Congenital flexion of the fingers is a common congenital hand deformity caused by several tissue dysplasias. These include deficiencies in the skin of the palmar surface, shortening of the superficial flexor tendons of the fingers, hypoplasia of the extensor tendon structures, misaligned attachment of the earthworm muscles, shortening of the collateral ligaments and the palmar plate, etc. These are the result of primary soft tissue structural or distribution abnormalities. Long-term uncorrected flexion deformity often results in secondary abnormalities of bone and joint structures. It has been reported that the disease has a genetic predisposition. Pathogenesis: (1) shortening, dysplasia, or abnormal stopping point of the finger flexor tendon; (2) abnormal starting point and stopping point of the earthworm muscle or muscle atrophy; (3) shortening and abnormal palmar plate; (4) abnormal skin and subcutaneous proliferation of ligamentous connective tissue structure. Clinical manifestations Loss or incomplete flexion and extension of the fingers, mainly straightening disorders. It occurs more frequently in the middle finger, ring finger and little finger. It may occur in one finger alone, in the proximal interphalangeal joint, or in the distal interphalangeal joint. There are three categories: Category 1: Finger flexion deformities occurring in infancy, with similar incidence in males and females, which are more common. Type 2: Finger flexion deformities occurring in adolescence, not due to trauma, are more common in females and often occur in the right hand. Type 3 Finger flexion deformities associated with various congenital malformations are most common in syndromes. Many syndromes are associated with finger flexion deformities, such as oculofacial finger syndrome, orofacial finger syndrome, juxtaposition of fingers and finger flexion deformities. In addition to syndromes, many congenital hand deformities are also associated with finger flexion deformities. For example, syndactyly, polydactyly, compound thumb deformity, split hand deformity, hand and finger hypoplasia, megalodactyly, windblown hand deformity, etc. can be accompanied by finger flexion deformity Treatment In mild cases, except for slight defects in appearance, no treatment is needed for those who do not affect function. For patients with functional deformity, early conservative treatment, such as massage and brace fixation in the straightened position, can improve the deformity in a few cases. If conservative treatment is ineffective or relapses, surgical orthopedics may be performed. Surgery includes: release of the contracted skin of the metacarpophalangeal and interphalangeal joints, skin grafting, release of the joint capsule, severance and partial excision of the contracted superficial flexor tendon, lengthening of the deep flexor tendon if necessary, and displacement of the superficial flexor tendon in place of the earthworm muscle and displacement of the beginning of the earthworm muscle.