Tibia valga after proximal metaphyseal fractures in childhood: a normal biologic response.

Seventeen children with 19 proximal tibial metaphyseal fractures were followed-up between 2 and 7 years after injury. Detailed measurements of the metaphyseal/diaphyseal/metaphyseal distances medially and laterally on the injured and noninjured sides demonstrated overgrowth. In four patients, the medial distance of the injured tibia was longer than the lateral distance, which was the same distance as the uninjured tibia. In 11 patients, there was an overgrowth of both the medial and lateral sides of the injured tibia, compared to the unijured tibia, and in each instance, the medial distance of the injured tibia was always longer than the lateral. In a patient with bilateral metaphyseal fractures, the medial length exceeded the lateral length in both tibias. In the child with metaphyseal and diaphyseal fractures, the medial side of the tibia with the metaphyseal fracture was the longest of the four measurements. In five of six patients with Harris lines, there was distal as well as proximal tibial metaphyseal overgrowth, but the distal line was always parallel to the physis and did not contribute to the valgus angulation. Thus there was not only a generalized increased growth proximally and distally, but there also was an eccentric proximal medial overgrowth in every patient.