Classification and treatment of postburn metacarpophalangeal joint extension contractures in children.

Two hundred and seventy-eight surgically treated postburn metacarpophalangeal joint extension contractures in children were reviewed. A classification system based on the limitation of passive metacarpophalangeal flexion was devised to direct surgical intervention and assess postoperative results. Type I (47%) digits demonstrated greater than 30 degrees of metacarpophalangeal flexion with the wrist fully extended, and scarring was generally limited to the dorsal skin. Type II (34%) digits demonstrated less than 30 degrees of metacarpophalangeal flexion with the wrist maximally extended, and scarring typically involved skin, dorsal apparatus, and metacarpophalangeal capsule. Type III (19%) digits were fixed in greater than 30 degrees of metacarpophalangeal hyperextension and often demonstrated incongruity or dorsal subluxation of the metacarpophalangeal joint. Improvement after reconstruction was seen in 95% of type I digits, 73% of type II digits, and 47% of type III digits. Failure to improve usually resulted from inadequate scar release/excision or from failure to release deep soft tissues (dorsal apparatus or metacarpophalangeal capsule). Thirty secondary procedures were done to improve an unsatisfactory result after the initial reconstruction. These included deep releases, metacarpophalangeal joint arthrodeses, and amputations. The ring and small fingers accounted for 65% of the digits in this study, 68% of the failures, and all seven amputations.