Increased stability by a novel femoral neck interlocking plate compared to conventional fixation methods. A biomechanical study in synthetic bone. (June 2020)

• Record Type: Journal Article
• Authors: Brattgjerd, Jan Egil; Steen, Harald; Strømsøe, Knut
• Is Part Of: Clinical biomechanics. Volume 76(2020)
• Publication Date: 2020-06
• Subjects: Femoral neck fracture -- Biomechanics -- Internal fixation -- Locking plate -- Composite bone; Biomechanics -- Periodicals; Osteopathic medicine -- Periodicals; Biomechanics -- Periodicals; Osteopathic Medicine -- Periodicals; 612.76
• DOI: 10.1016/j.clinbiomech.2020.104995
• Languages: English
• ISSNs: 0268-0033

Abstract

Abstract: Background: Stable fixation promotes union in the common femoral neck fractures, but high non-union rates due to fixation failure remain with traditional fixations. To enhance stability, a plate interlocking pins, but without further fixation to femur has been developed. To our knowledge, no comparison to other conventional fixation methods has been performed. We tested the hypothesis that the novel implant biomechanically leads to a more stable femoral neck fixation. Methods: Fifty synthetic femurs with a cervical wedge osteotomy were allocated to intervention with three hook-pins interlocked in a plate (Hansson Pinloc® System) or standard fixations with a two-hole Dynamic Hip Screw® plate with an anti-rotational screw, three cannulated screws (ASNIS® III) or two screws (Olmed® or Cannulated Hip Screws®). Quasi-static non-destructive torsion around the neck, anteroposterior bending and vertical compression were tested to detect stiffness. The specimen's deformation was evaluated after cyclic compression simulating weight-bearing. Local deformation of implant channels was measured. Fixation failure was defined by fissure formation. Findings: Compared to the conventional implants all together, the interlocked pins enhanced mean stiffness 130% in torsion and 33% in bending ( P < 0.001), while compressive stability was increased by a reduced deformation of 62% in average of the global test specimen and 95% decreased local implant channel deformation after cycling ( P < 0.001). In comparisons with each of the standard fixations the interlocking pins revealed no signs of adverse effects. Interpretation: The novel femoral neck interlocking plate allowed dynamic compression and improved multi-directional stability compared to the traditional fixations. Highlights: Biomechanical study of femoral neck fracture fixations The novel Hansson Pinloc® System with three pins locked in a plate was evaluated. Comparison to the conventional two or three screws or a sliding hip screw device Pinloc® stabilised torsion around the neck's length axis, bending and compression. No adverse effects (cortical fissures or complete fixation failures) with Pinloc®