Cockup deformity of the great toe hallux extensus.

Cockup of the great toe is characterized by persistent extension of the first metatarsophalangeal joint; the interphalangeal joint also may be involved. The syndrome has many causes, all easily diagnosed. Surgery is indicated in nearly every instance and will produce a corrected or improved result. The type of surgery--whether reefing, lengthening, or transposition of tendons, implant arthroplasty, or arthrodesis--is tailored to the underlying cause.