Objective Assessment of Syndesmosis Stability Using the Hook Test

Jakob Hallbauer; Philipp Schenk; Lea Herrmann; Bernhard Wilhelm Ullrich; Uta Biedermann; Britt Wildemann; Gunther Olaf Hofmann; Felix Christian Kohler

doi:10.3390/jcm12144580

Objective Assessment of Syndesmosis Stability Using the Hook Test

J Clin Med. 2023 Jul 10;12(14):4580. doi: 10.3390/jcm12144580.

Authors

Jakob Hallbauer¹, Philipp Schenk^{2

3}, Lea Herrmann¹, Bernhard Wilhelm Ullrich³, Uta Biedermann⁴, Britt Wildemann¹, Gunther Olaf Hofmann^{1

3}, Felix Christian Kohler¹

Affiliations

¹ Department of Trauma, Hand and Reconstructive Surgery, Jena University Hospital, Friedrich Schiller University Jena, 07747 Jena, Germany.
² Reseaserch Executive Department, BG Klinikum Bergmannstrost, 06112 Halle, Germany.
³ Department of Trauma and Reconstructive Surgery, BG Klinikum Bergmannstrost, 06112 Halle, Germany.
⁴ Institute of Anatomy I, Jena University Hospital, Friedrich Schiller University Jena, 07743 Jena, Germany.

Abstract

The hook test is a widely used intraoperative method for assessing syndesmosis stability. However, there are no recommendations regarding the force required to perform this test. Furthermore, the reliability of the test is unclear. Ten experienced surgeons performed hook tests on a cadaver bone model. The applied forces were recorded in a blinded manner. In addition, standardized hook tests with defined forces (50, 80, and 100 N) were performed on 10 pairs of cadaver lower legs and the syndesmosis was sequentially destabilized. Diastasis of the syndesmosis was recorded using an optical 3D camera system. A median force of 81 N (Range: 50 N-145 N) was applied. A proportion of 82% of the tests showed a force < 100 N. The data showed good intraraterreliability and poor interraterreliability. In the standardized investigation of the hook test on the cadaver bone model, both the force and the instability of the syndesmosis had a significant influence on the syndesmosis diastasis. Nevertheless, even with maximum instability of the syndesmosis, diastasis > 2 mm could only be measured in 12 of the 19 evaluable specimens. The widely used hook test shows a high variability when performed in practice. Even in a standardized manner, the hook test cannot detect a relevant syndesmosis injury.

Keywords: biomechanics; cadaver; clinical test; syndesmosis; trauma surgery; upper ankle joint.

Grants and funding

We would like to thank AO Trauma Germany for the support in the context of the promotion of young scientists (F.C.K.). We acknowledge support by the German Research Foundation Project-Nr. 512648189 and the Open Access Publication Fund of the Thueringer Universitaets- und Landesbibliothek Jena.