Non-traumatic flexion deformity of the proximal interphalangeal joint-its pathogenesis and treatment.

The pathogenesis of camptodactyly may be the lack of equilibrium between the flexion and extension forces. The imbalance must be a result of palmar translocation of lateral slips of the extensor apparatus due to anchoring of the middle phalanx in the flexed position by fibrous substrata, abnormal shortening of the flexor digitorum superficialis or abnormal insertion of the lumbricals. It is reasonable therefore to start dynamic splint therapy as early as possible and carry on for a long time. Long-standing malposition of the extensor lateral slips possibly introduced contracture of periarticular tissues and the transverse retinacular ligament, making treatment more difficult. For those patients resistant to dynamic splint therapy, a surgical procedure is necessary. Surgical procedures are discussed.