Spastic Equinovarus Foot (Cerebral Palsy)

• Cerebral palsy is the most common motor disability in childhood, with an incidence of approximately 2 to 3 per 1000 live births globally
• Equinovarus deformity affects roughly 15 to 30 percent of children with spastic CP, making it the most prevalent foot deformity
• Spastic diplegia (bilateral CP) carries the highest prevalence of equinovarus, followed by hemiplegia
• Unilateral involvement (hemiplegia) often shows more severe varus due to unopposed tibialis posterior spasticity

• Gait disturbance: Toe-walking, lateral border weight-bearing, tripping, and poor push-off
• Pain: Lateral foot pain from overloaded peroneal tubercle and fifth metatarsal base
• Skin breakdown: Callus formation over lateral border, risk of ulceration in severe cases
• Bracing difficulty: AFOs cannot adequately control dynamic varus, leading to poor compliance
• Progression: Untreated dynamic deformity progresses to fixed contracture with secondary bony changes

• Birth history: Prematurity, birth asphyxia, neonatal complications
• Motor milestones: Delayed sitting, crawling, walking
• CP classification: Topography (hemiplegia, diplegia, quadriplegia), GMFCS level
• Gait pattern: Toe-walking onset, tripping frequency, falling pattern
• Previous treatment: BTX-A injections, AFO use, prior surgeries
• Functional level: Community ambulation distance, assistive devices used
• Patient and family goals: Realistic expectations discussion is essential

• Inspect: Standing posture, foot progression angle, toe-walking pattern, lateral border callus
• Look: From behind - too many toes sign (hindfoot valgus) vs no toes visible (varus); from side - heel contact pattern
• Feel: Tibialis posterior tendon during inversion (overactive? palpable spasm?); peroneal tendon bulk
• Move: Passive ROM ankle (equinus), subtalar (varus correctability), forefoot (supination)
• Silfverskiold test: Distinguish gastrocnemius (improves with knee flexion) from soleus equinus (no change with knee flexion)
• Spasticity grading: Modified Ashworth Scale for TA, TP, gastrocnemius-soleus

• Cerebral palsy affects approximately 2 to 3 per 1000 live births worldwide, with higher rates in preterm and low-birth-weight infants
• Equinovarus is the most common foot deformity in CP, affecting approximately 15 to 30 percent of children with spastic subtypes
• Spastic diplegia has the highest association with bilateral equinovarus; hemiplegia typically produces unilateral deformity
• Global variation: Higher CP prevalence in low-resource settings due to higher preterm birth rates and limited perinatal care; however, access to gait analysis and SEMLS is concentrated in high-resource centres

• High-resource centres: 3-D gait analysis before SEMLS, custom AFOs, BTX-A programmes, specialist CP gait laboratories
• Middle-resource: Clinical gait analysis, BTX-A available, surgical SEMLS performed but with limited gait lab guidance
• Low-resource: Limited BTX-A access, clinical examination-based surgical decisions, limited post-operative rehabilitation, higher recurrence rates
• Universal principle: The surgical principles (dynamic vs fixed, TA vs TP driven, avoid over-lengthening) apply regardless of resource setting

The optimal age for SEMLS is debated. Most surgeons operate between ages 6 and 10 years. Earlier surgery (under 6) has higher recurrence rates due to continued growth and spasticity. Later surgery (over 12) risks fixed bony changes. The trend is toward operating when gait deterioration is documented rather than at a fixed age.

Gastrocnemius recession is preferred when the Silfverskiold test is positive, as it preserves soleus push-off power and reduces calcaneus gait risk. However, some surgeons argue that the distinction is less important than meticulous intraoperative tensioning. The consensus in high-resource practice favours recession for dynamic equinus.

Split transfers (SPLATT, SPOTT) are generally preferred over full transfers because they preserve some native function. However, in severe deformity, full TP transfer may provide greater corrective power. No head-to-head trials exist; choice is guided by severity and surgeon preference.

BTX-A is effective for dynamic deformity but does not prevent eventual surgery in most children. The controversy centres on whether repeated BTX-A cycles delay surgery unnecessarily or provide genuine benefit during growth. Current consensus: BTX-A is a bridge to surgery, not a substitute.