Frontal plane control in KAFOs is provided by which component?

Frontal plane control in KAFOs is provided by which component?

• A. Sagittal stability straps
• B. Pretibial band
• C. Infrapatellar band
• D. Posterior plastic shell

Answer: (D)

Frontal plane control is about resisting side‑to‑side (varus/valgus) movement at the knee. The posterior plastic shell acts as a rigid back wall that provides a strong buttress against sideways collapse, helping to maintain knee alignment in the coronal (frontal) plane when weight bearing. This containment is what keeps the knee from shifting medially or laterally, which is the primary role of the posterior shell in a KAFO. The other components mainly influence sagittal stability (front to back bending) or fit around the leg, but they don’t provide the same level of coronal plane restraint as the posterior shell.

Frontal plane control is about resisting side‑to‑side (varus/valgus) movement at the knee. The posterior plastic shell acts as a rigid back wall that provides a strong buttress against sideways collapse, helping to maintain knee alignment in the coronal (frontal) plane when weight bearing. This containment is what keeps the knee from shifting medially or laterally, which is the primary role of the posterior shell in a KAFO. The other components mainly influence sagittal stability (front to back bending) or fit around the leg, but they don’t provide the same level of coronal plane restraint as the posterior shell.