Treatment of trauma-induced femoral head necrosis with biodegradable pure Mg screw-fixed pedicle iliac bone flap

Abstract

Introduction: The avascular necrosis of the femoral head represents the death of bone tissue due to the lack of blood supply. The disease has a progressive evolution; it leads to femoral head collapse and severe arthritis when left untreated. The application of a pedicled bone flap graft is an effective treatment for femoral head necrosis. A pure Mg screw is a kind of degradable screw that can fix the grafted bone flap and prevent long-term stress occlusion and secondary dissection.

Case presentation: The report shows the results of the treatment of traumatic femoral head necrosis with a pedicled bone flap with pure Mg screw. A patient had avascular necrosis of the femoral head after 2 years of internal fixation of the femoral neck fracture. We removed the patient's internal fixation hollow nail, cleaned the necrotic bone tissue and took part of the same ipsilateral pedicle iliac bone graft in the femoral head defect with biodegradable pure Mg screw fixation. Within 2 years after the surgery, the patients had no significant progressive necrosis of the femoral head. Postoperative Harris scores showed that the patient's left hip function was significantly improved compared with his preoperative state. The pure Mg screw in the body had gradually degraded. After 2 years, the screw's diameter had been significantly reduced compared with 3 days after the surgery. The postoperative Harris score showed that the patient's left hip function was significantly improved compared with the second preoperative examination.

Discussion: The discussion includes the reasons for the choices of surgical approaches, the mode of pure Mg screw degradation and the postoperative functional assessment of the patient's left hip.

Conclusion: Pure Mg screw fixation pedicled bone flap transplantation is an effective surgical treatment for femoral head necrosis in young patients. Pure Mg screw is a biodegradable internal fixation device with good biocompatibility, which has a good clinical application prospects.

The translational potential of this article: Degradable pure Mg screw has the potential to preserve hip joint therapy for the treatment of femoral head necrosis.

Figure 1

Intraoperative photo. (A) Dissection of the pedicled iliac bone flap; (B) Fixation of the pedicled iliac bone flap with pure Mg screw.

Figure 2

Radiographic images of the femoral head hip over time. (A) The patient was implanted with three compression hollow screws for femoral neck fracture, and the femoral head had necrosis after 26 months; (B) 3 days postoperatively; (C) 1 year postoperatively and (D) 2 years postoperatively. The femoral head was dislocated laterally.

Figure 3

Representative CT diagram of the pure Mg screw over time. (A) The patient was implanted with three compression cannulated screws for femoral neck fracture, and the femoral head had necrosis after 26 months; (B) 3 days postoperatively; (C) 1 year postoperatively and (D) 2 years postoperatively. The pure Mg screw gradually degraded, and the bone flaps gradually almost merged.