Why does a medial calc slide work?

• A. Increases lateral arch support
• B. Reduces excess force on the medial arch
• C. Increases blood flow
• D. Stabilizes the calcaneus

Answer: (B)

Medializing the calcaneal tuberosity corrects hindfoot valgus, which changes the line of pull of the foot’s structures and the ground reaction force as you load the foot. By sliding the posterior part of the calcaneus toward the midline, the hindfoot becomes more neutral, reducing the abnormal valgus moment that normally drives excessive pronation. With that correction, the medial column isn’t forced into as much overload, so the load transmitted through the medial arch decreases. In short, the procedure lowers the abnormal stress on the medial arch, which is why it works. It isn’t primarily about increasing blood flow, adding lateral arch support, or simply stabilizing the calcaneus in isolation—the key effect is unloading the medial arch by realigning the hindfoot.