Can flat soles cause pain?

Can Flat Soles Cause Pain?

Flat soles themselves do not inherently cause pain, but in specific populations—particularly those with flat feet (pes planus), diabetes with neuropathy, or epidermolysis bullosa—flat, unsupportive footwear can contribute to pain by failing to redistribute plantar pressure and accommodate foot deformities.

Understanding the Relationship Between Flat Soles and Pain

In Healthy Individuals

• Flat feet are common in children and typically represent a normal variant that is flexible, painless, and of no functional consequence 1
• Most children with flatfeet are asymptomatic and will never require treatment 2
• In healthy adults without underlying foot pathology, flat soles are generally well-tolerated

In At-Risk Populations

Patients with Painful Flexible Flatfoot:

• Flat, unsupportive footwear fails to provide adequate arch support, leading to excessive plantar pressure and pain 3
• Both CAD-CAM and conventionally designed insoles significantly reduce pain compared to sham (flat) insoles in patients with painful flexible flatfoot, with pain scores of 27.84±18.41 mm and 27.05±16.82 mm respectively versus 46.39±20.18 mm with sham insoles 3
• Artificial arch supports effectively improve excessive peak pressure and body stability in flat feet, particularly in the inner hallux and forefoot regions 4

Diabetic Patients with Neuropathy:

• Patients at moderate-to-high risk for foot ulceration (IWGDF risk 2-3) have lost their ability to feel pain or pressure and cannot adequately judge footwear fit 5
• Flat soles without pressure redistribution fail to reduce plantar pressure at high-risk areas, increasing ulceration risk 5
• Therapeutic footwear with custom insoles reduces the risk of first-ever or recurrent foot ulcers with a relative risk of 0.53 (95% CI: 0.24-1.17) compared to patients' own footwear 5

Patients with Epidermolysis Bullosa:

• Footwear should have a flexible flat sole with heel support (not completely flat and rigid) to prevent blistering 5
• Shock-absorbing insoles and custom orthotics improve mobility and reduce blister severity in all EB patients 5

Clinical Algorithm for Footwear Recommendations

Step 1: Identify Patient Risk Category

Low Risk (No foot pathology):

• Flat soles are generally acceptable
• Focus on proper fit: adequate length, width, and depth 5

Moderate Risk (Painful flat feet, heel pain, plantar fasciitis):

• Avoid completely flat, unsupportive soles 6, 7
• Prescribe shoes with proper arch support and cushioning 6
• Consider over-the-counter or custom arch supports/insoles 6, 3
• For plantar fasciitis specifically, heel cushions and arch supports are first-line interventions 6

High Risk (Diabetes with neuropathy, healed foot ulcers):

• Strongly avoid flat, unsupportive soles 5
• Prescribe therapeutic footwear with demonstrated plantar pressure-relieving effect 5
• Use custom-made insoles or extra-depth shoes for foot deformities 5
• Footwear must be evaluated by trained professionals in standing position 5

Step 2: Address Specific Pain Patterns

Heel Pain:

• Stable, supportive shoes show small effects on pain at 6 months compared to flat flexible shoes 5
• Heel cushions, arch supports, and proper cushioning reduce pain in plantar fasciitis 6
• Open-backed shoes reduce pressure for Achilles tendinitis and retrocalcaneal bursitis 6, 8

Medial Knee Pain (Osteoarthritis):

• Laterally wedged insoles show inconsistent results and do not consistently relieve pain 5
• Full-length wedged insoles may have more consistently positive biomechanical effects than heel wedges 5
• Most evidence does not support lateral wedged insoles for pain relief in knee OA 5

Key Evidence Limitations and Caveats

• Wedged insoles for knee OA: Despite theoretical benefits, laterally wedged insoles have not consistently relieved pain and show mixed results for knee realignment 5
• Individual response variability: Some patients respond to interventions while others do not, with significant between-subject differences 5
• Flat feet in children: Inserts and shoe modifications lack convincing evidence for symptom relief and do not change foot shape 2
• Pain location matters: Posterior heel pain suggests Achilles tendonitis, lateral heel pain suggests Haglund's deformity, and pain relieved when barefoot but worsened by shoes suggests bursitis 6, 7

Common Pitfalls to Avoid

• Do not prescribe flat, unsupportive footwear for diabetic patients with neuropathy—this significantly increases ulceration risk 5
• Avoid assuming all flat feet require treatment—most are asymptomatic and represent normal variants 1, 2
• Do not rely solely on laterally wedged insoles for knee OA pain—evidence shows inconsistent benefits 5
• Ensure proper footwear fit is evaluated by trained professionals in at-risk populations, particularly those with loss of protective sensation 5