Article
The Biomechanical Stability of a Novel Bioabsorbable Magnesium (Mg-Zn-Ca) Alloy Bone Anchor for Rotator Cuff Repairs: An ex-vivo Cadaver Study
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Authors
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Stefan Schleifenbaum
- ZESBO, Klinik für Orthopädie, Unfallchirurgie und Plast. Chirurgie, Universität Leipzig, Leipzig, Germany
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Maximilian Kinsky
- AUVA Unfallkrankenhaus Meidling, Wien, Austria
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Maxim Honea
- Medizinische Universität Graz, Universitätsklinik für Orhtopädie und Traumatologie, Musculo-Skeletal Research Unit for Biomaterials, Graz, Austria
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Paul Siegert
- AUVA Unfallkrankenhaus Meidling, Wien, Austria
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Stefan Fischerauer
- Medizinische Universität Graz, Universitätsklinik für Orhtopädie und Traumatologie, Graz, Austria
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Niels Hammer
- Medizinische Universität Graz, Institut für Anatomie, Graz, Austria
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Annelie Martina Weinberg
- Universitätsklinik für Orthopädie und Traumatologie Graz, Graz, Austria
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Christian Wurnig
- AUVA Unfallkrankenhaus Meidling, Wien, Austria
| Published: | October 25, 2022 |
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Outline
Text
Objectives: Due to the limited anatomical area of the rotator cuff footprint, bioabsorbable anchors have been of recent interest in rotator cuff repairs in younger patients to enable improved bone stock in revision cases. In the case of tendon re-rupture, non-absorbable and now defunct anchors can cause mechanical conflict with the placement of new anchors. Magnesium alloy (ZX00) implants provide a promising biocompatible alternative that imply a safe and wholly predictable degradation pattern.
The purpose of this study was to ascertain the primary in-vitro biomechanical stability of a novel bioabsorbable magnesium alloy (ZX00: Mg-Zn-Ca) bone anchor in human cadaveric proximal humeri, indicated in the reconstruction of the rotator cuff.
Methods: 12 pairs of human Thiel fixed cadaveric humeri were prepared and freed from soft tissue. One 5.7 x 20.5mm ZX00 anchor and one 5.5mm x 16.3mm Arthrex Titanium FT Corkscrew anchor were inserted into the Supraspinatus footprint, approximately 15mm apart. After a diaphyseal osteotomy and fixation into plastic polymer filled vessel, the humeri were installed onto a Zwick Machine (Z020, Zwick Roell GmbH, Ulm). After the application of a 40N preload, cyclic loading was carried out between 10-50N at 0.5Hz over 200 cycles and 10-100N at 0.5Hz over 200 cycles. Provided that the construct is intact, ultimate load to failure was measured using an increasing axial load of 1mm/s., ultimate load to failure and mode of failure were recorded.
Results and conclusion: Overall 22 5.5mm x 16.3mm Arthrex Titanium FT Corkscrew anchors were tested against 20 ZX00 anchors. Results showed no statistically significant difference in ability to withstand initial cyclic loading, mode of failure or ultimate load to failure strengths between test and control anchors. The maximum tractional force loaded for the ZX00 anchors had a mean value of 240.4 N with a SD± 61.9. The corresponding value for the Arthrex Titanium FT Corkscrew anchors was 232.2 N with a SD± 45.6.
ZX00 bioabsorbable magnesium alloy anchors show an adequate initial biomechanical stability when compared to an industry standard control anchor in a cadaveric rotator cuff repair model. Nonetheless further studies are necessary to prove the influence of degradation on subsequent biomechanical stability during tendon healing and beyond.
