Intrawound navigation for custom-made acetabular component in revision total hip arthroplasty: Does it improve implant positioning?

Background: The number of hip revisions makes up over 12 % of all hip arthroplasty cases. For large acetabular defects custom-made acetabular component (CMAC) are required. Rates of malposition of CMACs are highly variable. Our study aims to develop a readily available, reliable and easily reproducible method for positioning of the CMAC. We tried to answer the following questions: 1) how often does the postoperative position of the implant corresponds to the planned one; 2) is the use of intrawound navigation improve the precision of acetabular implant position. Methods: This was a single-center observational cohort study and included two groups: the experimental group (use of 3D navigation for implant positioning) and the control group (no navigation use). All the patients were scheduled for acetabular revision surgery with custom-made 3D-printed acetabular components. All surgeries took place between 2016 and 2020. Results: 25 % freehand group, 85 % implants in the navigation group matched accuracy positioning criteria. The relative risk of malposition was significantly higher without the intraoperative navigation, with 5 times greater risk of malpositioning in the freehand group versus the navigation group. Conclusion: Navigation method allows planning of the implant and reamer sizes for optimal bone preparation and preservation. It provides easier implantation of the complex implant with reliable, stable primary fixation in massive bone defects. It reliably decreases malposition rate, allowing for implant placement in a proper position with sufficient bone-implant contact. Further research is needed to determine the relationship between CMAC position accuracy and long-term clinical and radiographic outcomes.

Standard Versus Custom-Made Acetabular Implants in Revision Total Hip Arthroplasty.

BACKGROUND: Today, various options are used for the reconstruction of acetabular bone loss in revision total hip arthroplasty (RTHA). The aim of the study was to compare the outcomes of using standard acetabular implants (SAIs) and custom-made acetabular implants (CMAIs) in RTHA in cases with extensive acetabular bone loss. METHODS: This was a comparative analysis of the results of 106 operations of RTHA performed during the period from January 2013 to December 2019. In 61 cases (57.5%), CMAIs were used. In 45 cases (42.5%), SAIs were implanted. RESULTS: The incidence of aseptic loosening of the acetabular component after RTHA in uncontained loss of bone stock of the acetabulum (type III-IV as per the Gross and Saleh classification) using the CMAI was less than that using the SAI (2.4% and 10.0%, respectively). The most significant differences in aseptic loosening rates were noted after implantation of the CMAI and SAI in pelvic discontinuity with uncontained bone defect (0% and 60.0%, respectively; P<.001). CONCLUSION: The ideal indications for the use of the CMAI are uncontained defects and pelvic discontinuity with uncontained loss of bone stock (types III-V Gross and Saleh classification). Treatment of these defects with the SAI leads to a higher incidence of aseptic loosening requiring re-revisions. Further observation is required to assess the effectiveness of using the CMAI and SAI in the long-term follow-up period.

Fibrin Glue Implants Seeded with Dental Pulp and Periodontal Ligament Stem Cells for the Repair of Periodontal Bone Defects: A Preclinical Study.

A technology to create a cell-seeded fibrin-based implant matching the size and shape of bone defect is required to create an anatomical implant. The aim of the study was to develop a technology of cell-seeded fibrin gel implant creation that has the same shape and size as the bone defect at the site of implantation. Using computed tomography (CT) images, molds representing bone defects were created by 3D printing. The form was filled with fibrin glue and human dental pulp stem cells (DPSC). The viability, set of surface markers and osteogenic differentiation of DPSC grown in fibrin gel along with the clot retraction time were evaluated. In mice, an alveolar bone defect was created. The defect was filled with fibrin gel seeded with mouse DPSC. After 28 days, the bone repair was analyzed with cone beam CT and by histological examination. The proliferation rate, set of surface antigens and osteogenic potential of cells grown inside the scaffold and in 2D conditions did not differ. In mice, both cell-free and mouse DPSC-seeded implants increased the bone tissue volume and vascularization. In mice with cell-seeded gel implants, the bone remodeling process was more prominent than in animals with a cell-free implant. The technology of 3D-printed forms for molding implants can be used to prepare implants using components that are not suitable for 3D printing.