Clinical Performance of Biodegradable Orthopedic Implants

Abstract

Biodegradable orthopedic implants fabricated from magnesium alloys, poly-L-lactic acid (PLLA), polyglycolic acid (PGA), and calcium phosphate composites offer the prospect of eliminating secondary removal surgeries that affect 30-40% of patients receiving metallic fixation hardware for fracture stabilisation. However, achieving the optimal balance between mechanical strength retention during bone healing and controlled degradation thereafter has proven challenging, with clinical outcomes varying substantially across implant materials, anatomical sites, and patient populations. This study presents the Biodegradable Orthopedic Implant Performance Assessment Framework (BOIPAF), evaluating five implant material platforms -- magnesium-zinc-calcium alloys, high-molecular-weight PLLA, PLGA-hydroxyapatite composites, iron-manganese alloys, and zinc-lithium-magnesium alloys -- across four clinical performance tasks: mechanical strength retention at 12 weeks, degradation rate predictability, bone healing quality, and adverse tissue response incidence. Our Biodegradable Implant Performance Score (BIPS) integrates mechanical adequacy, degradation concordance, healing quality index, adverse response rate, and imaging artefact burden. Magnesium-zinc-calcium alloys achieved the highest BIPS (0.914) through optimal degradation-healing synchronisation that maintained 85% of initial mechanical strength at 12 weeks while achieving complete resorption by 18 months, and PLGA-hydroxyapatite composites achieved the highest bone healing quality (0.955) through osteoconductive hydroxyapatite particles that stimulated new bone formation within the degrading polymer scaffold.