Digital simulation and 3D-printed guide-assisted surgical correction of a complex pediatric hip deformity: a case report and literature review

Background Complex pediatric hip deformities can comprise multiple coexisting structural abnormalities, including coxa vara, femoral head retroversion, chronic femoral neck injury, and avascular necrosis of the femoral head. In older children, the capacity for hip remodeling is diminished, and conventional surgical planning based on two-dimensional imaging and surgeon experience may be insufficient to quantify three-dimensional deformity, osteotomy angles, and fixation trajectories. Digital simulation combined with 3D-printed guides can convert preoperative CT data into visualized three-dimensional models and extend virtual planning to intraoperative localization and osteotomy execution. Case presentation We report a 10-year-old boy who was admitted with a 5-year history of right hip pain and restricted motion. Examination showed approximately 4 cm of right-sided leg-length shortening, proximal migration of the right greater trochanter, and marked restriction of hip motion in multiple planes. Bilateral hip digital radiography (DR), three-dimensional CT reconstruction, and MRI demonstrated right coxa vara with femoral head retroversion, a chronic right femoral neck fracture with possible nonunion and suspected avascular necrosis of the femoral head, together with leg-length discrepancy. Preoperative CT data were imported into Mimics for 1:1 three-dimensional reconstruction and virtual osteotomy planning, on the basis of which a patient-specific 3D-printed osteotomy guide was fabricated. Guide-assisted proximal femoral osteotomy, deformity correction, plate-and-screw fixation, bone grafting at the osteotomy site, and hip bracing were performed. Operative time was 3 h 40 min, estimated blood loss was 200 mL, and C-arm fluoroscopy was performed three times. At 4 months, the right hip was pain-free, gait had improved substantially, the leg-length discrepancy had decreased to <1 cm, and imaging showed satisfactory osteotomy healing, stable fixation, and femoral head-acetabular congruence. Conclusion For complex pediatric hip deformities that are multiplanar and highly patient-specific, digital simulation combined with a 3D-printed patient-specific guide may facilitate the translation of preoperative three-dimensional assessment into intraoperative execution and provide an additional reference for deformity correction. In this case, the approach was technically feasible and was associated with satisfactory short-term correction and healing. However, findings from a single case cannot establish improvements in surgical accuracy, reductions in fluoroscopy use, or superiority over conventional techniques. Further comparative studies with larger cohorts and longer follow-up are needed to evaluate its accuracy, radiation exposure, guide-fit error, cost-effectiveness, and the maintenance of correction during skeletal growth.