Definition

Posterior tibial tendon dysfunction (PTTD) represents a progressive degenerative condition of the posterior tibial tendon resulting in medial longitudinal arch collapse and hindfoot valgus deformity. It is the most common cause of adult acquired flatfoot deformity.

Epidemiology

Incidence and Prevalence:

• Peak incidence: 5th-6th decade of life
• Gender: Female predominance (3-10:1 ratio)
• Prevalence: 3.3% in women over 40 years
• Bilateral involvement: 10-20% of cases (usually asymmetric presentation)

Risk Factors:

Systemic factors:

• Obesity: BMI over 30 (strongest modifiable risk factor)
• Hypertension: Associated with tendon degeneration
• Diabetes mellitus: Impaired tendon healing and neuropathy
• Inflammatory arthropathy: Rheumatoid arthritis, seronegative arthropathy (psoriatic, reactive)

Iatrogenic factors:

• Corticosteroid exposure: Intra-tendinous injection (CONTRAINDICATED), systemic steroids
• Fluoroquinolone antibiotics: Associated with tendinopathy

Biomechanical factors:

• Pre-existing pes planus: Constitutional flatfoot with hypermobility
• Hindfoot valgus alignment: Increased eccentric loading on PTT
• First ray hypermobility: Loss of medial column stability
• Gastrocnemius contracture: Hindfoot equinus increases pronation moment

Australian Context:

PTTD prevalence is increasing in Australia due to:

• Aging population (18% over 65 years by 2030)
• Obesity epidemic (67% adults overweight/obese)
• High prevalence of diabetes (5.1% of population)

Natural History:

Without treatment, PTTD typically progresses:

• Stage I → II: 6-18 months (tendinitis to flexible deformity)
• Stage II → III: Years (flexible to rigid peritalar arthritis)
• Stage III → IV: Variable (rigid flatfoot to ankle valgus)

Early intervention with orthotics in Stage I can prevent progression in 70-80% of cases. Once Stage II deformity develops, progression to Stage III is common without surgical reconstruction.

Pathophysiology

The posterior tibial tendon undergoes degenerative changes rather than inflammatory tendinitis. The pathophysiological cascade involves:

Primary Tendon Pathology:

1. Zone of hypovascularity: 2-6cm proximal to navicular insertion represents a watershed zone between:

   • Musculotendinous blood supply (proximally)
   • Osseous blood supply from navicular (distally)

2. Repetitive microtrauma: Eccentric loading during stance phase causes:

   • Tendon fiber microtears
   • Myxoid degeneration
   • Collagen disorganization
   • Loss of type I collagen (replaced by type III)

3. Tendon elongation: Mechanical failure under physiological loads leads to:

   • Loss of dynamic arch support
   • Inability to control hindfoot eversion
   • Progression from tendinosis to partial/complete rupture

Secondary Static Restraint Failure:

4. Spring ligament attenuation: As PTT fails, increased load on spring ligament causes:
   • Superomedial band elongation
   • Plantar bands attenuation/rupture
   • Loss of static support to talar head
   • Talar head plantarflexion and medial displacement

Tertiary Bony Deformity:

5. Hindfoot valgus: Calcaneal eversion from:

   • Loss of PTT inverter function
   • Unopposed peroneal eversion force
   • Achilles tendon lateral vector (valgus thrust)

6. Peritalar subluxation: Progressive malalignment causes:

   • Talonavicular joint uncovering (forefoot abduction)
   • Subtalar joint subluxation (hindfoot valgus)
   • Calcaneocuboid joint impingement

7. Forefoot supination: Compensatory forefoot varus develops:

   • Relative to hindfoot valgus
   • First ray plantarflexion
   • Lateral column overload

Quaternary Arthritic Changes:

8. Rigid peritalar arthritis: Chronic malalignment leads to:

   • Subtalar joint arthritis
   • Talonavicular joint arthritis
   • Calcaneocuboid joint arthritis
   • Transition from flexible (Stage II) to rigid (Stage III)

9. Deltoid ligament insufficiency: Late-stage ankle involvement:

   • Medial ankle instability
   • Ankle valgus tilt (talar tilt in mortise)
   • Lateral tibiotalar impingement
   • Stage IV disease

Biomechanical Consequences:

• Loss of windlass mechanism: Plantar fascia cannot tighten arch with dorsiflexion
• Decreased Achilles mechanical advantage: Calcaneal eversion shortens moment arm
• Lateral column overload: Calcaneocuboid joint bears increased load (sinus tarsi pain)
• Forefoot pressures: Increased lateral forefoot pressures, risk of ulceration in diabetics

Surgical Anatomy

Posterior Tibial Tendon:

• Origin:

  • Posterior tibia (interosseous border)
  • Interosseous membrane
  • Proximal fibula (small contribution)

• Course:

  • Posterior compartment of leg
  • Behind medial malleolus (beneath flexor retinaculum)
  • Curves beneath sustentaculum tali
  • Fans out to multiple insertions

• Primary insertion: Navicular tuberosity (plantar-medial surface)

• Secondary insertions (broad fan attachment):

  • All three cuneiforms (medial, intermediate, lateral)
  • Metatarsal bases 2-4
  • Cuboid (occasional slips)
  • Spring ligament fibrocartilage (functional support)

• Blood supply:

  • Musculotendinous junction: Posterior tibial artery branches
  • Distal tendon: Navicular osseous vessels
  • Watershed zone: 2-6cm proximal to insertion (critical zone for degeneration)

• Function:

  • Primary: Hindfoot inversion, adduction
  • Secondary: Ankle plantarflexion, medial arch support
  • Dynamic arch stabilizer: Controls pronation during stance phase

Spring Ligament Complex (Plantar Calcaneonavicular Ligament):

• Components (three bands):

  1. Superomedial band (strongest): Sustentaculum tali to navicular
  2. Medioplantar oblique band: Middle calcaneus to navicular
  3. Inferior plantar longitudinal band: Plantar calcaneus to navicular

• Function:

  • Primary static support to talar head
  • Prevents talar plantarflexion and medial displacement
  • Fibrocartilaginous articulation with talar head

• Pathology in PTTD:

  • Attenuates secondarily after PTT failure
  • Superomedial band most commonly affected
  • Requires reconstruction if Grade 3-4 tear (Bluman classification)

Static Restraints:

• Plantar fascia: Windlass mechanism, arch support
• Long plantar ligament: Lateral column stabilization
• Interosseous talocalcaneal ligament: Subtalar stability
• Deltoid ligament: Medial ankle stability (fails in Stage IV)

Dynamic Support:

• Tibialis posterior: Primary arch stabilizer
• Flexor digitorum longus: Transfer donor, secondary arch support
• Flexor hallucis longus: Secondary arch support
• Tibialis anterior: Counterbalances tibialis posterior
• Peroneus longus: Plantarflexes first ray, lateral column support
• Gastrocnemius-soleus: Achilles loads hindfoot (equinus increases valgus)

Zones of PTT Pathology (surgical planning):

• Zone 1: Myotendinous junction to medial malleolus (rare pathology)
• Zone 2: Behind medial malleolus (tenosynovitis, stenosing tenosynovitis)
• Zone 3: Inframalleolar to navicular insertion (most common zone of degeneration)
• Zone 4: Insertion to navicular (insertional tendinopathy, avulsion)

Johnson & Strom Classification (Modified by Myerson)

The Johnson & Strom classification, modified by Myerson to include Stage IV, is the gold standard for staging PTTD. Staging determines treatment: conservative vs reconstruction vs arthrodesis.

Bluman Classification (Spring Ligament Pathology)

Used to grade spring ligament pathology on MRI or intraoperative assessment:

• Grade 1: Attenuation only (elongation without rupture)
• Grade 2: Partial-thickness tear
• Grade 3: Full-thickness rupture
• Grade 4: Complete disruption with talar head uncovering

Surgical relevance: Grade 3-4 requires spring ligament reconstruction with allograft augmentation or direct repair.

History

Presenting Complaint:

Pain:

• Location: Medial ankle/hindfoot (along PTT course from medial malleolus to navicular)
• Character: Aching, exacerbated by activity
• Progression: Insidious onset over months to years
• Exacerbating factors: Prolonged standing, walking on uneven ground, stairs

Swelling:

• Medial ankle swelling: Worse with activity, improves with rest
• Tenosynovitis: Fusiform swelling posterior to medial malleolus

Deformity:

• Progressive flatfoot: Gradual arch collapse
• Shoe wear changes: Medial heel breakdown, difficulty fitting shoes
• Gait abnormality: Antalgic gait, foot external rotation

Functional Limitation:

• Difficulty with stairs (especially descent)
• Problems on uneven ground
• Unable to run or perform sports
• Prolonged standing painful

Timeline:

• Acute onset: Rare (suggests rupture after steroid injection)
• Insidious onset: Typical (months to years)
• Progression:
  • Stage I symptoms: 6-18 months before deformity
  • Stage II: Years before rigidity
  • Stage III-IV: Variable progression

Risk Factor Assessment:

• Systemic: Obesity, hypertension, diabetes, inflammatory arthropathy
• Medications: Corticosteroids (injection or systemic), fluoroquinolones
• Biomechanical: Pre-existing flatfoot, hypermobility
• Occupational: Prolonged standing, repetitive impact activities

Physical Examination

Observation (Standing):

"Too Many Toes Sign" (pathognomonic):

• Technique: Stand behind patient, observe feet
• Normal: See heel and 1-1.5 lateral toes
• PTTD: See heel and over 2 lateral toes (forefoot abduction)
• Severity: More toes visible = greater forefoot abduction

Hindfoot alignment:

• Normal: 5-7 degrees valgus
• PTTD: Over 10 degrees valgus (compare to contralateral)
• Asymmetry: Side-to-side comparison critical

Arch height:

• Loss of medial longitudinal arch: Talar head prominence medially
• Medial ankle bulge: Displaced talus palpable
• Lateral column: Relative shortening

Forefoot:

• Forefoot varus: Relative forefoot supination (compensatory to hindfoot valgus)
• First ray: Plantarflexion, callosity under first metatarsal head

Gait observation:

• Antalgic gait: Shortened stance phase on affected side
• Foot progression angle: Excessive external rotation
• Heel strike: Valgus thrust with loading

Palpation:

Tendon course palpation:

• Tenderness: Along PTT from behind medial malleolus to navicular insertion
• Swelling: Tenosynovitis (fusiform vs nodular thickening)
• Gap: Palpable defect suggests rupture (rare)

Bony landmarks:

• Navicular tuberosity: Prominence with spring ligament failure
• Talar head: Medial and plantar prominence
• Sustentaculum tali: Tenderness
• Sinus tarsi: Lateral hindfoot impingement pain (calcaneocuboid)

Special Tests:

Single Heel Raise Test (GOLD STANDARD)

Technique:

1. Patient stands on one leg (affected side)
2. Patient raises heel off ground
3. Observe hindfoot from behind

Normal response:

• Heel inverts as patient rises onto forefoot
• Arch reconstitutes
• Can perform 10+ repetitions

PTTD findings:

• Stage I: Can perform but painful, normal inversion
• Stage II-IV: CANNOT perform OR performs without heel inversion
• Bilateral testing: Compare to contralateral side

Interpretation:

• Sensitivity: 100% for Stage II or greater
• Specificity: 85% (other flatfoot causes may also fail test)

Passive Correction Test (Stage II vs III Differentiation)

Technique:

1. Patient sitting or supine
2. Examiner inverts heel manually
3. Palpate talonavicular joint while inverting
4. Assess if arch reconstitutes

Interpretation:

• Stage II (flexible): Deformity fully corrects, talonavicular reduces
• Stage III (rigid): Deformity persists, peritalar joints rigid, crepitus

Coleman Block Test (Forefoot vs Hindfoot Driven)

Technique:

1. Stand patient on 1-inch block under lateral foot (5th metatarsal hangs off)
2. Observe hindfoot alignment

Interpretation:

• Forefoot-driven: Hindfoot valgus corrects (flexible forefoot varus)
• Hindfoot-driven: Hindfoot valgus persists (PTTD pattern)

Flexibility Assessment:

Hindfoot range of motion:

• Inversion/eversion: Compare to contralateral
• Stage II: Flexible but deformed
• Stage III: Rigid, crepitus

Forefoot supination:

• Flexible: Corrects with hindfoot neutral positioning
• Fixed: Persistent forefoot varus (rare in PTTD)

First ray mobility:

• Hypermobile: Dorsiflexion/plantarflexion over 10mm
• Contributes to: Medial column instability

Neurovascular Examination:

Vascular assessment:

• Dorsalis pedis pulse: Palpate, document
• Posterior tibial pulse: Palpate, document
• Ankle-brachial index: If PVD suspected (diabetics, smokers)

Neurological assessment:

• Sensation: Light touch, 2-point discrimination (exclude neuropathy)
• Motor: Tibialis posterior (inversion strength), peroneals, ankle dorsiflexors
• Reflexes: Achilles reflex

Tarsal tunnel syndrome screening:

• Tinel's sign: Tap posterior tibial nerve behind medial malleolus
• Positive: Paresthesias in plantar foot (coexisting in 10% PTTD)
• Sensory: Medial and lateral plantar nerve distributions

Differential Diagnosis

Other Causes of Adult Acquired Flatfoot:

Inflammatory arthropathy:

• Rheumatoid arthritis, psoriatic arthritis
• Features: Polyarticular involvement, systemic symptoms, synovitis
• Differentiation: Inflammatory markers, rheumatoid factor, anti-CCP

Tarsal coalition:

• Features: Rigid flatfoot since adolescence, limited subtalar motion
• Differentiation: C-sign on lateral radiograph, CT confirms coalition

Charcot arthropathy:

• Features: Diabetic neuropathy, midfoot collapse, rocker-bottom deformity
• Differentiation: Loss of protective sensation, midfoot warmth/swelling, fragmentation on radiograph

Lisfranc injury:

• Features: Traumatic onset, midfoot swelling, abduction stress pain
• Differentiation: History of trauma, midfoot tenderness, radiographic diastasis

Plantar fascia rupture:

• Features: Acute medial arch pain, palpable defect, previous plantar fasciitis
• Differentiation: History of sudden pain (often during sports), bruising

Medial Ankle Pain Differentials:

Tarsal tunnel syndrome:

• Features: Burning paresthesias, positive Tinel's, night symptoms
• Differentiation: Nerve conduction studies, predominantly sensory symptoms

Deltoid ligament injury:

• Features: Acute trauma, lateral ankle ecchymosis (eversion mechanism)
• Differentiation: History of trauma, ankle stress radiographs

Accessory navicular syndrome:

• Features: Prominence since childhood, os naviculare on radiograph
• Differentiation: Longstanding symptoms, characteristic radiographic appearance

Algorithm

View larger

Non-Operative Management

Indications:

• Stage I: ALL patients initially (first-line treatment)
• Stage II-IV: Medical comorbidities precluding surgery, patient preference, non-ambulatory
• Contraindication to surgery: Severe peripheral vascular disease, uncontrolled diabetes, active infection

Contraindications to Conservative Management:

• Progressive deformity despite bracing (Stage II)
• Failed trial of appropriate conservative measures
• Patient desire for deformity correction (conservative does NOT correct)

Success Rates of Conservative Management

Stage I:

• Success rate: 70-80% respond to immobilization + UCBL orthotic
• Definition of success: Pain reduction, functional improvement, no progression
• Duration of trial: 6 months minimum before considering surgical intervention

Stage II:

• Success rate: 30-40% achieve symptom control with Arizona AFO
• Limitation: Does NOT correct deformity, only controls symptoms
• Natural history: Most progress to Stage III despite bracing

Stage III-IV:

• Role: Palliative only
• Limitation: Does not prevent progression
• Indication: Non-surgical candidates only

Indications for Surgery

Stage I:

• Failed conservative management over 6 months
• Persistent pain limiting activities of daily living
• MRI-confirmed tendinosis or partial tear

Stage II:

• Failed conservative management (3-6 months trial)
• Progressive deformity despite appropriate bracing
• Functional impairment affecting quality of life
• Patient desire for deformity correction

Stage III:

• Symptomatic rigid deformity
• Failed conservative management
• Functional limitation

Stage IV:

• Progressive ankle valgus deformity
• Pain and dysfunction
• Patient fit for major surgery

Contraindications

Absolute:

• Active infection
• Severe peripheral vascular disease precluding healing
• Non-ambulatory patient (surgery provides no functional benefit)

Relative:

• Uncontrolled diabetes: HbA1c over 8% (optimize to under 7.5%)
• Smoking: Advise cessation minimum 6 weeks, ideally 12 weeks
• Obesity: BMI over 40 (encourage weight loss, assess realistic goals)
• Peripheral neuropathy: Risk of Charcot arthropathy post-surgery
• Poor bone quality: Osteoporosis (assess with DEXA if indicated)
• Inflammatory arthropathy: Active synovitis (optimize medical management)

Preoperative Optimization

Diabetes control:

• Target HbA1c under 7.5% (preferably under 7%)
• Defer elective surgery if over 8%
• Involve endocrinology/diabetes team

Smoking cessation:

• Minimum 6 weeks preoperatively
• Ideally 12 weeks
• Counseling, nicotine replacement therapy
• Document compliance

Weight loss:

• BMI reduction improves outcomes
• Realistic goal: 5-10% body weight reduction
• Dietitian referral
• Bariatric surgery consideration if BMI over 40

Vascular assessment:

• Indications: Diabetes, smoking, peripheral vascular disease symptoms
• Ankle-brachial index: Abnormal if under 0.9
• Referral to vascular surgery: If ABI under 0.7 or claudication

Cardiac assessment:

• Indications: Major surgery (triple arthrodesis, pantalar fusion)
• Functional capacity: Assess exercise tolerance
• Cardiology referral: If poor functional capacity or cardiac history

Intraoperative Complications

Neurovascular injury:

Sural nerve injury (most common):

• Incidence: 5-10% in lateral approaches (MDCO, lateral column lengthening, triple arthrodesis)
• Prevention: Careful identification and protection throughout procedure
• Management:
  • If identified: Primary repair if transection
  • Postoperative neuropathic pain: Gabapentin, referral to pain specialist

Saphenous vein/nerve injury:

• Incidence: 5% in medial approach (FDL transfer)
• Prevention: Retract anteriorly during dissection
• Management: Avoid ligation of saphenous vein if possible, nerve injury as above

Posterior tibial neurovascular bundle:

• At risk: Medial approach, aggressive retraction
• Prevention: Gentle retraction, awareness of anatomy
• Management: Vascular repair if injury, nerve repair/reconstruction

Fracture:

Calcaneal fracture during MDCO:

• Incidence: 2-5%
• Cause: Aggressive osteotome use, osteoporotic bone
• Prevention: Oscillating saw for osteotomy, gentle technique
• Management:
  • Intraoperative: Fixation with additional screws/plate
  • Alter postoperative protocol: Longer non-weight-bearing

Talar fracture:

• At risk: Triple arthrodesis (aggressive preparation)
• Prevention: Careful joint preparation, avoid excessive subchondral bone removal
• Management: Fixation, bone graft, prolonged immobilization

Early Postoperative Complications (Under 6 Weeks)

Wound healing problems:

Superficial wound dehiscence:

• Incidence: 5-10% (higher in diabetics, smokers, obese patients)
• Risk factors: Diabetes, smoking, obesity, malnutrition, steroid use
• Prevention:
  • Optimize comorbidities preoperatively
  • Careful tissue handling
  • Avoid excessive tension on closure
  • Avoid hematoma (use drain if large dissection)
• Management:
  • Minor: Local wound care, allow to heal by secondary intention
  • Major: Debridement, delayed closure vs flap coverage

Deep infection:

• Incidence: 2-5%
• Risk factors: Diabetes, immunosuppression, prolonged surgery, hematoma
• Presentation: Fever, wound erythema, purulent drainage
• Management:
  • Early (under 3 weeks): Debridement, irrigation, retain hardware if stable
  • Late (over 3 weeks): Debridement, consider hardware removal, IV antibiotics (6 weeks)
  • Organisms: Staphylococcus aureus (most common), MRSA, Gram-negatives

Hematoma:

• Incidence: 5%
• Prevention: Meticulous hemostasis, drain placement (remove 24-48 hours)
• Management:
  • Small: Observation
  • Large/expanding: Evacuation

Cast-related complications:

Pressure sores:

• Prevention: Adequate padding, cast checks, education
• Management: Cast removal, wound care

Compartment syndrome:

• Rare: Under 1%
• Presentation: Severe pain out of proportion, pain with passive stretch
• Management: Emergency cast removal, assessment, fasciotomy if confirmed

Late Postoperative Complications (Over 6 Weeks)

Non-union:

Calcaneal osteotomy non-union:

• Incidence: 2-5%
• Risk factors: Smoking, diabetes, inadequate fixation, infection
• Presentation: Persistent pain at osteotomy site, hardware failure
• Diagnosis: Radiographs (lucency, sclerosis, no bridging bone), CT scan
• Management:
  • Symptomatic: Revision osteotomy, bone graft, rigid fixation
  • Asymptomatic: Observation

Triple arthrodesis non-union:

• Incidence: 10-15% overall
  • Talonavicular: 5% (lowest)
  • Subtalar: 10%
  • Calcaneocuboid: 15% (highest)
• Risk factors: Smoking, diabetes, obesity, inadequate fixation, malnutrition
• Presentation: Persistent pain, inability to weight-bear
• Diagnosis: Radiographs, CT scan (gold standard)
• Management:
  • Revision fusion with bone graft (iliac crest autograft or BMP)
  • Rigid fixation (plate and screws)
  • Address risk factors (smoking cessation, diabetes control)

Malunion:

Residual valgus deformity:

• Incidence: 5-10%
• Cause: Under-correction during surgery, inadequate MDCO medial displacement
• Prevention: Intraoperative fluoroscopy, assess alignment
• Management:
  • Mild: Orthotics, observation
  • Severe: Revision osteotomy

Over-correction (varus):

• Incidence: 2-5%
• Cause: Excessive MDCO medial displacement
• Presentation: Lateral foot overload, 5th metatarsal pain, inversion instability
• Management:
  • Orthotics (lateral heel wedge)
  • Revision osteotomy if severe

Hardware complications:

Hardware irritation:

• Incidence: 10-15%
• Presentation: Palpable hardware, pain, skin irritation
• Management: Hardware removal after union (minimum 12 months post-surgery)

Hardware failure:

• Incidence: 5%
• Cause: Non-union, inadequate fixation, premature weight-bearing
• Management: Revision fixation with bone graft

Recurrent deformity:

Stage II reconstruction failure:

• Incidence: 10-15% at 5 years
• Causes:
  • Unrecognized Stage IIB (inadequate lateral column lengthening)
  • Inadequate MDCO correction
  • Spring ligament failure
  • Progressive peritalar arthritis (Stage III)
• Presentation: Return of pain, deformity, functional limitation
• Management:
  • Flexible recurrence: Revision reconstruction (repeat MDCO, add LCL if not done)
  • Rigid arthritis: Triple arthrodesis

FDL transfer rupture/elongation:

• Incidence: 5%
• Cause: Inadequate fixation, premature mobilization
• Presentation: Recurrent arch collapse
• Management: Revision transfer or progress to triple arthrodesis

Adjacent joint arthritis:

Ankle arthritis (post-triple arthrodesis):

• Incidence: 20-30% at 10 years
• Cause: Altered biomechanics, increased ankle stress
• Presentation: Ankle pain, stiffness, reduced range of motion
• Management:
  • Conservative: Orthotics, NSAIDs, activity modification
  • Surgical: Ankle arthrodesis or ankle replacement (consider TTC fusion)

Midfoot arthritis (post-pantalar fusion):

• Incidence: 30-40% at 10 years
• Cause: Complete loss of ankle/hindfoot motion, stress on midfoot
• Presentation: Midfoot pain, TMT joint arthritis
• Management: Midfoot fusion, orthotics

Complex regional pain syndrome (CRPS):

• Incidence: 2-5%
• Presentation: Severe pain out of proportion, allodynia, skin changes (color, temperature), edema
• Management:
  • Early recognition critical
  • Physiotherapy (desensitization)
  • Medications (gabapentin, pregabalin, ketamine)
  • Nerve blocks (sympathetic blocks)
  • Referral to pain specialist

Landmark Studies and Systematic Reviews

Guidelines, Registries and Global Practice

Global Epidemiology

PTTD is the most common cause of adult acquired flatfoot deformity (AAFD), driven by degenerative (not inflammatory) change in the tendon and progressing to fixed deformity if untreated (Bubra et al. 2015, J Family Med Prim Care; DOI). It predominantly affects women in the fifth-to-sixth decades, with obesity, hypertension and diabetes as the principal systemic associations. There is no national joint-replacement-style registry for flatfoot reconstruction; surgical-volume and outcome data derive from institutional series and the foot-and-ankle literature rather than population registries.

Terminology Shift (Important for Modern Practice)

In 2020 an international expert consensus (Myerson, Deland and colleagues) recommended retiring the terms "PTTD" and "AAFD" in favour of "progressive collapsing foot deformity (PCFD)", replacing the linear Johnson & Strom/Myerson stages with a flexible/rigid classification across multiple deformity classes (A-E: hindfoot valgus, midfoot/forefoot abduction, forefoot varus, peritalar subluxation/dislocation, ankle valgus). The traditional Johnson & Strom (Myerson-modified) staging (Johnson & Strom 1989, Clin Orthop Relat Res; DOI not assigned, PMID 2912622) remains the dominant examination framework and is used throughout this topic, but candidates should recognise PCFD nomenclature.

Side-by-Side Guidance and Practice Variation

Evidence Level

The evidence base is predominantly Level II-IV cohort and comparative series (e.g. Wacker/Saxby 2002; Ettinger 2019), with biomechanical/cadaveric support for soft-tissue reconstruction (Choi/Deland 2003) and expert-consensus classification work (Johnson & Strom 1989; PCFD consensus 2020). High-quality RCTs comparing reconstruction strategies are lacking, so recommendations are graded on expert consensus and cohort outcomes rather than Level I data.

Australian Practice Context

Australian foot-and-ankle practice aligns with the staging-driven algorithm above. Conservative care uses custom UCBL orthoses and Arizona-type AFOs (prescribed through accredited orthotists); short-course NSAIDs (e.g. ibuprofen, naproxen) are PBS-listed for symptomatic relief in early disease only. Smoking cessation support is available via Quitline (13 7848), an important pre-operative optimisation step given the impact of smoking on osteotomy and fusion union rates. Rising prevalence is anticipated with population ageing, high rates of overweight/obesity, and diabetes.

Current Controversies and Ongoing Research

Controversy 1: Isolated MDCO vs MDCO + FDL Transfer for Stage IIA

Pro isolated MDCO:

• Less invasive
• Preserves FDL function (digital flexion)
• Some studies show 75% success with isolated MDCO in Stage IIA

Pro MDCO + FDL transfer:

• Strong medium-term cohort support (Wacker/Saxby 2002: mean AOFAS 48.8 to 88.5, only 2/44 failures)
• Addresses tendon pathology directly and restores dynamic arch support
• Durable correction with preserved subtalar motion

Current consensus: MDCO + FDL transfer is the standard joint-sparing reconstruction, but isolated MDCO is acceptable in highly selected Stage IIA patients with minimal tendon pathology.

Controversy 2: Evans vs Cotton Osteotomy for Stage IIB

Evans (calcaneal lengthening):

• Addresses lateral column shortening directly
• Higher non-union rate (10%)
• Lateral column pain common (30%, usually resolves)

Cotton (medial cuneiform opening wedge):

• Addresses first ray hypermobility
• Lower non-union rate (5%)
• Does not address lateral column directly

Current consensus: Evans preferred for most Stage IIB cases, Cotton reserved for patients with first ray hypermobility or calcaneocuboid arthritis.

Controversy 3: Early Weight-Bearing Post-Surgery

Traditional protocol: Non-weight-bearing 6-12 weeks

Accelerated protocol: Protected weight-bearing at 2-4 weeks in CAM boot

Evidence: Limited RCTs. Some studies suggest accelerated weight-bearing safe with rigid internal fixation (locking plates), but higher risk of hardware failure and non-union. Current consensus: Non-weight-bearing until radiographic evidence of healing.

Future Directions

Ongoing research:

• Biologic augmentation (PRP, stem cells) for Stage I tendon healing
• Patient-specific 3D-printed cutting guides for osteotomies (improved accuracy)
• Minimally invasive techniques for FDL transfer
• Ankle replacement (vs fusion) for Stage IV with good bone stock
• Long-term outcomes of spring ligament reconstruction (over 10 years)