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Gille J.,University of Lubeck | Oheim R.,University of Lubeck | Riepenhof H.,BG Traumahospital Hamburg | Voigt C.,Diakoniekrankenhaus Friederikenstift gGmbH | Juergens C.,BG Traumahospital Hamburg
Sports Medicine, Arthroscopy, Rehabilitation, Therapy and Technology | Year: 2012

We present a new technique to remove plates from the proximal tibia arthroscopic-assisted with all advantages of the minimally invasive surgery and the possibility to treat concomitant intraarticular pathologies. The initial results (n = 7) are promising with an increase of the Lysholm score in all cases studied [preop. median 78 (range 32-100), postop. median 89 (range 60-100)]. In conclusion, arthroscopic-assisted hardware removal at the proximal tibia is feasible and may provide patients with all the benefits of minimal-invasive hardware removal. The described technique can be recommended for all surgeons familiar with arthroscopic surgery. © 2012 Gille et al.; licensee BioMed Central Ltd.


Katthagen J.C.,Diakoniekrankenhaus Friederikenstift gGmbH | Schwarze M.,Laboratory of Biomechanics and Biomaterials | Meyer-Kobbe J.,Diakoniekrankenhaus Friederikenstift gGmbH | Voigt C.,Diakoniekrankenhaus Friederikenstift gGmbH | And 2 more authors.
Clinical Biomechanics | Year: 2014

Background: The objective of this study was to investigate the biomechanical effects of medial fracture gap augmentation in locked plating of an unstable 2-part proximal humeral fracturewith calcar screws and insertion of a corticocancellous bone block. Furthermore the mechanical behavior of dynamic locking screws in the nonparallel arrangement of a proximal humeral plate was of interest. Methods: Thirty-two fresh frozen humeriwere randomized in four equal groups. An unstable 2-part fracturewas fixed by locked plating in all specimens. The basic screw setup was supplemented by additional calcar screws in one group. Humeral head screws were replaced by dynamic locking screws in a second group. The third group featured an additional corticocancellous femoral head allograft. Assessment of stiffness was followed by cyclic loading and load to failure tests. Resulting stiffness, fracture gap deflection and ultimate load were compared utilizing Bonferroni corrected t-test for independent samples. Findings: The mechanical effect of additional calcar screws was non-significant as compared to the basic screw configuration whereas bone block insertion significantly increased construct stiffness and failure load. The use of dynamic locking screws did not significantly reduce construct stiffness when compared to conventional locking screws. Interpretation: Additional calcar screws alone did not improve the initial biomechanical properties of an unstable 2-part proximal humeral fracturemodel.However bone block augmentation appeared to be a reliable alternative of additional bony support by raising stiffness and failure load. Dynamic locking screws did not show their expected dynamic component when used in a non-parallel arrangement. © 2014 Elsevier Ltd. All rights reserved.


Katthagen J.C.,Diakoniekrankenhaus Friederikenstift gGmbH | Schwarze M.,Laboratory of Biomechanics and Biomaterials | Bauer L.,Diakoniekrankenhaus Friederikenstift gGmbH | Meyer-Kobbe J.,Diakoniekrankenhaus Friederikenstift gGmbH | And 3 more authors.
Revue de Chirurgie Orthopedique et Traumatologique | Year: 2015

Background: The objective of this study was to evaluate the biomechanical effect of an additional unlocked calcar screw compared to a standard setting with three proximal humeral head screws alone for fixation of an unstable 2-part fracture of the surgical neck. Hypothesis: The additional calcar screw improves stiffness and failure load. Methods: Fourteen fresh-frozen humeri were randomized into two equal sized groups. An unstable 2-part fracture of the surgical neck was simulated and all specimens were fixed with the MultiLoc®-nail. Group I represented a basic screw setup, with three locked head screws and two unlocked shaft screws. Group II was identical with a supplemental unlocked calcar screw (CS). Stiffness tests were performed in torsional loading, as well as in axial and in 20° abduction/20° adduction modes. Subsequently cyclic loading and load to failure tests were performed. Resulting stiffness, displacement under cyclic load and ultimate load were compared between groups using the t-test for independent variables (α=0.05). Results: No significant differences was observed between the groups in any of the biomechanical parameters. Backing out of the CS was observed in three cases. Discussion: The use of an additional unlocked calcar screw does not provide mechanical benefit in locked nailing of an unstable 2-part fracture of the surgical neck. Level of evidence: Level III. Experimental biomechanical study with human specimen. © 2015 Elsevier Masson SAS.


Katthagen J.C.,Diakoniekrankenhaus Friederikenstift gGmbH | Schwarze M.,Laboratory of Biomechanics and Biomaterials | Warnhoff M.,Diakoniekrankenhaus Friederikenstift gGmbH | Voigt C.,Diakoniekrankenhaus Friederikenstift gGmbH | And 2 more authors.
Injury | Year: 2016

Introduction: The main purpose was to compare the biomechanical properties of a carbon-fibre reinforced polyetheretherketone (CF-PEEK) composite locking platewith pre-existing data of a titanium-alloy plate when used for fixation of an unstable 2-part fracture of the surgical neck of the humerus. The secondary purpose was to compare the mechanical behaviour of locking bolts and conventional locking cancellous screws. Methods: 7 pairs of fresh frozen human humeri were allocated to two equal groups. All specimens were fixed with the CF-PEEK plate. Cancellous screws (PEEK/screw) were compared to locking bolts (PEEK/ bolt) for humeral head fixation. Stiffness, fracture gap deflection and ultimate load as well as load before screw perforation of the articular surface were assessed. Results were compared between groups and with pre-existing biomechanical data of a titanium-alloy plate. Results: The CF-PEEK plate featured significantly lower stiffness compared to the titanium-alloy plate (P < 0.001). In ultimate load testing, 6 out of 14 CF-PEEK plates failed due to irreversible deformation and cracking. No significant difference was observed between results of groups PEEK/screw and PEEK/bolt (P > 0.05). Discussion: The CF-PEEK plate has more elastic properties and significantly increases movement at the fracture site of an unstable proximal humeral fracture model compared to the commonly used titanium-alloy plate. The screw design however does neither affect the constructs primary mechanical behaviour in the constellation tested nor the load before screw perforation. © 2016 Elsevier Ltd. All rights reserved.


Katthagen J.C.,Diakoniekrankenhaus Friederikenstift gGmbH | Schwarze M.,Laboratory of Biomechanics and Biomaterials | Bauer L.,Diakoniekrankenhaus Friederikenstift gGmbH | Meyer-Kobbe J.,Diakoniekrankenhaus Friederikenstift gGmbH | And 3 more authors.
Orthopaedics and Traumatology: Surgery and Research | Year: 2015

Background: The objective of this study was to evaluate the biomechanical effect of an additional unlocked calcar screw compared to a standard setting with three proximal humeral head screws alone for fixation of an unstable 2-part fracture of the surgical neck. Hypothesis: The additional calcar screw improves stiffness and failure load. Methods: Fourteen fresh frozen humeri were randomized into two equal sized groups. An unstable 2-part fracture of the surgical neck was simulated and all specimens were fixed with the MultiLoc®-nail. Group I represented a basic screw setup, with three locked head screws and two unlocked shaft screws. Group II was identical with a supplemental unlocked calcar screw (CS). Stiffness tests were performed in torsional loading, as well as in axial and in 20° abduction/20° adduction modes. Subsequently cyclic loading and load-to-failure tests were performed. Resulting stiffness, displacement under cyclic load and ultimate load were compared between groups using the t-test for independent variables (α=0.05). Results: No significant differences were observed between the groups in any of the biomechanical parameters. Backing out of the CS was observed in three cases. Discussion: The use of an additional unlocked calcar screw does not provide mechanical benefit in locked nailing of an unstable 2-part fracture of the surgical neck. Level of evidence: Level III. Experimental biomechanical study with human specimen. © 2015 Elsevier Masson SAS.

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