Hammer toe, mallet toe and claw toe are common deformities of 2 to 4 toes. Hammer toe is defined as a toe with the metatarsophalangeal joint (MPJ) in neutral or dorsiflexion, the proximal interphalangeal joint (PIPJ) in flexion, and the distal interphalangeal joint (DIPJ) in neutral or dorsiflexion. A mallet toe is a toe with the metatarsophalangeal joint in neutral position, the proximal interphalangeal joint in neutral position, and the distal interphalangeal joint in flexion. Claw toe refers to dorsiflexion of the metatarsophalangeal joint of the affected toe and flexion of both the distal and proximal interphalangeal joints. The common causes of hammer toe, mallet toe and claw toe are: 1, wearing inappropriate shoes, 2, overly long toes, 3, compression of adjacent toe deformities such as bunion compression of the second toe, 4, post-traumatic injury: tendon injury, osteo-fascial compartment syndrome, 5, arthritis: rheumatoid arthritis, diabetes mellitus, 6, neuromuscular disease: cerebral palsy, post-polio, 7, high arched foot, flat foot, ankle ptosis, 8, genetic factors. Genetic factors. After the occurrence of such toe deformities in patients with Qu Xintao of the Department of Orthopedics, General Hospital of Jinan Military District, painful calluses are caused by the flexion of the interphalangeal joints and the touching of the ends of the toes to the ground. The flexion of the proximal interphalangeal joints, which causes friction between the dorsal side of this joint and the shoe surface, can also cause painful calluses. Due to the dorsal extension of the metatarsophalangeal joint, the base of the proximal phalanx squeezes the dorsal side of the metatarsal head, which can cause three consequences.1, damage to the dorsal cartilage of the metatarsal head, which later causes ischemic necrosis of the metatarsal head and even the formation of osteoarthritis.2, sinking of the metatarsal head, which causes the formation of painful calluses on the metatarsal side of the metatarsal head.3, dislocation of the metatarsophalangeal joint Depending on the occurrence of the deformity, it can be classified as 1, congenital 2, acquired. According to whether the deformity can be passively corrected or not, it can be classified as 1, flaccid, the deformity can be completely passively corrected 2, semi-rigid, the deformity can be partially passively corrected. 3, rigid, deformity can not be passively corrected. According to the degree of deformity, it can be divided into, 1, mild: MPJ and IPJ joints without fixed contracture, deformity worsens after foot weight-bearing. 2, moderate: PIPJ has fixed contracture, MPJ has no hyperextension deformity. 3, Severe: PIPJ has fixed contracture, MPJ has fixed hyperextension deformity. Treatment 1, non-surgical treatment Clean up hyperkeratotic skin, foot pads, and wear loose shoes. 2, surgical treatment For flexion deformity, arthroplasty or joint fusion is usually feasible. For dorsal extension deformity of the metatarsophalangeal joint, the treatment is more complicated. Firstly, the dorsal joint capsule of the metatarsophalangeal joint needs to be removed, the lateral collateral ligament and the metatarsal plate need to be released, and the extensor tendon needs to be extended if the metatarsal bone is not surgically shortened or the metatarsophalangeal joint is obviously dislocated and shortened. However, due to the often long 2nd metatarsal, injury to the dorsal cartilage of the metatarsal head and dislocation of the metatarsophalangeal joint, osteotomy of the neck of the metatarsal head or osteotomy of the metatarsal trunk is required to shorten and elevate the metatarsal head. If the dorsal deformity of the metatarsophalangeal joint cannot be corrected, the flexor digitorum longus tendon can be severed from the base of the distal phalanx, split longitudinally, and transposed and fixed to the dorsal side of the base of the proximal phalanx. Hammer toe, mallet toe, and claw toe are common deformities of 2 to 4 toes. Hammer toe refers to neutral or dorsal extension of the metatarsophalangeal joint (MPJ), flexion of the proximal interphalangeal joint (PIPJ), and neutral or dorsal extension of the distal interphalangeal joint (DIPJ) of the affected toe. A mallet toe is a toe with the metatarsophalangeal joint in neutral position, the proximal interphalangeal joint in neutral position, and the distal interphalangeal joint in flexion. Claw toe is defined as dorsiflexion of the metatarsophalangeal joint of the affected toe and flexion of both the distal and proximal interphalangeal joints. The common causes of hammer toe, mallet toe and claw toe are: 1, wearing inappropriate shoes; 2, overly long toes; 3, compression of adjacent toe deformities, such as bunion compression of the second toe; 4, post-traumatic injury: tendon injury, fascial compartment syndrome; 5, arthritis: rheumatoid arthritis, diabetes mellitus; 6, neuromuscular disease: cerebral palsy, post-polio; 7, high arched feet, flat feet, ankle ptosis; 8, genetic factors. Genetic factors. When such toe deformities occur in patients, painful calluses are caused by the flexion of the interphalangeal joint, which causes the end of the toe to touch the ground, and the flexion of the proximal interphalangeal joint, which causes friction between the dorsal side of that joint and the shoe surface. Due to the dorsal extension of the metatarsophalangeal joint, the base of the proximal phalanx squeezes the dorsal side of the metatarsal head, which can cause three consequences.1, damage to the dorsal cartilage of the metatarsal head, which later causes ischemic necrosis of the metatarsal head and even the formation of osteoarthritis.2, sinking of the metatarsal head, which causes the formation of painful calluses on the metatarsal side of the metatarsal head.3, dislocation of the metatarsophalangeal joint Depending on the occurrence of the deformity, it can be classified as 1, congenital 2, acquired. According to whether the deformity can be passively corrected or not, it can be classified as 1, flaccid, the deformity can be completely passively corrected 2, semi-rigid, the deformity can be partially passively corrected. 3, rigid, deformity can not be passively corrected. According to the degree of deformity, it can be divided into, 1, mild: MPJ and IPJ joints without fixed contracture, deformity aggravated after foot weight-bearing. 2, moderate: PIPJ has fixed contracture, MPJ has no hyperextension deformity. 3, Severe: PIPJ has fixed contracture, MPJ has fixed hyperextension deformity. Treatment 1, non-surgical treatment Clean up hyperkeratotic skin, foot pads, and wear loose shoes. 2, surgical treatment For flexion deformity, arthroplasty or joint fusion is usually feasible. For dorsal extension deformity of the metatarsophalangeal joint, the treatment is more complicated. Firstly, the dorsal joint capsule of the metatarsophalangeal joint needs to be removed, the lateral collateral ligament and the metatarsal plate need to be released, and the extensor tendon needs to be extended if the metatarsal bone is not surgically shortened or the metatarsophalangeal joint is obviously dislocated and shortened. However, due to the often long 2nd metatarsal, injury to the dorsal cartilage of the metatarsal head and dislocation of the metatarsophalangeal joint, osteotomy of the neck of the metatarsal head or osteotomy of the metatarsal trunk is required to shorten and elevate the metatarsal head. If the dorsal deformity of the metatarsophalangeal joint cannot be corrected, the flexor digitorum longus tendon can be severed from the base of the distal phalanx, split longitudinally, and transposed and fixed to the dorsal side of the base of the proximal phalanx.