A REGIONAL APPROACH TO CLASSIC METAPHYSEAL LESIONS IN ABUSED INFANTS - THE DISTAL TIBIA

OBJECTIVE. The purpose of this study was to analyze systematically the spectrum of morphologic alterations of classic metaphyseal lesions (C ML) involving the distal tibia of abused infants and to identify featu res that assist in the radiologic diagnosis and assessment of healing. MATERIALS AND METHODS. Thirty-one infants who died with evidence of i nflicted injury were studied with high-detail skeletal surveys, resect ed-specimen radiography, and histopathologic analysis, The number of f ractures identified, the portions of the distal tibial metaphyses invo lved, and the age of the lesion were assessed. RESULTS. A total of 16 CML of the distal tibia were noted, Eight infants had unilateral injur y that always involved the left side, and four had bilateral lesions, When a CML was visible radiographically, it was always seen along the medial aspect of the metaphysis; lateral metaphyseal involvement was e vident with more extensive injuries and always accompanied medial invo lvement, Fractures tended to be less conspicuous when acute and were m ore easily recognized with healing, especially with specimen radiograp hy, Radiographically, the typical fracture separated a medial fragment that was tall and triangular; this appearance was histologically rela ted to the undercutting of the long subperiosteal bone collar, In heal ing lesions, extension of hypertrophic chondrocytes from the growth pl ate into the region of the fracture was a consistent finding. CONCLUSI ON. CML of the distal tibia have distinctive radiologic and histopatho logic characteristics that relate to the anatomy of the region. Visual ization of these fractures depends on the quality of the radiographs o btained, An understanding of the radiologic and histopathologic featur es of CML should aid in the recognition of this strong indicator of in fant abuse.