompose the total effect of treatment on the outcome into (1) the "indirect effect" (ie, the portion acting through the mediator) and (2) the "direct effect."

RESULTS

The effect of hip exercise on pain and squats was not mediated by any of the strength or psychological mediators analyzed. All indirect effects were small and showed wide 95% confidence intervals (CIs) that contained zero (eg, for pain-free squats: abduction strength, -0.13; 95% CI: -0.49, 0.23; Tampa Scale of Kinesiophobia, -0.17; 95% CI: -0.64, 0.30).

CONCLUSION

Hip strength improved after hip exercise, yet strength did not mediate improvements in pain and pain-free squats, and alternative psychological mediators were not implicated. J Orthop Sports Phys Ther 2021;51(12):602-610. doi:10.2519/jospt.2021.10674.

Does foot mobility affect the outcome in the management of patellofemoral pain with foot orthoses versus hip exercises? A randomised clinical trial

Objectives

To test (i) if greater foot pronation (measured as midfoot width mobility) is associated with better outcomes with foot orthoses treatment, compared with hip exercises and (ii) if hip exercises are superior to foot orthoses, irrespective of midfoot width mobility.

Methods

A two-arm parallel, randomised superiority clinical trial was conducted in Australia and Denmark. Participants (18–40 years) were included who reported an insidious onset of knee pain (≥6 weeks duration); ≥3/10 numerical pain rating, that was aggravated by activities (eg, stairs, squatting, running). Participants were stratified by midfoot width mobility (high ≥11 mm change in midfoot width) and site, randomised to foot orthoses or hip exercises and blinded to objectives and stratification. Success was defined a priori as much better or better on a patient-perceived 7-point scale at 12 weeks.

Results

Of 218 stratified and randomised participants, 192 completed 12-week follow-up. This study found no difference in success rates between foot orthoses versus hip exercises in those with high (6/21 vs 9/20; 29% vs 45%, respectively) or low (42/79 vs 37/72; 53% vs 51%) midfoot width mobility. There was no association between midfoot width mobility and treatment outcome (Interaction effect p=0.19). This study found no difference in success rate between foot orthoses versus hip exercises (48/100 vs 46/92; 48% vs 50%).

Conclusion

Midfoot width mobility should not be used to help clinicians decide which patient with patellofemoral pain might benefit most from foot orthoses. Clinicians and patients may consider either foot orthoses or hip exercises in managing patellofemoral pain.

Trial registration number

ACTRN12614000260628.

The efficacy of foot orthoses in individuals with patellofemoral osteoarthritis: a randomised feasibility trial

Background

Foot orthoses have the potential to be an efficacious treatment for patellofemoral osteoarthritis (PFOA) but have not been evaluated in clinical trials in this population. This study aimed to determine the: (i) feasibility of conducting a randomised controlled trial (RCT) investigating the efficacy of foot orthoses in individuals with PFOA; and (ii) effects of foot orthoses versus flat shoe inserts on pain, function, and knee-related quality of life (QOL).

Methods

This 6-week, single-blinded pilot RCT randomly allocated participants with PFOA to receive foot orthoses or flat inserts. The primary outcome of feasibility was determined via the following parameters: one participant recruited per week, 20% (35 h/week) adherence to the intervention, 50% log book completion rate, and < 20% drop-out, with results reported using descriptive statistics. Secondary outcomes included average and maximum pain severity (100 mm visual analogue scale), Anterior Knee Pain Scale, and Knee injury and Osteoarthritis Outcome Score, analysed using analysis of covariance.

Results

Twenty-six participants (16 women; mean (SD) age of 60 (8) years) with PFOA were recruited. All feasibility parameters were exceeded, with three participants recruited per week, > 20% (37.2 [9.8] hours/week) adherence to the intervention, 69.2% (18/26) log-book completion, and 3.8% (1/26) drop-outs. The most common adverse events were arch irritation and shoe fit issues, which were more common in the foot orthoses group (67.9% versus 32.1%). There was a trend for the foot orthoses group to report larger improvements in average and maximum pain than the flat insert group, with the mean difference for maximum knee pain severity (21.9 mm, 95% CI − 2.1 to 46.0) exceeding the minimal clinically important difference (15 mm). The estimated sample size for a full-scale RCT is 160 participants. Suggestions to improve study design include a greater number of face-to-face follow-up appointments, a larger variety of foot orthoses to reduce rates of adverse events, and increasing follow-up time to determine long-term efficacy.

Conclusion

This study supports the feasibility of a full-scale RCT to determine the efficacy of foot orthoses versus flat inserts in individuals with PFOA.

Trial registration

The trial protocol was retrospectively registered with the Australian and New Zealand Clinical Trials Registry (ANZCTR number: 12616001287426).

Distinct patterns of variation in the distribution of knee pain

The patient’s expression of pain using digital-body maps expands analytic opportunities for exploring the spatial variation of bodily pain. A common knee pain condition in adolescents and adults is patellofemoral pain (PFP) and recently PFP was shown to be characterized by a heterogeneous distribution of pain. Whether there are important patterns in these distributions remains unclear. This pioneering study assesses the spatial variation of pain using principal component analysis and a clustering approach. Detailed digital-body maps of knee pain were drawn by 299 PFP patients of mixed sex, age, and pain severity. Three pain distribution patterns emerged resembling an Anchor, Hook, and an Ovate shape on and around the patella. The variations in pain distribution were independent of sex, age, and pain intensity. Bilateral pain associated with a longer duration of pain and the majority characterized by the Hook and Ovate pain distributions. Bilateral and/or symmetrical pain between the left and right knees may represent symptoms associated with longstanding PFP. The distinct patterns of pain location and area suggest specific underlying structures cannot be ruled out as important drivers, although central neuronal mechanisms possibly exemplified by the symmetrical representation of pain may play a role in individuals with longstanding symptoms.

Journal of Foot and Ankle Research: the first ten years

Journal of Foot and Ankle Research (JFAR) was launched in July 2008 as the official research publication of the Society of Chiropodists and Podiatrists (UK) and the Australasian Podiatry Council, replacing both the British Journal of Podiatry and the Australasian Journal of Podiatric Medicine. This editorial celebrates the 10 year anniversary of the journal.

2018 Consensus statement on exercise therapy and physical interventions (orthoses, taping and manual therapy) to treat patellofemoral pain: recommendations from the 5th International Patellofemoral Pain Research Retreat, Gold Coast, Australia, 2017

Patellofemoral pain affects a large proportion of the population, from adolescents to older adults, and carries a substantial personal and societal burden. An international group of scientists and clinicians meets biennially at the International Patellofemoral Research Retreat to share research findings related to patellofemoral pain conditions and develop consensus statements using best practice methods. This consensus statement, from the 5th International Patellofemoral Research Retreat held in Australia in July 2017, focuses on exercise therapy and physical interventions (eg, orthoses, taping and manual therapy) for patellofemoral pain. Literature searches were conducted to identify new systematic reviews and randomised controlled trials (RCTs) published since the 2016 Consensus Statement. The methodological quality of included systematic reviews and RCTs was graded using AMSTAR and PEDro, respectively. Evidence-based statements were developed from included papers and presented to a panel of 41 patellofemoral pain experts for consensus discussion and voting. Recommendations from the expert panel support the use of exercise therapy (especially the combination of hip-focused and knee-focused exercises), combined interventions and foot orthoses to improve pain and/or function in people with patellofemoral pain. The use of patellofemoral, knee or lumbar mobilisations in isolation, or electrophysical agents, is not recommended. There is uncertainty regarding the use of patellar taping/bracing, acupuncture/dry needling, manual soft tissue techniques, blood flow restriction training and gait retraining in patients with patellofemoral pain. In 2017, we launched the International Patellofemoral Research Network (www.ipfrn.org) to consolidate and grow our patellofemoral research community, facilitate collaboration and disseminate patellofemoral pain knowledge to clinicians and the general public. The 6th International Patellofemoral Research Retreat will be held in Milwaukee, Wisconsin, USA, in October 2019.

Impairment-Based Rehabilitation Following Hip Arthroscopy: Postoperative Protocol for the HIP ARThroscopy International Randomized Controlled Trial

Synopsis The number of hip arthroscopies for the management of femoroacetabular impingement syndrome and other hip intra-articular conditions has grown exponentially in the last decade. Postoperative rehabilitation is part of the treatment algorithm, although there is a lack of high-quality studies on the efficacy of both surgery and postoperative rehabilitation programs. It is known that impairments can be present up to 2 years after hip arthroscopy, with individuals exhibiting reduced function and quality of life when compared to those of similar age, highlighting a need to improve postoperative care. Postoperative rehabilitation programs aim to improve hip function; however, the description of interventions as well as criteria for progression are lacking in the literature. The aim of this clinical commentary was to present a targeted clinical rehabilitation approach for individuals undergoing hip arthroscopy. J Orthop Sports Phys Ther 2018;48(4):336-342. doi:10.2519/jospt.2018.8002.

The psychological features of patellofemoral pain: a cross-sectional study

Background and aims:

Patellofemoral pain (PFP) is a prevalent and debilitating musculoskeletal condition, considered to have a mechanical aetiology. As such, the physical impairments associated with PFP are well documented and have helped characterise different physical phenotypes. But little is known about the relationship between PFP and psychological well-being. In this study, we aimed to: (1) compare psychological profiles between groups with and without PFP; (2) compare psychological profiles and condition severity between PFP subgroups; and (3) explore relationships between psychological factors and their contribution to disability. We expected to find higher levels of psychological impairment, especially kinesiophobia and catastrophizing in the PFP group. We also expected to identify a sub-group for who worsening levels of disability correspond with worsening psychological well-being.

Methods:

One hundred participants with PFP (72 females, mean±SD age 27±5 years, BMI 25.3±4.8 kg/m2) completed measures of pain, disability, and psychological features (kinesiophobia, catastrophizing, anxiety and depression). Fifty controls, matched by sex, age and activity level (36 females, age 27±5 years, BMI 22.9±4.5 kg/m2) also completed psychological measures. The Knee injury and Osteoarthritis Outcome Score (KOOS) was used to cluster PFP participants (K-means cluster analysis) into more and less severe sub-groups. Differences between the control and PFP groups were analysed using t-tests, analysis of variance, Mann-Whitney U-tests or χ 2 tests as appropriate (p<0.05). Pearson correlations were used to explore relationships between psychological measures. Backward stepwise regression (p out >0.05) evaluated how the psychological factors potentially relate to disability.

Results:

Psychological features did not differ between PFP and pain-free groups. But differences were apparent when the PFP cohort was subgrouped. Compared to controls, the more-severe group had significantly higher levels of depression (MD 1.8, 95% CI 0.8–2.8; p≤0.001) and catastrophizing (MD 5.7, 95% CI 2.4–9; p≤0.001). When compared to less-severe cases, the more-severe group also demonstrated significantly higher levels of kinesiophobia (MD 4.3, 95% CI 2.1–6.5; p≤0.001), depression (MD 1.5 95% CI 0.5–2.6; p=0.01) and catastrophizing (MD 4.9, 95% CI 1–8.8; p=0.01). The weakest relationship between psychological factors was found between kinesiophobia and anxiety (r=0.29; p=0.02). While the strongest relationship existed between depression and anxiety (r=0.52; p≤0.001). Both kinesiophobia (β −0.27, 95% CI −0.265 to −0.274) and depression (β −0.22, 95% CI −0.211 to −0.228) were associated with disability as defined by the KOOS in the regression model (R 2=0.17, p≤0.001).

Conclusions:

Those with more-severe PFP-related disability have higher levels of psychological impairment than less-severe cases. Kinesiophobia seems to stand as an important factor in the experience of PFP, because it was elevated in the PFP group, significantly differed between the PFP sub-groups and contributed to explaining disability. Contrary to our hypothesis, levels of catastrophizing in the PFP group and severe sub-group were low and seemingly not important.

Implications:

These findings draw attention to psychological factors to which clinicians assessing PFP should show vigilance. They also highlight psychological impairments that might be worthwhile targets in optimising PFP management.

Capturing patient-reported area of knee pain: a concurrent validity study using digital technology in patients with patellofemoral pain

BACKGROUND

Patellofemoral pain (PFP) is often reported as a diffuse pain at the front of the knee during knee-loading activities. A patient's description of pain location and distribution is commonly drawn on paper by clinicians, which is difficult to quantify, report and compare within and between patients. One way of overcoming these potential limitations is to have the patient draw their pain regions using digital platforms, such as personal computer tablets.

OBJECTIVE

To assess the validity of using computer tablets to acquire a patient's knee pain drawings as compared to paper-based records in patients with PFP.

METHODS

Patients (N = 35) completed knee pain drawings on identical images (size and colour) of the knee as displayed on paper and a computer tablet. Pain area expressed as pixel density, was calculated as a percentage of the total drawable area for paper and digital records. Bland-Altman plots, intraclass correlation coefficient (ICC), Pearson's correlation coefficients and one-sample tests were used in data analysis.

RESULTS

No significant difference in pain area was found between the paper and digital records of mapping pain area (p = 0.98), with the mean difference = 0.002% (95% CI [-0.159-0.157%]). A very high agreement in pain area between paper and digital pain drawings (ICC = 0.966 (95% CI [0.93-0.98], F = 28.834, df = 31, p < 0.001). A strong linear correlation (R2 = 0.870) was found for pain area and the limits of agreement show less than ±1% difference between paper and digital drawings.

CONCLUSION

Pain drawings as acquired using paper and computer tablet are equivalent in terms of total area of reported knee pain. The advantages of digital recording platforms, such as quantification and reporting of pain area, could be realized in both research and clinical settings.