Efficacy of 8-plate hemiepiphysiodesis for genu valgum deformity correction in children with hereditary multiple exostoses

Objective To explore the surgical timing, technique and prognosis for pediatric genu valgum deformity with hereditary multiple exostoses by 8-plate. Methods From July 2009 to July 2014, the clinical data were reviewed for 15 children of genu valgum deformity with multiple exostoses treated by 8-plate.There were 11 boys and 4 girls with an average age of 10.2 (4.3-13.5) years.The involved knees were left (n=6), right (n=5) and bilateral (n=4). Angular deformity changes were evaluated by anatomical lateral distal femoral angle, medial proximal tibial angle and mechanical axis deviation. Results Hemiepiphysiodesis included 15 femurs and 14 tibias.The average follow-up period was 26.5 (9-49) months.The average duration from stapling to staple removal was 15.2 (5-31) months.Amount of angular correction by 8-plate at distal femur was 5.1~11.4°(averaged 7.5°) and at proximal tibia, 2.3~14.5°(averaged 7.0°). Correction velocity at 14 femurs was 0.3~1.1°/M (averaged 0.6°/M) and at 12 tibias 0.2~1.0°/M(averaged 0.5°/M). Seventeen legs had mechanical axes in zone + 1 or -1, one leg in zone + 3, one leg in zone -2 and the total good rate reached 89.5%.There were 22 femurs or tibias with a follow-up period of >6 months after 8-plate removal.Eleven rebounded at the latest follow-up. Conclusions The technique of 8-plate hemiepiphysiodesis is mini-invasive and effective for pediatric genu valgum deformity with hereditary multiple exostoses.Patients should be treated promptly, rational therapeutic regimen provided and close monitor mandatory until skeletal maturity. Key words: Exostoses, multiple hereditary; Genu valgum; Growth plate