[Study of virtual reality technology combined with reduction plasty of femoral head in treatment of coxa plana].

Objective: To explore the feasibility of virtual reality (VR) technology combined with reduction plasty of the femoral head in the treatment of coxa plana and evaluate its effectiveness.

Methods: Three patients with coxa plana were selected as the research objects between October 2018 and October 2020, all of them were male, aged 15-24 years. Preoperative surgical planning was performed using VR technology; 256 rows of CT data of hip joint were imported into software to generate three-dimensional (3D) imaging, simulate the surgical process, and determine the matching relationship between the femoral head and acetabulum. According to the preoperative planning, reduction plasty of the femoral head under surgical dislocation, relative lengthening of the femoral neck, and periacetabular osteotomy were performed. The reduction of osteotomy size of femoral head and rotation angle of acetabulum were confirmed by C-arm fluoroscopy. The healing of the osteotomy were assessed by radiological examination after operation. The Harris score of hip function and visual analogue scale (VAS) score were recorded before and after operation. The femoral head roundness index, center-edge (CE) angle, and femoral head coverage were measured by X-ray films.

Results: Three operations were completed successfully, and the operation time was 460, 450, and 435 minutes, and the intraoperative blood loss was 733, 716, and 829 mL, respectively. All patients were infused with 3 U suspension oligoleucocyte and 300 mL frozen virus inactivated plasma after operation. No postoperative complication occurred, such as infection and deep vein thrombosis. Three patients were followed up 25, 30, and 15 months, respectively. CT showed good healing of the osteotomy at 3 months after operation. The VAS score and Harris score at 12 months after operation and at last follow-up, as well as the femoral head rounding index, hip CE angle, and femoral head coverage at 12 months after operation significantly improved when compared with those before operation; the hip function was evaluated by the Harris score at 12 months after operation, and all three patients were good.

Conclusion: VR technology combined with reduction plasty of the femoral head can achieve satisfactory short-term effectiveness in the treatment of coxa plana.