A 6-month-old female infant presents with persistent bilateral clubfoot deformity despite 4 months of Ponseti casting. The mother reports good compliance with the treatment protocol, and radiographs show persistent medial deviation of the talus with incomplete correction of the varus. The child's foot cannot be passively abducted beyond 20 degrees despite weekly casting. What is the most appropriate next step in management?

Explanation

## Management of Resistant CTEV: When Ponseti Fails **Key Point:** When CTEV fails to respond adequately to Ponseti casting (defined as inability to achieve >50° abduction or persistent varus after 8–12 weeks of appropriate casting), surgical intervention becomes necessary. ### Definition of Ponseti Failure **High-Yield:** Failure criteria include: - Inability to achieve ≥50° foot abduction after 8–12 weeks of weekly casting - Persistent varus deformity despite adequate casting - Recurrent deformity after initial correction - Atypical or complex presentations (e.g., associated with syndromes) This patient has been in treatment for 4 months with only 20° abduction — well below the success threshold. ### Surgical Options for Resistant CTEV | Procedure | Indications | Timing | Success Rate | |-----------|-------------|--------|---------------| | Posteromedial Release (PMR) | Failed Ponseti; persistent varus/equinus | 6–12 months of age | 85–90% | | Achilles Tenotomy | Residual equinus only | 8–12 weeks of casting | 95%+ | | Anterior Tibial Tendon Transfer | Dynamic supination; recurrent deformity | After initial correction | Variable | | Osteotomy | Late presentation; bony deformity | >2 years of age | 80–85% | **Clinical Pearl:** Posteromedial release (PMR) is the gold standard surgical procedure for Ponseti-resistant CTEV. It involves release of: 1. Posterior joint capsule (talocalcaneal and talonavicular) 2. Medial collateral ligaments 3. Medial plantar fascia 4. Soft tissue contractures ### Why Not Continue Casting? **Warning:** Continuing aggressive casting beyond 8–12 weeks in a non-responsive foot risks: - Skin necrosis and pressure ulcers - Iatrogenic midfoot break (rocker-bottom deformity) - Permanent tissue damage - Loss of tissue plasticity The 4-month duration with minimal progress indicates true Ponseti failure, not inadequate compliance. ### Why Not Achilles Tenotomy Alone? Achilles tenotomy addresses only the equinus component. This patient has: - Persistent varus (medial deviation of talus) - Adductus (forefoot inversion) - Limited abduction (20° vs. target >50°) These require comprehensive soft tissue release, not tenotomy alone. **Mnemonic: SURGICAL INDICATIONS** — **S**evere residual deformity, **U**nable to achieve 50° abduction, **R**ecurrent varus, **G**reat toe cannot dorsiflex, **I**nadequate response after 8–12 weeks, **C**omplex anatomy, **A**ge 6–12 months optimal, **L**ate presentation.