Guided Growth Treatment for Genu Valgum Secondary to Juxtaphyseal Recurrent Aneurysmal Bone Cyst of the Distal Femur

An 11 year 6 month old male with a history of recurrent aneurysmal bone cyst involving the distal metaphysis of the left femur presented with increasing asymmetric genu valgum affecting the left lower extremity. Plain radiographs and MRI scan confirmed the distal femoral valgus related to the recurrent juxtaphyseal lesion without any discrete bony bar. He underwent guided growth treatment with application of an extraperiosteal non-locking plate across the ipsilateral medial distal femoral physis as a same-day procedure. Over the next several months, progressive correction of his angular deformity was noted. After mild intentional overcorrection, the plate was removed 2 years postoperatively. At a 5-year follow-up, he was skeletally mature with equal leg lengths and symmetric physiologic alignment of his lower extremities. In a skeletally immature patient with a “sick” but viable physis, guided growth treatment using an extraperiosteal plate is a viable alternative to more invasive osteotomies.