The syndesmosis joint, located between the tibia and fibula, is critical to maintaining the stability and function of the ankle joint. Damage to the ligaments that support this joint can lead to ankle instability, chronic pain, and a range of other debilitating conditions. Understanding the kinematics of a healthy joint is critical to better quantify the effects of instability and pathology. However, measuring this movement is challenging due to the anatomical structure of the syndesmosis joint. Biplane Video Xray (BVX) combined with Magnetic Resonance Imaging (MRI) allows direct measurement of the bones but the accuracy of this technique is unknown. The primary objective is to quantify this accuracy for measuring tibia and fibula bone poses by comparing with a gold standard implanted bead method. Written informed consent was given by one participant who had five tantalum beads implanted into their distal tibia and three into their distal fibula from a previous study. Three-dimensional (3D) models of the tibia and fibula were segmented (Simpleware Scan IP, Synopsis) from an MRI scan (Magnetom 3T Prisma, Siemens). The beads were segmented from a previous CT and co-registered with the MRI bone models to calculate their positions. BVX (125 FPS, 1.25ms pulse width) was recorded whilst the participant performed level gait across a raised platform. The beads were tracked, and the bone position of the tibia and fibula were calculated at each frame (DSX Suite, C-Motion Inc.). The beads were digitally removed from the X-rays (MATLAB, MathWorks) allowing for blinded image-registration of the MRI models to the radiographs. The mean difference and standard deviation (STD) between bead-generated and image-registered bone poses were calculated for all degrees of freedom (DOF) for both bones.Abstract
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Methods
Syndesmotic ankle injuries are present in one fourth of all ankle trauma and may lead to chronic syndesmotic instability as well as posttraumatic ankle osteoarthritis. The main challenge remains distinguishing them from other types of ankle trauma. Currently, the patient's injured and non-injured ankles are compared using plain radiographs to determine pathology. However, these try to quantify 3D displacement using 2D measurements techniques and it is unknown to what extent the 3D configuration of the normal ankle syndesmosis is symmetrical. We aimed to assess the 3D symmetry of the normal ankle syndesmosis between the right and left side in a non- and weightbearing CT. In this retrospective comparative cohort study, patients with a bilateral non-weightbearing CT (NWBCT; N=28; Mean age=44, SD=17.4) and weight-bearing CT (WBCT; N=33; Mean age=48 years; SD=16.3) were analyzed. Consecutive patients were included between January 2016 and December 2018 when having a bilateral non-weightbearing or weightbearing CT of the foot and ankle. Exclusion criteria were the presence of hindfoot pathology and age less than 18 years or greather than 75 years. CT images were segmented to obtain 3D models. Computer Aided Design (CAD) operations were used to fit the left ankle on top of the right ankle. The outermost point of the apex of the lateral malleolus (AML), anterior tubercle (ATF) and posterior tubercle (PTF) were computed. The difference in the coordinates attached to these anatomical landmarks of the left distal fibula in the ankle syndesmosis with respect to right were used to quantify symmetry. A Cartesian coordinate system was defined based on the tibia to obtain the direction of differences in all six degrees of freedom. Statistical analysis was performed using the Mann-Whitney U test to allow comparison between measurements from a NWBCT and WBCT. Reference values were determined for each 3D measurement in a NWBCT and WBCT based on their 2SD. The highest difference in translation could be detected in the anterior-posterior direction (Mean APNWBCT= −0.01mm; 2SD=3.43/Mean APWBCT=−0.1mm; 2SD=2.3) and amongst rotations in the external direction (Mean APNWBCT=−0.3°; 2SD=6.7/Mean APWBCT=-0,2°; 2SD=5.2). None of these differences were statistically significant in the normal ankle syndesmosis when obtained from a NWBCT compared to a WBCT (P>0.05). This study provides references values concerning the 3D symmetry of the normal ankle syndesmosis in weightbearing and non-weightbearing CT-scans. These novel data contribute relevantly to previous 2D radiographic quantifications. In clinical practice they will aid in distinguishing if a patient with a syndesmotic ankle lesion differs from normal variance in syndesmotic ankle symmetry.
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 4.5mm 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? 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 700N 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 10Nm 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.Background
Methods
Introduction and Objective. Postoperative management regimes vary following open reduction and internal fixation of unstable ankle fractures. There is an evolving understanding that poorer outcomes could be associated with non-weight bearing protocols and immobilisation. Traditional non-weight bearing cast immobilisation may prevent loss of fixation, and this practice continues in many centres. The aim of this systematic review and meta-analysis is to compare the complication rate and functional outcomes of early weight-bearing (EWB) versus late weight-bearing (LWB) following open reduction and internal fixation of ankle fractures. Materials and Methods. We performed a systematic review with a meta-analysis of controlled trials and comparative cohort studies. MEDLINE (via PubMed), Embase and the Cochrane Library electronic databases were searched inclusive of all date up to the search time. We included all studies that investigated the effect of weight-bearing following adults ankle fracture fixation by any means. All ankle fracture types, including isolated lateral malleolus fractures, isolated medial malleolus fractures, bi-malleolar fractures, tri-malleolar fractures and
