Clinical Assessment: Leg/Ankle Pain - 20-Year-Old Female, 15 Days Duration

Overview

Differential Diagnosis by Anatomical Location

At the Ankle Joint

Below the Ankle Joint

Top Diagnoses for This Presentation

1. Stress Fracture (HIGH PRIORITY in young female)

• Young women are at particular risk - female military recruits have well-documented high rates of stress fractures.
• Common sites: fibula (most common), navicular, metatarsals, medial malleolus.
• Presents as aching pain worsening with activity, point tenderness over bone.
• Pain over the medial malleolus or lateral malleolus directly = stress fracture until proven otherwise.
• X-ray often normal in early stages - MRI or bone scan needed.
• Ask about: new activity or training regimen, irregular menstrual cycles, dietary calcium intake (female athlete triad).
• (Firestein & Kelley's, p. 958; also Rockwood & Green's Fractures in Adults 10th ed)

2. Ankle Ligament Sprain / Lateral Ligament Injury

• Most common ankle injury overall. Anterior talofibular ligament (ATF) is the most commonly injured.
• Even without a clear traumatic event, repetitive micro-trauma can occur.
• Tenderness anterior to the lateral malleolus, pain with inversion.
• Subacute presentation (15 days) may indicate inadequately treated or unrecognized sprain.
• (Swanson's Family Medicine Review)

3. Peroneal Tendon Pathology

• Pain posterior to the lateral malleolus.
• Can mimic lateral ankle sprain - often missed (only 60% of peroneal tendon disorders are diagnosed at initial presentation).
• Includes tenosynovitis, longitudinal "split" tears, tendon subluxation with a "popping" sensation.
• Resisted eversion reproduces pain; tenderness along posterolateral fibula.
• (Campbell's Operative Orthopaedics 15th Ed, 2026)

4. Tarsal Tunnel Syndrome

• Compression of the posterior tibial nerve in the tarsal tunnel (behind medial malleolus).
• Burning pain + paresthesias on the medial ankle and plantar foot.
• Symptoms worsen with standing/walking, may radiate proximally.
• Positive Tinel's sign at the tarsal tunnel.
• (Miller's Review of Orthopaedics 9th Ed; Adams & Victor's Principles of Neurology 12th Ed)

5. Sinus Tarsi Syndrome

• Lateral hindfoot pain localized to the sinus tarsi (just anterior and distal to fibula tip).
• Tenderness on palpation at this site.
• Often post-traumatic (following ankle sprain).
• (Campbell's Operative Orthopaedics 15th Ed, 2026)

6. Posterior Tibial Tendon Dysfunction (PTTD)

• Posteromedial pain along the course of the posterior tibial tendon.
• Can present in young active women.
• Associated with progressive flatfoot deformity.
• Single heel raise test - inability to rise on tiptoe on affected side.
• (Firestein & Kelley's, p. 957)

7. Osteochondral Lesion of the Talus (OCD)

• Central or posterior ankle pain, often with swelling.
• Can present after minor trauma.
• Frequently missed on plain X-ray - MRI needed for diagnosis.
• (Firestein & Kelley's, p. 5769)

8. Inflammatory Arthropathy (Reactive Arthritis / Early Seronegative SpA)

• A 20-year-old female with ankle joint pain of 15 days warrants consideration of reactive arthritis or early psoriatic/undifferentiated SpA.
• Ask about: recent gastrointestinal or urogenital infection, skin changes, eye redness, back pain, family history.
• Typically presents with warm, swollen joint.

Key History Points to Elicit

• Exact location: At the joint itself vs. below/behind it?
• Onset: Sudden (traumatic) vs. gradual (overuse)?
• Activity: New exercise, walking, sports, standing job?
• Character: Aching (bone/tendon) vs. burning/tingling (nerve)?
• "Popping": Suggests peroneal tendon subluxation
• Menstrual history + dietary habits: Screen for female athlete triad (amenorrhoea + low energy + low bone density)
• Morning stiffness, systemic symptoms: Screen for inflammatory arthritis
• Bilateral vs. unilateral

Examination Checklist

1. Inspect: swelling, bruising, deformity, arch shape (flatfoot?)
2. Palpate each anatomical landmark systematically (see table above)
3. Range of motion: dorsiflexion (normal 10-20°), plantarflexion (40-50°), hindfoot inversion/eversion
4. Special tests:
   • Thompson test (Achilles rupture)
   • Tinel's sign at tarsal tunnel (medial ankle)
   • Anterior drawer test (ATF integrity)
   • Forced plantarflexion (posterior impingement)
   • Single heel raise (posterior tibial tendon)
   • Resisted eversion (peroneal tendons)

Investigations

Summary

1. Stress fracture - do not miss, especially if she is active; requires MRI if X-ray is negative
2. Ligament injury - even without clear trauma history
3. Peroneal tendon pathology - often misdiagnosed as ankle sprain
4. Tarsal tunnel syndrome - if burning or paresthesias are present
5. Inflammatory arthropathy - if joint is swollen, warm, or systemic features are present