Invisible Injuries in Ankle Fractures

Category: Ankle, Trauma, Biomechanical Introduction/Purpose: Ankle fractures are often associated with ligamentous injuries of the distal tibiofibular syndesmosis, the deltoid ligament and are predictive of ankle instability, early joint degeneration and long-term ankle dysfunction. Detection of lig...

Full description

Bibliographic Details
Main Authors: Robin Blom MD, PhD candidate, Markus Knupp MD, Beat Hintermann MD, Sjoerd Stufkens MD, PhD
Format: Article
Language:English
Published: SAGE Publishing 2017-09-01
Series:Foot & Ankle Orthopaedics
Online Access:https://doi.org/10.1177/2473011417S000121
_version_ 1818214235207892992
author Robin Blom MD, PhD candidate
Markus Knupp MD
Beat Hintermann MD
Sjoerd Stufkens MD, PhD
author_facet Robin Blom MD, PhD candidate
Markus Knupp MD
Beat Hintermann MD
Sjoerd Stufkens MD, PhD
author_sort Robin Blom MD, PhD candidate
collection DOAJ
description Category: Ankle, Trauma, Biomechanical Introduction/Purpose: Ankle fractures are often associated with ligamentous injuries of the distal tibiofibular syndesmosis, the deltoid ligament and are predictive of ankle instability, early joint degeneration and long-term ankle dysfunction. Detection of ligamentous injuries and the need for treatment remain subject of ongoing debate. In the classic article of Boden it was made clear that injuries of the syndesmotic ligaments were of no importance in the absence of a deltoid ligament rupture. Even in the presence of a deltoid ligament rupture, the interosseous membrane withstood lateralization of the fibula in fractures up to 4.5 mm above the ankle joint. Generally, syndesmotic ligamentous injuries are treated operatively by temporary fixation performed with positioning screws. But do syndesmotic injuries need to be treated operatively at all? Methods: The purpose of this biomechanical cadaveric study was to investigate the relative movements of the tibia and fibula, under normal physiological conditions and after sequential sectioning of the syndesmotic ligaments. Ten fresh-frozen below-knee human cadaveric specimens were tested under normal physiological loading conditions. Axial loads of 50 Newton (N) and 700 N were provided in an intact state and after sequential sectioning of the following ligaments: anterior-inferior tibiofibular (AITFL), posterior-inferior tibiofibular (PITFL), interosseous (IOL), and whole deltoid (DL). In each condition the specimens were tested in neutral position, 10 degrees of dorsiflexion, 30 degrees of plantar flexion, 10 degrees of inversion, 5 degrees of eversion, and externally rotated up to 10 Nm torque. Finally, after sectioning of the deltoid ligament, we triangulated Boden’s classic findings with modern instruments. We hypothesized that only after sectioning of the deltoid ligament; the lateralization of the talus will push the fibula away from the tibia. Results: During dorsiflexion and external rotation the ankle syndesmosis widened, and the fibula externally rotated after sequential sectioning of the syndesmotic ligaments. After the AITFL was sectioned the fibula starts rotating externally. However, the external rotation of the fibula significantly reduced when the external rotation torque was combined with axial loading up to 700 N as compared to the external rotation torque alone. The most relative moments between the tibia and fibula were observed after the deltoid ligament was sectioned. Conclusion: Significant increases in movements of the fibula relative to the tibia occur when an external rotation torque is provided. However, axial pressure seemed to limit external rotation because of the bony congruence of the tibiotalar surface. The AITFL is necessary to prevent the fibula to rotate externally when the foot is rotating externally. The deltoid ligament is the main stabilizer of the ankle mortise.
first_indexed 2024-12-12T06:16:57Z
format Article
id doaj.art-3737bb93e73143dc941bc5c0df24a9a6
institution Directory Open Access Journal
issn 2473-0114
language English
last_indexed 2024-12-12T06:16:57Z
publishDate 2017-09-01
publisher SAGE Publishing
record_format Article
series Foot & Ankle Orthopaedics
spelling doaj.art-3737bb93e73143dc941bc5c0df24a9a62022-12-22T00:35:00ZengSAGE PublishingFoot & Ankle Orthopaedics2473-01142017-09-01210.1177/2473011417S000121Invisible Injuries in Ankle FracturesRobin Blom MD, PhD candidateMarkus Knupp MDBeat Hintermann MDSjoerd Stufkens MD, PhDCategory: Ankle, Trauma, Biomechanical Introduction/Purpose: Ankle fractures are often associated with ligamentous injuries of the distal tibiofibular syndesmosis, the deltoid ligament and are predictive of ankle instability, early joint degeneration and long-term ankle dysfunction. Detection of ligamentous injuries and the need for treatment remain subject of ongoing debate. In the classic article of Boden it was made clear that injuries of the syndesmotic ligaments were of no importance in the absence of a deltoid ligament rupture. Even in the presence of a deltoid ligament rupture, the interosseous membrane withstood lateralization of the fibula in fractures up to 4.5 mm above the ankle joint. Generally, syndesmotic ligamentous injuries are treated operatively by temporary fixation performed with positioning screws. But do syndesmotic injuries need to be treated operatively at all? Methods: The purpose of this biomechanical cadaveric study was to investigate the relative movements of the tibia and fibula, under normal physiological conditions and after sequential sectioning of the syndesmotic ligaments. Ten fresh-frozen below-knee human cadaveric specimens were tested under normal physiological loading conditions. Axial loads of 50 Newton (N) and 700 N were provided in an intact state and after sequential sectioning of the following ligaments: anterior-inferior tibiofibular (AITFL), posterior-inferior tibiofibular (PITFL), interosseous (IOL), and whole deltoid (DL). In each condition the specimens were tested in neutral position, 10 degrees of dorsiflexion, 30 degrees of plantar flexion, 10 degrees of inversion, 5 degrees of eversion, and externally rotated up to 10 Nm torque. Finally, after sectioning of the deltoid ligament, we triangulated Boden’s classic findings with modern instruments. We hypothesized that only after sectioning of the deltoid ligament; the lateralization of the talus will push the fibula away from the tibia. Results: During dorsiflexion and external rotation the ankle syndesmosis widened, and the fibula externally rotated after sequential sectioning of the syndesmotic ligaments. After the AITFL was sectioned the fibula starts rotating externally. However, the external rotation of the fibula significantly reduced when the external rotation torque was combined with axial loading up to 700 N as compared to the external rotation torque alone. The most relative moments between the tibia and fibula were observed after the deltoid ligament was sectioned. Conclusion: Significant increases in movements of the fibula relative to the tibia occur when an external rotation torque is provided. However, axial pressure seemed to limit external rotation because of the bony congruence of the tibiotalar surface. The AITFL is necessary to prevent the fibula to rotate externally when the foot is rotating externally. The deltoid ligament is the main stabilizer of the ankle mortise.https://doi.org/10.1177/2473011417S000121
spellingShingle Robin Blom MD, PhD candidate
Markus Knupp MD
Beat Hintermann MD
Sjoerd Stufkens MD, PhD
Invisible Injuries in Ankle Fractures
Foot & Ankle Orthopaedics
title Invisible Injuries in Ankle Fractures
title_full Invisible Injuries in Ankle Fractures
title_fullStr Invisible Injuries in Ankle Fractures
title_full_unstemmed Invisible Injuries in Ankle Fractures
title_short Invisible Injuries in Ankle Fractures
title_sort invisible injuries in ankle fractures
url https://doi.org/10.1177/2473011417S000121
work_keys_str_mv AT robinblommdphdcandidate invisibleinjuriesinanklefractures
AT markusknuppmd invisibleinjuriesinanklefractures
AT beathintermannmd invisibleinjuriesinanklefractures
AT sjoerdstufkensmdphd invisibleinjuriesinanklefractures