Abstract
We reviewed 16 metaphyseal-diaphyseal junction (MDJ) fractures treated over the four-year period 1997 to 2000. MDJ fractures occur in the area proximal to the supracondylar fossae and distal to the intersection of the metaphyseal flange and diaphysis of the humerus.
MDJ fractures are far less common than displaced classic supracondylar (SC) fractures: on average we see four MDJ and 80 SC fractures a year. The mean age of patients with MDJ fractures is 4.8 years, while the mean age of patients with SC fractures is 6.3 years. MDJ fractures are more often the result of a violent force: 56% occurred in falls and 38% in pedestrian traffic accidents, while 100% of SC fractures were due to falls. Only 1% of SC fractures were compound, while 13.5% of MDJ fractures were. MDJ fractures were of the extension type in 63% and of the flexion type in 37%. Only 3.7% of SC fractures were of the flexion type.
We treated four of the 16 MDJ fractures conservatively in a U-slab and 12 with percutaneous pinning (three with cross pinning, nine with one or both pins up the intramedullary shaft).
At a mean follow-up of two years (1 to 4) there were 11 satisfactory and five poor results. Three of the four patients managed conservatively had a poor result with varus malunion. The other two poor results were in percutaneously pinned fractures. One was pinned in varus and one refractured after the pins were removed at three weeks.
We conclude that MDJ fractures are distinct from SC fractures, and that percutaneous pinning is the best form of treatment. Because the fractures are more diaphyseal, immobilisation for four weeks rather than three is advised to prevent refracture.
The abstracts were edited by Prof. M.B.E. Sweet. Correspondence should be addressed to him at the Department of Orthopaedic Surgery, Medical School, University of the Witwatersrand, 7 York Road, Parktown, 2193 South Africa
