Advancements in Biodegradable Orthopaedic Implants: A Literature Review.

Abstract

Background: Biodegradable orthopaedic implants have emerged as an innovative alternative to traditional permanent metallic or inert polymer implants, aiming to provide mechanical support during critical healing phases and subsequently degrade in vivo. Their primary advantage lies in eliminating the need for a second surgery to remove hardware, thus potentially reducing patient morbidity and healthcare costs. Despite these benefits, challenges related to unpredictable degradation kinetics, mechanical strength, and biocompatibility have restricted their widespread clinical application.

Methods: This review synthesizes existing literature on the historical development of biodegradable orthopaedic implants, the range of biomaterials investigated-including polymers (e.g., PLA, PLGA), metals (e.g., Mg, Fe, Zn), and bio ceramics (e.g., HA, TCP)-and the manufacturing techniques used, such as extrusion, injection molding, and advanced additive manufacturing. We have searched across major databases like Pubmed, Scopus, Google scholar and Science direct. We considered the articles published from 1985 till 2024. We used the search strategy incorporating the Medical Subject headings(MeSH).The following keywords were used "biodegradable orthopedic implants", "resorbable implants", "absorbable fixation devices", "polylactic acid(PLA)", "PLGA", "Polycaprolactone(PCL)", "Magnesium alloys", "zinc alloys", "bioceramics", "tricalcium phosphate", "fracture fixation", "implant degradation", "corrosion", "hydrolytic degradation", "biocompatibility", "inflammatory response", "toxicology", "FDA guidelines", "biodegradable implant approval", "clinical trials", "long-term outcomes", "postmarket surveillance". Boolean operators AND and OR were used to combine keywords (e.g., "biodegradable implants" AND "magnesium alloys" AND "fracture fixation"). Filters were used to select the articles published only in English. The mechanisms of degradation for different material classes were examined, alongside preclinical and clinical findings. Regulatory guidelines and ongoing innovations, including multifunctional (e.g., drug-delivering) and smart biodegradable implants, were also analysed.

Results: Findings indicate that biodegradable polymers offer well-characterized degradation profiles and have been successfully used in lower-load applications, including paediatric fracture fixation and ligament repairs. Magnesium- and iron-based alloys show promise in load-bearing contexts, although controlling corrosion remains an ongoing challenge. Composite approaches that integrate metals, polymers, and ceramics can better tailor mechanical properties and degradation rates to specific clinical needs. Early clinical results generally demonstrate favourable outcomes in fracture fixation, spinal surgery, and maxillofacial procedures; however, long-term data and large-scale trials are still limited.

Conclusion: Biodegradable implants represent a transformative step in orthopaedic care, offering the potential to reduce implant-related complications and secondary procedures. Continued innovations in material science, manufacturing, and surface engineering will be crucial to address current challenges around degradation control, mechanical integrity, and biocompatibility. As the regulatory framework matures and cost barriers diminish, biodegradable implants are poised to become a mainstay in musculoskeletal repair, ultimately advancing toward more patient-specific and regenerative therapies.