Adult Acquired Flatfoot Deformity

Goals: Reduce inflammation, offload PTT, control pain

• Immobilization: CAM walker boot or short leg cast, non-weight-bearing or protected weight-bearing
• NSAIDs: Oral anti-inflammatories (if no contraindications)
• Ice: 15-20 minutes TDS over medial ankle
• Activity modification: Avoid prolonged standing, stairs, uneven ground
• Rest: PTT needs unloading to allow healing/reduction of inflammation

Goals: Restore function, prevent recurrence, transition to orthotic

• Progressive weight-bearing: Gradual transition from boot to supportive footwear
• Physiotherapy: PTT strengthening (resisted inversion), intrinsic muscle strengthening, proprioception
• Orthotic prescription: UCBL (University of California Berkeley Laboratory) insert or AFO (ankle-foot orthosis)
• Footwear advice: Firm heel counter, medial arch support, avoid flat flexible shoes

Goals: Prevent progression, maintain function, surveillance

• Orthotic compliance: Daily use in all footwear
• Weight management: Reduce mechanical load on PTT
• Activity modification: Avoid high-impact activities, use walking aids if needed
• Surveillance: 6-12 monthly review to assess for progression to Stage II
• Progression criteria: Increasing deformity, too many toes sign, failed single heel rise = surgical referral

Purpose: Correct hindfoot valgus by medializing calcaneus under tibia.

Options:

• Medializing calcaneal osteotomy (MCO): Simple medial translation of posterior fragment. Easy, reproducible. Most common choice.
• Koutsogiannis osteotomy: Medial slide PLUS lateral closing wedge. Greater correction power, useful for severe valgus.

Technique: Oblique osteotomy 1-1.5cm distal to posterior facet. Shift 8-12mm medially. Fix with 2 screws (lag technique or position screws).

Rationale: Shifts ground reaction force medial to subtalar axis, creating inversion moment.

Purpose: Restore dynamic arch support (replace failed PTT).

Why FDL over FHL?

• Better excursion (longer muscle belly, better arc of contraction)
• Less donor morbidity (FHL is stronger toe flexor, more missed if transferred)
• Easier harvest (medial approach)
• Sufficient strength (clinical outcomes equivalent or better than FHL)

Technique: Harvest FDL through plantar foot incision (master knot of Henry). Transfer through drill hole in navicular (anterior to posterior, exit dorsal cortex). Tension with foot in neutral hindfoot alignment and slight inversion. Fix with interference screw or suture anchor.

Rationale: Provides active inversion force and dynamic arch support during gait.

Indications: Significant forefoot abduction (talonavicular uncovering greater than 30%, AP talo-first metatarsal angle greater than 20 degrees).

Technique: Osteotomy anterior process of calcaneus, 1-1.5cm posterior to calcaneocuboid joint. Distract 8-12mm. Insert structural bone graft (allograft or autograft from iliac crest). Fix with plate or graft shape alone.

Effect: Corrects forefoot abduction, increases arch height (windlass effect), reduces talonavicular uncovering.

Caution: Overcorrection leads to rigid lateral column overload pain, calcaneocuboid arthritis. Limit lengthening to 10-12mm maximum.

Indication: Isolated gastrocnemius contracture (ankle dorsiflexion less than neutral with knee extended, but improves with knee flexed).

Technique: Strayer procedure (proximal gastrocnemius recession) or Baumann procedure (distal gastrocnemius recession at musculotendinous junction).

Rationale: Equinus forces hindfoot into valgus (compensatory). Correcting gastrocnemius contracture prevents recurrence.

Mandatory: Perform Cotton test in clinic AND confirm under anaesthesia.

Positive test: Hindfoot valgus persists when first ray is elevated (plantarflexed). Indicates forefoot varus is DRIVING hindfoot valgus.

Purpose: Correct fixed forefoot varus by plantarflexing first ray, removing the driver of compensatory hindfoot valgus.

Technique (Cotton osteotomy):

• Dorsal opening wedge osteotomy of medial cuneiform
• Insert structural bone graft (typically 5-8mm height)
• Fix with plate or screws
• Plantarflexes first ray, corrects forefoot varus

Alternative (Lapidus fusion): Medial cuneiform-first metatarsal fusion in plantarflexed position. More rigid correction, useful if TMT arthritis present.

Critical: This addresses the CAUSE of the deformity in IIB. Without it, the hindfoot correction will fail.

Indications: Isolated subtalar arthritis, rigid hindfoot valgus, talonavicular joint MOBILE and NON-arthritic.

Technique: Medial or lateral approach. Resect articular cartilage from posterior facet. Correct hindfoot valgus. Fix with screws (typically 2-3 large lag screws, cannulated or solid).

Advantages: Preserves talonavicular and calcaneocuboid joints (some midfoot motion retained). Faster rehabilitation than triple fusion.

Disadvantages: May not fully correct if talonavicular instability present. Higher risk of adjacent joint arthritis (talonavicular, ankle) long-term.

Indications: Rigid hindfoot valgus with talonavicular arthritis or instability. Need for greater correction power. Stage III with severe deformity.

Technique: Fuse subtalar, talonavicular, and calcaneocuboid joints. Correct hindfoot valgus, restore arch, address forefoot abduction. Fix each joint (screws or plates).

Advantages: Most powerful correction. Addresses all components of deformity. Lower recurrence rate than isolated subtalar fusion.

Disadvantages: Eliminates all hindfoot motion (significant functional loss). Accelerates ankle arthritis (increased loads). Longer rehabilitation, higher nonunion risk (3 joints to heal).

Pearl: Modern trend is towards "modified" triple (preserve calcaneocuboid if non-arthritic) to retain some hindfoot motion.

FDL transfer: Consider in Stage IIIA (flexible forefoot, minimal talonavicular arthritis). Provides some dynamic support even after fusion.

Lateral column lengthening: May still be needed if severe forefoot abduction and rigid calcaneocuboid prevents fusion.

Ankle monitoring: Stage III patients are at risk for progression to Stage IV (deltoid attenuation). Counsel about future ankle issues.

Supine on radiolucent table (Jackson table or standard with radiolucent foot extension).

• Head: Neutral, adequate airway access
• Upper body: Arms on arm boards or across chest (depends on anaesthetic preference)
• Pelvis: Centered on table, neutral alignment
• Operative leg: Hip neutral rotation (or slight external rotation), knee extended or slight flexion (bump under knee for relaxation)
• Non-operative leg: Abducted and supported on leg holder or pillow (out of C-arm path)

• Bony prominences: Sacrum, heels (non-operative), elbows
• Nerves at risk: Ulnar nerve (elbow padding), peroneal nerve at fibular head (if leg externally rotated or in leg holder)
• Pressure areas: Ensure heel of operative foot OFF table (ankle hanging free or on bolster)

Thigh tourniquet (standard):

• Apply over cast padding to proximal thigh
• Exsanguinate with Esmarch or elevation
• Pressure: 250-300 mmHg (adjust for patient size/BP)
• Expected time: 90-120 minutes (multiple osteotomies + transfer)

Advantages: Bloodless field aids dissection, tendon identification, osteotomy precision Disadvantages: Tourniquet pain (limited by anaesthetic), time limit (deflate and re-exsanguinate if exceeds 2 hours)

• Prep: Circumferential ankle and foot to mid-calf. Include proximal calf if anticipating gastrocnemius recession.
• Draping: Stockinette over foot, U-drape or split sheet isolating foot and ankle
• Landmarks exposed: Medial malleolus to toes (medial approach for FDL, medial cuneiform), lateral calcaneus (for MCO through lateral or oblique approach, Evans if needed)
• C-arm positioning: Ensure adequate AP, lateral, oblique views of foot AND hindfoot alignment view possible without repositioning patient. Test BEFORE prep/drape.

Lateral oblique approach:

• Incision: 4-5cm longitudinal, centered over lateral wall of calcaneus, 1cm inferior to peroneal tendons
• Start at posterior tuberosity, extend anteriorly parallel to plantar surface
• Landmarks: Lateral wall of calcaneus palpable subcutaneously, stay INFERIOR to peroneal tendons

Dissection:

• Incise skin and subcutaneous tissue
• Identify sural nerve (runs posterior to lateral malleolus, may have branches crossing field) - retract or protect
• Incise periosteum longitudinally over lateral calcaneal wall
• Elevate periosteum superiorly and inferiorly with periosteal elevator - STAY subperiosteal to protect soft tissues

Level: 1-1.5cm distal to posterior facet of subtalar joint (to avoid intra-articular cut).

Orientation: Oblique from posterosuperior to anteroinferior (approximately 45 degrees to plantar surface).

Fluoroscopy: Obtain lateral view to confirm level. Mark osteotomy line with electrocautery or marking pen on bone.

Rationale: Oblique orientation increases surface area for healing and allows translation without shortening.

Technique:

• Use oscillating saw with wide blade (for thick calcaneal cortex)
• Start posteriorly, cut anteroinferiorly maintaining oblique angle
• Irrigate continuously (prevent thermal necrosis)
• Complete osteotomy - confirm with gentle manipulation (posterior fragment should be mobile)
• Protect soft tissues (plantar nerves, Achilles medially) with retractors during sawing

Check: Fluoroscopy lateral view - confirm osteotomy complete, no intra-articular extension.

Translation:

• Grasp posterior fragment with bone clamp or Schanz pin
• Translate MEDIALLY (typically 8-12mm depending on preoperative deformity and intraoperative assessment)
• Assess correction: Hindfoot should align neutral to slight varus on hindfoot alignment view (Saltzman)
• Avoid overcorrection (greater than 5mm medial = risk of varus)

Temporary fixation: Large K-wire or guidewire across osteotomy to hold reduction

Definitive fixation:

• Two 6.5mm or 7.0mm cannulated screws (most common): Insert from posterior fragment into anterior fragment, lag technique (glide hole posteriorly, thread hole anteriorly). Aim for bicortical purchase anteriorly.
• Alternative: Plate fixation if comminution or osteoporotic bone (locking plate provides better fixation)

Fluoroscopy: Confirm screw position (AP, lateral views), adequate translation, no intra-articular screws.

Approach: Curvilinear incision centered over navicular tuberosity, extending posteriorly along medial ankle (can extend to posterior tibial tendon if debriding/excising diseased PTT).

Length: 6-8cm to allow access to both navicular insertion site and FDL posterior to medial malleolus.

Dissection:

• Incise skin and subcutaneous tissue
• Identify and protect saphenous vein and nerve (run anterior to incision)
• Incise flexor retinaculum (over PTT and FDL tendons)
• Identify PTT (larger, more anterior), FHL (posterior, deeper), FDL (between PTT and FHL)

Technique:

• Open sheath of FDL (longitudinal incision in sheath)
• Confirm identity: Pull on tendon and watch lesser toes flex (pathognomonic for FDL)
• Mobilize FDL proximally and distally with blunt dissection
• Transect FDL at level of navicular (or distally if harvesting through plantar foot)

Plantar foot harvest (if maximal length needed):

• Small incision plantar midfoot over master knot of Henry (crossing point of FDL and FHL)
• Identify FDL (splits to 4 slips for lesser toes)
• Transect at master knot or distal to it
• Pass proximal end through medial ankle incision using tendon passer or blunt clamp

Technique:

• Expose navicular tuberosity (remove any diseased PTT remnants if present)
• Mark tunnel entry site on plantar aspect of navicular tuberosity (slightly inferior and medial to normal PTT insertion)
• Drill tunnel: 7-8mm diameter, anterior to posterior, exit dorsal cortex of navicular (or drill anterior-posterior and tap out dorsally with small curette)
• Ensure tunnel is smooth (pass tendon passer through to confirm)

Fluoroscopy: Confirm tunnel does NOT violate talonavicular joint (lateral view).

Tensioning:

• Pass FDL through navicular tunnel (plantar to dorsal) using tendon passer or suture
• Position foot: Hindfoot neutral to slight varus, ankle neutral dorsiflexion
• Apply tension to FDL (should feel firm, not slack, but not overtightened - aim for slight inversion force when tensioned)

Fixation options:

• Interference screw (bioabsorbable or metal, 6-7mm): Insert into tunnel alongside tendon, compresses tendon against bone. Gold standard - strong immediate fixation.
• Suture anchor (dorsal cortex): Anchor tendon to dorsal exit point with suture anchor. Alternative if tunnel too large or tendon quality poor.
• Tenodesis screw and washer (dorsal cortex): Pass tendon, fold back, secure with screw and spiked washer over tendon. Traditional technique.

Check:

• Fluoroscopy: Confirm interference screw or anchor within bone, not intra-articular
• Clinical: Foot should be in slight inversion with tensioned transfer
• Range of motion: Move ankle/hindfoot to ensure transfer is not overtightened (prevents equinus or restricted motion)

If diseased PTT present:

• Debride degenerative portions (if partial tear with some intact fibers)
• OR completely excise (if complete rupture, macerated tissue)
• Send to pathology if concern for inflammatory etiology (e.g., seronegative arthropathy)

Rationale: Leaving diseased PTT may cause ongoing pain (source removal improves outcomes).

Approach: Oblique incision over anterior process of calcaneus, just posterior to calcaneocuboid joint.

Length: 4-5cm to allow osteotomy and graft insertion.

Dissection:

• Incise skin and subcutaneous tissue (beware sural nerve branches)
• Identify extensor digitorum brevis muscle (originates from anterior calcaneus) - can split or elevate superiorly
• Expose lateral wall of anterior calcaneus with subperiosteal dissection
• Identify calcaneocuboid joint (use fluoroscopy lateral view if uncertain)

Level: 1-1.5cm POSTERIOR to calcaneocuboid joint (to avoid intra-articular cut and preserve joint).

Orientation: Oblique from dorsal-lateral to plantar-medial (parallel to CC joint surface).

Fluoroscopy lateral: Mark osteotomy site with K-wire or cautery to confirm position.

Technique:

• Use oscillating saw to create osteotomy (through lateral cortex, into medial cortex but do NOT complete medially - maintain medial hinge for stability)
• Distract osteotomy using lamina spreader or osteotomes (progressive widening)
• Target distraction: 8-12mm (measured with ruler or calibrated osteotomes)
• Caution: Do NOT over-distract (greater than 12mm) - risk of calcaneocuboid overload and arthritis

Fluoroscopy: Confirm distraction width, parallel distraction (not hinged open dorsally or plantarly).

Graft options:

• Allograft tricortical iliac crest (most common): Pre-shaped, sterile, avoids donor site morbidity. Size to match distraction (8-10-12mm heights available).
• Autograft iliac crest: If allograft not available or patient/surgeon preference. Harvest from ipsilateral anterior iliac crest (adds operative time, donor site pain).
• Femoral head allograft: Can be morselized or shaped into wedge.

Insertion: Impact graft into osteotomy site (use mallet gently), ensure flush with lateral cortex, medial hinge intact.

Fixation: Typically graft shape provides stability (wedge effect). Can add small plate (2-3 holes, dorsal surface) if unstable or concern for graft displacement.

Fluoroscopy: AP and lateral views to confirm graft position, no intra-articular extension, maintained distraction.

Clinical: Forefoot abduction should be corrected (visual alignment of forefoot relative to hindfoot).

Fluoroscopy AP foot: Talonavicular coverage improved (navicular more congruent with talar head), reduced uncovering angle.

Intraoperative stress test: Apply varus stress to hindfoot and assess if arch rises (confirms lateral column lengthening effect).

• Deflate tourniquet (if used) and achieve hemostasis (electrocautery, ties)
• Copious irrigation (3L normal saline minimum across all incisions)
• Inspect wounds for any bleeding vessels or hematoma

Drain: Generally NOT used for routine Stage II reconstruction (small incisions, good hemostasis).

Consider drain if:

• Large dissection (e.g., extensive PTT excision, multiple osteotomies with significant dead space)
• Ongoing oozing despite adequate hemostasis
• High-risk patient (anticoagulation, bleeding disorder)

Type: 10 Fr Blake or Hemovac (small suction drain), remove POD 1-2 when output less than 30mL/24h.

Deep layer (if applicable): Absorbable suture (2-0 or 3-0 Vicryl) for periosteum/deep fascia if needed (usually not required for small incisions).

Subcutaneous: 3-0 or 4-0 absorbable (Vicryl, Monocryl) to close dead space and approximate dermis.

Skin: Options based on surgeon preference and wound tension:

• Subcuticular (3-0 or 4-0 Monocryl): Best cosmesis, less scarring. Suitable if low tension, good skin quality.
• Interrupted nylon (3-0 or 4-0): Simple, reliable. Remove POD 10-14.
• Staples: Fast, for larger incisions or obese patients. Remove POD 10-14.

Dressing:

• Sterile non-adherent dressing (e.g., Xeroform, Adaptic) over incisions
• Fluffed gauze for padding
• Soft roll bandage (circumferential, non-constrictive)

Splint:

• Below-knee plaster or fiberglass backslab (posterior slab from toes to below knee)
• Position: Ankle neutral dorsiflexion, hindfoot neutral to slight varus (to protect MCO and FDL transfer tensioning)
• Well-padded (especially over malleoli, heel, dorsum of foot)
• Secure with overwrap bandage (NOT circumferential cast - allow for swelling)

Purpose: Immobilization protects osteotomies and FDL transfer during initial healing (first 2 weeks until sutures removed and transition to cast/boot).

Goals: Protect osteotomies and FDL transfer, prevent swelling and complications.

• Immobilization: Below-knee backslab (posterior slab), transition to cast at 2 weeks after suture removal
• Weight-bearing: Strict non-weight-bearing (crutches or walker, NO weight on operative foot)
• Elevation: Leg elevated above heart level as much as possible (reduces swelling)
• Ice: 20 minutes every 2-3 hours over cast (NOT directly on skin)
• DVT prophylaxis: Aspirin 100mg daily OR enoxaparin (if high risk - obesity, prior DVT, prolonged immobility). Mechanical prophylaxis (foot pumps, TED stockings) if possible.
• Pain management: Multimodal (paracetamol + NSAID + opioid PRN), wean opioids by week 2
• Wound check: POD 10-14 for suture/staple removal, inspect for infection

Goals: Continue protection, begin gentle ankle motion (out of cast), monitor for healing.

• Immobilization: Below-knee circumferential cast or CAM walker boot (removable)
• Weight-bearing: Continue non-weight-bearing (osteotomies not yet healed)
• Physiotherapy: Gentle ankle range of motion exercises OUT of cast/boot (plantarflexion, dorsiflexion only - NO inversion/eversion). Knee and hip exercises to prevent stiffness.
• Radiographs: 6-week X-rays (AP, lateral foot, hindfoot alignment) to assess osteotomy healing, hardware position

Goals: Transition to weight-bearing, advance range of motion, restore gait.

• Immobilization: CAM walker boot (allows progressive weight-bearing)
• Weight-bearing: Progressive weight-bearing if radiographs show healing:
  • Weeks 6-8: Touch weight-bearing to partial (25-50% body weight), progress as tolerated
  • Weeks 8-10: Partial to full weight-bearing in boot
  • Weeks 10-12: Full weight-bearing in boot, transition to supportive shoe + orthotic
• Physiotherapy: Active ankle ROM (all planes), proprioception exercises (balance board), gait re-education (normal heel-toe pattern), FDL strengthening (resisted inversion)
• Precautions: NO high-impact activities (running, jumping), avoid uneven ground

Goals: Restore full function, strengthen supporting muscles, prevent recurrence.

• Footwear: Transition to supportive athletic or walking shoes with custom orthotic (UCBL or similar to support arch)
• Weight-bearing: Full unrestricted weight-bearing (out of boot)
• Physiotherapy: Progressive resistance exercises (ankle strengthening - inversion, eversion, plantarflexion, dorsiflexion), calf strengthening (heel raises), proprioception, sport-specific training if applicable
• Activity progression: Low-impact activities (walking, cycling, swimming) → gradual return to higher-impact if appropriate
• Radiographs: 3-month and 6-month follow-up X-rays to confirm union, assess alignment

Goals: Maintain correction, monitor for recurrence, prevent adjacent joint arthritis.

• Orthotic compliance: Daily use in ALL footwear (critical to prevent recurrence)
• Footwear: Firm heel counter, medial arch support, avoid flat flexible shoes
• Activity modification: Avoid prolonged barefoot walking, high-impact repetitive loading
• Surveillance: Annual radiographs for first 2-3 years to monitor for recurrence, then as needed if symptomatic
• Weight management: Maintain healthy BMI to reduce mechanical load
• Patient education: Recognize signs of recurrence (increasing arch sag, hindfoot valgus, pain) and report early

Similar to Stage II: Backslab, strict non-weight-bearing, elevation, DVT prophylaxis, pain management, wound check at 2 weeks.

• Immobilization: Circumferential cast (below-knee or short leg)
• Weight-bearing: Strict non-weight-bearing (arthrodesis sites need 8-12 weeks to fuse)
• Radiographs: 6-week X-rays to assess fusion progress (looking for trabecular bridging, no hardware loosening)

• Immobilization: Continue cast OR transition to CAM boot if radiographs show early fusion
• Weight-bearing: Begin progressive weight-bearing if radiographic evidence of fusion (trabecular bridging across at least 50% of fusion site)
  • If no clear fusion: Continue non-weight-bearing, repeat X-rays at 10-12 weeks
• Rationale: Arthrodesis is slower to heal than osteotomy (cartilage removal, larger surface area). Need radiographic confirmation before loading.

• Footwear: Transition to supportive shoe (often rocker-bottom sole to compensate for loss of hindfoot motion)
• Weight-bearing: Full weight-bearing once fusion confirmed (radiographs show solid bridging bone, no lucency at fusion site)
• Physiotherapy: Ankle ROM (limited due to fusion but maximize remaining motion), strengthening, gait re-education (compensatory strategies for rigid hindfoot)
• Radiographs: 3-month and 6-month CT or X-ray to confirm solid fusion

• Footwear: Permanent rocker-bottom or modified shoes (to aid rollover with rigid hindfoot)
• Surveillance: Annual radiographs to monitor for adjacent joint arthritis (ankle, naviculocuneiform)
• Expectations: Patients have stiff hindfoot but stable, pain-free (if fusion successful). Functional limitations on uneven ground, stairs.