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Pes Cavus Masterclass - BOFAS Lectures of Distinction

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Key takeaways

News and Commentary

Sponsorship & Session Focus

This video is a sponsored BOFAS “Lectures of Distinction” session focused on pes cavus (high-arched) foot deformity in the context of biomechanics and surgical decision-making, particularly in neuromuscular conditions such as CMT.

A central theme is the use of a structured algorithm to determine:

  • Which level(s) of the foot to correct
  • Whether deformities are flexible vs rigid

1) Ramsey Healthcare Sponsor Message (Context)

The opening segment explains Ramsey Healthcare’s UK presence and patient safety initiatives, emphasizing:

  • Scale: multi-country operations, large staff and patient volumes
  • Accreditation / performance claims: endoscopy accreditation; hospital ratings; patient recommendation rate
  • Safety culture program: “Speaking Up for Safety,” encouraging staff to raise concerns
  • Partnerships & integrated patient journeys, including collaboration with the NHS

2) Core Medical Lecture: Understanding Cavus Deformity

Definition & Key Features

A cavus foot is typically characterized by:

  • High arched structure
  • Does not flatten on weight-bearing

Neurological Cause & Subtypes

Cavus is frequently not isolated; it often has a neurological origin (framed as common—up to about two-thirds of cases in their framing).

They describe four cavus subtypes:

  1. Pure cavus / subtle cavus
    • Often driven by the first ray
  2. Cavovarus / “classical” cavus (neuromuscular origin)
    • Includes toe clawing and described forefoot pronation patterns
  3. Cavus with equinovarus features
    • Suggests tightness with a supination-related pattern
  4. Calcaneal cavus / posterior cavus
    • Hindfoot-driven (e.g., discussed in a polio context)

Hindfoot / Forefoot Balance Concepts

Key concepts include:

  • Calcaneopelvic unit
    • Used for hindfoot mechanics and “tendon guy ropes”
    • Tibialis posterior and peroneus brevis are mentioned for inversion/eversion control
  • Forefoot-to-hindfoot relationship
    • Correcting hindfoot alignment can worsen forefoot pronation
    • Therefore, balancing forefoot mechanisms is critical
  • Tripod stability concept
    • Forefoot and heel support points must be stable
    • Compensations are required if one point is abnormal

Coleman Block Test (Practical Assessment)

They reference the Coleman block test to assess whether cavus is:

  • Forefoot-driven vs hindfoot-driven

However, they stress context matters:

  • A tight Achilles can limit correction during testing
  • The Achilles may need to be relaxed (e.g., tested with the patient lying down) to avoid misinterpretation

3) Surgical Framework / Algorithm (Main Analysis)

General Principles

The operative approach emphasizes:

  • Correct positioning of the foot relative to the leg
  • Achieve a plantigrade, flat, balanced foot
  • Since cavus is multi-level, surgeons must think level-by-level:
    • Ankle → hindfoot → midfoot → forefoot

“Where Is the Deformity Coming From?” Checks

They repeatedly prompt surgeons to clarify deformity origin at multiple levels:

  • Ankle equinus origin
    • Is it arising from the ankle itself, or secondary to midfoot mechanics?
    • Over-lengthening the Achilles in the wrong scenario can worsen heel pitch / heel pain
  • Hindfoot varus
    • Determine if it is flexible or fixed
    • Flexible may be addressed with osteotomy; fixed often requires fusion
  • Forefoot compensation
    • After hindfoot correction, evaluate how the forefoot responds
    • Forefoot pronation/adduction patterns may change

Flexible vs Rigid Algorithm (High-Level Takeaway)

  • If flexible:
    • Prefer osteotomies and tendon balancing
    • A typical sequence mentioned:
      • Lateralizing calcaneal osteotomy
      • Forefoot osteotomy if needed (e.g., first metatarsal dorsiflexion)
      • Tendon transfers (commonly tibialis posterior, sometimes peroneus-related)
  • If fixed:
    • Prefer fusions at the relevant hindfoot/midfoot joints
    • Tendon balancing as required

Common “Exam-Style” Principle

  • Flexible deformity → osteotomies
  • Fixed deformity → fusions
  • Tendon transfer is often used to rebalance muscle forces

4) Case Series: Applying the Algorithm

Across multiple cases, they demonstrate repeated decision points:

  • Determine flexibility
  • Identify the source (ankle vs midfoot vs hindfoot)
  • Correct alignment while balancing tendon forces

Case 1 (K. Mulhoter): 38-Year-Old with Progressive Bilateral Deformities

Issues

  • Claw hallux
  • Shoe irritation
  • Lateral forefoot pain
  • Balance problems

Assessment

  • Deformity suggests cavus with hindfoot varus and neuromuscular origin (suspected CMT/similar)
  • Flexibility testing used a modified Coleman block approach
    • Attention to Achilles tightness
    • Testing in lying position with relaxed Achilles

Likely diagnosis

  • Charcot-Marie-Tooth type 2 pattern discussed

Treatment (flexible pathway)

  • Achilles lengthening (percutaneous)
  • Lateralizing calcaneal osteotomy (hindfoot-driven varus)
  • Tendon transfer (tibialis posterior to address inversion / foot drop mechanisms)
  • Forefoot balancing, including:
    • First ray dorsiflexion osteotomy
    • Management of clawing via changing extensor balance and fusion of the IP joint component

Key cautions / teaching

  • Correcting the hindfoot can temporarily worsen forefoot pronation
  • Forefoot dorsiflexion is often needed for tripod balance

Clinical Q&A notes

  • Differentiating where equinus comes from (ankle vs midfoot/other joints)
  • Warning against simply lengthening Achilles without confirming equinus origin
  • Plantar fascia release: they state they rarely do routine plantar fascial release in their cavus correction practice (noting differing international approaches)

Case 2 (Matt): 27-Year-Old with CMT1a, Rigid Cavovarus + Ankle Instability

Issues

  • Unstable shoe fit
  • Lateral pain
  • Very limited walking without crutches
  • Bracing no longer workable

Assessment

  • Imaging: hindfoot varus/cavus, ankle tilt/instability, significant malalignment
  • Important proximal factor: valgus knee alignment
    • They argue management should consider the joint above

Treatment strategy

  1. Proximal tibial osteotomy to correct knee alignment first
  2. Later ankle ligament reconstruction (Broström-type)
    • Ligaments incompetent, arthritis minimal
  3. Hindfoot is completely rigid/irreducible
    • Proceed with double arthrodesis (subtalar and talonavicular region implied)
  4. Tendon transfer (tibialis posterior)
    • Careful correction of hindfoot / heel position

Additional caution

  • Residual equinus origin may persist (ankle vs midfoot/plantaris)
  • Possible need for secondary procedures if issues remain

Case 3 (Vivek): 28-Year-Old with CMTX, Severe Cavovarus + Foot Drop

Presentation

  • Fixed cavus and equinus features
  • Toe clawing
  • Hindfoot described as relatively flexible

Assessment

  • Coleman block testing considered
  • Achilles tightness can distort interpretation
  • They also assess with lying/relaxed testing

Treatment

  • Achilles lengthening
  • Calcaneal osteotomy
  • “Vegetar” (wedge) tarsectomy for midfoot correction
    • Computer-assisted planning mentioned
  • Tendon transfer

Teaching emphasis

  • Joint-sparing goals
  • Correcting at the appropriate level, especially in a young patient

Case 4 (Vivek/Matt Live Demo): 23-Year-Old with Foot Drop + Flexible Deformity

Gait / symptoms

  • High-steppage gait (foot drop)
  • Poor balance

Teaching focus

  • Muscle imbalance patterns:
    • Relative weakness (e.g., tibialis anterior and peroneus brevis vs tibialis posterior dominance)

Operative teaching points

  • Incision planning for tibialis posterior harvest and peroneal-related transfer placement
  • Extended lateral approach for calcaneal osteotomy
  • Percutaneous Achilles lengthening
  • First metatarsal dorsiflexion osteotomy (first ray dorsiflexion)
  • Tendon transfers and alignment markers/pins intraoperatively

Outcome

  • Heel brought to neutral
  • Improved forefoot/toe alignment

Case 5 (Alex): 55-Year-Old with Delayed Presentation, Fixed Severe Cavovarus + Foot Drop

Presentation

  • Fixed deformity with hindfoot varus
  • Ankle rotation
  • Cavus and adducted forefoot
  • Curly/toe clawing

Assessment

  • Imaging suggests ankle osteoarthritis and severe fixed hindfoot alignment issues
  • Subtalar joint essentially rigid
  • Deformity does not correct into valgus

Treatment (fixed pathway)

  • TTC fusion (ankle + subtalar region fused; “hyperfusion” mentioned)
    • Addresses arthritis/pain and helps correct ankle rotational deformity
  • Forefoot procedures:
    • Tibialis tendon transfer for adduction correction
    • Forefoot balancing (metatarsal dorsiflexion osteotomy)
  • Toe deformity handled as part of forefoot correction planning

5) Overall Conclusions from the Session

The presenters’ shared message:

  • Cavus deformity management is not one-size-fits-all
  • Surgical decisions depend on:
    • Where the deformity originates
    • Whether each component is flexible vs fixed
  • The plan must be balanced, targeting:
    • A plantigrade
    • Stable tripod
  • Often requires multi-level correction plus tendon balancing
  • Deformities in other joints (e.g., valgus knees) can change operative sequencing and outcomes
  • Practical testing (e.g., Coleman block) and Achilles relaxation during assessment are crucial to avoid misattributing equinus origin

Presenters / Contributors

  • Andy Jones (CEO, Ramsey Healthcare UK) — sponsor segment
  • Howard Davis (Sheffield) — host/moderator (BOFAS Lecture of Distinction)
  • Karen Mulhotra
  • Matt Welkin
  • Naim (case discussion participant)
  • Vivek (case discussion participant)
  • Alex (case discussion participant)
  • Amara (audience Q&A contributor)
  • Viv Balochander (audience Q&A contributor)

Original video