What Do We Know About the Pathoanatomy of Talar Neck Malunions? Results From a 3D Morphometric Analysis

Category: Trauma; Hindfoot Introduction/Purpose: Malunions of the talar neck significantly alter the foot biomechanics and predispose patients to arthrosis and poor functional outcomes. Recent interest has focused on the surgical correction of these deformities, with corrective talar neck osteotomy emerging as a safe and effective treatment for malunions without ankle arthrosis. While a talus malunion is traditionally thought to cause a varus deformity due to the shortening of the medial talar neck, the pathoanatomy of these deformities remains unclear and sparsely reported in the literature. Therefore, this study aimed to investigate the three- dimensional changes in morphometric parameters of the talar neck after malunion and to determine how these changes affect the architecture of the foot. Methods: Adult patients with a talar neck malunion without ankle arthrosis (Rammelt and Zwipp Type 1-3) were prospectively included. Weight-bearing (WB) AP, Lateral and long axial radiographs, and CT scans of both feet were obtained. 3D models of both tali were generated. The malunion side was mirrored and superimposed on the normal side, and distance maps were generated to identify pathoanatomic changes. Deviation of the talar neck in the axial plane (declination angle [DA]), sagittal plane (inclination angle [IA]), coronal plane (torsion angle [TA]) as well as the medial and lateral neck lengths (MNL and LNL) were measured on the 3D talus models using a semi-automated GEOGEBRA script. AP and Lateral Meary’s angle and the hindfoot moment arm (HMA) was determined on WB radiographs. The t-test was used to compare the talar neck parameters, and correlation coefficients were used to determine the association between talar neck parameters and foot radiographic parameters. Results: 10 patients, 6 males, and 4 females, with a mean age of 32.4 years were included. There were 4 cases of Rammelt and Zwipp Type 1 deformity, and 6 cases of Type 3 deformity. Axial plane changes included varus deviation of the talar neck in 8 cases and valgus deviation in 2. Sagittal plane changes included dorsiflexion of the talar neck in 4, neutral alignment in 3 cases, and plantarflexion in 3 cases. The TA was increased in all cases. TA and MNL had a moderate positive correlation with AP Meary’s angle and, and a moderate negative correlation with Lateral Meary’s Angle. DA and MNL had a moderate positive correlation with the HMA. Conclusion: Talar neck malunions are complex three-dimensional deformities resulting in the common varus and dorsiflexion variants, as well as less common valgus and plantarflexion variants. Despite the variation in malunion types, all cases are characterized by an increased TA. Furthermore, the combination of increased TA and DA and decreased MNL leads to forefoot adduction and hindfoot varus. Due to the intricate and diverse three-dimensional nature of these deformities, surgeons must conduct a comprehensive evaluation of the pathoanatomy before planning surgical correction

Chevron vs Oblique Medial Displacement Calcaneal Osteotomy - Which Is More Stable? Results From a Finite Element Analysis Study

Category: Hindfoot; Ankle Introduction/Purpose: The medial displacement calcaneal osteotomy is used to correct hindfoot valgus in adult-acquired flatfoot disease(AAFD). This is done by means of an oblique cut, which is then translated medially. The chevron variant of the MDCO has gained popularity in recent times. This osteotomy involves a V-cut, with the apex of the V placed anteriorly. This is thought to be inherently more stable than the conventional MDCO owing to its geometrical design and higher contact area, especially with higher magnitudes of translation of the osteotomized fragment. However, it is technically more demanding, and many surgeons may not be familiar with the technique. Moreover, there is no literature comparing the stability of the chevron and oblique MDCO. Hence, we conducted this study to address this knowledge gap. Methods: Computed Tomography (CT) scan of the foot of a patient diagnosed with Johnson stage 2 AAFD was segmented and converted into a 3D computational model. Subsequently, oblique and chevron (160o V-angle) calcaneal osteotomies were performed virtually. For each variant, the osteotomized fragment was translated medially by 8-, 10- and 12-mm and then fixed virtually with two 6.5 mm screws. The six models were imported into a Finite Element Software (ANSYS v19) and subjected to 500 N axial loading through the tibia to simulate a single-leg stance. The von Mises stresses at the osteotomy interfaces and the screws, and the total displacement of the posterior fragment was recorded for each model. Results: The compiled simulation results are presented in Table 1. For both osteotomies, the overall stresses at the osteotomy contact site and the screws increased incrementally with increasing medial translation. Similarly, sagittal plane displacement of the anterior fragment was noted to follow a similar trend. Across all translation levels, the stresses were recorded to be lower for chevron MDCO when compared to the oblique variants. Relative fragment displacement was also noted to be lower for the chevron MDCO. Conclusion: The chevron osteotomy results in lower contact stresses and osteotomy fragment displacement and may prove to be a more stable alternative to the oblique MDCO. However, these results need to be replicated in a larger cohort of patients, as well as in cadaveric studies to determine if surgeons can permit early weight-bearing with the chevron MDCO

Epidemiology, Pathoanatomy and Clinicoradiologic Correlations of Quadrimalleolar Ankle Fractures: A Cross-Sectional Study

Category: Ankle; Trauma Introduction/Purpose: The term ‘quadrimalleolar fracture’ (QMF) describes a trimalleolar (TM) ankle fracture with an associated Chaput or Wagstaffe fracture. Optimal fixation of these injuries not only allows for bone-to-bone healing but also facilitates syndesmotic reduction. However, this is a relatively new concept, and the literature on QMFs is limited to a few case series. Hence, we conducted this study to determine the epidemiology, patterns, and clinicoradiologic correlations of QMFs. The primary objective of this study was to describe the prevalence and patterns of QMFs. The secondary objective was to determine if certain clinical or radiological parameters were associated with different types and patterns of QMFs. Methods: A retrospective analysis of ankle fractures presenting to three tertiary referral hospitals was undertaken. Adult patients (≥18 years) presenting with an acute, traumatic TM ankle fracture over 3 years (July 2018 to July 2021) were included. Isolated medial and lateral malleolar fractures, bimalleolar ankle fractures, pediatric patients, pilon fractures, pathological fractures, and those with delayed presentation or (≥3 weeks of injury) were excluded. Clinical demographic variables were obtained from the patients’ medical records. AP, lateral, and mortise ankle radiographs, and CT scans, (axial, coronal, and sagittal sections along with 3D volume reconstructed models) whenever available, were evaluated in detail. Demographics and radiological parameters were compared between TM and QMF, as well as between different types of QMFs. Odds ratios with 95% confidence intervals were determined to test the strength of association. Results: A total of 876 adult patients with ankle fractures were included after the screening, of which 323 had a TM ankle fracture for which a CT scan had been performed. A total of 159 AITFL avulsions were identified, yielding a prevalence of 18.2% amongst all ankle fractures and 26.1% in ankle fractures where a CT scan had been performed. TMFs had the significantly highest proportion of CT-confirmed AITFL avulsions (44.4%) in comparison to unimalleolar (4.4%) and bimalleolar fractures (6.4%) (P < 0.0001). Age and osteoporosis were significant associations of QMFs. Avulsion of the medial malleolus, Weber B fibular fracture, and supination external rotation mechanism were significantly associated with Wagstaffe fractures. Size of the Chaput fracture was inversely related to that of the posterior malleolar fracture. Conclusion: Quadrimalleolar ankle fractures account for a significant proportion of ankle fractures. The strengths of this study include a large sample size, which was derived from three different hospitals, consecutive inclusion (or exclusion) of cases, strict adherence to the STROBE guidelines, and the fact that only CT-confirmed cases were used to determine clinic-radiological associations. Wagstaffe and Chaput fractures have distinct clinical and radiological correlations. However, further research is needed to determine the optimal fixation protocols for these injuries

Talar Neck Malunions: Evaluation of Kinematics, Pedobarographic Changes and Patient Reported Outcome Measures

Category: Trauma; Hindfoot Introduction/Purpose: Malunion is a disabling complication of talar neck fractures and is prevalent in approximately 17% of cases. The impact of talar neck malunions (TNM) on foot biomechanics and functional outcomes is not well established. The available evidence is primarily derived from cadaveric studies which have demonstrated that TNMs result in reduced motion and significant alterations in contact characteristics of the subtalar joint. Owing to the paucity of literature on this subject, we conducted this study to evaluate the kinematic and pedobarographic changes and functional outcomes associated with TNMs. Methods: In this study, adult patients with talar neck malunions (TNM) without ankle arthrosis were prospectively enrolled over a 5-year period. The Rammelt and Zwipp classification was utilized to categorize the deformities. Demographic data and ankle and subtalar range of motion were assessed. Weight-bearing anteroposterior (AP), lateral, and long axial radiographs, as well as CT scans of both feet, were obtained. Dynamic pedobarography was performed to evaluate gait kinematics and plantar pressure distribution. Functional outcomes were evaluated using the Manchester Oxford Foot Questionnaire (MOxFQ), Visual Analog Score, and the EQ5D questionnaire. The t-test was utilized to compare the range of motion, pedobarographic and kinematic parameters between the normal and pathologic foot. Furthermore, correlation coefficients were calculated to determine the strength of the association between changes in talar neck geometry, plantar pressures, kinematics, and functional outcomes. Results: A total of 10 patients, 6 males, and 4 females, with a mean age of 32.4 years were enrolled. On the TNM side, significant increases were observed in step length and step time, while significant decreases were noted in the single limb support time and single limb support center of pressure line. Moreover, midfoot forces were significantly increased, whereas the forefoot and hindfoot forces were significantly decreased on the TNM side. A strong positive correlation was found between midfoot force and the talar torsion angle, and a moderate negative correlation was observed between hindfoot and midfoot forces and the inclination angle. A strong positive correlation was also noted between high midfoot pressures and VAS Scores, MOxFQ scores, and the EQ5D walking and usual activities domains. Conclusion: This study demonstrates that TNMs are associated with decreased single limb support time, increased step length and time, increased midfoot pressures, and decreased forefoot and hindfoot pressures. Additionally, an increase in talar neck torsion after TNM is linked with higher midfoot pressures, which can lead to higher levels of pain and poorer function. Our findings provide valuable insights into the altered foot biomechanics after TNMs, which can assist surgeons in offering optimal management strategies for these patients

A Novel Ultrasonographic Method to Detect Intra-Operative Syndesmotic Malreduction – the “Gap Penetrance” Sign

Category: Ankle; Other Introduction/Purpose: Anatomical reduction of the distal syndesmosis can be challenging. There is ongoing debate and variability in the methods used for evaluating the accuracy of reduction, including radiography, intra-operative CT, arthroscopy, and direct visualization. Tornetta et al. have described a method called ‘the articular surface method’ that evaluates the relationship between the articular cartilage of the distal anteromedial fibula and the anterolateral tibia as being significantly more accurate for detecting malreduction. However, it entails an additional surgical incision over the distal aspect of the ankle. The aim of this study was to find a non-invasive method using ultrasound to assess the accuracy of reduction in syndesmotic injuries. Methods: A cadaveric syndesmotic instability model was created by dissecting the PITFL, IOL, and AITFL through a small posterior incision. The fibula was fixed in incremental degrees of rotational malreduction to achieve a malreduction of 3, 5, and 7 mm. A blinded observer assessed the syndesmosis using a portable ultrasound device. The probe was placed in its short axis at the level of the ankle joint then moved proximally until both the anteromedial fibular and anterolateral tibial articular surfaces were visualized simultaneously in one view. In a reduced syndesmosis, the distal articular surfaces of the tibia and fibula overlap. This relationship is altered in a malreduced syndesmosis, which allows ultrasonographic waves to ‘penetrate’ through the malreduced articular surfaces and be readily detected. This sign was graded positive if an acoustic signal penetrated between the distal articular surfaces of the tibia and fibula, and negative if no acoustic signal was detected. Results: The gap penetrance sign was positive in all 3 instances of malreduced syndesmoses, and negative in an anatomically reduced syndesmosis. Figure 1 illustrates the outcomes in a reduced syndesmosis and malreduced syndesmosis, respectively. Conclusion: We introduced a novel sign that can be used as a surrogate of the ‘articular surface method’ to detect syndesmotic malreduction. It is accurate, can obviate the need for a separate surgical incision for direct visualization, permits rapid point-of- care evaluation in the operating room, and minimizes radiation exposur

Do Syndesmotic Injury Patterns Influence Functional and Radiological Outcomes in Complex Ankle Fractures? A Retrospective Cohort Study

Category: Ankle; Trauma Introduction/Purpose: Syndesmosis injury can be of a varying magnitude; little information exists about the influence of degree of initial syndesmotic injury/instability on functional outcomes in ankle fractures, nor is there any correlation of this with follow up radiological parameters. Aims and Objectives: To identify and define morphological patterns of syndesmotic injury in ankle fractures according to a zone based evaluation, and correlate initial degree of instability with mid-term functional and radiological outcomes using validated scores Design: Retrospective cohort study, to review a prospective question. Methods: 40 complex ankle fractures out of 120 ankle fractures in our ankle registry met the inclusion criteria ie significant documented syndesmosis involvement needing stabilization, with all initial clinical and radiological records available. The patients were followed up between January 2020 to July 2021. Injury characteristics, fracture morphology of posterior malleolus, medial malleolus and fibula were noted and classified by validated classification systems based on x-rays and CT scan. The syndesmosis was analyzed on axial CT scan; it was divided into 3 zones, A,B,C from anterior to posterior, and degree of displacement and morphology was noted. Immediate post-operative radiographs were evaluated for fracture and syndesmosis reduction. The patients were evaluated at final follow up with both ankle specific scores (Olerud Molander score, Ankle-Hindfoot scale, Manchester-Oxford Foot questionnaire) and quality of life score (SF-12). Ankle Osteoarthritis grade was used to evaluate radiological outcomes. Results: Mean follow-up was 19 months. 22(55%) patients had syndesmotic widening on plain radiographs; however in pre- operative CT scan evaluation 40(100%) patients had syndesmotic injury based on the Zone evaluation of the syndesmosis. 22 patients had Zone A injury (widening, AITFL, Chaput, Wagstaff). 22 patients had widening of Zone B. Zone C was involved in 30 patients (PM fracture,PITFL involvement). At final follow up; the mean OMAS was 83.38±16.35, mean Ankle-Hindfoot scale= 88±9.98, mean Mox-FQ score=27.15±13.35 & mean SF-12 were (MCS=56.59±8.24, PCS=51.18±8.48). There was no significant difference in outcome scores based on fracture types, Posterior malleolus morphology, or based on zones of syndesmosis injury. Syndesmosis malreduction contributed to significantly poorer outcomes (SF-12, OMAS, MoxFQ) Conclusion: Despite a zonal classification of syndesmotic injury on CT and more clarity of injury patterns, we could not corelate the site and extent of syndesmotic injury with final functional and radiological outcomes. The one factor that has significant influence is initial accurate reduction of both the malleolar fractures and syndesmosis injury. In this the CT based axial classification may play a role

Three-Dimensional Mapping of Chaput Tubercle Fractures: Evaluation of Morphologic Characteristics and Anterior Inferior Tibiofibular Ligament Involvement

Category: Ankle; Trauma Introduction/Purpose: Chaput tubercle fractures, which are thought to represent tibial-sided avulsions of the anterior inferior tibiofibular ligament (AITFL), are prevalent in up to 30% of trimalleolar ankle fractures. The optimal treatment of small Chaput avulsions is debatable; direct fixation with suture anchor devices and indirect (syndesmotic) fixation are considered as viable options, with proponents on both sides. Moreover, recent literature highlights the potential anatomical alterations to the incisura tibialis resulting from malreduction of large Chaput fragments, furthering the case for direct fixation. Hence, we performed a CT- based three-dimensional fracture mapping study to identify the morphological characteristics of these fractures, and to determine whether they consistently involve the AITFL, tibial plafond and incisura tibialis. Methods: This study included adult patients who had an ankle fracture with a Chaput component; the scheme described by Rammelt et al. was used to classify these fractures. CT scans were obtained, and 3D models were generated. The models were superimposed over a statistical shape model of the right tibia which served as a template and fracture lines were marked. The footprints of proximal and main bands of the AITFL and Basset’s ligament were also marked on the template tibia. The tibial template along with the fracture lines was then imported into MATLAB, and an automated script was used to determine the fragment size (length, breadth, and height), fracture surface area, involvement of the tibial plafond, tibial incisura, and the anterior inferior tibiofibular ligament (AITFL) and Basset’s ligament. Fracture maps and heat maps were generated. Agglomerative cluster analysis using Ward’s linkage was used to identify discrete fracture categories. Results: 76 patients, 21 males and 55 females were included in this study. Cluster analysis identified two distinct groups of fractures, each with two unique subgroups. We present this as a modification of the existing classification system. The first group, corresponded to Rammelt Type 1 fractures (sub centimetric extra-articular avulsion fractures, n=47). Of these, 19% (n=9) did not involve the AITFL, which we termed as Type 1a, and 91% (n=48) involved the AITFL, which we termed as Type 1b. The second group consisted of large intra-articular fractures that corresponded to Rammelt Type 2 injuries. Of these 23% (n=6) involved only the incisura, which we termed as Type 2a; 77 % involved both the incisura and the tibial plafond and were termed as Type 2b. Conclusion: We propose a modification of the existing classification of Chaput fractures on the basis of quantitative fracture mapping. This study provides new insights into the morphological characteristics of Chaput fractures. 19% of small Chaput fractures do not involve the AITFL and may not require direct fixation. Conversely, all large-sized fragments involve the incisura and necessitate anatomical reduction to achieve accurate syndesmotic reduction. Our proposed modification can aid in surgical decision-making, particularly in choosing between direct and indirect syndesmotic fixation

Clinical Outcomes of Insertional Achilles Tendinopathy Patients Treated with Reattachment and Dorsal Closing Wedge Calcaneal Osteotomy: A Meta-analysis

Category: Hindfoot; Sports Introduction/Purpose: Posterior heel pain at the Achilles tendon insertion is a prevalent and debilitating condition that is not yet fully understood. It results from a combination of bony and soft tissue abnormalities, including insertional Achilles tendinopathy, retrocalcaneal bursitis, and posterosuperior bony prominence. While the most commonly used surgical technique for treatment is debridement and reattachment of the tendon, dorsal closing wedge calcaneal osteotomy (DCWCO) has recently gained popularity. In this meta-analysis, we aimed to analyze the published literature related to both surgical techniques and compare their outcomes. Our hypothesis was that DCWCO can provide similar clinical outcomes with a lower complication rate. Methods: We conducted a literature search in Medline, Embase, and Scopus databases. Clinical studies reporting at least one of the clinical outcomes among AOFAS score and complications, with an open technique and sufficient data to extract and pool, were included. The extraction was made by two users using the Covidence platform. Studies with less than 10 patients or less than 12 months follow-up were excluded. Initial search yielded 329 papers, and after excluding duplicates and irrelevant studies, 43 papers were left. After a full-text review of these 43 papers, we found 15 papers eligible for meta-analysis. We used the Modified Coleman Methodology to assess the quality of papers. Results: Out of the 15 articles, seven included reattachment patients, while eight included DCWCO patients. 171 feet underwent reattachment, while 239 feet underwent DCWCO. The average follow-up of patients was significantly higher in the DCWCO group (42.2 months) than reattachment group (23.2 months). The average AOFAS score improvement was similar between the groups. The total complication numbers were 30 (16.6%) in the reattachment group and 28 (9.2%) in the DCWCO group, but the difference did not reach significance since the confidence intervals were overlapping. However, wound complications were significantly more common in Reattachment group (10.1%) compared to DCWCO (2.5%). The number of revision surgeries and neurological complications (sural neuritis, hypersensitivity, etc.) were similar between the groups. The average AOFAS score improvement was similar between the groups. Conclusion: Both techniques yielded comparable clinical outcomes. The overall complication rate was similar, but DCWCO exhibited a lower wound complication rate than reattachment. Therefore, the study results imply that DCWCO can provide similar clinical outcomes with fewer wound complications. However, further well-designed studies are necessary to reach a definitive conclusion on this matter and compare both techniques in the same study setting

Effect of Dorsal Closing Wedge Calcaneal Osteotomy on Foot Alignment and Biomechanics in Patients with Insertional Achilles Tendinopathy

Category: Hindfoot; Sports Introduction/Purpose: The use of a dorsal closing wedge calcaneal osteotomy (DCWCO) in the treatment of insertional Achilles tendinopathy (IAT) has recently gained popularity. The anatomical changes imposed by the osteotomy are believed to improve both the biological and mechanical processes involved in IAT. However, the impact of shortening the Achilles leverage arm after DCWCO and the full impact of DCWCO on foot anatomy and function is not well understood. This study aimed to examine the effects of DCWCO on the 3D alignment and biomechanics of the foot and ankle in IAT patients through simulated models of DCWCO. The hypothesis was that DCWCO would significantly impact foot alignment and decrease gastrocsoleus lever arm. Methods: Six weightbearing ankle CTs of patients with IAT were identified from the clinical database. Bone segmentation was performed and DCWCOs were conducted in standardized planes with six variations, resulting in a total of 36 foot models. Two plantar osteotomy starting points were defined as 1-cm anterior (posterior osteotomy) and 2-cm anterior (anterior osteotomy) to the most plantar point of calcaneus. The osteotomies were extended to dorsal surface at 1-cm anterior to posterosuperior calcaneus with 6, 10, or 14-mm wedges anteriorly. After the osteotomies, the posterior part of the calcaneus was rotated around the plantar starting point until proper bone contact was achieved. Achilles reconstruction was also performed using pre-defined Achilles insertion points. All models were then transferred to a MATLAB-based algorithm for automated measurements. These measurements included talocalcaneal, calcaneal pitch, Böhler, and Achilles tendon sagittal angles, Achilles moment arm, Achilles- posterosuperior calcaneus distance, and difference in soleus-Achilles length. Results: Anteriorly placed osteotomy caused more significant decrease in the Böhler angle (p < 0.001). Evaluation of the posteriorly placed osteotomy separately showed no significant decrease in the Böhler angle for patients with more than 30- degrees of preoperative Böhler angle (p=0.26). However, patients with a preoperative Böhler angle less than 30-degrees showed a significant decrease, approaching values close to 5-degrees (p=0.004). Gastrocsoleus moment arm decrease was found to be 2-3% by using force/moment equation. The change in the distance between Achilles tendon and the posterosuperior calcaneus was similar between anterior and posterior osteotomies, with less than 3-mm in a 6-mm wedge and more than 5-mm in a 10-mm wedge osteotomy. The calculations showed that ankle dorsiflexion can increase by one degree for each mm of resection. Conclusion: An anteriorly placed starting point for a DCWCO can negatively affect foot alignment and offer limited benefits for Achilles decompression. If the preoperative Böhler angle is less than 30, a DCWCO can significantly decrease the Böhler angle, potentially putting the subtalar joint at risk for arthritis by increasing the load as reported by some finite element studies. The maximum decrease in gastrocsoleus power is less than 3%, which may be clinically insignificant. A posterior starting point with 10- mm wedge can be adequate to move Haglund around 5-mm anteriorly and can move Achilles insertion 10-mm superiorly to decrease tension

Congruent Weber-B Ankle Fractures do not affect Tibiotalar Contact Mechanics: No Need for the Scalpel?

Category: Trauma; Ankle Introduction/Purpose: Weber-B ankle fractures represent an increasingly common injury world-wide, and the decision for operative fixation often hinges on the stability and congruency of the ankle. While tibiotalar displacement is typically evaluated using the medial clear space on plain radiographs, this method remains prone to inaccuracy because of x-ray beam rotation and manual measurement errors. Furthermore, the influence of these fractures on the mechanical environment of the ankle remains unknown. The recent advent of weightbearing cone-beam CT (WBCT) overcomes these drawbacks by imaging during bipedal stance, allowing a 3D anatomical and mechanical analysis. Therefore, the aim of this study was to analyze the 3D mortise displacement and contact mechanics in weber B ankle fractures by use of WBCT in comparison to their healthy contralateral side. Methods: In this retrospective study, our ankle trauma database was searched for Weber-B ankle fractures imaged by bilateral WBCT imaging between 2015 and 2022. Exclusion criteria consisted of metal or motion artifacts, presence of ankle osteoarthritis, and an age less than 18 years or more than 75 years. Segmentation into 3D models of bone was performed semi-automatically, while personalized cartilage layers were modeled based on a previously validated methodology. Bilateral ankle models were imported in custom-made Matlab® script for an automated anatomical and mechanical analysis. 3D mortise congruency was evaluated by use of following parameters: fibular length, talocrural angle, distance mapping of the medial gutter and tibiofibular clear space distance mapping. Contact mechanics were evaluated by the mean and maximum contact stress of the tibia and talus, as well as the contact area (Figure 1). A student’s T-test was performed to investigate the difference between the fractured and healthy side. Results: Thirty-two patients, with mean age 38.50 years (SD = 15.81 ) and weight 79.12 kg (SD = 16,24), were confirmed eligible for analysis. Statistical analysis revealed that there were no significant differences for all anatomical parameters (P > 0.05). The mean contact stress of the fractured and healthy side was 2.10 (SD = 0.42) MPa and 2.10 (SD = 0,41) MPa, respectively, whereas the maximum stress was 7.67 MPa (SD = 1.55) and 7,47 MPa (SD = 1,67), respectively. No statistical significant differences were found between all mechanical parameters (P > 0.05). Conclusion: This study demonstrates that contact mechanics are not affected in Weber-B fractures with a congruent mortise. Therefore, non-operative treatment could be considered, as there will theoretically be no increased risk for the patients to develop posttraumatic osteoarthritis in the long term. In clinical practice, WBCT could prove useful to determine the 3D anatomical and mechanical environment of ankle fractures and guide patients towards (non-) operative treatment. However, further studies should focus on the minimal clinical important difference/rehabilitation factors associated with mortise malalignment based on concomitant contact stress increase, which would warrant and identify which cases need surgical reduction