Effect of Subtalar Joint Mobilization and Myofascial Trigger Point Release on Pain and Disability in Plantar Fasciitis

Introduction

The foot, essential for support and locomotion, relies on its arches as elastic springs for walking, running, and jumping. The plantar fascia, a thickened fibrous structure on the sole, plays a key role in these functions. The fascia originates from the medial tubercle of the calcaneum. It extends to the heads of the metatarsal bones, providing attachment to the skin and deeper structures, maintaining the longitudinal arches, and offering shock absorption.¹

Plantar fasciitis results from stretching and collagen degeneration of the plantar fascia at its calcaneal origin, characterized by the absence of inflammatory cells and considered a degenerative pathology. Risk factors include reduced dorsiflexion, increased plantar flexion, excessive foot pronation, prolonged weight-bearing activities, elevated body mass index (BMI), sub-calcaneal spurs, and subtalar joint dysfunction.¹

The fascia's role in supporting and stabilizing structures is critical yet often overlooked. Degenerative changes in the body, whether muscular, nervous, or circulatory, are reflected in the fascia. Myofascial Trigger Point Release (MTrP) helps stretch and loosen the fascia, increasing pain-pressure thresholds locally and reducing referred pain fields.² This hands-on therapy breaks down scar tissue, relaxes muscles and myofascial, and restores good posture, addressing fascial entrapment patterns caused by deficient circulation and nutrient supply. Direct pressure on sarcomeres during MTrP release relaxes muscles, increases sarcomere length, reduces muscle tension, and decreases pain.^2,3

The subtalar joint, a synovial articulation between the talus and calcaneus, plays a crucial role in foot inversion and eversion. Subtalar joint mobilization helps control pain, improve mobility, and decrease traction stress on the plantar fascia, enhancing foot function. Manual therapy, including soft tissue manipulation and joint mobilization, is effective in treating plantar heel pain.¹

Conservative management options such as cryotherapy, therapeutic ultrasound, electrical stimulation, whirlpool, and NSAID administration via iontophoresis are reported to be successful. Therapeutic ultrasound increases tissue temperature and improves fascia extensibility, with non-thermal effects modulating inflammatory responses. Stretching exercises are designed to increase soft tissue extensibility, promote wellness, and reduce injury risk.^4,5,6 Elasticity, visco-elasticity, and plasticity are properties of soft tissue that facilitate stretching and recovery.

This study compares the effectiveness of subtalar joint mobilization and Myofascial Trigger Point Release, combined with conventional therapy, on pain and disability in plantar fasciitis patients.

Materials and Methods

This study compared the effectiveness of subtalar joint mobilization and myofascial trigger point release (MTrP) combined with conventional therapy for treating plantar fasciitis, a degenerative condition marked by collagen degeneration at the calcaneal tuberosity. Factors such as reduced dorsiflexion, increased plantar flexion, excessive foot pronation, weight-bearing activities, elevated BMI, and subtalar joint dysfunction influence this condition. Sixty-four participants aged 20-45 with plantar fasciitis were divided into two groups. Group A received subtalar joint mobilization with conventional therapy, and Group B received MTrP with traditional treatment, including stretching, therapeutic ultrasound, and cryotherapy.

Participants were screened using the windlass test and met the criteria, including the presence of an identifiable MTrP within the calf muscle and tenderness at the origin of the plantar fascia. Exclusion criteria included red flags to manual therapy, calcaneal spur, diabetes, post-menopausal status, previous foot and ankle surgery, recent trauma or fracture, deformities, neurological disorders, and pregnancy.

Pain and disability were measured using the Visual Analog Scale (VAS) and Foot and Ankle Disability Index (FADI) pre-and post-intervention. The VAS measures pain intensity on a 0-100 mm line, is reliable for tracking treatment outcomes, and correlates well with other pain scales.⁷ The FADI assesses functional limitations in foot and ankle disorders, with strong reliability and sensitivity, particularly in chronic ankle instability.⁸ Subtalar joint mobilization involved traction and inversion/eversion movements, while MTrP involved vertical downward pressure on MTrP until muscle resistance was perceived, followed by longitudinal strokes.

Sample Size Estimation

The sample size was determined based on an assumed prevalence of plantar fasciitis 0.5 due to the unavaila-bility of specific literature data. With a significance level (α) of 0.05 (Zα/2 = 1.96) and a power (1-β) of 80% (Z1-β = 0.842), the margin of error (D) was set at 15% (0.15). ά = 0.05. Thus, each group (Group A and Group B) consisted of 32 participants, resulting in a total sample size of 64.

Data Analysis

Data collected for the study was entered into MS Excel and analyzed using R software version 4.2.1. Descriptive statistics were employed to present categorical variables as frequency tables with percen-tages and quantitative variables as means with standard deviations or medians with interquartile ranges, along with 95% confidence intervals. Results were also illustrated using bar graphs, pie charts, tables, and scatter diagrams.

Descriptive analysis of age, BMI, VAS, and FADI:

Table 1 summarizes the descriptive statistics for both groups’ age, BMI, VAS, and FADI. Group A had a mean age of 29.03 ± 8.11 years, while Group B was slightly older at 30.94 ± 7.94 years. BMI was higher in Group A (23.46 ± 2.82 kg/m²) compared to Group B (22.11 ± 2.94 kg/m²), with moderate variability in both groups.

VAS scores showed a reduction in pain post-test for both groups. Group A’s mean VAS decreased from 7.00 ± 0.76 to 4.53 ± 0.88, while Group B’s dropped from 7.06 ± 0.76 to 3.59 ± 0.76, indicating more significant pain relief in Group B.

FADI scores improved post-test, with Group A decrea-sing from 73.16 ± 8.92 to 61.78 ± 8.05 and Group B from 76.28 ± 6.14 to 57.84 ± 8.00, suggesting better functional recovery in Group B. Overall, both groups showed improvement, with Group B demonstrating more significant pain reduction and functional gains. In the data that was subjected to the normality test, Kolmogorov- Smirnov test, it was observed that age, BMI, FADI and VAS are distributed normally, whereas PDQ-8, MDS-UPDRS, and CGSI are non-normal. Based on this information, the Wilcoxon-Signed Ranked Test was used for non-normal data, and the paired t-test was used for normally distributed parameters.

The Kolmogorov-Smirnov (K-S) normality test indi-cated that in Group A, both age (K-S = 0.2081, P = 0.0011) and BMI (K-S = 0.2023, P = 0.0018) were non-normally distributed, In contrast, in Group B, age (K-S = 0.1277, P > 0.1000) and BMI (K-S = 0.1248, P > 0.1000) followed a normal distribution. The VAS scores exhibited non-normal distributions in both groups for pre-test and post-test measures (P < 0.0001). The FADI scores in Group A showed normal distributions for both pre-test (K-S = 0.1354, P > 0.1000) and post-test (K-S = 0.1021, P > 0.1000). In Group B, FADI pre-test scores were non-normal (K-S = 0.1697, P = 0.0197), whereas post-test scores followed a normal distribution (K-S = 0.1015, P > 0.1000).

Inferential Statistics

The difference in means of VAS and FADI was tested using the student’s unpaired t-test/Wilcoxon rank-sum test for between-group comparisons, subject to the normality assumption, the student’s paired t-test/ Wilcoxon signed-rank test was applied for within group comparisons based on normality. A 95% confidence interval for the mean difference was also computed. Results were considered statistically significant when P ≤ 0.05. The findings were interpreted based on the P value and the 95% confidence interval for the difference in means.

Unpaired t Test

Table 3 displays the results of a between-group comparison of BMI using Student's unpaired t-test. The t-test shows a t-value of 1.871 with a P value of 0.0651, indicating that the difference in BMI between Group A and Group B is not statistically significant.

Table 4 presents the Mann-Whitney U-test results for VAS and FADI between groups. Pre-test VAS and FADI showed no significant difference (P > 0.05). However, post-test VAS (U = 217, P < 0.0001) and post-test FADI (U = 89, P < 0.0001) were highly significant, indicating a greater reduction in pain and improvement in function in group B compared to group A.

Table 5 presents a between-group comparison of VAS and FADI scores using the Mann-Whitney U-test. Pre-test comparisons show no significant differences between groups, while post-test comparisons reveal highly substantial improvements in both measures. The pre-test VAS score between groups A and B was not significantly significant. However, there was a substantial reduction in the pain score of group B as compared to group A (P < 0.001). The FADI of the pre-test between both groups was not significant; however, it was highly significant in the post-test.

Discussion

This study evaluated subtalar joint mobilization versus myofascial trigger point release t(MTrP), each combined with conventional therapy, in reducing pain and disability in plantar fasciitis patients. Plantar fasciitis, a degenerative condition marked by collagen degene-ration at the calcaneal tuberosity, is influenced by reduced dorsiflexion, excessive foot pronation, and high BMI. Participants were divided into two groups: one receiving subtalar joint mobilization and the other MTrP, both with conventional therapy (stretching, strengthening exercises, ultrasound, and cryotherapy). Pain and disability were measured using the VAS and FADI.

Results indicated significant pain and disability redu-ction in both groups, with MTrP being more effective. MTrP works by stretching and loosening the fascia, increasing pain-pressure thresholds, and reducing muscle tension and tenderness. Subtalar joint mobilization enhances joint mobility, reducing traction stress on the plantar fascia and improving foot function.

Supporting studies found significant pain relief with MFR and improved pain and disability with subtalar joint mobilization, respectively.^3,6 Another study found that MFR effectively reduces pain and improves function in plantar fasciitis.³

The study suggests incorporating MTrP into standard treatment protocols and combining myofascial release with other therapeutic modalities for optimal results. Further research should explore long-term benefits and mechanisms to optimize treatment approaches for plantar fasciitis.

Both groups showed significant pain and disability reduction, with MTrP being more effective. MTrP loosens fascia, increases pain-pressure thresholds, breaks down scar tissue, relaxes muscles, and improves posture, while subtalar joint mobilization enhances mobility and reduces plantar fascia stress. The study supports incorporating MTrP into standard treatment for plantar fasciitis and combining it with joint mobilization for comprehensive care. ^9,10

However, this study has several limitations. The short-term follow-up restricts understanding of long-term effects, and the small sample size limits generalizability. The absence of a control group makes distinguishing treatment effects from natural recovery difficult. Additionally, individual variations in pain perception, adherence to home exercises, and differences in foot biomechanics could have influenced outcomes. Future research should address these gaps by conducting long-term studies, exploring biomechanical and neuromuscular effects, and using more extensive randomized controlled trials to optimize treatment strategies.

Conclusion

This study demonstrates that subtalar joint mobilization and (MTrP) effectively reduce pain and disability in plantar fasciitis, with MTrP yielding superior results. Given its significant impact on pain relief and mobility, MTrP should be incorporated into standard care large-scale, long-term studies are needed to confirm these findings and optimize treatment strategies.

Conflicts of interest

Nil