With high thermal stability, excellent mechanical properties, suitable biocompatibility and radiolucency, polyaryletherketones (PAEKs) have been widely used in biomedical field such as trauma, spinal implants, craniomaxillofacial repair and so on. However, PAEKs are bio-inert in nature and often show weak osteointegration with host bone, limiting their further utilization in biomedical application. Therefore, how to improve the bioactivity and osteointegration of PAEK implants has become the focus in biomedical field. This paper reviews the current research advance and some existed problems in bioactive PAEKs, and outlooks the possible solution.
Objective To investigate the validity of improving the femur’s mechanical characteristics by implanting calcium phosphate ceramic screws after removing dynamic hip screw (DHS). Methods The three dimensional finite element model of the femur was built based on the CT scanning of a normal male volunteer. Then the models of the femur with and without DHS were established. According to calcium phosphate ceramic screws with porosity and apparent elastic modulus, 80% and 0.1 GPa were set as group A, 50% and 1.0 GPa as group B, and 30% and 1.5 GPa as group C. Von Mises stress distribution and maximum stress were recorded when the joint was maximally loaded in a gait cycle. Results The Von Mises in normal femoral shaft was uniform; no phenomena of stress concentration was observed and the maximum stress located at the joint load-bearing site of the proximal femur. The stress concentration was observed in the femur without DHS, and the maximum stress located at the distal femur around the screw hole. By comparing several different calcium phosphate ceramic screws, the stress distribution of group B was similar to normal femur model, and the maximum stress located at the joint load-bearing site. The other screws of groups A and C showed varying degrees of stress concentration. Conclusion Implanting calcium phosphate ceramic screw can improve the mechanical characteristics of the femur after removing dynamic hip screw, and the calcium phosphate ceramic screw with 50% porosity and 1.0 GPa apparent elastic modulus is suitable for implanting.
Objective To explore the feasibility of using biomechanical indicators as supplementary measures to the Musculoskeletal Tumor Society (MSTS) score for amputee patients. Methods Thirteen patients who underwent hemipelvectomy between June 2020 and April 2024 were enrolled. There were 9 males and 4 females with an average age of 59.2 years (range, 49-73 years). Participants performed gait tests at self-selected speeds using three assistive devices (prosthesis, single crutch, and double crutches). Motion data were analyzed using a customized OpenSim model. Biomechanical parameters of the intact limb exhibiting common characteristics were screened through correlation and sensitivity analyses. Test-retest reliability of selected parameters was assessed to evaluate their potential as MSTS score supplements. Results All biomechanical parameters showed significant positive correlations with MSTS scores across assistive devices (P<0.05). Seven parameters demonstrated Pearson correlation coefficients>0.8, including walking speed, maximum hip angle, maximum hip moment, peak hip flexion moment, peak hip extension moment, hip flexion impulse, and hip extension impulse. Among these, maximum hip moment, hip flexion impulse, and hip extension impulse exhibited significant between-group differences in adjacent MSTS score levels (P<0.05), indicating high sensitivity, along with excellent test-retest reliability (ICC>0.74, P<0.01). Conclusion Biomechanical indicators statistically qualify as potential supplements to MSTS scoring. Maximum hip moment, hip flexion impulse, and hip extension impulse demonstrate particularly high sensitivity to MSTS score variations.
Regulatory science of medical devices serves the scientific research and regulatory activities for supervision of medical devices. Principles of science and transparency and conduction of evidence-based study, which is advocated in Evidence-based science(EBS), also apply to regulatory science of medical devices, including using evidence-based scientific tools and methods to demonstrate the safety and effectiveness, as well as quality, efficacy and cost-effectiveness of total life cycle of medical products, target customers, and scope. EBS provides both new methods and tools for regulatory science for medical devices, and provides a new basis for further scientific regulatory decisions.