Temporary hemiepiphysiodesis with the eight-Plate for angular deformities: mid-term results.

BACKGROUND

Angular deformities can be treated with corrective osteotomies and application of internal or external fixation. In children, this major intervention can be avoided with temporary hemiepiphysiodesis (i.e., guided growth). Recently, a new device called the eight-Plate Guided Growth System, consisting of a two-hole plate and two screws, was presented as an alternative to the widely used Blount staple to perform temporary hemiepiphysiodesis in children.

METHODS

Forty-three patients (54 physes, 51 limbs) underwent treatment between August 2004 and December 2005 with average follow-up after plate insertion of 2 years 2 months (range, 1 year 6 months to 2 years 6 months). Rate of correction and reversibility of this intervention were calculated.

RESULTS

Average age at eight-Plate implantation was 9 years 7 months (age range, 4 years 0 months to 14 years 3 months). eight-Plates were inserted for an average 14.2 months (range, 5.0-27.4 months). No growth disturbance was observed. Mechanical lateral distal femoral angle changed an average 10.00 degrees (range, 1-18 degrees) or 0.65 degrees/month (range, 0.05-1.22 degrees/month). Medial proximal tibial angle changed an average 7.78 degrees (range, 0-14 degrees) or 0.58 degrees/month (range, 0.13-1.67 degrees/month). In the two distal tibial cases, lateral distal tibial angle improved 6 degrees and 10 degrees (average change, 0.44 degrees/month). Mechanical axis deviation improved an average 25.4 mm (range, 0-74 mm) or 1.73 mm/month (range, 0-6.4 mm/month). Ten patients (13 limbs) had more than 10 months of radiographic follow-up after plate removal; ten limbs showed average rebound of 15.7 mm or 1.0 mm/month, indicating the reversibility of this procedure. Four cases failed to achieve correction.

CONCLUSIONS

The eight-Plate effectively treats angular deformities in growing children and is less likely to extrude spontaneously than the Blount staple. We have not observed growth disturbance or other complications related to this device.