Vinsamlegast notið þetta auðkenni þegar þið vitnið til verksins eða tengið í það: http://hdl.handle.net/1946/26877
Total Hip Arthroplasty (THA) is one of the most common and successful orthopaedic surgery in the world. This clinical procedure improves the quality of life for patients with chronic hip pain, by restoring their hip function with biocompatible prosthetic implants. However, there are still potential advances that can be made in selecting the optimal implant fixation techniques. Currently there are 2 main methods: cemented and uncemented fixation. The uncemented fixation is based on press fitting procedure where bone growth into the porous surface of the implants is induced for long term fixation. The cemented technique uses bone cement to ensure fixation to the bone within the femoral cavity.
Due to the absence of a rigorous methodology to select implant fixation, the decision is based on general clinical evaluation such as: patient age, gender and femoral X-ray. The consequence of inappropriate selection may lead to periprosthetic fracture during press fitting and/or high cost in revision surgery from cemented implant.
This study proposes a novel approach based on computer tomography scans (CT) and finite element analysis for calculating pre-operative bone quality and fracture risk during press fitting simulation. The method was applied on 20 patients undergoing THA where 10 were selected for cemented implant and 10 for uncemented. In one case the patient fractured following the press fitting method and was therefore used for validating the simulation methodology.
The results indicate that 3 out of 10 patients selected for uncemented fixation should have been selected for cemented fixation, that would have prevented an actual case of intraoperative fracture. From the cemented group 4 patients were identified with bone quality that could withstand the press fitting procedure. The overall results show that the current clinical evaluation doesn’t reflect the real bone quality and further analysis is required for the developing computational tools to assess bone quality on a subject specific basis.
Keywords: Total Hip Arthroplasty (THA), cemented, uncemented, finite element analysis (FEA), computed tomography (CT), press fitting, fracture risk.