Correction of bone angular deformities: experimental analysis of staples versus 8-plate

Hemi-epiphysiodesis should always be considered as an effective treatment to correct axial limb deformity in children. The use of the 8-plate as opposed to conventional staples provides firm fixation to both sides of the physis, acting mainly upon the epiphyseal growth site of the implant insertion. The aim of our study is to compare the effectiveness of both devices for performing angular corrections.

Seventeen rabbits of 18 months of age were treated with an 8-plate in the distal femur and a staple in the contralateral femur. Eight weeks later, the level of deformity produced by each device was evaluated both radiographically and histologically.

Axial deformity: the staples produced an average deviation of 48.1 degrees, and the 8-plate produced an average deviation of 49.1 degrees (P=0.44). Final longitudinal growth of the femurs: we recorded an average of 83.17 degrees for the staples and 85.7 degrees for the 8-plate. Histologic analysis: no significant difference was observed between both femurs of the same specimen; however, a slight difference was recorded when analyzing the results of different animals.

Correction was achieved in less time when using conventional staples. The long-term effectiveness of both epiphysiodesis is similar. Longitudinal growth inhibition is lower when using 8-plate.

Although both methods are effective in stopping the growth, the 8-plate has better grasp to the bone or epiphyseal cartilage avoiding extrusion in small children. The correction is faster using a staple and that is the reason why we prefer its usage in patients with little remnant growth.