Temporary hemiepiphyseal arrest using a screw and plate device to treat knee and ankle deformities in children: a preliminary report.

PURPOSE: Traditionally, angular deformities are treated by means of osteotomy. In patients who are skeletally immature, this major intervention can be avoided by influencing or guiding the growth of the affected physis. Recently, a new device was presented as an alternative to the widely used Blount staple. Stevens developed a technique using a two-hole, non-locking plate with two screws to perform temporary hemiepiphysiodesis in children. We studied the effectiveness of this new device in correcting angular deformities in children even younger than 5 years of age.

METHODS: We evaluated our first series of 11 patients (17 eight-Plates) who underwent treatment for angular deformities of various origins and were followed to completion of correction. The average age at hemiepiphysiodesis was 10 years and 2 months (age range 4 years and 11 months-13 years and 8 months). The device was inserted in the lateral distal femur (two cases), the medial distal femur (eight cases), the lateral proximal tibia (two cases), the medial proximal tibia (four cases), and the medial distal tibia (one case).

RESULTS: The eight-Plate was inserted for an average of 9.5 months (range 5-13 months). The joint orientation angles and the mechanical axis improved in all patients, with the exception of one 13-year and 8-month-old boy with a resected osteosarcoma and a compromised growth plate. In valgus cases (12 limbs, 13 eight-Plates), the mechanical axis deviation improved by an average of 30.7 mm (range 13-55 mm). In varus cases (four limbs, four eight-Plates), the mechanical axis deviation improved by an average of 38.8 mm (range 0-74 mm). No hardware failures, extrusion, growth arrest, or other complications were observed. None of our patients required an osteotomy or repeat eight-Plate insertion.

CONCLUSIONS: We consider the eight-Plate to be an ideal tool for treatment of angular deformities in growing children. It allows for precise insertion and is reliable. It is also less likely to extrude like the Blount staple.