gms | German Medical Science

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2018)

23.10. - 26.10.2018, Berlin

Virtual Morphological Analysis of Different Intramedullary Proximal Humerus Nails in the Chinese Population

Meeting Abstract

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  • presenting/speaker Tobias Harnoss - Unfallchirurgie Kempten, Kempten, Germany
  • Andreas Lenich - Helios Kliniken, Klinik für Unfallchirurgie, Orthopädie und Sportorthopädie, München, Germany
  • Ulrich Schreiber - OT Medizintechnik GmbH, München, Germany
  • Xiaoming Wu - Shanghai General Hospital, Shanghai, China

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2018). Berlin, 23.-26.10.2018. Düsseldorf: German Medical Science GMS Publishing House; 2018. DocPT16-1479

doi: 10.3205/18dkou655, urn:nbn:de:0183-18dkou6554

Veröffentlicht: 6. November 2018

© 2018 Harnoss et al.
Dieser Artikel ist ein Open-Access-Artikel und steht unter den Lizenzbedingungen der Creative Commons Attribution 4.0 License (Namensnennung). Lizenz-Angaben siehe http://creativecommons.org/licenses/by/4.0/.


Gliederung

Text

Objectives: The treatment of proximal Humerus fractures with IM-nails becomes demanding with a decreasing Humerus size, especially when both Tubercles are fractured. In populations with a smaller anatomy than the Western world, e.g. China, this might be one of the reasons why intramedullary nailing is rarely used.

The aim of the study was to virtually compare the quality of fracture treatment between 3 different IM-nails, focusing on small Humeri having a fracture of both Tubercles. Another objective was the evaluation if side-specific implants are superior in the treatment of these fractures compared to a universal but polyaxial nail with the possibility to freely direct the proximal screws within a cone of 20°.

Methods: The CT-data basis consisted of 32 non-fractured Chinese Humeri with an average anatomical neck diameter Cav of 43.49 mm (36.7-50.24 mm). The data significantly follows a normal distribution and therefore comprehensively represents the Chinese population. With a focus on small Humeri, we chose 14 bones with an anatomical neck diameter C smaller than Cav.

Using a CAD-Software, a simplified fracture of both Tubercles was virtually simulated for each specimen (see Figure 1 [Abb. 1] left part).

Via a virtual implantation the quality of fracture treatment of three intramedullary implants, namely DePuy Synthes MultiLoc, Stryker T2 and OTM PolyAxNail PH, was evaluated. MultiLoc and T2 provide a side-specific variant, OTM PolyAxNail is a universal, polyaxial nail.

The implantation was considered successful if the distance between all four proximal screws to the fracture line was at least 5 mm. The measurement was performed in two directions anterior-posterior and medial-lateral.

Results and conclusions: For Humeri with C<39.85 mm a satisfying fracture treatment could not be achieved with all of the tested intramedullary nails.

For Humeri with C>39.85 mm MultiLoc and T2 managed to sufficiently treat 1 out of 9 Humeri. The implantation of OTM PolyAxNail PH was successful in 6 out of 9 cases.

There is a correlation between the Humerus size, in specific the anatomical neck diameter C, and the quality of fracture treatment, using intramedullary nails, when both Tubercles are fractured. With the investigated implants it is impossible to treat very small Humeri (C<39.85 mm). The use of the polyaxial implant allowed to avoid the vulnerable fracture lines due to the possibility of polyaxial screw placement. A benefit of a side-specific implant variant could not be found. The limitation of this study is that the fracture lines are simulated in a simplified manner: the fractures of the Tubercle are represented as 2D straight "cut offs", which therefore does not fully represent the clinical situation.