What causes pain on the dorsum of the foot upon flexion?

Dorsal Foot Pain on Flexion: Differential Diagnosis

Pain on the dorsum of the foot during flexion most commonly results from extensor tendonitis, stress fractures of the metatarsals or midfoot bones, deep peroneal nerve entrapment, or midfoot arthritis.

Primary Diagnostic Considerations

Extensor Tendonitis

• Extensor tendon inflammation from overuse or repetitive dorsiflexion causes pain directly over the dorsum of the foot that worsens with active toe extension or resisted dorsiflexion
• Point tenderness localizes along the extensor tendons running across the dorsal foot surface
• Pain typically increases with activity and improves with rest

Stress Fractures

• Metatarsal stress fractures are among the most common stress fractures in the foot and present with dorsal foot pain that worsens with weight-bearing and activity 1
• The American Academy of Family Physicians notes that patients typically report increased walking or running activity before symptom onset 2
• Navicular stress fractures cause pain over the dorsal midfoot that intensifies with push-off during gait 1
• Initial radiographs have poor sensitivity (12-56%) for detecting stress fractures, so negative X-rays do not exclude the diagnosis 3
• If clinical suspicion remains high despite negative radiographs, MRI or technetium bone scanning should be obtained after 1-2 weeks of persistent symptoms 3, 2

Deep Peroneal Nerve Entrapment

• The deep peroneal nerve can become entrapped as it crosses the dorsum of the foot, causing burning pain, numbness, or tingling in the first web space between the great toe and second toe 4
• Pain may worsen with dorsiflexion due to increased tension on the entrapped nerve 4
• Tinel's sign over the dorsal foot (tapping produces electric-like sensations) suggests nerve involvement 4

Midfoot Arthritis

• Osteoarthritis of the tarsometatarsal or midtarsal joints causes dorsal foot pain that worsens with weight-bearing and dorsiflexion 3
• Radiographs can identify joint space narrowing, osteophytes, and subchondral sclerosis 3

Diagnostic Algorithm

Clinical Examination

• Palpate for point tenderness along extensor tendons, metatarsal shafts, navicular bone, and over the deep peroneal nerve course on the dorsal foot 5
• Assess pain with resisted dorsiflexion of the foot and toes to evaluate for tendonitis
• Perform Tinel's sign over the dorsum of the foot to assess for nerve entrapment 4
• Evaluate for edema or swelling localized to the dorsal foot, which suggests acute injury or stress fracture 2

Imaging Approach

• Weight-bearing radiographs of the foot should be obtained initially for all patients with dorsal foot pain 3
• If radiographs are negative but pain persists beyond 1 week, MRI without contrast or CT without contrast are equivalent alternatives for detecting stress fractures 5
• The American College of Radiology recommends technetium bone scanning for suspected stress fractures when initial radiographs are negative, as symptoms often precede radiographic findings 3, 2

Treatment Based on Diagnosis

For Extensor Tendonitis

• Rest and activity modification to reduce repetitive dorsiflexion movements 6
• NSAIDs for pain relief and inflammation reduction 6
• Ice therapy applied through a wet towel for 10-minute periods 6
• Gradual return to activity once pain resolves

For Stress Fractures

• Activity modification with non-weight-bearing crutches if needed for pain relief 2
• Pneumatic bracing or walking boot to facilitate healing 2
• Gradual increase in activity only after pain resolves and examination shows improvement 2
• Surgical consultation for high-risk locations (navicular), nonunion, or recurrent fractures 2

For Deep Peroneal Nerve Entrapment

• Conservative management includes activity modification, NSAIDs, and avoiding tight footwear that compresses the dorsal foot 4
• If symptoms persist despite 6-8 weeks of conservative treatment, surgical decompression may be indicated, with 60% excellent and 20% good outcomes reported 4

Critical Pitfalls to Avoid

• Do not rely solely on initial radiographs to exclude stress fractures, as sensitivity ranges from only 12-56% 3
• Reexamine patients 3-5 days post-injury if initial examination is limited by swelling, as excessive edema can obscure findings 5
• Consider neurologic causes when patients describe burning, tingling, or numbness rather than purely mechanical pain 7
• Avoid corticosteroid injections near extensor tendons due to risk of tendon rupture 6

When to Refer

• No improvement after 6-8 weeks of appropriate conservative treatment 6
• Suspected high-risk stress fractures (navicular, fifth metatarsal base) requiring advanced imaging or potential surgical intervention 2
• Persistent nerve entrapment symptoms despite conservative management 4