Can plantar fasciitis on one foot cause plantar fasciitis on the other foot?

Plantar Fasciitis and Bilateral Involvement

No, plantar fasciitis in one foot does not directly cause plantar fasciitis in the contralateral foot, but biomechanical compensation patterns may increase the risk of developing it bilaterally.

Understanding Plantar Fasciitis

Plantar fasciitis is a common degenerative condition affecting the plantar fascia, characterized by:

• Pain on the plantar surface of the foot, particularly with first steps in the morning or after prolonged sitting 1
• Tenderness to palpation at the anteromedial calcaneus (proximal plantar fascial insertion) 1
• Discomfort that can be elicited by passive ankle/first toe dorsiflexion 2

Risk Factors for Bilateral Development

While one foot developing plantar fasciitis doesn't directly cause it in the other foot, several mechanisms may lead to bilateral involvement:

• Altered Gait Mechanics: When experiencing pain in one foot, patients often modify their gait to reduce weight-bearing on the affected side, potentially increasing stress on the contralateral foot 3
• Shared Risk Factors: Common risk factors that affect both feet simultaneously include:
  • Obesity/increased body mass index 1
  • Prolonged standing 1
  • Limited ankle dorsiflexion 1
  • Excessive foot pronation 2
  • Tight Achilles tendon 4
  • Foot structure abnormalities (pes cavus or pes planus) 4

Diagnostic Considerations

When evaluating suspected bilateral plantar fasciitis:

• Diagnosis is primarily clinical, based on history and physical examination 1
• Imaging is rarely needed for initial diagnosis but may be considered for recalcitrant cases 2
• When imaging is necessary:
  • Ultrasonography shows increased plantar fascia thickness with good sensitivity (80%) and specificity (88%) 5
  • MRI allows accurate characterization of the plantar fascia and is considered the most sensitive imaging study 5
  • Both can detect complete and partial tears of the plantar fascia 5

Management Implications for Bilateral Cases

When plantar fasciitis affects both feet, treatment should address:

• Biomechanical Factors: Proper footwear that fits well and provides adequate support 5
• Stretching Protocols: Plantar fascia-specific stretches and calf stretching for both feet 3
• Activity Modification: Decrease cyclical repetitive loading of the plantar fascia 3
• Orthotic Support: Consider appropriate orthotics if foot deformities are present 5
• Addressing Proximal Factors: Trigger point release along the posterior lower extremity may help decrease pain and improve function 6

Prevention of Contralateral Involvement

To reduce the risk of developing plantar fasciitis in the unaffected foot:

• Ensure proper weight distribution when walking with assistive devices 5
• Consider a shoe lift on the contralateral limb when using offloading devices for the affected foot 5
• Address any underlying risk factors that could affect both feet 1
• Implement preventive stretching and strengthening exercises bilaterally 3

Clinical Pearls and Pitfalls

• Pearl: 90% of patients improve with conservative treatment within 12 months 1, 2
• Pitfall: Focusing treatment solely on the symptomatic foot while ignoring biomechanical compensation patterns that may lead to contralateral involvement
• Pearl: Ultrasonography is a reasonable and inexpensive diagnostic tool for persistent pain beyond three months 1
• Pitfall: Failing to address shared risk factors that may predispose both feet to developing plantar fasciitis

Remember that while plantar fasciitis in one foot doesn't directly cause it in the other foot, the underlying risk factors and compensatory gait patterns may contribute to bilateral development.