A 6-month-old girl with a history of bilateral CTEV treated with Ponseti casting presents to the orthopedic clinic. Casting was completed 2 months ago, and the feet achieved a plantigrade position. However, the parents report that they stopped using the abduction brace 4 weeks ago because the child 'seemed fine.' On examination, the left foot shows recurrent inversion and plantarflexion. Radiographs confirm relapse of the deformity. What is the most important factor that contributed to this relapse?

Explanation

## Relapse in CTEV: The Critical Role of Bracing Compliance **Key Point:** Relapse in CTEV is most commonly caused by **premature discontinuation or non-compliance with the abduction brace**, not by failure of the initial Ponseti casting. The brace is essential to prevent recurrence for years after initial correction. ### Understanding CTEV Relapse | Phase | Duration | Goal | Key Intervention | |-------|----------|------|------------------| | **Correction Phase** | 5–8 weeks | Achieve plantigrade foot | Serial Ponseti casting | | **Maintenance Phase** | 3–5 years | Prevent relapse | Continuous abduction bracing | | **Observation Phase** | Until skeletal maturity | Monitor for late recurrence | Periodic clinical review | **High-Yield:** The Ponseti method corrects the deformity, but **does not permanently alter the underlying soft-tissue biology**. The shortened medial ligaments and abnormal muscle insertions retain their tendency to contract. The brace maintains the correction by holding the foot in abduction and external rotation, counteracting this intrinsic recoil. ### Why Bracing Is Non-Negotiable **Clinical Pearl:** Relapse rates are: - **<5%** with strict brace compliance (23 hours/day for 3 months, then night-time only until age 4–5) - **30–50%** with poor compliance or early discontinuation - **>80%** if bracing is abandoned immediately after casting In this case, the parents stopped bracing at 4 months post-casting (when the child should still be in 23-hour daily bracing). This is the classic scenario for relapse. ### Bracing Protocol 1. **Weeks 0–12 post-casting:** Denis Browne bar or similar abduction brace, **23 hours/day** 2. **Months 3–5 years:** Night-time bracing only (8–10 hours) 3. **Age 5+ years:** Discontinue if no signs of relapse **Warning:** Many families mistakenly believe that once the foot looks normal, bracing can stop. This is the leading cause of preventable relapse. Education and reinforcement at every visit are essential. ### Why Other Options Are Incorrect #### Option A: Inadequate Initial Correction - If initial Ponseti casting had been inadequate, the foot would not have achieved a plantigrade position in the first place - The fact that the foot was normal 2 months ago (immediately post-casting) proves the initial correction was successful - Relapse occurring 4 weeks after brace discontinuation is the hallmark of non-compliance, not inadequate initial correction #### Option C: Underlying Neuromuscular Disorder - CTEV associated with neuromuscular disease (arthrogryposis, cerebral palsy, spina bifida) typically presents with **bilateral, rigid deformities** and **additional features** (contractures, weakness, developmental delay) - This child had isolated bilateral CTEV (likely idiopathic) and achieved good correction with Ponseti casting - Neuromuscular CTEV would be suspected at birth or would show resistance to casting, not relapse after successful correction and brace discontinuation - No mention of developmental delay, weakness, or other neurological signs #### Option D: Progression of Genetic Mutation - CTEV is multifactorial (genetic + environmental factors), not a progressive genetic disorder - The deformity is **present at birth** and does not worsen over time if properly managed - Genetic mutations do not cause relapse; they cause the initial deformity - Relapse is a biomechanical problem (loss of brace support), not a genetic one ### Management of This Relapse ```mermaid flowchart TD A[Relapsed CTEV after Ponseti]:::outcome --> B{Severity of relapse?}:::decision B -->|Mild: partial inversion only| C[Resume intensive bracing<br/>+ repeat Ponseti casting if needed]:::action B -->|Moderate-to-severe: full deformity recurrence| D[Repeat Ponseti casting<br/>+ stricter brace protocol]:::action C --> E[Educate family on bracing compliance]:::action D --> E E --> F[If relapse recurs despite compliance:<br/>consider surgical intervention]:::action F --> G[Posteromedial release or<br/>selective soft-tissue procedures]:::action ``` **Clinical Pearl:** Most relapses respond well to a **repeat course of Ponseti casting** (4–6 weeks) followed by **intensified bracing education** and close follow-up. Surgical intervention is only needed if relapse recurs despite strict brace compliance. ## Summary Relapse in CTEV is predominantly a problem of **non-compliance with bracing**, not failure of the initial correction. The Ponseti method corrects the deformity, but the brace maintains it. Families must understand that bracing is a 3–5 year commitment, and early discontinuation is the leading preventable cause of relapse.