Which orthosis is used for low lumbar L4-L5?

• A. AFO
• B. KAFO
• C. SMO
• D. Foot orthosis

Answer: (A)

For a low lumbar lesion like L4–L5, knee function is typically preserved, so the brace needed should focus on the ankle and foot to improve gait without restricting the knee. An ankle-foot orthosis provides targeted stabilization at the ankle joint, helps control foot drop by supporting dorsiflexion during swing, and promotes a more normal heel strike and push-off during stance. This support reduces energy costs of walking and improves safety and stability on uneven surfaces.

A knee-ankle-foot orthosis would unnecessarily immobilize the knee and is more appropriate when knee control itself is compromised, which isn’t usually the case at this level. A supramalleolar orthosis is a smaller device that offers limited ankle control and is typically used for milder foot deformities or specific pediatric applications; it doesn’t provide the same robust ankle stabilization needed for a functional gait in this context. A foot orthosis alone addresses the arch and forefoot but lacks the needed ankle joint control to manage foot drop and proper alignment during walking.

So, the ankle-foot orthosis is the best choice for low lumbar L4–L5 because it stabilizes the ankle and foot without restricting knee movement, optimizing gait for this lesion level.