Comparative Long-term Outcomes of All-polyethylene vs Metal-backed Tibial Components in Total Knee Replacement: An Indian Perspective

Introduction:A total knee replacement is a surgical procedure to treat severe arthritis in the knee joint.The cruciate-sacrificing prosthetic design is one of the most frequently used in total knee replacement (TKR).There has been debate regarding whether metal-backed tibia (MB) or allpolyethylene (AP) tibial components are better for implants in terms of lifespan, clinical results, and complication rates.The big role played by selecting appropriate knee joint implants for osteoarthritis in developing countries is with economic constraints.Metal and all-polyethylene monoblock essentially can serve this purpose in knees without defects in bones that do not require modularity like stem extensions or augments.The aim of this study was to compare the long-term clinical and radiological results of metal-backed vs all-polyethylene cruciate-sacrificing total knee replacements.Long-term application of all-polyethylene tibial implants against the backdrop of better-designed implants/instrumentation coupled with an increasing use of TKR and continuous economic pressures on health care could represent a potential for enormous cost savings without jeopardizing patient clinical outcomes.Materials and methods: This prospective study involves 200 TKR procedures using Depuy PFC AP implants and MB implants 100 in each group, conducted between January 2011 and January 2012, with 12-years follow-up.Patients age > 50 years with a definite diagnosis of osteoarthritis, severe knee pain or dysfunction disabling normal work and life, ineffectiveness of conservative treatment, and TKRs that did not necessitate bone grafting, modular stems or augments, or more constrained designs were included.Functional outcomes were assessed using the Knee Society Score (KSS), Western Ontario and McMaster University Osteoarthritis Index (WOMAC), and range of motion (ROM).Radiological assessments were performed to check for signs of loosening and malalignment.Implant survival was measured by revision surgery rates. Results:The study cohort included 130 females and 70 males, with an average age of 61.3 years.Both the MB and AP groups showed significant improvement in KSS, WOMAC, and ROM over 12-years, with no statistically significant difference between the two groups.The implant survival rate was 96% for AP and 94% for MB.Aseptic loosening occurred in 2 AP and 3 MB cases, with polyethylene wear observed in the MB group due to micromotion, while the AP group showed only minimal poly wear. Conclusion:The long-term outcomes of both AP and MB tibial components in TKR show comparable clinical and radiological success, with both designs significantly improving pain relief and functional outcomes in patients with severe knee arthritis.AP implants, in particular, demonstrated similar functional improvements and radiological stability, while offering the added benefit of reduced polyethylene wear.Given the lower cost of AP components, they represent a cost-effective solution in resource-limited settings without sacrificing patient outcomes.