Internal fixation with biodegradable high purity magnesium screws in the treatment of ankle fracture.

Background: Metal plates and screws are widely used as internal fixations in the treatment of ankle fracture. However, there are many disadvantages such as "stress shielding" effect and the need for secondary surgical removal, which potentially affected the blood supply around the fracture site. In recent years, many studies confirmed that the biodegradable high purity magnesium (Mg) screws exhibited sufficient mechanical strength with adequate degradation rate for effective bone healing, avoiding the need for implant removal operations. Method: We conducted a prospective study on patients with ankle fractures treated at Affiliated Zhongshan Hospital of Dalian University between January 2020 and January 2021. Twenty-four patients (twelve patients for each group) with ankle fractures were treated with high purity Mg screws or conventional titanium alloy plates and screws. Hematological examinations were performed in the early postoperative period, X-ray examinations were performed in the long-term postoperative follow-up. Postoperative complications, including infection, failure of internal fixation and malunion, were recorded during the follow-up. The visual analogue scale (VAS) was used to evaluate postoperative pain perceived by the patients, and the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot scoring system was used to evaluate their postoperative ankle function. Results: All patients achieved good fracture alignment, and imaging examination showed that the biodegradable high purity Mg screws degraded gradually without breakage or displacement. None of the patients experienced infection, failure of internal fixation, malunion or other complications in both groups. Conclusion: The results showed that biodegradable high purity Mg screws could be effectively used in the clinical treatment of ankle fractures, ensuring safety and satisfactory postoperative functional recovery.The translational potential of this article: The biodegradable high purity Mg screws could provide sufficient mechanical strength and fixation stability for ankle fracture. Our study extended the clinical application of the biodegradable high purity Mg screws for fracture.