Universität zu Köln

Babasiz, Tamara ORCID: 0009-0008-2514-7611, Wegmann, Kilian ORCID: 0000-0001-5961-1912, Rausch, Valentin ORCID: 0000-0001-7987-5173, Leschinger, Tim ORCID: 0000-0003-1319-6949, Müller, Lars Peter ORCID: 0000-0001-9769-6865 and Ott, Nadine ORCID: 0000-0001-7865-8425 (2026). Influence of anteromedial facet defects of the coronoids process on the posterior bundle of the medial collateral ligament in human cadaveric specimens. Journal of Shoulder and Elbow Surgery, 35 (5). e631-e639. Elsevier. ISSN 1058-2746

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Abstract

Background: Anteromedial facet (AMF) fractures of the coronoid process are typically accompanied by tears of the lateral collateral ligament (LCL) and the posterior bundle of the medial collateral ligament (pMCL). Addressing the bone defect and repairing the LCL is essential in the acute setting to prevent persistent varus posteromedial rotatory instability (VPMRI) and subsequent progression to osteoarthritis. However, pMCL repair is not typically performed. Therefore, the present biomechanical study investigates the amount of stress experienced by the pMCL in cases of anteromedial facet defects and its role in contributing to VPMRI of the elbow. Methods: Nine fresh-frozen cadaveric elbows were tested under varus loading (3 Nm) with elbow flexion at 30◦, 60◦, and 90◦ in 3 distinct bone defect scenarios: (A) non-fractured coronoid; (B) anteromedial facet fracture, subtype II; and (C) anteromedial facet fracture, subtype III. The strain of the LCL and the ulnar collateral ligament (UCL) with its anterior (aMCL) and posterior bundles (pMCL) were measured quantitively via strain gauges (μm/m), as an estimate for their involvement in the instability pattern. Results: Across all scenarios, the highest strain of the pMCL under varus force was observed with elbow flexion at 30◦ with a supinated forearm (mean = 171.72 μm/m, min 22.79 μm/m, max 348.9 μm/m, SD = 110.5 μm/m), while the aMCL remained relaxed. The degree of elbow flexion significantly influenced the strain on the pMCL under varus force (P = .01). Strain on the pMCL increased in scenario B (162.45 μm/m, SD 122.2 μm/m) and scenario C (185.1 μm/m, SD 117.8 μm/m). There was no statistically significant difference between both scenarios (P = .96). Conclusion: The pMCL is notably influenced by varus force, particularly with elbow flexion at 30◦. AMF coronoid fractures resulted in a higher strain of the pMCL. Repairing the pMCL in cases of AMF defects could enhance elbow stability.

Item Type:	Article
Creators:	Creators Email ORCID ORCID Put Code Babasiz, Tamara UNSPECIFIED https://orcid.org/0009-0008-2514-7611 UNSPECIFIED Wegmann, Kilian UNSPECIFIED https://orcid.org/0000-0001-5961-1912 UNSPECIFIED Rausch, Valentin UNSPECIFIED https://orcid.org/0000-0001-7987-5173 UNSPECIFIED Leschinger, Tim UNSPECIFIED https://orcid.org/0000-0003-1319-6949 UNSPECIFIED Müller, Lars Peter UNSPECIFIED https://orcid.org/0000-0001-9769-6865 UNSPECIFIED Ott, Nadine UNSPECIFIED https://orcid.org/0000-0001-7865-8425 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-812615
Identification Number:	10.1016/j.jse.2025.09.004
Journal or Publication Title:	Journal of Shoulder and Elbow Surgery
Volume:	35
Number:	5
Page Range:	e631-e639
Number of Pages:	9
Date:	May 2026
Publisher:	Elsevier
ISSN:	1058-2746
Language:	English
Faculty:	Faculty of Medicine
Divisions:	Faculty of Medicine > Orthopädie > Klinik und Poliklinik für Orthopädie und Unfallchirurgie
Subjects:	Medical sciences Medicine
Uncontrolled Keywords:	Keywords Language Coronoid fractures ; anteromedial facet ; posteromedial rotatory instability ; posterior bundle ; LC L ; MCL ; strain gauges ; biomechanical English
['eprint_fieldname_oa_funders' not defined]:	Publikationsfonds UzK
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/81261