Intrinsic foot muscle size and quality in a single leg weight bearing position across foot posture types in individuals with Patellofemoral Pain compared to healthy

Impairments in peroneal muscle size and activation in individuals with patellofemoral pain in weight-bearing position

BACKGROUND

Patellofemoral pain (PFP) is characterized by chronic pain in the anterior aspect of the knee during loading activities. Many studies investigating muscle morphology changes for individuals with PFP focus on the proximal joints, however, few studies have investigated muscles of the foot and ankle complex. This study aimed to explore the differences in peroneal muscle size and activation between individuals with PFP and healthy controls using ultrasound imaging in weight-bearing.

METHODS

A case-control study in a university lab setting was conducted. Thirty individuals with PFP (age: 20.23 ± 3.30 years, mass: 74.70 ± 27.63 kgs, height: 161.32 ± 11.72 cm) and 30 healthy individuals (age: 20.33 ± 3.37 years, mass: 64.02 ± 11.00 kgs, height: 169.31 ± 9.30 cm) participated. Cross-sectional area (CSA) images of the peroneal muscles were taken in non-weight bearing and weight-bearing positions. The functional activation ratio from lying to single-leg standing (SLS) was calculated.

RESULTS

There was a statistically significant (p = 0.041) group (PFP, healthy) by position (non-weight-bearing, weight-bearing) interaction for the peroneal muscle CSA with a Cohen's d effect size of 0.2 in non-weight-bearing position and 0.7 in weight-bearing position. The functional activation ratio for the healthy group was significantly more (p = 0.01) than the PFP group.

CONCLUSION

Peroneal muscles were found to be smaller in size in those with PFP compared to the healthy subjects in the weight-bearing SLS position. This study found that those with PFP have lower activation of peroneal muscles in functional position.

Adolescent exercise-related lower leg pain musculotendinous characteristics

BACKGROUND

Exercise-related lower leg pain (ERLLP) is one of the most common injuries among adolescent runners; however, there is limited information available on lower extremity musculotendinous characteristics in relationship to injury. Ultrasound imaging has previously been used to evaluate musculotendinous structures among adults with chronic lower limb injuries. Similar measurement approaches may be adopted to assess young runners with ERLLP.

OBJECTIVE

To compare ultrasound-derived lower extremity musculotendinous thickness, echogenicity, and muscle fiber pennation angles between adolescent runners with and without ERLLP.

DESIGN

Cross-sectional design.

SETTING

Hospital-affiliated sports injury prevention center.

PARTICIPANTS

Twenty-eight adolescent runners with (N = 14) and without ERLLP (N = 14).

INTERVENTIONS

Runners' patellar and Achilles tendons, and tibialis anterior, medial gastrocnemius, abductor hallicus, and flexor digitorum brevis muscles were assessed with ultrasound imaging using standardized procedures.

MAIN OUTCOME MEASURES

Separate repeated measures multivariate analyses of covariance (covariate: gender) were used to compare groups and limbs for mass-normalized musculotendinous thickness, musculotendinous echogenicity, and extrinsic ankle muscle fiber pennation angles.

RESULTS

The adolescent ERLLP group had reduced average muscle size for all structures except the tibialis anterior compared to the uninjured group (mean difference [MD] range: -0.12-0.49 mm/kg; p range: .002-.05), and reduced average medial gastrocnemius pennation angles on their case limb compared to their contralateral limb and the uninjured group (MD range: -3.7-6.4°; p < .001). The ERLLP group additionally had reduced average patellar and Achilles tendon size (MD range: -0.14--0.15 mm/kg; p range: .02-.03), and lower Achilles tendon echogenicity compared to uninjured counterparts (MD: -18; p = .02).

CONCLUSIONS

Adolescent runners with ERLLP exhibited morphological musculotendinous changes that may occur either as a result of or as a contributing factor to pain and persistent dysfunction. The findings highlight key targets for rehabilitation for young, injured runners, particularly intrinsic foot muscle strengthening.

Evidence for Intrinsic Foot Muscle Training in Improving Foot Function: A Systematic Review and Meta-Analysis

OBJECTIVE

To critically assess the literature focused on strength training of the intrinsic foot muscles (IFMs) and resulting improvements in foot function.

DATA SOURCES

A search of electronic databases (PubMed, CINAHL, Scopus, and SPORTDiscus) was completed between January 2000 and March 2022.

STUDY SELECTION

Randomized control trials with an outcome of interest and at least 2 weeks of IFM exercise intervention were included. Outcomes of interest were broadly divided into 5 categories of foot posture (navicular drop and Foot Posture Index), namely: balance, strength, patient-reported outcomes, sensory function, and motor performance. The PEDro scale was used to assess the methodologic quality of the included studies with 2 independent reviewers rating each study. Studies with a PEDro score greater than 4/10 were included.

DATA EXTRACTION

Data extracted by 2 independent reviewers were design, participant characteristics, inclusion and exclusion criteria, type of intervention, outcomes, and primary results. We performed a random-effects meta-analysis to analyze the difference between intervention and control groups for each outcome when at least 2 studies were available. Standardized mean differences (SMDs) describe effect sizes with 95% CIs (SMD ranges). When the CI crossed zero, the effect was not significant.

DATA SYNTHESIS

Thirteen studies were included, and IFM exercise interventions were associated with decreasing navicular drop (SMD range = 0.37, 1.83) and Foot Posture Index (SMD range = 1.03, 1.69) and improving balance (SMD range = 0.18, 1.86), strength (SMD range = 0.06, 1.52), and patient-reported outcomes for disability (SMD range = 0.12, 1.00), with pooled effect sizes favoring the IFM intervention over the control. The IFM exercises were not superior (SMD range = -0.15, 0.66) for reducing pain. We could not perform a meta-analysis for sensory function and motor performance, as only 1 study was available for each outcome; however, these results supported the use of IFM strength training.

CONCLUSIONS

Strength training of the IFMs was helpful for patients in improving foot and ankle outcomes.

Poor Mental Health Indicators in Individuals With Patellofemoral Pain

CONTEXT

Patellofemoral pain (PFP) is a common source of knee pain in active individuals, accounting for a large number of knee injuries examined in sports medicine clinics. As a chronic condition, PFP can affect mental health. However, this effect has not yet been studied in individuals with PFP.

OBJECTIVE

To determine how subjective physical and mental health measures in individuals with PFP differed from those measures in pain-free individuals.

DESIGN

Case-control study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

Volunteers for the study were 30 people with PFP (19 women, 11 men; age = 20.23 ± 3.32 years, height = 166.69 ± 6.41 cm, mass = 69.55 ± 13.15 kg) and 30 matched pain-free individuals (19 women, 11 men; age = 20.33 ± 3.37 years, height = 169.31 ± 9.30 cm, mass = 64.02 ± 11.00 kg).

MAIN OUTCOME MEASURE(S)

Current and worst pain levels in the past 24 hours were determined using a visual analog scale (VAS). The Anterior Knee Pain Scale, Fear Avoidance Belief Questionnaire, and Lower Extremity Functional Scale were administered. Physical and mental health measures were obtained using a modified 12-item Short Form Health Survey. Scores for 2 subscales on the modified Short Form-12 were weighted and calculated: physical component and mental component.Independent t tests were calculated to compare variables between groups. Coefficient correlations were used to measure the associations between the variables.

RESULTS

Individuals with PFP reported lower levels of physical (pain free: 56.13 ± 1.63, PFP: 50.54 ± 7.10, P < .001) and mental (pain-free: 53.32 ± 4.71, PFP: 48.64 ± 10.53, P = .03) health. In the PFP group, we found moderate negative correlations between the VAS score for current pain and mental health (r = -0.52, P < .01) and between the VAS score for worst pain in the past 24 hours and mental health (r = -0.46, P = .01) and between activity limitations in individuals with PFP and fear avoidance beliefs (r = -0.61, P < .01).

CONCLUSIONS

Our results should encourage clinicians, especially musculoskeletal rehabilitation professionals, to acknowledge the importance of a whole-person approach when treating or planning rehabilitation programs for individuals with PFP.

A Novel Intrinsic Foot Muscle Strength Dynamometer Demonstrates Moderate-To-Excellent Reliability and Validity

Background

Intrinsic foot muscle (IFM) weakness can result in reduced foot function, making it crucial for clinicians to track IFM strength changes accurately. However, assessing IFM strength can be challenging for clinicians, as there is no clinically applicable direct measure of IFM strength that has been shown to be reliable and valid with the foot on the ground.

Purpose

The purpose was to investigate the intra-rater and inter-rater reliability of a novel, budget-friendly IFM dynamometer and determine its agreement with a handheld dynamometer (HHD). The researchers also examined correlations of foot morphology and activity level to IFM strength.

Study design

Descriptive Laboratory Study.

Methods

Two assessors measured IFM strength of 34 healthy volunteers (4 male, 30 female; age=21.14±2.57, height=164.66 ±7.62 cm, mass=64.45±11.93 kg) on two occasions 6.62±0.78 days apart with the novel dynamometer to assess intra- and inter-rater reliability. The HHD was used to measure IFM in the first session in order to assess validity.

Results

For the novel dynamometer, intra- and inter-rater reliability was moderate-to-excellent (ICC = 0.73 - 0.95), and the majority of the strength tests were within the 95% limits of agreement with the HHD. Wider foot morphology and a higher number of days walking over the prior seven days had small but significant correlations with IFM strength (dominant foot r = 0.34, non-dominant foot r = 0.39; r = -0.33, -0.39 respectively).

Conclusion

This novel IFM dynamometer is a budget-friendly ($75) tool that was shown to be reliable and valid in a healthy population.

Levels of evidence

Level 3©The Author(s).

Muscle Quality Assessment by Ultrasound Imaging of the Intrinsic Foot Muscles in Individuals with and without Plantar Fasciitis: A Case-Control Study

Objective: The primary aim of the present study was to compare the echo intensity (EI) and echovariation (EV) of the intrinsic foot muscles (IFMs) between individuals with and without plantar fasciitis (PF), using ultrasound imaging. The secondary objective was to study the intra-rater reliability of the echotexture variables. Methods: A case−control study was conducted with 64 participants, who were divided into the following two groups: A, the PF group (n = 32); B, the healthy group (n = 32). Results: The comparison between the two groups did not identify significant differences (p > 0.05) between the flexor hallucis brevis (FHB), flexor digitorum brevis (FDB), quadratus plantae (QP) and abductor hallucis brevis (AHB) variables for the EI and EV. Moreover, excellent intra-rater reliability was reported for the following ultrasound imaging EI variables: ABH (ICC = 0.951), FHB (ICC = 0.949), FDB (ICC = 0.981) and QP (ICC = 0.984). Conclusions: The muscle quality assessment using the EI and EV variables did not identify differences in the FHB, FDB, AHB and QP muscles between individuals with and without PF through USI evaluation. The reliability of all the IFM measurements was reported to be excellent.