The terms hammertoe and clawfoot are often used interchangeably, but they actually describe different defects.
In a hammertoe, the joint between the phalanx proximalis and the phalanx media is bent and between phalanx media and phalanx distalis is stretched. A clawed toe also has an (over)stretch in the little joint between the ossa metatarsalia and the phalanx proximalis (the MTP or MetaTarsoPhalangeal joint).
Due to the deviation in position of a hammertoe and a clawfoot, the toe gets pinched against the top of the shoe by the "PIP-joint" (proximal interphalangeal joint), causing extra calluses on the knuckles. With claw toes and mallet toes, the tips of the toes "hammer" against the ground when walking. The toes put more strain on the "MTP joint" which results in extra calluses under the sole of the foot.
The treatment consists of correct shoe advice, the manufacture of a silicone orthosis and/or podiatric insoles.
If, despite the above measures, the pain persists, surgical treatment may be suggested.