Flat Foot Reconstruction: Fundamentals, Techniques, and Clinical Pearls

Fundamentals of flat foot reconstruction

• Flat foot (pes planus or pes plano valgus) is a complex deformity involving loss or collapse of the medial longitudinal arch with contact of the foot to the ground during gait, especially through the heel strike and into push-off.
• Three arches of the foot:
  • Medial longitudinal arch
  • Lateral longitudinal arch
  • Transverse arch (Lisfranc region)
• Medial longitudinal arch components: calcaneus, talus, navicular, and the first three metatarsals; supported by ligaments such as the plantar calcaneo-navicular (spring) ligament, long and short plantar ligaments, deltoid ligaments, and the plantar fascia.
• Lateral longitudinal arch components: calcaneus, cuboid, and the 4th–5th metatarsals; not typically fused unless absolutely necessary due to adaptation problems in the foot.
• Transverse arch components: metatarsal bases, cuboid, and cuneiforms; sometimes referred to as the Lisfranc area; supported by the plantar calcaneonavicular (spring) ligament and the deep transverse metatarsal ligaments.
• Muscular support: tibialis posterior is particularly important; intrinsic foot muscles also contribute to arch height maintenance.
• Types of flat feet:
  • Congenital (present at birth) and congenital-flexible vs rigid varieties
  • Acquired: due to ligamentous weakening, tendon tearing (e.g., posterior tibial tendon dysfunction), trauma, or arthritis; can be rigid or flexible; can be associated with Charcot foot in diabetics or insensate feet.
• Flexible vs rigid deformation:
  • Flexible flat foot can be realigned with soft-tissue procedures or subtalar joint stabilization and often addresses posterior muscle tightness.
  • Rigid flat foot may require realignment osteotomies and/or joint fusions to restore a functional arch.
• Pathophysiology and driving factors:
  • Posterior tibial tendon dysfunction (PTTD) and posterior muscle group tightness (gastroc/Achilles) may drive collapse.
  • Soft tissue laxity and ligamentous failure (plantar fascia, deltoids, spring ligament) contribute to arch collapse.
• Surgical and non-surgical strategies aim to restore arch height, correct hindfoot alignment, preserve joint motion when possible, and avoid over-weaponizing the lateral column.
• Internal orthotic concept in flexible flat feet: subtalar arthroresis in the sinus tarsi can act as an internal orthotic to control subtalar motion and influence midtarsal realignment, potentially preventing progression to rigid deformity in pediatric patients.

Clinical assessment and imaging

• Evaluation uses clinical exam and radiographs to determine deformity magnitude and plan treatment; radiographs guide surgical planning but exact angles need not be memorized for every case.
• Lateral view findings:
  • Reduced calcaneal height; calcaneus may be parallel to the ground or plantarflexed.
• Axial views (talus/calcaneal axial views) help identify coalitions:
  • Talocalcaneal coalition (between talus and calcaneus)
  • Calcaneonavicular coalition (CN bar) between the anterior process of the calcaneus and the navicular.
• Common radiographic metrics include variation in hindfoot alignment and arch-related angles that inform the surgeon's plan.
• Functional metrics used to assess outcomes include ACFAS and AOFAS scores to measure patient-reported outcomes and functional improvement.

Classification and terminology

• Meyerson flat foot classification is historically used for posterior tibial tendon dysfunction (PTTD).
• Progressive collapsing foot deformity (PCFD) is a newer classification framework proposed by a consensus group for progressive collapse patterns.
• In practice, the emphasis is on recognizing the deformity type and planning the appropriate procedure, not solely on classification label.
• Journal and scholarly references: Journal of Foot & Ankle Surgery (JFAS) is a commonly used peer-reviewed journal for this topic; advertising in specialized journals is common in the field.

Non-surgical options and initial management (relevant for context)

• In flexible flat foot, less invasive measures may be used to delay or reduce progression, including soft-tissue balancing and posterior muscle lengthening when indicated.
• Plantar fascia release, when considered, typically involves release of the medial band only to preserve the central/lateral bands which support the arch.
• Temporary internal joint control (e.g., subtalar arthoresis) can be used to influence midfoot mechanics in pediatric patients at risk of progression to rigid deformity.

Primary surgical options for rigid or advanced deformities

• Medial double arthrodesis (single medial incision): fusion of the talonavicular (TN) joint and the subtalar joint (STJ).

  • Indications: rigid pes planus/pes plano valgus, stage 3 adult-acquired flat foot deformity, when CC joint fusion is not necessary.
  • Advantages: avoids calcaneocuboid (CC) fusion, reduces wound complications, lowers operative time, and lowers risk to neurovascular structures via a medial approach.
  • Disadvantages/limits: may not address all cases where CC joint fusion is required; long-term results depend on proper patient selection and meticulous technique.
  • Operative technique highlights:
  • Single medial incision running from near the tip of the medial malleolus to the naviculocuneiform (NC) joint.
  • Exposure between the posterior tibial tendon (PTT) and flexor digitorum longus (FDL) tendon; in severe PTTD, consider PT tendon resection.
  • FDL transfer to augment/ reinforce the posterior tibial tendon when indicated (e.g., in kids or during Kidner procedures for accessory navicular).
  • TN joint preparation: remove cartilage thoroughly using burs and osteotomes; use an AO distractor and Hinterman retractor to expose joint and ensure complete cartilage removal for reliable fusion.
  • Subtalar joint fusion: preserve talar blood supply; distraction helps joint reduction; fixation typically uses cannulated headless screws (Accutrak) sized around $ext{4.7–7.5 mm}$; configuration is important for stability (Delta construct is most stable).
  • Screw sizing conventions: TN screws often around $5.5 ext{ mm}$ in smaller patients; subtalar fixation often uses $7.0 ext{ mm}$ screws; you can also use 5.5 mm if necessary.
  • Neutral alignment is achieved by fixing the STJ first to set hindfoot position, then reducing and fixing the TN joint.
  • Optional neutralizing plate can be used over the medial column for added stability.
  • Intraoperative fluoroscopy is essential to verify proper joint positions.
  • Postoperative plan: early stability facilitates quicker rehab, with radiographic union expected within weeks and progressive weight-bearing as directed.
  • Outcomes and literature:
  • Medial double provides a viable alternative to full triple arthrodesis with advantages including fewer wound complications and shorter operative times.
  • TN joint fusion carries nonunion risk around the range of ~19 ext{–}20 ext{ extbackslash%}; CC joint nonunion risk is similar, but overall fusion strategy should minimize nonunions through meticulous technique and joint preparation.
  • Historical data from the 1990s–2000s demonstrated that TN fusion preserves motion of remaining joints and achieves deformity correction without CC fusion; subsequent studies showed medial approaches reduced complications and produced comparable corrections to triple in many cases.
  • 2021 International Orthopedics and 2022 systematic reviews/meta-analyses suggest that the medial double can yield outcomes comparable to or better than triple in certain adult-acquired flat foot patients, with favorable recovery and complication profiles.

• Other adjunct fusion and osteotomy options for the hindfoot and midfoot, often used in combination with or as alternatives to TN/STJ fusion:

  • Evans calcaneal osteotomy (lateral column lengthening): lengthens the lateral column to help elevate the midfoot and correct valgus heel.
  • Cotton osteotomy (medial calcaneal displacement osteotomy, MDCO): realigns the posterior facet and improves talar alignment by shifting the calcaneus medially.
  • Coots MDCO (medial displacement calcaneal osteotomy): another pattern of calcaneal adjustment to address hindfoot valgus.
  • Murphy's advancement (tendon transfer technique): advancement of the Achilles tendon insertion to reduce spasticity and help realign hindfoot in specific cases.
  • Tarsal or midfoot osteotomies (e.g., base of first ray realignment) using wedges or plates.
  • Joint-sparing strategies emphasize preservation of arthritic joints when possible.

• Grafts and biologics

  • Autograft options: hip, proximal tibia, calcaneus for structural grafting; autologous bone grafts can be harvested with minimal morbidity in many cases.
  • Allograft options: putty, structural grafts, non-structural graft materials to fill defects.
  • Biologic adjuncts: BMA, BMAC or autologous bone graft from the donor site to enhance fusion biology; biologics can be harvested using specialized systems and integrated into grafting steps.
  • Graft size considerations: avoid grafts larger than about $8 ext{ mm}$ in many osteotomies (e.g., Evans) to prevent lateral column over-lengthening and subsequent calcaneocuboid joint instability.
  • Graft fixation options when used: staples (nitinol S-shaped staples) or small plates to stabilize grafts; choice depends on surgeon preference and intraoperative stability.
  • Intraoperative sizing aids: lollipops or sizers to confirm correction before graft placement.

• Fixation hardware and instrumentation (AccuMed portfolio references)

  • Accutrak II headless compression screws: available in sizes such as $ext{4.7, 5.5, 7.5 mm}$; short and long thread variants; threads should be placed on the opposite side of the joint being fused for optimal compression.
  • Plate options: wedge or neutralizing plates for medial column stabilization or to address specific corrections (e.g., Cotton or Evans); however, many surgeons favor leaving plates out in favor of screw fixation due to cost and comparable stability.
  • S-shaped nitinol staples (S-back): useful for achieving compression across small tarsal-metatarsal joints and NC joints where screw fixation is challenging; allows direct visualization during placement; removal can be challenging but feasible.
  • Distractors and retractors for joint preparation:
  • AO distractor to aid joint exposure.
  • Hinterman retractor (Doktor B. Ed Hinterman, Belgium) to assist TN joint preparation.
  • Wedge plates and dilators to facilitate corrections (e.g., Cotton osteotomy, Evans osteotomy) and to help with plate-assisted corrections when needed.
  • Graft delivery and handling tools (e.g., lollipop sizing gauges) to plan and confirm graft choices.

• MIS vs open approaches and practical considerations for the OR

  • MIS (minimally invasive) or mini-open for calcaneal osteotomies is used by some surgeons, though others prefer a clean linear incision for precise exposure and controlled correction.
  • Advantages of medial approach: better visualization of neurovascular structures, direct access to TN joint, reduced wound exposure, and potentially shorter operative times.
  • Importance of having the right retractors and distractors available for TN joint prep to optimize outcomes in ASC settings where instrumentation variety may be limited.
  • Surgeon preference and experience significantly influence the choice of screws, plates, and graft materials; reps should be prepared with a full set of options to tailor to the surgeon’s technique.

• Case vignettes (illustrative cases to reinforce concepts)

  • “Dirty dancing” case: TN and STJ fusion via medial approach with bone spur removal; 48 minutes turnkey time; fusion radiographically in 5 weeks; weight bearing in 4 weeks; return to regular shoes in 8 weeks; patient satisfaction high.
  • 76-year-old female dancer with PT tendon tear and collapsing foot: medial double (TN + STJ fusion) performed; tourniquet time ~52 minutes; radiographic fusion at 5 weeks; weight-bearing at 5 weeks; return to dancing around 12 weeks post-clearance.
  • Valgus ankle case: TN joint fusion plus Evans graft into lateral calcaneus and fibular lengthening to optimize ankle replacement readiness; tourniquet ~79 minutes; return to regular shoes by 10 weeks; subsequent ankle replacement about 2 years later with good function.
  • Club foot with bilateral deformity: Murphy’s Achilles advancement plus medial double fusion; use of headless cannulated screws; navicular elevation implied by realignment; good functional outcome.
  • 49-year-old female with valgus deformity and arch collapse: realignment with Evans osteotomy and Cotton (MDCO) to elevate talus and restore arch; graft placed laterally; improved navicular-cuneiform alignment; preservation of uninvolved joints; improved foot posture without fusion.
  • 37-year-old active runner: valgus foot; Evans and Coutts osteotomies performed; improved heel position; alignment of navicular-cuneiform joint; maintained joint integrity.
  • 86-year-old patient: medial double with comprehensive realignment; substantial functional improvement and return to activities; emphasizes patient quality of life improvements with joint-sparing strategies when possible.
  • Emphasizes in all cases the value of addressing the hindfoot first to obtain a stable hindfoot position before final TN fusion and to consider staged procedures when concomitant ankle pathology is suspected.

• Practical takeaways for sales reps and teams (clinical pearls)

  • For the TN joint, focus on joint prep quality and distraction techniques; having a good retractor system (e.g., Hinterman) and distractors in the tray can make the procedure smoother.
  • Fixation strategy: Delta (triangle) configuration for STJ fusion offers higher stiffness and less deflection; screw diameter is less critical than achieving correct trajectory and purchase.
  • Avoid CC joint fusion unless symptomatic disease necessitates it; medial double reduces wound risk and simplifies recovery while still achieving deformity correction.
  • In cases where calcaneal realignment requires a large shift medially, considering plates for stability may be useful, but many surgeons prefer two screws across the osteotomy due to cost and comparable fixation.
  • Sizing and selection of screws (e.g., $4.7, 5.5, 7.5 ext{ mm}$) should align with the joint being fused (TN vs STJ) and patient size.
  • Graft strategies: use autograft or allograft as needed; avoid oversized grafts (> $8 ext{ mm}$) in Evans procedures to prevent lateral column instability and CC joint degeneration.
  • Biologics: advantages include improved fusion biology and the opportunity to bill for grafting; harvest systems enable BMA/BMAC or autograft collection through small incisions.
  • Be prepared with a full portfolio: ACCUTRAK headless screws, wedge plates, S-back staples, distractors, retractors, graft materials, and biology offerings to support the surgeon’s plan.
  • Cost consideration and outpatient shift: increasing emphasis on cost- and outcome-effective strategies; medial double often yields shorter operative times and potentially lower overall costs while delivering equivalent or superior recovery outcomes relative to triple arthrodesis in many cases.

Key literature and historical context

• Biomechanics (late 1990s): beading and testing showed that including the TN joint in fusion substantially reduces motion in remaining joints; TN fusion preserved more motion in subtalar joints compared with CC fusion scenarios.
• 1995 study: double arthrodesis (TN + STJ effectively) achieved equivalent deformity correction to triple while sparing the CC joint.
• 2005 Foot and Ankle Clinics retrospective: medial approach to triple fusion reduced wound complications; medial double avoided CC joint involvement with similar correction.
• 2013 Hyer et al.: medial approach did not increase valgus risk; odds ratio for increased valgus in the triple group was higher than medial double.
• 2015 DeVries: hindfoot deformity can be addressed adequately without CC fusion; CC fusion not strictly necessary for many deformities.
• 2021 International Orthopedics: double arthrodesis offers comparable functional outcomes to triple for stage 3 and above.
• 2022 systematic review: 184 articles screened; 13 met criteria; medial double superior to triple in recovery and complication rates.

Biologics and grafting specifics

• Autograft sources: hip, proximal tibia, calcaneus; harvesting through small incisions.
• Allografts: putty, structural, non-structural options.
• Graft sizes: generally avoid grafts larger than ~$8 ext{ mm}$ in Evans procedures to minimize lateral column stress and potential arthritis.
• Graft fixation support: staples or small plates depending on stability and surgeon preference.

Summary and practical implications

• Medial double arthrodesis has emerged as a robust, less invasive alternative to traditional triple arthrodesis for many rigid flat foot scenarios, offering comparable deformity correction with fewer wound complications and shorter operative times.
• A thorough TN joint prep, careful distraction, and stable fixation (preferably Delta configuration with appropriate screw sizing) are critical to successful outcomes.
• Graft choice and biologics can support fusion and correction but must be used judiciously to avoid over-lengthening the lateral column.
• The surgeon’s choice of fixation hardware (screws vs plates), MIS vs open approach, and staging strategy should be tailored to patient anatomy, deformity severity, and comorbidities.
• Reps should be prepared with a full portfolio and practical tips to support the surgeon in the OR and in postoperative planning, including cost considerations and ASC workflows.

Follow-up and contact

• If you have radiographs or questions, Dr. Miller offers his HIPAA-compliant email for follow-up discussions and case reviews.
• The session emphasizes ongoing education and collaboration between the surgeon and the sales team to optimize patient outcomes.