Salter-Harris Type-IV fractures of the epiphysis extend through the articular cartilage, epiphysis, physis, and metaphysis and have a high rate of complications secondary to premature partial closure of the physis. In this study we attempted to determine which Type-IV fractures of the distal end of the tibia result in premature partial closure, how the various treatment modalities affect the risk of premature physeal closure, and how the complication itself might be best managed. Thirty-two Type-IV fractures of the distal end of the tibia were seen at the Mayo Clinic during a five-year period. Eighteen injuries involved the medial malleolus, thirteen were so-called triplane fractures, and one was a fracture of the lateral part of the plafond. In the eighteen ankles with a fracture that involved the medial malleolus, extension of the fracture into the metaphysis could often be appreciated only on oblique roentgenograms. The patients' ages at the time of fracture ranged from one year and one month to fifteen years and six months old. In nine of the eighteen tibiae with a fracture of the medial malleolus premature partial closure of the distal physis developed, resulting in angular deformity or limb-length discrepancy sufficient to require operative treatment (epiphyseodesis, corrective osteotomy, or excision of a physeal bar). A physeal bar was best detected by tomograms made in two planes and by scanograms. Bar formation may be treated by excision of the bar, arrest of the whole physis, osteotomy, or combinations of these procedures. Of the thirteen patients with a triplane fracture and the one with a Type-IV fracture of the lateral part of the plafond, all fourteen were near maturity at the time of injury, and no growth-arrest problems developed.