AN

Lowman Procedure (Navicular–Cuneiform Arthrodesis with Tibialis Anterior Transfer)

Overview of the Lowman Procedure

  • Primary Goal: Correct flexible flatfoot deformity by restoring medial arch height and stability.
  • Core Components:
    • Arthrodesis (fusion) of the navicular–cuneiform joint.
    • Tibialis Anterior (TA) tendon transfer through the osteotomy site.
    • Augmentation of the spring ligament complex via rerouted tendon segment.
    • Possible Achilles tendon lengthening if equinus is present.

Mnemonic & Historical Context

  • Mnemonic: Think of actor Rob Lowe “low to the ground.”
    • "Rob Lowe" → "Low-man" → Lowman procedure.
    • Visual cue: Rob Lowe crouched low, emphasizing plantar-flexed fusion and arch elevation.

Step-by-Step Surgical Technique

  • 1. Plantar Closing-Wedge Osteotomy
    • Site: Navicular–cuneiform joint.
    • Creates a wedge with the apex dorsally, allowing plantar flexion of the forefoot on the midfoot.
  • 2. Osteotomy Closure & Fusion
    • The plantar wedge is closed; bony surfaces apposed.
    • Internal fixation applied to achieve solid arthrodesis.
  • 3. Tibialis Anterior Tendon Transfer
    • TA is detached distally.
    • Rerouted through the osteotomy site.
    • Secured proximally, converting its line of pull to dorsiflex the medial column (arch) instead of the ankle alone.
  • 4. Spring Ligament Augmentation
    • A split portion of the transferred TA (or PT if chosen) is routed over “Rob Lowe’s head”—a metaphor for wrapping under the navicular.
    • Tendon segment allowed to fibrose/scar → becomes a check-rein ligament that reinforces the calcaneonavicular (spring) ligament.
    • Distal attachment: Calcaneus.
  • 5. Ancillary Procedure (Optional)
    • Percutaneous or open Achilles tendon lengthening when gastrocnemius–soleus tightness contributes to deformity.

Biomechanical Rationale & Functional Impact

  • Plantar-flexed Arthrodesis
    • Positions the medial column downward, raising the arch when weight-bearing.
    • Locks the navicular-cuneiform joint, limiting pathologic sag in the sagittal plane.
  • Repositioned TA Muscle Action
    • Origin remains at upper tibia; new insertion more proximal on medial column.
    • Produces dorsiflexion force on the arch, counteracting midfoot collapse.
  • Spring Ligament Reinforcement
    • Addresses attenuation/rupture commonly seen in flexible flatfoot.
    • Acts as a biologic graft that matures into a ligament-like structure.
  • Achilles Lengthening
    • Reduces equinus force that perpetuates midfoot break-down.

Indications & Contraindications (Implied)

  • Indications (inferred from purpose):
    • Symptomatic flexible flatfoot with medial column sag.
    • Failure of conservative measures (orthotics, PT).
  • Contraindications/Considerations:
    • Rigid flatfoot (fusion alone may not correct hindfoot).
    • Severe osteopenia compromising fusion integrity.

Post-operative Considerations (Not explicitly in transcript but contextually important)

  • Immobilization in cast/boot until fusion consolidation (≈ 6–8 weeks).
  • Progressive weight-bearing once radiographic union confirmed.
  • Physical therapy for gait normalization and TA re-education.

Key Takeaways / Examination Pearls

  • “Lowman = Low to the ground” → plantar-flexed navicular-cuneiform fusion.
  • TA tendon transfer rerouted through osteotomy → dorsiflexes arch, not ankle.
  • Spring ligament augmentation via tendon split → prevents future midfoot collapse.
  • Optional Achilles lengthening: addresses concomitant equinus.
  • Remember Rob Lowe crouching for visual memory of procedure mechanics.