Flatfoot Examination
Adult flatfoot examination requires systematic assessment of the posterior tibial tendon, hindfoot alignment, and flexibility of the deformity. Examiners expect you to perform the single heel raise test, too-many-toes sign, and differentiate flexible from rigid flatfoot.
Quick Reference One-Pager
Key Tests
- Single heel raise test (PTT function)
- Too-many-toes sign (forefoot abduction)
- Jack test (flexibility)
- Silfverskiöld (gastrocnemius tightness)
PTT Assessment
- Tenderness posterior to medial malleolus
- Swelling along tendon course
- Weakness of inversion in plantarflexion
- Can't perform single heel raise
Alignment
- Hindfoot valgus (from behind)
- Forefoot abduction (too-many-toes)
- Medial arch collapse
- Midfoot sag
Staging (Johnson-Strom)
- Stage I: PTT tenosynovitis, no deformity
- Stage II: Flexible flatfoot, PTT dysfunction
- Stage III: Rigid flatfoot, subtalar arthritis
- Stage IV: Ankle valgus added
Pathophysiology
Adult Acquired Flatfoot
Anatomy:
- PTT inserts on navicular, cuneiforms, and MT 2-4 bases
- Primary dynamic stabilizer of medial arch
- Inverts hindfoot and locks transverse tarsal joints
Pathophysiology Sequence:
- PTT degeneration/inflammation
- PTT elongation/rupture
- Spring ligament failure
- Hindfoot valgus develops
- Forefoot abduction (talonavicular subluxation)
- Lateral structures (sinus tarsi) impinge
- Subtalar arthritis (rigid)
- Ankle valgus (end-stage)
Risk Factors:
- Female, middle-aged, obesity
- Hypertension, diabetes
- Inflammatory arthritis
- Steroid injections near tendon
Understanding PTT Failure: When PTT fails:
- Peroneus brevis is unopposed → Hindfoot everts (valgus)
- Transverse tarsal joints unlock → Forefoot abducts
- Spring ligament stretches → Talar head drops medially
- Weight shifts lateral → Sinus tarsi pain
This explains all the clinical findings!
Observation
Standing Assessment
From Behind:
- Hindfoot alignment (valgus heel)
- "Too-many-toes sign" (abducted forefoot)
- Achilles tendon alignment (lateral bow)
From Medial Side:
- Medial arch height (collapsed)
- Talar head prominence (medial)
- Navicular drop
From Front:
- Forefoot supination (compensatory)
- Callosity pattern
From Lateral Side:
- Midfoot sag
- Rocker-bottom appearance (severe)
Special test
Too-Many-Toes Sign
Detect forefoot abduction
Technique
- 1Stand behind patient
- 2Count visible toes lateral to heel on each side
Positive Sign
More than 2 toes visible lateral to heel (normally 1-2)
Indicates
Forefoot abduction - transverse tarsal joint incompetence due to PTT failure
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Palpation
PTT Assessment
Course of PTT:
- Posterior to medial malleolus
- Along medial calcaneus
- To navicular insertion
Palpation Findings:
- Tenderness along tendon course
- Swelling (tenosynovitis)
- Thickening or gap (rupture)
- Navicular insertion tenderness
Compare with Normal Side:
- Tendon should be easily palpable
- Crepitus with movement
Specific Tests
Special test
Single Heel Raise Test
PTT function and hindfoot flexibility
Technique
- 1Patient stands facing wall, hands on wall for balance
- 2Stand on affected leg only
- 3Rise onto tiptoes repeatedly (aim for 10 repetitions)
Positive Sign
Inability to perform heel raise, pain, or failure of heel to invert
Indicates
PTT dysfunction - normally heel should invert with heel raise
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Interpreting Single Heel Raise:
- Normal: Heel inverts, can do 10+ repetitions
- Stage I PTTD: Can do but painful
- Stage II PTTD: Weak, few reps, heel doesn't invert fully
- Stage III-IV: Cannot do at all (rigid subtalar or ankle)
The heel MUST be observed from behind - inversion is the key finding!
Special test
Jack Test (Hubscher Maneuver)
Assess flexibility of flatfoot
Technique
- 1Patient standing, weight-bearing on flat feet
- 2Passively dorsiflex the great toe
Positive Sign
Medial arch reconstitutes (rises) with great toe dorsiflexion
Indicates
FLEXIBLE flatfoot (windlass mechanism intact). If arch doesn't rise, suggests rigid flatfoot
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Special test
PTT Strength Test
Direct PTT power assessment
Technique
- 1Patient sits with foot hanging, ankle in full plantarflexion
- 2Ask patient to invert foot against resistance
Positive Sign
Weakness of inversion compared to normal side
Indicates
PTT weakness or rupture
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Special test
Silfverskiöld Test
Differentiate gastrocnemius from Achilles tightness
Technique
- 1Assess passive ankle dorsiflexion with knee extended
- 2Repeat with knee flexed (relaxes gastrocnemius)
Positive Sign
Dorsiflexion improves with knee flexion (greater than 10° difference)
Indicates
Isolated gastrocnemius tightness (amenable to gastrocnemius recession)
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Flexibility Assessment
Flexible vs Rigid Flatfoot
Flexible Flatfoot:
- Arch present non-weight-bearing
- Arch collapses with weight-bearing
- Jack test positive (arch reconstitutes)
- Subtalar motion preserved
- Hindfoot valgus corrects when on tiptoes
Rigid Flatfoot:
- Arch absent even non-weight-bearing
- Jack test negative
- Subtalar motion restricted
- Hindfoot valgus doesn't correct
- Often painful (arthritis)
Assessment Technique:
- Manual correction of hindfoot valgus
- Subtalar ROM (inversion/eversion)
- Talonavicular mobility
- Midtarsal joint assessment
Staging (Johnson-Strom Modified)
- ptt
- Tenosynovitis, intact
- deformity
- None
- flexibility
- N/A
- treatment
- NSAIDs, immobilization, orthotics
- ptt
- Elongated/dysfunctional
- deformity
- Mild hindfoot valgus
- flexibility
- Flexible
- treatment
- Orthotics +/- FDL transfer, calcaneal osteotomy
- ptt
- Elongated/dysfunctional
- deformity
- Greater than 30% talar uncoverage
- flexibility
- Flexible
- treatment
- FDL transfer, calcaneal osteotomy, +/- lateral column lengthening
- ptt
- Dysfunctional/ruptured
- deformity
- Fixed hindfoot valgus
- flexibility
- Rigid
- treatment
- Triple arthrodesis or subtalar fusion
- ptt
- Dysfunctional
- deformity
- Ankle valgus added
- flexibility
- Rigid
- treatment
- Pan-talar fusion or tibiotalocalcaneal fusion
Staging Determines Surgery:
- Flexible (I-II): Soft tissue reconstruction + osteotomy
- Rigid (III): Fusion (subtalar ± triple)
- Ankle involved (IV): Include ankle in fusion
Flexibility testing is therefore CRITICAL for surgical planning!
Associated Assessment
Complete Examination
Ankle:
- Deltoid ligament integrity
- Lateral ankle pain (sinus tarsi impingement)
- Ankle ROM (often tight in equinus)
Forefoot:
- First ray position (elevatus common)
- Lesser toe deformities
- Callus pattern
Neurovascular:
- Pulses (atherosclerosis common in risk group)
- Sensation (diabetes association)
- Tarsal tunnel symptoms (nerve stretch)
Contralateral Side:
- Often bilateral
- Compare for staging
Differential Diagnosis
- age
- Middle-aged+
- onset
- Gradual
- ptt
- Dysfunctional
- features
- Unilateral initially
- age
- Child/adolescent
- onset
- Since walking
- ptt
- Normal
- features
- Arch with tiptoe, often asymptomatic
- age
- Adolescent
- onset
- Gradual
- ptt
- Normal
- features
- Rigid, painful, limited subtalar motion
- age
- Variable
- onset
- Gradual
- ptt
- May be involved
- features
- Bilateral, other joints affected
- age
- Diabetic
- onset
- Acute/subacute
- ptt
- Variable
- features
- Neuropathic, swollen, warm
- age
- Birth
- onset
- Congenital
- ptt
- N/A
- features
- Rigid rocker-bottom
Summary Presentation
“52-year-old obese woman with progressive medial foot and ankle pain over 2 years, now difficulty walking.”
Examination Sequence
Systematic Approach
- Observe standing: Hindfoot valgus, too-many-toes, arch collapse
- Observe gait: Antalgic, toeing out
- Palpate PTT: Tenderness, swelling along course
- Single heel raise: Function and heel inversion
- Jack test: Flexibility (windlass mechanism)
- Manual correction: Hindfoot valgus correctability
- Silfverskiöld: Gastrocnemius tightness
- Subtalar motion: Inversion/eversion (rigid vs flexible)
- Ankle: ROM, deltoid, valgus tilt
- Neurovascular: Pulses, sensation
Examiner Tips
Do
- Perform single heel raise correctly (observe inversion from behind)
- Assess flexibility with Jack test
- Test PTT power (inversion in plantarflexion)
- Check for gastrocnemius tightness (Silfverskiöld)
- Stage the deformity (guides treatment)
Don't
- Forget to view heel raise from behind
- Miss rigid vs flexible distinction
- Omit ankle valgus assessment (Stage IV)
- Forget neurovascular exam (diabetes association)
- Miss contralateral foot examination