Anterior column acetabulum fracture fixation with a screw-augmented acetabular cup-a biomechanical feasibility study

Till Berk; Ivan Zderic; Peter Schwarzenberg; Roman Pfeifer; Tatjana Pastor; Sascha Halvachizadeh; R Geoff Richards; Boyko Gueorguiev; Hans-Christoph Pape

doi:10.1016/j.clinbiomech.2023.106095

Anterior column acetabulum fracture fixation with a screw-augmented acetabular cup-a biomechanical feasibility study

Clin Biomech (Bristol, Avon). 2023 Oct:109:106095. doi: 10.1016/j.clinbiomech.2023.106095. Epub 2023 Sep 16.

Authors

Till Berk¹, Ivan Zderic², Peter Schwarzenberg³, Roman Pfeifer⁴, Tatjana Pastor⁵, Sascha Halvachizadeh⁶, R Geoff Richards⁷, Boyko Gueorguiev⁸, Hans-Christoph Pape⁹

Affiliations

¹ AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland; Department of Trauma, University Hospital Zurich, Raemistrasse 100, 8091 Zurich, Switzerland. Electronic address: Till.Berk@usz.ch.
² AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland. Electronic address: ivan.zderic@aofoundation.org.
³ AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland. Electronic address: peter.schwarzenberg@aofoundation.org.
⁴ Department of Trauma, University Hospital Zurich, Raemistrasse 100, 8091 Zurich, Switzerland; Harald-Tscherne Laboratory for orthopedic and Trauma Research, University of Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland. Electronic address: roman.pfeifer@usz.ch.
⁵ AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland; Department of Plastic and Hand Surgery, Inselspital University Hospital Bern, University of Bern, Switzerland. Electronic address: Tatjana.pastor@aofoundation.org.
⁶ Department of Trauma, University Hospital Zurich, Raemistrasse 100, 8091 Zurich, Switzerland; Harald-Tscherne Laboratory for orthopedic and Trauma Research, University of Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland. Electronic address: Sascha.Halvachizadeh@usz.ch.
⁷ AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland. Electronic address: geoff.richards@aofoundation.org.
⁸ AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland. Electronic address: boyko.gueorguiev@aofoundation.org.
⁹ Department of Trauma, University Hospital Zurich, Raemistrasse 100, 8091 Zurich, Switzerland; Harald-Tscherne Laboratory for orthopedic and Trauma Research, University of Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland. Electronic address: Hans-Christoph.Pape@usz.ch.

PMID: 37757678
DOI: 10.1016/j.clinbiomech.2023.106095

Abstract

Backround: The beneficial effects of unrestricted postoperative full weight bearing for elderly patients suffering hip fractures have been demonstrated. However, there is still existing disagreement regarding acetabular fractures.The aim of this biomechanical study was to evaluate the initial load bearing capabilities of different fixation constructs of anterior column fractures (ACFs) in osteoporotic bone.

Methods: Artificial pelvises with ACFs were assigned to three groups (n = 8) and fixed with either a 7.3 mm partially threaded antegrade cannulated screw (group AASS), an anteriorly placed 3.5 mm plate (group AAPF), or a press-fit acetabular cup with screw augmentation (group AACF). All specimens underwent ramped loading from 20 N preload to 200 N at a rate of 18 N/s, followed by progressively increasing cyclic testing at 2 Hz until failure performed at a rate of 0.05 N/cycle. Relative displacements of the bone fragments were monitored by motion tracking.

Findings: Initial stiffness (N/mm) was 118.5 ± 34.3 in group AASS, 100.4 ± 57.5 in group AAPF, and 92.9 ± 44.0 in group AACF, with no significant differences between the groups, p = 0.544. Cycles to failure were significantly higher in groups AACF (8364 ± 2243) and AAPF (7827 ± 2881) compared to group AASS (4440 ± 2063), p ≤ 0.041.

Interpretation: From a biomechanical perspective, the minimally invasive cup fixation with screw augmentation demonstrated comparable stability to plate osteosynthesis of ACFs in osteoporotic bone. The results of the present study do not allow to conclusively answer whether immediate full weight bearing following cup fixation shall be allowed. Given its similar performance to plate osteosynthesis, this remains rather an utopic wish and a more conservative approach deems more reasonable.

Keywords: Acetabulum fracture; Anterior column fracture; Biomechanics; Feasibility; Full weight bearing.

MeSH terms

Acetabulum / surgery
Aged
Biomechanical Phenomena
Bone Plates
Bone Screws
Feasibility Studies
Fracture Fixation, Internal / methods
Fractures, Bone* / surgery
Hip Fractures* / surgery
Humans
Osteoporosis*
Spinal Fractures*