2nd knuckle does not bend on both big toes?

I inherited a condition from my father where the 2nd knuckle on both big toes (the knuckle next to the toe nail) is rigid. The next knuckle (the one that attaches to the foot bones) does flex. This condition causes the big toe to act as rigid platform… good for walking and great for “flip-flops” as the big toe is not flush up against the 2nd toe and can easily slip into the “flip flop” strap. I guess I’ve evolved to wear flip-flops :-). Has anyone else heard of this genetic fluke?