Hexapod Frame Correction of Proximal Tibial Recurvatum Caused Indirectly by a Femoral Aneurysmal Bone Cyst in an Adolescent

Abstract

Case: A 16-year-old boy presented with a recurrent distal femur aneurysmal bone cyst accompanied by a combined sagittal knee deformity (20° of femoral antecurvatum and 26.8° of tibial recurvatum) and limb shortening. After preoperative planning, the treatment involved new intralesional curettage, phenolization, and bone allograft filling. Additional procedures included distal extension femoral osteotomy with plate fixation, and proximal tibial osteotomy with, gradually corrected through a hexapod frame. At 2-year follow-up, lower limbs exhibited normoalignment and equal length. Conclusion: Complex knee deformities may occur with tumoral lesions around the knee but can be effectively addressed through double osteotomy and application of a hexapod frame.