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Category: Ankle; Trauma Introduction/Purpose: Weightbearing CT (WBCT) scan provides an ability to compare the ankle joints bilaterally in a 3D manner under physiologic load. According to our recent investigations, 3D volume measurement of the syndesmosis, if measured up to 5cm proximal to the tibial plafond, can detect the instability with an accuracy of 90%, sensitivity of 95.8%, and specificity of 83.3%. However, these values can differ based on the knowledge and experience of the human interpreter. Deep learning, as a subset of machine learning, has shown promising potentials in processing and analyzing images and detecting abnormalities within the images using deep convolutional neural networks (DCNN). Herein, we aimed to assess the accuracy, sensitivity, and specificity of 3D volume WBCT evaluation using DCNN algorithms in patients with subtle syndesmotic instability. Methods: In this study 140 bilateral ankle WBCT scans of patients with subtle syndesmotic instability who were diagnosed intraoperatively were allocated to the patient group. The control group comprised 140 bilateral ankle WBCT images of healthy individuals. We utilized inception V3 model for our DCNN. Data augmentation and transfer learning were used; however, the images were not preprocessed in terms of change in size and resolution. The data were divided as 80:10:10 for training, validation, and test subsets, respectively. The outcome of the study was expressed as sensitivity, specificity, F-score, and the area under the curve (AUC). Results: The performance of our DCNN algorithm showed a sensitivity of 99.41%, specificity of 99.34%, F-score of 99.37%, and 99.99% AUC ( Figure 1 ). The change in loss value of the train data was plateaued after 40 iterations. Axial images were the most appropriate images that were used by the algorithm to detect the instability. Conclusion: In this study we observed that using DCNN in the process of WBCT image interpretation for diagnosis of syndesmotic instability, particularly in subtle cases, makes this modality almost perfect with a very small chance of missing a case. Training a DCNN using a greater number of inputs is still recommended to improve the validity and reliability of this method. Providing a heat map will also help clinicians discover the process of decision-making by these algorithms as DCNNs are sometimes called 'black box'.

Category: Ankle; Sports; Trauma Introduction/Purpose: Malreduction of the fibula within the incisura is often caused by an eccentric clamp or screw placement and short fibular length. Weightbearing computed tomography (WBCT) has proven to be a reliable method to diagnose syndesmotic instability and can be used as a template to determine the syndesmotic axis and optimal position to place the clamp. We aimed to determine the anatomic axis of the syndesmosis, or the trans-syndesmotic angle (TSA) in healthy individuals on WBCT, and to see if side-to-side and gender based variations exist. We also aimed to determine the clamp's medial tine placement along the trans-syndesmotic axis. Methods: The study group was made up of patient population without ankle injury who underwent bilateral foot and ankle WBCT imaging (n = 100; 200 ankles). Measurements on bilateral WBCT images included: 1) TSA at 1cm, 2cm, and 3cm proximal to tibial plafond, respectively; 2) Medial tine of the clamp positioning at 1cm and 2 cm along the syndesmotic axis. The medial tine clamp position was described in terms of the percentage of anterior to posterior tibial diameter from the anterior cortical boundary. In addition, the aforementioned TSA measurements were compared to historically defined 30 degrees of syndesmotic axis. Paired t-test was used to compare side to side and gender based differences. A p-value < 0.05 was considered statistically significant. Results: In the uninjured healthy population, the mean trans-syndesmotic angles were 17.60, 21.60, and 24.10 at 1cm, 2cm, and 3cm proximal to the tibial plafond respectively. The clamp's medial tine should be positioned 24.7% and 21.3% of the AP tibial cortical distance, posterior to the anterior tibial cortex at 1cm and 2 cm proximal to the tibial plafond. There was no significant side to side or gender based differences for any of the measurements. Additionally, all three weightbearing TSA measurements were significantly larger than the historically defined syndesmotic angle of 30 degrees (pConclusion: Preoperative WBCT imaging provides a reliable template to determine TSA and to plan optimal clamp tine positioning along the syndesmotic axis. Our study has established normal ranges for cross-sectional syndesmotic axis measurements during weight-bearing and established that no differences exist between laterality and gender in patients without syndesmotic injury.

Category: Ankle; Trauma Introduction/Purpose: In the setting of an isolated lateral malleolar fracture, stability is predicated by whether the deep deltoid ligament is intact. Portable ultrasound (P-US) has also been used in the clinical setting, allowing dynamic and non-invasive evaluation at the point of care. This study aimed to determine the cutoff values, as well as its sensitivity and specificity for diagnosing supination external rotation (SER) ankle injury stage IVb (with complete deltoid ligament rupture) using the P-US. Methods: Ten fresh-frozen cadaveric specimens were used. Medial ankle instability was assessed by the P-US. The assessment was performed with all structures intact and later with sequential transection of the AITFL, Weber-B fibular fracture, the PITFL, the superficial and deep deltoid ligament. In all scenarios, three loading conditions were considered, including the GST, the external rotation stress test (45N), and the simulated weight-bearing (750N). The P-US measurement of the MCS was assessed at the anteromedial aspect and inferomedial aspect of the ankle joint. The P-US measurement of the MCS was assessed by placing the ultrasound probe perpendicularly to the medial gutter at the anteromedial aspect and inferomedial aspect of the ankle joint. Three different MCS distances were measured, as demonstrated in Figure 1. To determine the sensitivity and specificity of the diagnosis of SER injury type IV using the P-US, a receiver operating characteristic (ROC) curve analysis was performed. Results: The MCS optimal cutoff point to distinguish SER ankle injury stage IVb from other injury stages ranged from 10.4 to 13.8 during the GST, 4.2 to 7.9mm during the weight-bearing stress, and 10.6-17.9mm during the external rotation stress test (Table 1). All P-US cutoff values provided acceptable sensitivity (60-100%), specificity (84-100%), and the area under ROC curve (0.8-1.0) for diagnosing SER ankle injury stage IVb. Conclusion: MCS cutoff points assessed with the P-US under the GST, weight-bearing, and the external rotation stress test demonstrate high sensitivity and specificity for detecting SER ankle injury stage IVb. The cutoff values vary depending on which loading condition is being used. Additional clinical studies are necessary in the in vivo setting to better understand the implications of these test conditions.

Category: Ankle; Ankle Arthritis; Basic Sciences/Biologics; Trauma Introduction/Purpose: Osteoarthritis (OA) is the most common degenerative joint disorder, characterized mainly by progressive articular cartilage degradation, subchondral bone thickening, osteophyte formation, and synovial inflammation. About 80% of ankle OA is believed to be post-traumatic and affects the younger population leading to a higher risk of disabilities during life. Mesenchymal stem cells (MSCs) have shown promising effects in preventing the degenerative process of OA via paracrine effect and great differentiation potential. Recently, using chondrocyte conditioned medium (CCM) that contains all necessary secretomes was shown to enhance MSC differentiation and regeneration of the cartilage tissue. In this study, we aimed to assess the effects of intraarticular injection of MSCs plus CCM on the degenerative process of monoiodoacetate (MIA)-induced ankle OA in rats. Methods: Fifty male rats were randomly divided into 5 groups (n=10): Non-treated control group (C); the group treated with intra-articular Hyaluronic acid (HA). Hyaluronic acid has shown beneficial effects on the degenerative process of OA in different reports. The other treatment groups received intraarticular synovial derived MSCs (5′105), intraarticular CCM, and intraarticular MSCs combined with CCM (MSC+CCM), respectively. Induction of ankle OA was conducted via 1 mg MIA injection in the right tibiotarsal joint for two consecutive days. Three months after starting the treatments, radiological assessments of joint space width (Normal=0, reduced=1, abcent=2) and osteophytes of the tibia and talus (No osteophyte=0, small=1, moderate=2, severe=3) were performed. Ankle specimens were obtained for histopathological examination of the joint surface, matrix, cell distribution, cell viability, subchondral bone, and mineralization; lower scores indicated more severe damages. Scores for each assessment were recorded. Mann-Whitney U test was used for comparisons and p-valueResults: Our findings showed significant differences between the controls and the treatment groups regarding all pathological scores including joint surface, matrix, cell distribution, cell viability, subchondral bone, and mineralization, that were higher and radiological scores including joint space width and osteophytes of the tibia and talus that were lower in the controls (P0.05). However, although not statistically noticeable, the MSC+CCM group showed slightly better outcomes, both radiologically and histopathologically, compared to the MSC and CCM groups ( Figure 1 ). Conclusion: Our results showed that the combination of CCM can have a similar effect on the degenerative changes in ankle OA. However, the combination of MSC+CCM showed better scores regarding pathological and radiological evaluation. Although further studies with a greater population seem to be needed to validate these outcomes, our study indicates the efficacy of CCM in reducing the degenerative rate of OA. CCM is also known as 'secret factors' since it is still a 'black box' in terms of identifying its content and effects.