Are Contoured Sandals Just as Good as Orthotics for Heel Pain? A Closer Look at the Research

If you’ve ever experienced plantar heel pain—especially that stabbing discomfort when your foot hits the floor first thing in the morning—you’ve probably come across a range of treatment suggestions: stretching, physical therapy, night splints, orthotics, injections, even surgery in severe cases. But what if pain relief could come from something as simple as changing the type of sandal you wear?

That’s exactly what a 2015 randomized controlled trial set out to test. Published in PLOS ONE and conducted by researchers at the University of Queensland and Regis University, the study compared three footwear interventions for plantar heel pain: contoured sandals, flat flip-flops, and in-shoe orthoses.

The results were surprising—and promising. Let’s break down what the study found, why it matters, and how we can interpret these results in a clinical or personal context.

🌟 Study Overview

Title:

Orthosis-Shaped Sandals Are as Efficacious as In-Shoe Orthoses and Better than Flat Sandals for Plantar Heel Pain: A Randomized Control Trial
Vicenzino B, McPoil TG, Stephenson A, Paul SK. (PLOS ONE, 2015)

Purpose:

To determine whether a commercially available contoured sandal—designed with a footbed resembling an orthotic—provides relief for plantar heel pain as effectively as traditional shoe inserts (orthotics), and more effectively than flat flip-flops.

Hypotheses:

1. Contoured sandals would be superior to flat flip-flops in reducing heel pain.

2. Contoured sandals would be equally effective as in-shoe orthoses.
   
   

🔬 Study Design

Type:

Randomized controlled trial (RCT), parallel-group, intention-to-treat analysis.

Participants:

• N = 150 adults (mean age 50 ± 12 years)

• All had plantar heel pain >4 weeks

• Pain had to be at least 3/10 on a numeric scale and worse with the first steps in the morning

• Exclusions: recent steroid injection, severe comorbidities, foot trauma, high athletic activity, current orthotic or sandal use
  
  

Intervention Groups:

1. Contoured Sandal Group (n = 49):

• Wore commercially available sandals with an orthotic-style contoured footbed (Vionic brand).
  
  

2. Flat Flip-Flop Group (n = 50):

• Wore flat thong-style sandals with no contour or support.
  
  

3. In-Shoe Orthotic Group (n = 51):

• Used over-the-counter, prefabricated full-length foot orthoses (also from Vionic).
  
  

Participants wore their assigned footwear or orthotics during all waking hours for 12 weeks.

Blinding:

• Participants and fitting staff were not blinded (due to the nature of the devices).
  Outcome assessors were blinded.
  
  

📊 Outcome Measures

Primary Outcomes (measured at 4, 8, and 12 weeks):

1. Global Rating of Change (GROC) – 15-point scale of perceived improvement
   
   

2. Lower Extremity Functional Scale (LEFS) – 20-item questionnaire on lower limb function (max score = 80)
   
   

Secondary Outcomes:

• Numeric Rating Scale (NRS) for heel pain severity

• Foot and Ankle Ability Measure (FAAM)

• Foot Posture Index (FPI)
  
  

📈 Key Findings

✅ Contoured sandals outperformed flat flip-flops

• At 12 weeks, 61% of participants in the contoured sandal group reported a meaningful improvement (GROC ≥13), versus just 34% in the flat flip-flop group.

• Odds Ratio (OR) = 0.32 [95% CI: 0.14–0.77]; p = 0.01

• Number Needed to Treat (NNT) = 4
  → For every 4 people who use contoured sandals instead of flat flip-flops, 1 additional person will experience substantial improvement.
  
  

✅ Contoured sandals performed similarly to in-shoe orthotics

• 59% of the orthotic group reported improvement (essentially the same as the sandal group).

• No significant statistical difference between contoured sandals and orthoses (p = 0.79).
  
  

✅ LEFS scores improved more with contoured sandals

• Median improvement = +10 points (exceeding minimal clinically important difference of 9).

• 57% of the contoured sandal group met that threshold, compared to 34% of the flip-flop group.

• Again, no significant difference between sandals and orthotics.
  
  

❌ Flat flip-flops fared the worst

• Only 34% showed meaningful improvement on GROC.

• LEFS scores showed the smallest functional gains.

• Heel pain reduction was also smaller compared to the other two groups.
  
  

🧠 Interpreting the Mechanisms

Although this study wasn’t designed to uncover why contoured sandals work, the authors offered several hypotheses:

1. Improved Load Distribution
   The contoured shape of the sandal likely increases plantar surface contact, reducing pressure on the heel and providing a more even distribution of load.
   
   

2. Arch Support & Heel Cup
   The midfoot support and deeper heel cup may reduce strain on the plantar fascia and limit excessive pronation.
   
   

3. Ease of Use for First-Step Pain
   Unlike orthoses that require a closed-in shoe, sandals can be slipped on immediately upon waking—possibly reducing the intense “first-step pain” that defines plantar heel pain.
   
   

4. Sensory Feedback
   Increased contact with the foot may enhance proprioceptive feedback, improving neuromuscular control and comfort.
   
   

⚖️ Strengths of the Study

• Randomized, controlled design

• Validated outcome tools (GROC, LEFS, FAAM)
  Intention-to-treat analysis strengthens reliability

• Practical relevance: Tested real-world footwear interventions
  Low dropout rate: Only 9% lost to follow-up over 12 weeks
  
  

🧱 Limitations

1. Lack of participant blinding
   Participants knew what they were wearing, which introduces possible placebo or expectation effects.
   
   

2. No compliance tracking
   Researchers didn’t measure how consistently participants wore the assigned devices.
   
   

3. Short follow-up
   The study lasted 12 weeks, so we don’t know if benefits are sustained over 6+ months.
   
   

4. Single manufacturer
   All devices were from the same brand (Vionic), which limits generalizability across other sandal or orthotic types.
   
   

5. Potential conflict of interest
   The study was funded in part by Vionics International, the sandal/orthotic manufacturer. However, authors stated that the funder had no role in data analysis or reporting.
   
   

👟 Practical Implications

This study provides strong support for recommending contoured sandals as a first-line conservative treatment for plantar heel pain—especially when:

• The person prefers open footwear (e.g., during warm weather)
  They're looking for a cost-effective, over-the-counter solution

• They're not ready for or cannot tolerate in-shoe orthotics
  
  

Contoured sandals may also be ideal for:

• Morning use to reduce first-step pain
  Indoor wear at home (instead of going barefoot)

• Travel or casual environments where supportive closed shoes aren’t feasible
  
  

💬 Final Thoughts

The 2015 Vicenzino et al. study is a high-quality randomized trial that adds meaningful evidence to a commonly overlooked solution: supportive sandals. Their findings show that contoured flip-flops are not just better than flat sandals—they’re as good as traditional orthotics for many people with plantar heel pain.

In clinical practice or self-care, that opens up more flexible and user-friendly options—literally.

Bottom line? If you’re dealing with plantar heel pain, and you find yourself barefoot or wearing flat sandals for much of the day, switching to a contoured pair may offer a low-cost, evidence-based step toward relief.

Reference:
Vicenzino B, McPoil TG, Stephenson A, Paul SK. Orthosis-shaped sandals are as efficacious as in-shoe orthoses and better than flat sandals for plantar heel pain: A randomized control trial. PLOS ONE. 2015;10(12):e0142789. doi:10.1371/journal.pone.0142789