Can flip flops cause hammer toes?

Chronic : Wearing of flip flops cause instability across the metatarsal (toe joints) and thus would cause the toes to "grip" the ground more during walking. This can lead to hammer toes or "contractures" that over time, will need to be surgically straightened if they become rigid and do not reduce or return to normal straight if you push down on the toe.

Hammertoes: Are inherited, just like the structures of other body parts are. While great for business, flip-flops do not cause hammertoes, however tight shoes and even flip-flops can certainly make them feel worse. You need to be very careful how you pick your parents.

May contribute: A hammertoe is an contracture or a bending of the toe joint which results from a muscle or tendon imbalance due to the mechanical or structural changes in the foot. This can be hereditary or due to environmental factors such as tight shoes. This bending can lead to abnormal pressure distribution resulting in pain, swelling, blistering, and corns.