Multiplanar CT Depicts Complex Ankle Fractures

Triplane fractures, in which fracture lines occur in three planes of the ankle, comprise approximately 6-10% of ankle fractures in young people, according to Stephen D. Brown, M.D., instructor in radiology at Harvard Medical School, and are usually sports-related injuries.

All 51 individuals demonstrated bone separation along the front part of the growth plate of the tibia. There were 33 "classic” two-fragment fractures as seen in medical textbooks, but the classic three fragment fracture, which involves a separation at Kump's bump, "was not in this series,” said Dr. Brown, lead author of the study. Three fragment fractures were observed but they involved different fracture patterns than what has been previously observed as the most common.

In fact, according to Dr. Brown, the study discovered that half of the triplane fracture patterns described in the literature probably occur only infrequently or never at all. This is explained by the typical pattern of closure in the growth plate. Also, "the medial malleolar variety of triplane fracture previously considered rare, was very common. In one-fourth of the patients in our cohort, fractures involved the medial malleolus, but spared the plafond,” stated Dr. Brown.

This new study, published in the November 2004 issue of the America Journal of Roentgenology, clarifies the anatomy of these complicated multidimensional fractures and allows physicians to depict these fractures more consistently, and will help in the collaboration between radiologists who diagnose these fractures and the orthopedic surgeons who treat them. The study suggests using a general classification system--the Salter-Harris scheme--to help describe the appearance of these fractures in each different dimension as seen with CT with multiplanar reconstruction.

"This is the largest published series on these types of fractures to date, and is the first one in which all fractures were imaged and analyzed using multiplanar CT,” observed Dr. Brown.




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