Abstract
BackgroundThe optimal internal fixation strategy for vertical femoral neck fractures (VFNFs) in nongeriatric patients remains uncertain. Therefore, the purpose of this study was to compare the clinical prognoses and underlying mechanical characteristics of a novel off-axis screw technique with dynamic hip screws (DHSs) and three traditional parallel screws.MethodsThis study included a clinical investigation and a patient-specific finite element analysis (FEA). In the clinical investigation, VFNF patients were grouped by fixation type: (1) use of three parallel screws (G-TRI); (2) augmentation with an off-axis screw (G-ALP); and (3) DHS with an anti-rotational screw (G-DHS). Fixation failures (nonunion, femoral neck shortening (FNS), varus deformation, screw cut-out) and avascular necrosis (AVN) consequent to the three types of fixations were compared. In the FEA, twenty-four fixation models with the three fixation types were created based on the data of eight healthy volunteers. Models were assessed under walking conditions. Stiffness, interfragmentary motion (IFM), and implant stress were evaluated.ResultsIn the clinical investigation, the fixation failure rate was significantly (p < 0.05) lower in G-ALP (18.5%) than in G-DHS (37.5%) and G-TRI (39.3%). No significant difference in AVN was observed among the three fixation groups. In the FEA, stiffness and implant stress in the G-DHS models were significantly (p < 0.05) higher, and the IFM of G-ALP was significantly (p < 0.05) lower among the groups.ConclusionsAmong fixation types for VFNFs, the off-axis screw technique exhibited better interfragmentary stability (lowest IFM) and a lower fixation failure rate (especially FNS). Analyzing interfragmentary stability in biomechanical experiments is more consistent with clinical prognosis than construct stability for VFNFs, suggesting that internal fixations should aim for this outcome.
Highlights
The optimal internal fixation strategy for vertical femoral neck fractures (VFNFs) in nongeriatric patients remains uncertain
The dynamic compression effect of cannulated screws and lag screws was simulated by using a preload of 224 N for cannulated screws and 591 N for Dynamic hip screws (DHS), which was the same value per mm2 that we described previously [11]
(18.5% vs. 37.5%) when it was implanted using the offaxis technique. By investigating their biomechanical characteristics, we found that DHS fixation had the best construct stability, while the off-axis screw technique had the best interfragmentary stability
Summary
The optimal internal fixation strategy for vertical femoral neck fractures (VFNFs) in nongeriatric patients remains uncertain. The treatment of vertical femoral neck fractures (VFNFs) in patients younger than 60 years of age is problematic [1]. This is primarily because of the highenergy violent nature of the trauma, an inherently unfavorable blood supply to the femoral neck, inherent biomechanical instability, and use of an inappropriate fixation strategy. Typical prognoses for internal fixations are disappointingly poor, with fixation failure rates reaching as high as 41.9% and avascular necrosis rates reaching as high as 16–21% [2, 3] These complications severely impair functional outcomes and result in arthroplasties, which lead to a lower quality of life for younger patients. Cannulated screws can be described as a “load-sharing” device, which is better for stable fractures
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
