Peppering Injection for Plantar Heel Pain: A Double-Blind Randomized Feasibility Study (a Short Report)

Abstract

Background:

Plantar heel pain affects up to 10% of individuals and often limits activity. Corticosteroid injections provide short-term relief, though emerging evidence suggests that benefits may derive from mechanical stimulation rather than pharmacologic effect. This pilot study evaluated the feasibility of a double-blind randomized trial comparing corticosteroid vs saline delivered via a standardized infracalcaneal peppering (fenestration) technique. Exploratory outcomes included short-term changes in Foot Function Index (FFI) and visual analog scale (VAS) pain scores.

Methods:

A total of 495 adults were identified via electronic health record queries, research registries, and targeted outreach; 76 were screened (assessed for eligibility) and 41 were enrolled and randomized (21 corticosteroid; 20 saline). Feasibility metrics included recruitment yield, visit completion, protocol adherence, and data completeness. Exploratory analyses used unadjusted linear mixed effects models.

Results:

Feasibility was demonstrated through adequate recruitment, 76% study completion (31/41), high protocol adherence, and low missingness of scheduled outcome measurements (3%). Baseline characteristics were comparable. Exploratory unadjusted estimates favored saline: FFI change −3.2 points (95% CI: −6.1, −0.4), VAS First-Step Pain change −6.6 mm (95% CI: −10.7, −2.4), and VAS General Pain change −3.0 mm (95% CI: −6.6, 0.7); between-group differences were below published minimal important difference (MID) thresholds (≈7 points for FFI Total; ≈9 mm for VAS).

Conclusion:

A randomized peppering-injection trial was feasible, and early unadjusted signals are consistent with a mechanically mediated effect independent of corticosteroid pharmacology. Larger, longer-term trials—including non-injection controls—are required to evaluate clinical effectiveness.

Level of Evidence:

Level II, pilot feasibility study.

Visual Abstract

Introduction

Plantar heel pain—commonly presenting as plantar fasciitis—is one of the most frequent foot disorders, accounting for 1 to 2 million medical visits and substantial direct costs annually. ¹ First-line management typically includes orthoses, stretching, strengthening, and activity modification, though adherence is often poor and relief may be slow. ² Commonly used procedural therapies include corticosteroid injection, extracorporeal shockwave therapy, and percutaneous needle tenotomy.

Corticosteroid injections are widely used for short-term pain reduction, but long-term benefit is inconsistent, and complications such as fat pad atrophy, skin changes, and plantar fascia rupture are documented. ³ Furthermore, histopathologic studies suggest plantar fasciitis is degenerative rather than inflammatory, challenging the rationale for anti-inflammatory treatments. ⁴

Mechanical approaches, including percutaneous needle tenotomy (eg, Tenex, TenJet), have shown promise for refractory cases but require specialized equipment and procedural suites. A simpler clinic-based alternative is needle peppering (fenestration). In conditions such as lateral epicondylitis, peppering may stimulate local healing responses independent of injectate composition. ⁵ Infracalcaneal (plantar) entry targets the fascia’s wider transverse dimension, potentially improving mechanical coverage over traditional medial injections. ⁶

We conducted a double-blind pilot randomized trial to assess feasibility of comparing corticosteroid vs saline delivered via a standardized peppering technique and to generate exploratory efficacy estimates to inform a future adequately powered randomized controlled trial.

Methods

Study Design

This double-blind, randomized, single-center pilot trial (ClinicalTrials.gov NCT05868577) was conducted between October 2023 and September 2024 at Wake Forest University School of Medicine, Department of Orthopaedic Surgery (High Point, NC), with institutional review board approval (Wake Forest University Health Sciences IRB 00095622). Reporting followed CONSORT. The primary objective was feasibility (recruitment yield, retention, protocol adherence, and data completeness). Exploratory outcomes included short-term changes in FFI and VAS pain scores. ⁷

Participants and Randomization

Adults aged ≥18 years with plantar heel pain defined by first-step pain and medial calcaneal tubercle tenderness were recruited via electronic health record queries, research registries, and targeted social media. Exclusion criteria were prior heel surgery/trauma, injection therapy within 3 months, pregnancy, and corticosteroid or local anesthetic allergy. Symptom duration and prior conservative treatments (orthoses, stretching/strengthening, medications) were recorded. During the recruitment period, 495 potential participants were identified, 76 were screened (assessed for eligibility), and 41 were enrolled and randomized (Figure 1D).

Figure 1.

Injection protocol, clinical landmarks, and participant flow. This figure includes 4 panels: (A) Clinical palpation of the medial calcaneal tubercle. (B) Syringe masking for blinding. (C) Infracalcaneal injection approach for the peppering technique (red star marks the traditional medial approach entry point). (D) CONSORT diagram showing participant flow through the study.

Participants were randomized 1:1 (corticosteroid vs saline) using sex-stratified permuted blocks of size 8 in REDCap. Allocation concealment was maintained by a coordinator preparing masked syringes; syringes were opaque-wrapped. Participants and treating clinician remained blinded.

Baseline and Follow-up

Baseline assessments included demographics, symptom duration, prior treatments, FFI, and VAS First-Step and General Heel Pain. Weightbearing radiographs and musculoskeletal ultrasonographs were obtained descriptively (Supplemental Figure 1). An index ultrasonograph documented plantar fascia thickness; values >4 mm are typically observed in symptomatic plantar fasciitis cohorts. ⁸ FFI and VAS were collected at 2, 4, 8, and 12 weeks. Observed per-visit means for each outcome by randomized group are provided in Supplemental Table S1. Eligibility was based on clinical criteria; imaging was descriptive and did not determine inclusion.

Interventions

All participants received a single standardized infracalcaneal peppering injection (Supplemental Video). Using a 25-gauge needle and 3-mL syringe, the plantar fascia enthesis was accessed via a single infracalcaneal entry point; 25 fenestrations were performed with slow withdrawal, redirecting without exiting the skin. Preparation included alcohol cleansing and ethyl chloride spray; pressure and dressing followed. An infracalcaneal approach aligns with the fascia’s broader transverse enthesis for wider mechanical coverage than the medial entry, which traverses a narrower sagittal thickness. ⁶ In addition, consensus statements recommend injection “close to” the origin but do not specify above, below, or within the fascia, leaving placement imprecise. ⁹

Injectates included (1) corticosteroid: 1 mL dexamethasone 4 mg/mL + 1 mL 1% lidocaine; and (2) saline solution: 1 mL 0.9% saline + 1 mL 1% lidocaine. We selected a clear, nonparticulate dexamethasone to maximize blinding integrity; adjudicating steroid formulation efficacy was outside this pilot’s scope. All received standardized stretching/strengthening instructions. Related adverse events were assessed at each visit by open-ended query and examination.

Statistical Analysis

Feasibility outcomes were summarized with exact (Clopper-Pearson) 95% CIs. Primary exploratory efficacy analyses used unadjusted linear mixed effects models with fixed effects for treatment, time, and their interaction (treatment × time) and a random intercept for participant. This likelihood-based approach incorporated all available repeated-measures data from randomized participants under a Missing at Random assumption (ie, intention-to-treat–like). Overall, 3% of scheduled outcome measurements were missing despite a 24% participant-level dropout, because most noncompleters contributed ≥1 postbaseline time point. A prespecified complete-case sensitivity analysis was performed only at the 4-week time point, selected because corticosteroid benefit is typically greatest within 1 month. ³ Descriptive summaries are mean (SD) or n (%). Analyses used R 4.3 (dplyr for data processing, GenBinomApps for exact CIs, and lme4 for mixed models). Given the exploratory objective, efficacy comparisons are presented as point estimates and 95% CIs; any P values are unadjusted and hypothesis-generating.

Results

Participant Characteristics and Feasibility

Forty-one participants were randomized (21 corticosteroid; 20 saline). Baseline demographics, symptom duration, prior treatments, patient-reported outcomes, and imaging were similar between groups (Table 1). Thirty-one participants (76%, 95% CI: 60–88) completed the 12-week visit. Across all scheduled assessments (205 expected measurements), 3% of outcome measurements were missing, reflecting partial data contribution from most noncompleters despite a 24% participant-level dropout rate and occasional capture of PROMs outside in-clinic visits. Missed clinic visits (31/205; 15%, 95% CI 11-21) occurred primarily among noncompleters. Baseline characteristics were comparable between completers and noncompleters. No related adverse events were identified: descriptive imaging findings are shown in Table 1; mean plantar fascia thickness was 5.1 mm (SD 1.7) in the corticosteroid group and 5.2 mm (SD 2.8) in the saline group, consistent with symptomatic plantar fasciitis.

Table 1.

Baseline Characteristics: (A) Demographics, Symptom Duration, Prior Treatments, Baseline PROMs, and Imaging by Treatment Group. (B) Baseline Characteristics by Completion Status. ^a

A. Baseline Demographics, Patient-Reported Outcomes, and Imaging Characteristics by Intervention Group
Variable	Corticosteroid Injection(n = 21)	Saline Injection(n = 20)
Age, y	54.0 ± 12.4	53.5 ± 13.1
Body mass index	30.3 ± 6.3	35.3 ± 10.3
Sex (female)	21 (100)	15 (75)
Ethnicity: Hispanic or Latino	2 (10)	1 (5)
Race
Asian	0 (0)	1 (5)
Black	1 (5)	2 (10)
Unknown	1 (5)	1 (5)
Diabetes mellitus diagnosis	4 (20)	1 (5)
Clinical duration of symptoms at baseline, d	205 ± 323	125 ± 217
Initial FFI total score	41.7 ± 11.3	45.5 ± 14.4
Initial VAS first-step heel pain	61.0 ± 20.6	72.3 ± 13.8
Initial VAS general heel pain	47.0 ± 16.6	49.4 ± 17.9
Heel spur size (radiograph, mm)	5.1 ± 3.3	5.1 ± 3.9
Heel spur present (n)	17 (81.0)	14 (70.0)
Plantar fascia thickness (ultrasonography, mm)	5.1 ± 1.7	5.2 ± 2.8
B. Baseline Demographics by Study Completion Status
Variable	Completed Study(n = 31)	Did Not Complete Study(n = 10)
Intervention
Corticosteroid injection	16 (52)	5 (5)
Saline injection	15 (48)	5 (5)
Age, y	55.8 ± 13.1	47.5 ± 9.1
Body mass index	32.5 ± 9.1	33.4 ± 8.0
Sex (female)	27 (87)	9 (90)
Ethnicity: Hispanic or Latino	3 (10)	0 (0)
Race
Asian	1 (3)	0 (0)
Black	3 (10)	0 (0)
Unknown	2 (6)	0 (0)

Abbreviations: FFI, Foot Function Index; PROMs, Patient-Reported Outcome Measures; VAS visual analog scale.

a

Values are presented as mean ± SD for continuous variables and as n (%) for categorical variables.

Exploratory Efficacy

Exploratory unadjusted mixed effects estimates favored saline compared with corticosteroid over 12 weeks (Figure 2):

• FFI: −3.2 points (95% CI: −6.1, −0.4)

• VAS First-Step Pain: −6.6 mm (95% CI: −10.7, −2.4)

• VAS General Pain: −3.0 mm (95% CI: −6.6, 0.7)

Figure 2.

Changes in Foot Function Index (FFI) and Visual Analog Scale (VAS) heel pain scores over 12 weeks for corticosteroid and saline injection patients. Unadjusted linear mixed effects estimates with shaded 95% CIs for (A) FFI Total, (B) VAS First-Step Pain, and (C) VAS General Heel Pain. Lower values indicate improvement.

Both groups demonstrated within-group reductions in FFI and VAS from baseline to 12 weeks; for example, VAS First-Step Pain declined from 61.0 to 36.1 mm in the corticosteroid arm and from 72.3 to 23.9 mm in the saline arm (Supplemental Table S1). By contrast, the between-group differences (saline minus corticosteroid) were below published MIDs (≈7 points for FFI Total; ≈9 mm for VAS), consistent with the exploratory, feasibility-focused design.

Sensitivity Analysis

At 4 weeks (complete cases)—a time window when corticosteroid effects are typically greatest—group differences were small with wide CIs (Supplemental Figure 2):

• FFI: −0.1 (95% CI: −4.9, 5.2)

• VAS First-Step Pain: −5.1 mm (95% CI: −14.0, 3.9)

• VAS General Pain: −4.1 mm (95% CI: −12.2, 4.2)

Future Sample Size

Assuming a 10-mm detectable difference in VAS General Pain, intraclass correlation 0.44, 25% attrition, 80% power, and α = 0.05, a future trial would require approximately 248 participants (124 per group).

Discussion

This pilot study evaluated the feasibility of a standardized infracalcaneal peppering injection for plantar heel pain and explored whether symptom changes differed between corticosteroid and saline injectates. The infracalcaneal approach engages the fascia’s transverse enthesis, offering wider coverage than traditional medial injections. ⁶ Needle peppering has shown therapeutic effects in other tendinopathies via mechanical stimulation, independent of injectate composition ⁵ ; our exploratory point estimates with 95% CIs are consistent with this literature.

Although not powered for efficacy, unadjusted mixed effects point estimates and 95% CIs indicated greater mean improvement in the saline group across FFI and VAS outcomes. Within-group reductions were observed in both arms (Figure 2; Supplemental Table S1), and interpretation is guided by published MID thresholds. Collectively, these exploratory data support the plausibility that mechanical effects, rather than corticosteroid pharmacology, contribute meaningfully to post-injection improvement.

Strengths include the randomized, double-blind design; standardized intervention; validated outcomes; and prespecified feasibility criteria, which were met. Retention (76%) and low outcome-level missingness (3%) support the practicality of conducting larger trials using this protocol in outpatient settings. Tolerability (eg, procedural pain, 24-48-hour soreness, early activity limitation, or rescue analgesic use) was not systematically quantified in this pilot. A full-scale trial should include brief, time-anchored tolerability measures to characterize patient experience more precisely.

Limitations include the absence of a noninjection control group, restricting attribution of effects to the injection itself; 12-week follow-up; and potential insensitivity of FFI for highly active patients. Future randomized trials should include an exercise-only control group (standardized stretching and strengthening), which were advised and logged—but not analyzed—in this pilot, limiting isolation of injection-specific effects. Additionally, the predominantly nonathletic pilot sample may limit generalizability to athletic or highly physically active populations. Procedural variables (needle gauge, number of fenestrations, injectate volume and type—including corticosteroid formulation) and potential mechanical effects warrant further study; although ultrasonographic guidance may improve precision, current evidence does not clearly demonstrate superior clinical outcomes over palpation-guided techniques. ⁹ Imaging confirmed typical fasciopathy features but was not intended to predict outcomes in this pilot. Saline itself may exert therapeutic effects in plantar fasciitis, complicating interpretation of “placebo” responses. ¹⁰ Alternatives such as percutaneous needle tenotomy (eg, Tenex, TenJet) show promising results for recalcitrant cases but require specialized equipment and procedural suites, whereas peppering injections are deliverable during routine care with minimal resource demands.

Conclusion

In this double-blind pilot trial, a standardized infracalcaneal peppering injection was feasible to implement in outpatient clinical settings, with acceptable retention and minimal missing data. Exploratory unadjusted findings suggest that symptom improvements may primarily reflect mechanical stimulation rather than corticosteroid pharmacology, a hypothesis that warrants evaluation in a larger adequately powered trial.

Supplemental Material

sj-pdf-1-fao-10.1177_24730114261441626 – Supplemental material for Peppering Injection for Plantar Heel Pain: A Double-Blind Randomized Feasibility Study (a Short Report)

Supplemental material, sj-pdf-1-fao-10.1177_24730114261441626 for Peppering Injection for Plantar Heel Pain: A Double-Blind Randomized Feasibility Study (a Short Report) by Michael A. Jones, Garrett S. Bullock, Kerry A. Danelson, David W. Robinson, Dekarlos M. Dial and David R. Sinacore in Foot & Ankle Orthopaedics