Most common cause of peroneal spastic flatfoot?

Most common cause of peroneal spastic flatfoot?

• A. Tarsal coalition
• B. Posterior tibial tendon deficiency
• C. Calcaneal fracture
• D. Arthritis

Answer: (A)

The key idea is that peroneal spastic flatfoot is most strongly linked to tarsal coalition, a abnormal connection between hindfoot bones that restricts subtalar motion and causes pain. In children, the calcaneonavicular coalition is the most common type and classically presents with a rigid flatfoot and a guarding, painful response that triggers the peroneal muscles to spasm in an attempt to evert and stabilize the foot. This peroneal guarding gives the appearance of a flatfoot with a stiff, valgus hindfoot, which is why a coalition stands out as the best answer. Other causes can produce flatfoot, but they don’t typically produce the characteristic peroneal spasm associated with coalition. Posterior tibial tendon deficiency is a common cause of adult-onset flatfoot and involves medial arch collapse without the same spastic response. Calcaneal fractures or arthritis can deform the hindfoot but don’t usually present with the same peroneal guarding sign seen in coalition-related flatfoot.

The key idea is that peroneal spastic flatfoot is most strongly linked to tarsal coalition, a abnormal connection between hindfoot bones that restricts subtalar motion and causes pain. In children, the calcaneonavicular coalition is the most common type and classically presents with a rigid flatfoot and a guarding, painful response that triggers the peroneal muscles to spasm in an attempt to evert and stabilize the foot. This peroneal guarding gives the appearance of a flatfoot with a stiff, valgus hindfoot, which is why a coalition stands out as the best answer.

Other causes can produce flatfoot, but they don’t typically produce the characteristic peroneal spasm associated with coalition. Posterior tibial tendon deficiency is a common cause of adult-onset flatfoot and involves medial arch collapse without the same spastic response. Calcaneal fractures or arthritis can deform the hindfoot but don’t usually present with the same peroneal guarding sign seen in coalition-related flatfoot.