What is the most likely diagnosis and appropriate management for a patient with a three‑week history of right heel pain localized to a C‑shaped band on the lateral heel, worsened by weight‑bearing activities, first‑step morning pain and descending stairs, after walking in flip‑flops and playing pickleball, and relieved by rest, ice and NSAIDs?

Diagnosis and Management of Right Lateral Heel Pain

This patient most likely has a calcaneal stress fracture, and the appropriate management includes immediate activity modification with protected weight-bearing, avoidance of aggravating activities (especially pickleball), and consideration for advanced imaging if symptoms persist beyond one week.

Clinical Reasoning for Diagnosis

The C-shaped lateral heel pain pattern is highly characteristic of calcaneal stress fracture rather than plantar fasciitis. Several key features distinguish this diagnosis:

Diagnostic Features Pointing to Calcaneal Stress Fracture

• Pain localization to the lateral calcaneal wall (described as C-shaped on the lateral and posterior heel) is the classic presentation for calcaneal stress fracture, with tenderness slightly posterior to the subtalar joint facet 1.

• Progressive onset after increased activity (walking in flip-flops and playing pickleball) followed by worsening pain with continued weight-bearing is the typical history for stress fracture 1, 2.

• Pain with the calcaneal squeeze test should be assessed—squeezing the calcaneus from medial to lateral produces pain in stress fractures but not in plantar fasciitis 1.

Why This is NOT Plantar Fasciitis

While plantar fasciitis causes first-step morning pain, several features argue against this diagnosis:

• Plantar fasciitis produces medial plantar heel pain at the insertion of the plantar fascia on the medial tubercle of the calcaneus, not lateral or C-shaped pain 3, 2, 4.

• The lateral and posterior heel pain distribution described here does not match the typical medial plantar location of plantar fasciitis 2.

Immediate Management Algorithm

Phase 1: Initial Conservative Management (Weeks 1-2)

• Immediately discontinue all high-impact activities, particularly pickleball, running, and prolonged walking 1, 5.

• Protected weight-bearing with supportive footwear (absolutely no flip-flops) and consider a walking boot if pain is severe 1.

• Continue NSAIDs (ibuprofen) for pain control and anti-inflammatory effect 5.

• Ice therapy after any weight-bearing activities, which the patient is already doing effectively 5.

• Modify yoga practice to avoid poses that load the heel or require push-off movements 5.

Phase 2: Imaging Decision Point (Week 1-2)

• Obtain weight-bearing radiographs of the foot initially to exclude other pathology and look for stress fracture, though sensitivity is only 12-56% early in the course 1, 6.

• If radiographs are negative but pain persists beyond 1 week, proceed to MRI without contrast or CT without contrast, which are equivalent alternatives for detecting stress fractures 1.

• Alternatively, technetium bone scanning can detect stress fractures before they become radiographically visible 1.

Critical Pitfalls to Avoid

• Do not assume plantar fasciitis based solely on morning pain—the lateral location is the key distinguishing feature that points to stress fracture 1, 2.

• Never inject corticosteroids in or near the heel in this scenario, as this is contraindicated near the Achilles tendon and could worsen a stress fracture 1, 5.

• Do not allow continued high-impact activities like pickleball during the healing phase, as this will prevent fracture healing and prolong symptoms 1.

• Recognize that initial radiographs may be normal—symptoms often precede radiographic findings in stress fractures, so negative X-rays do not exclude the diagnosis 1, 6.

Reassessment Timeline

• Reexamine at 3-5 days if initial swelling limited the examination 1.

• Expect improvement within 6-8 weeks with appropriate activity modification and protected weight-bearing 5.

• Refer to orthopedics or sports medicine if no improvement after 6-8 weeks of conservative treatment, or if advanced imaging confirms a significant stress fracture requiring immobilization 1, 5.

Alternative Diagnoses to Consider

If the calcaneal squeeze test is negative and imaging rules out stress fracture, consider:

• Haglund's deformity with retrocalcaneal bursitis, which causes posterior and lateral heel pain from a prominent posterior superior calcaneus 1, 2.

• Calcaneofibular ligament sprain, though this typically follows a specific inversion injury rather than gradual onset 1.

• Sinus tarsi syndrome, which presents with lateral heel pain and instability on uneven surfaces 2.