Determination of the Optimal Syndesmosis Fixation Angle Using Mortise View of The Ankle Joint

Background: Syndesmosis is an important soft tissue component supporting the ankle stability and commonly injured accompanying with ankle fractures. The accurate reduction and fixation of syndesmosis is essential to obtain better functional results. Therefore, we aimed to find a practical method using the mortise view of ankle to determine the optimal syndesmosis fixation angle intraoperatively. Methods: We randomly selected 200 adults (100 women and 100 men) between 18 - 60 years of age. Three-dimensional anatomical models of tibia and fibula were created using Materialise MIMICS 21. We created a best fit plane on articular surface of medial malleolus and a ninety degrees vertical plane to medial malleolus plane. We determined two splines on cortical borders of tibia and fibula distant from the most superior point of ankle joint in horizontal view. We created two spheres that fit to the predefined splines. The optimal syndesmosis fixation angle was determined measuring the angle between the line connecting the center points of spheres, and the ninety degrees vertical plane to medial malleolus plane. Results: We observed no statistically significant difference between gender groups in terms of optimal syndesmosis fixation angles. The mean age of our study population was 47.1 {plus minus} 10.5. The optimal syndesmosis fixation angle according to mortise view was found as 21 {plus minus} 4.3 degrees. Conclusions: We determined the optimal syndesmosis fixation angle as 21 {plus minus} 4.3 degrees in accordance with the mortise view of ankle. The surgeon could evaluate the whole articular surface of ankle joint with the medial and lateral syndesmotic space in mortise view accurately and at the same position syndesmosis fixation could be performed at 21 {plus minus} 4.3 degrees.

Anatomic and Radiographic Safe Zone for Posterior Malleolar Screw Placement

Background: The most appropriate treatment and management of posterior malleolar fractures (PMFs) lacks consensus. Indirect reduction and fixation with posterior to anterior (PA) screw shows promise by avoiding the risks associated with direct reduction or indirect anterior to posterior approaches. Some authors have raised concerns about potential risk to nearby structures with the PA technique, including hardware prominence into the syndesmosis. This study highlights use of the posteromedial vertical syndesmotic line (PVSL) as a fluoroscopic landmark, helping surgeons avoid intrasyndesmotic placement. Study aims are to evaluate PVSL correspondence with posterior border of the incisura tibialis and to define a safe zone between this line and flexor hallucis longus tendon. Methods: Indirect PA screw placement was completed on 10 cadaveric specimens, followed by fluoroscopy in mortise and lateral views. Dissection was performed to assess screw placement relative to the posteromedial border of the syndesmosis. The posterior border of the syndesmosis was marked with a radiopaque wire. Repeat imaging was completed to validate the fluoroscopic PVSL is representative of the posteromedial border of the tibial incisura. Results: On dissection, 9 out of 10 cadavers had accurate screw placement with no penetration into the syndesmosis. Corresponding imaging showed the screw head to be medial to the marker on mortise view. For the specimen with penetration into the syndesmosis, imaging confirmed that the screw head was lateral to the marker on mortise views. The radiopaque marker correlated with the PVSL for all specimens when comparing anatomic to radiographic findings. A radiographic safe zone is defined for the PA screw 12 mm medial to the PVSL to ensure no iatrogenic injury to the flexor hallucis longus tendon. Conclusion: This study demonstrated that a posterior incisura tibialis fluoroscopic landmark is unambiguous in localizing the posterior syndesmotic border and that screws medial to this line are safely out of the syndesmosis, while screws placed lateral are either in or at risk of intrasyndesmotic placement. A safe zone is defined for screw placement. Clinical Relevance: This article describes a radiographic and clinical safe zone for fixation and hardware placement during open reduction internal fixation (ORIF) of PMFs. This information will assist surgeons in avoiding intrasyndesmotic hardware placement as well as injury to deep soft tissue structures.

The Value of Additional Gravity Stress Radiographs for Decision Making in the Treatment of Isolated Type B Distal Fibular Fractures

Background: Prior to treatment decisions concerning isolated Weber type B ankle fractures, assessment of the stability of the ankle joint is mandatory. The gravity stress (GS) radiograph is a radiographic tool to determine stability. We hypothesized that this additional GS radiograph would lead to fewer operative treatments by applying the criterion of operative treatment when medial clear space (MCS) > superior clear space (SCS) + 2 mm on the GS radiograph, compared with the nonstressed mortise view criteria of advising operative treatment in case of MCS > SCS + 1 mm. Methods: This retrospective comparative cohort study analyzed 343 patients aged between 18 and 70 years with an isolated Weber type B ankle fracture diagnosed at the emergency department between January 2014 and December 2019. The cohort was divided into 2 groups based on whether an additional GS radiograph was performed. Group I consisted of 151 patients in whom a regular mortise and lateral radiograph were performed. Group II comprised 192 patients, with an additional GS radiograph. Primary outcome was type of treatment (conservative vs operative). Secondary outcomes were patient-reported functional outcomes and pain. Results: Baseline characteristics of both groups did not differ. In group I, surgery was performed in 60 patients (39.7%) compared with 108 patients (56.3%) in group II ( P = .002). In the operatively treated patients, the mean MCS on regular mortise view was significantly smaller in patients in whom an additional GS radiograph was performed compared to patients without an additional GS radiograph (4.1 mm vs 5.2 mm, P < .001). Mean Olerud-Molander Ankle Score and mean visual analog scale (VAS) for pain did not differ significantly between groups I and II. Conclusions: Contrary to what was hypothesized, the introduction of an additional gravity stress radiograph, by which operative treatment was indicated if the MCS was wider than the SCS + 2 mm, did not result in reduced operative treatment of Weber type B ankle fractures when operative treatment was indicated for MCS > SCS + 1 mm on non-gravity stress radiographs. Level of Evidence: Level III: retrospective comparative study.

Implications of the Overlapping Degree Between Proximal Fibula and Tibia for Placing the Optimal Syndesmotic Screw: A Virtual Cadaveric Study

Background: To determine the optimal direction of the syndesmotic screw and introduce a consistent landmark for practical application by analyzing three-dimensional (3D) modeling and virtual implantation.Methods: A total of 102 cadaveric lower legs (50 males and 55 females, average height of 160.6 ± 7.1cm) were used to reconstruct a 3D model by using the Mimics® software and the joint morphology was evaluated. Syndesmotic cylinders (Ø3.5 mm/Length 100 mm) were transversely placed in the proximal end of the incisura fibularis for simulating screw fixation. The tibial proximal cylinder, which was tangent to the posterior tibial condyles, was traced and the angle between the two cylinders was measured as the tibial torsion angle (TTA). After rotating the syndesmotic cylinder parallel to the ground, the overlapping degree between the proximal fibula and tibia were assessed as a radiologic indicator. Results: Concerning tibial torsion, the TTA was an average of 36.7° (range, 17.2°–54.4°, SD 8.78) When the syndesmotic cylinder was rotated to be parallel to the ground, the proximal fibula had non- or linear overlap with the lateral border of the tibia, regardless of the joint morphology. In this nonoverlapping view, compared to the mortise view, the three criteria for normal fibular length could be better visualized. Conclusion: The syndesmotic cylinder in the proximal end of the incisura fibularis could be consistently placed parallel to the ground by internally rotating the tibia until there was a non- or linear overlap between the proximal fibula and the tibia, regardless of the joint morphology.

Alignment of the Incisura Fibularis with the Lateral Border of the Talus on Mortise View Radiographs in Ankle Injuries

Category: Ankle, Trauma Introduction/Purpose: Diagnoses of ankle injuries utilize plain radiographs in three views: anteroposterior (AP), lateral, and mortise. Mortise view has greater sensitivity and accuracy in assessment of the distal tibiofibular syndesmosis through visualization of the mortise clear space. Current radiologic diagnostic parameters, like medial tibiotalar clear space and tibiofibular clear space, are inconsistent and unreliable because no consensus exists to measure these parameters. However, the incisura fibularis (IF) is a consistent landmark in assessing syndesmotic stability. We believe that in ankles without fracture, dislocation, or syndesmotic disruption, the IF aligns with the lateral border of the talus when observed on mortise view radiographs. This study seeks to determine a novel, more reliable radiologic parameter in diagnosis of the ankle mortise by evaluating this alignment. Methods: We retrospectively reviewed adult patient charts from 2012-2017 and selected 100 mortise radiographs: 23 bimalleolar fractures, 14 trimalleolar fractures, 13 fibular fractures, and 50 that were negative for fracture, dislocation, and syndesmotic disruption. We analyzed preoperative radiographs (after closed reduction, if displacement occurred) and postoperative radiographs at least 3 months after open reduction/internal fixation. Mechanism of injury, laterality of radiograph, and gender of patient were not considered in this sample. We evaluated the IF and talus alignment by drawing a line from the proximal IF, through the inferior tibia, to the lateral border of the talus (IFT line in Figure 1). We considered alignments < 1 mm from our IFT line to have mortise congruence since mortise widening >/= 1 mm can decrease contact area of the tibiotalar joint and cause instability. Chi-squared analysis compared non- fracture radiographs to pre- and postoperative fracture radiographs to determine significance with p < 0.05. Results: Among radiographs without fracture, dislocation, and syndesmotic disruption, 46/50 showed alignment < 1 mm from the IFT line. 14/50 preoperative radiographs had alignment < 1 mm from the IFT line: 2 bimalleolar fractures, 4 trimalleolar fractures, and 8 fibular fractures. 43/50 postoperative radiographs had alignment < 1 mm from the IFT line: 19 bimalleolar fractures, 13 trimalleolar fractures, and 11 fibular fractures. Chi-squared analysis determined statistical significance in comparison of non-fracture radiographs with preoperative radiographs by chi-squared statistic = 42.6667 and p < 0.00001. Chi-squared test showed no significance (p > 0.05) in comparison of non- fracture radiographs with postoperative fracture radiographs by chi-squared statistic = 0.9193 and p = 0.337657. Chi-squared test did not show significance among the different types of fractures. Conclusion: We implemented a novel approach to determine a more reliable radiologic parameter in evaluation of the ankle mortise by assessment of the alignment of the IF with the lateral border of the talus on mortise view radiographs. Radiographs without fracture, dislocation, or syndesmotic disruption have alignment < 1 mm from the IFT line, which suggests mortise congruence. Alignment >/= 1 mm may indicate mortise incongruence, distal tibiofibular syndesmotic instability, and talar shift. We conclude that the IFT line can be utilized to appraise the ankle mortise in distal tibiofibular syndesmotic injuries on mortise view radiographs.

Ankle Gravity Stress View in the Seated Position: A Technical Tip

Category: Ankle Introduction/Purpose: Diagnosis of mortise instability in the apparent isolated lateral malleolus fracture can be challenging and often relies on stress radiography. While the gravity stress view (GSV) is commonly utilized, it traditionally requires the patient to assume the lateral decubitus position for imaging of the ankle. This can be difficult and uncomfortable for the patient and may be unsafe in particular situations. Furthermore, transferring the patient back and forth to obtain this positioning is time-intensive for the radiology technician and disruptive to clinic throughput. Therefore, we describe a simple technique that allows acquisition of the GSV of the ankle while the patient remains seated. The technique involves minimal patient movement and is simple for the staff to position appropriately. Methods: The patient is seated on either a stable office chair with arms for safety or in a wheelchair. The affected limb is then placed on a padded stool with the foot extended past the edge of the stool. The patient is instructed to maintain the ankle in a comfortable resting position. They are then encouraged to externally rotate at the ipsilateral hip. If needed, a small bump can be placed underneath the contralateral hip to further increase external rotation of the affected limb at the hip. The ankle and foot should be approximately 15 degrees internally rotated relative to the plane of the floor once the leg has been appropriately positioned. The leg should be held straight with the ankle at the level of the chair seat. This places the ankle in an optimal angle for obtaining a mortise view. The radiograph is then obtained in standard fashion. Results: N/A Conclusion: Obtaining the GSV in the seated position offers several advantages. First, the patient is placed in a seated position, which is more time-efficient than transferring the patient to the radiology table and avoids the potential danger of patients falling. Second, external rotation of the hip is generally well-tolerated in isolated leg injuries. Third, this positioning more reliably places the ankle in approximately 15 degrees of internal rotation to obtain the optimal mortise view and assess mortise symmetry. Finally, patient comfort is increased as this technique obviates transferring patients or placing their hip directly on a rigid radiology table.

Relationship between osteophyte and arthroscopic findings in osteoarthritis of ankle

Category: Ankle Introduction/Purpose: Mortise view weight-bearing radiograph is widely used for the diagnosis of osteoarthritis of ankle. Thickness of the articular cartilage cannot be accurately evaluated in the evaluation of joint space from weight-bearing radiograph, because lateral tibiotalar joint space is maintained in valgus type osteoarthritis in some cases. There are few reports on the relation between osteophyte and the articular cartilage injury. We considered that it might be possible to estimate the cartilage injury more accurately by examining osteophytes. The purpose of this study is to analyze the relationship between the location and grade of osteophytes in weight-bearing radiograph and cartilage injury in arthroscopic findings was analyzed. Methods: Twenty-one anklets of 21 patients consisted of 10 males and 10 females, with mean age of 61.4 years (31-79 years), who underwent arthroscopic surgery for osteoarthritis in our department were included. Weight-bearing radiograph were taken before surgery. Location and grade of osteophytes were evaluated using Ankle and Hindfoot Radiographic Osteoarthritis Scoring reported by Kraus et al. Arthroscopic findings were evaluated with International Cartilage Repair Society (ICRS) Grade at a total of 20 sites (9 areas of tibia and talar in tibiotalar joint, medial malleolus and lateral malleolus). The correlation between radiographic findings and arthroscopic findings were analyzed. Results: In Mortise view, strong correlations were found between lateral tibial osteophyte grade and ICRS grade of the center (talus R = 0.69, tibia R = 0.76), the central lateral (tibia R = 0.79), the posterior center (talus R = 0.72, tibia R = 0.74) and the posterior lateral of the tibiotalar joint (talus R = 0.63, tibia R = 0.76). There are moderate correlations between distal fibular osteophyte grade and ICRS grade of the medial inner (tibia R = 0.74) and the posterior medial of the tibiotalar joint (talus R = 0.61, tibia = 0.63). In lateral view, there are moderate correlations between posterior talar osteophyte grade and ICRS grade at the center of the tibiotalar joint (talus R = 0.61, tibia R = 0.60). Conclusion: From this study, there was a strong correlation between location and grade osteophyte and the articular cartilage injury. Osteoarthritis progression is caused by degeneration of the cartilage because of the joint instability, and osteophytes were formed by traction force or impaction. This study showed that local cartilage injury is thought to be related to osteophytes. By evaluating the location and size of osteophytes, the articular cartilage injury might be predicted accurately before arthroscopic surgery.

Clinical Significance of Lateral Ankle Radiograph after the Reduction of a Syndesmosis Injury

Category: Trauma Introduction/Purpose: To introduce reliable and newly developed radiographic measures based on a lateral ankle radiograph to assess a syndesmotic reduction after screw fixation and to compare with the radiographic measures based on the anteroposterior (AP) and mortise radiographs. Methods: The postoperative ankle radiographs of 34 ankle fracture cases after screw fixation for concurrent syndesmosis injury were reviewed. Two radiographic parameters were measured on each AP and mortise radiograph; tibiofibular clear space (TFCS) and tibiofibular overlap (TFO). Five radiographic parameters were measured on the true lateral radiographs; the anteroposterior tibiofibular (APTF) ratio, anterior tibiofibular ratio (ATFR), posterior tibiofibular ratio (PTFR), distances of intersection of the anterior fibular border and the tibial plafond to anterior cortex of the tibia (AA’), and the intersection of posterior fibular border and tibial plafond to the tip of the posterior malleolus (BB’). In addition, the distance (XP) between the fibular posterior margin (X) crossing tibial plafond or the posterior malleolus and posterior articular margin (P) of the tibial plafond was measured on the lateral view. Results: Using TFCS and TFO in the AP and mortise radiographs, malreductions of syndesmosis were estimated in 17 of 34 cases (50.0%). Using the introduced and developed radiographic measures in the lateral radiographs, syndesmotic malreductions were estimated in 16 out of 34 cases (47.1%). Seventeen cases (50.0%) showed no evidence of postoperative diastasis using the radiographic criteria on the AP and mortise view, 10 cases (58.8%) of whom showed evidence of a malreduction on the lateral radiograph. The newly developed measurements, XP, were measured 0 in 11 out of 34 cases (32.4%). Conclusion: The reduction of syndemosis after screw fixation can be accurately assessed intraoperatively with a combination of several reliable radiographic measurements of lateral radiograph and traditional radiographic measurements of AP and mortise radiograph. Using various radiographic parameters selectively, malreduction could be prevented even when some parameters are difficult to measure because of implants or when posterior malleolar fracture is accompanied.

Syndesmotic Injury Assessment With Lateral Imaging During Stress Testing in a Cadaveric Model

Background: External rotation, lateral, and sagittal stress tests are commonly used to diagnose syndesmotic injuries, but their efficacy remains unclear. The purpose of this study was to characterize applied stresses with fibular motion throughout the syndesmotic injury spectrum. We hypothesized that sagittal fibular motion would have greater fidelity in detecting changes in syndesmotic status compared to mortise imaging. Methods: Syndesmotic instability was characterized using motion analysis during external rotation, lateral, and sagittal stress tests on cadaveric specimens (n = 9). A progressive syndesmotic injury was created by sectioning the tibiofibular and deltoid ligaments. Applied loads and fibular motion were synchronously measured using a force transducer and motion capture, respectively, while mortise and lateral radiographs were acquired to quantify clinical measurements. Fibular motion in response to these 3 stress tests was compared between the intact, complete lateral syndesmotic injury and lateral injury plus a completely sectioned deltoid condition. Results: Stress tests performed under lateral imaging detected syndesmotic injuries with greater sensitivity than the clinical-standard mortise view. Lateral imaging was twice as sensitive to applied loads as mortise view imaging. Specifically, half as much linear force generated 2 mm of detectable syndesmotic motion. In addition, fibular motion increased linearly in response to sagittal stresses (Pearson’s r [ρ] = 0.91 ± 0.1) but not lateral stresses (ρ = 0.29 ± 0.66). Conclusion: Stress tests using lateral imaging detected syndesmotic injuries with greater sensitivity than a typical mortise view. In addition to greater diagnostic sensitivity, reduced loads were required to detect injuries. Clinical Relevance: Syndesmotic injuries may be better diagnosed using stress tests that are assessed using lateral imaging than standard mortise view imaging.