A Southeast Asian Experience in Biodegradable Implants: Tips and Tricks for Radiological Findings

Nondegradable implants, such as titanium or steel screws, are commonly used in orthopedic surgery as they provide strength and stability. However, metallic implants have been associated with multiple issues, such as additional surgery to remove hardware, interference with imaging modalities, and stress shielding. Biodegradable magnesium-based implants are an innovative alternative due to good biocompatibility and osteoconductivity, similar to Young's elastic modulus to bone, and they exhibit less metallic distortion in imaging modalities. The MAGNEZIX compression screw became the first magnesium implant to be approved for use in humans and has been widely used ever since, most commonly in foot and ankle conditions, with generally good outcomes. Despite its advantages, implant biodegradation introduces unique imaging challenges that can be misinterpreted as complications. This article aimed to familiarize radiologists and clinicians with the expected imaging findings of magnesium-based implants to reduce unnecessary advanced imaging and misdiagnosis. Pre-operative and post-operative radiological images of 75 patients with foot and ankle injuries who were treated with MAGNEZIX screws between 2020 and 2022 in Changi General Hospital were retrospectively evaluated. Selected cases are presented in detail to illustrate key principles in understanding radiological findings of MAGNEZIX screws. Seven cases are presented in detail with pre-operative and serial post-operative images, along with each case emphasizing a key learning point essential to understanding when interpreting radiological images of patients who receive MAGNEZIX screws as part of their treatment. Key takeaways include the following points: (1) recognizing the normal evolution and degradation pattern of magnesium implants and being aware of potential pitfalls, (2) the importance of correlating radiological findings with clinical assessment, (3) effective multidisciplinary communication, and (4) staying updated with ongoing literature on degradable magnesium-based implants. Biodegradable implants, such as MAGNEZIX screws, are an innovative and effective alternative to metallic implants in orthopedic surgery. However, knowledge of the expected imaging findings of magnesium-based implants after insertion is essential in reducing unnecessary advanced imaging and misdiagnosis.