The relationship between calcaneofibular ligament injury and ankle osteoarthritis progression: A comprehensive analysis of stress distribution and osteophyte formation in the subtalar joint

Ankle osteoarthritis (OA) mainly arises from trauma, particularly lateral ligament injuries. Among lateral ligament injuries, ankles with calcaneofibular ligament (CFL) injuries exhibit increased instability and can be a risk factor ankle OA progression. However, the relationship between CFL injury and OA progression remains unclear. Therefore, this study aims to assess the relationship between CFL injuries and ankle OA by investigating stress changes and osteophyte formation in subtalar joint. We retrospectively reviewed the magnetic resonance imaging (MRI) and plain radiographic evaluations of 100 ankles of 91 patients presenting with chronic ankle instability (CAI), ankle OA, or other ankle conditions. The association between CFL injuries on the oblique view of MRI and the severity of ankle OA (based on Takakura-Tanaka classification) was statistically evaluated. Additionally, 71 ankles were further subjected to CT evaluation to determine the association between the CFL injuries and the Hounsfield unit (HU) ratios of the subtalar joint and medial gutter, and the correlation between the subtalar HU ratios and osteophyte severity were statistically evaluated. CFL injury was observed in 35.9% (14/39) of patients with stage 0, 42.9% (9/21) with stage 1, 50.0% (10/20) with stage 2, 100% (9/9) with stage 3a, and 90.9% (10/11) with stage 3b. CFL-injured ankles exhibited higher HU ratios in the medial gutter and lower ratios in the medial posterior subtalar joint compared to uninjured ankles. A negative correlation was observed between medial osteophyte severity and the medial subtalar joint HU ratio. Our findings suggest that CFL injuries are common in severe ankle OA impairing the compensatory function of the subtalar joint through abnormal stress distribution and osteophyte formation.

Category: Ankle Introduction/Purpose: Acute inversion ankle sprains are among the most common musculoskeletal injuries. Higher grade sprains, which include anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) injury, can be particularly problematic and often require surgical repair. The implications of CFL injury on ankle instability are unclear. We aim to evaluate the impact of CFL injury on ankle stability and subtalar joint biomechanics. We hypothesized that CFL injury will result in decreased stiffness and torque, and alteration of ankle contact mechanics compared to the uninjured ankle in a cadaveric model. Methods: Twenty matched cadaveric ankles dissected of skin and subcutaneous tissue were mounted to an Instron with 20° of ankle plantar flexion and 15° of internal rotation. Intact specimens were axially loaded to body weight, then underwent inversion stress along the anatomic axis of the ankle from 0 to 20° (simulating inversion injury) for three cycles. ATFL and CFL were sequentially sectioned, and inversion testing repeated for each condition. Stiffness and change in torque were recorded using an Instron, and pressure and contact area were recorded using a calibrated Tekscan sensor system. Inversion angle of the talus and calcaneus relative to the ankle mortise were recorded using a three-dimensional motion capture system. Paired t tests were performed for inter and intra-group comparisons. Results: Stiffness and torque did not significantly decrease after sectioning of the ATFL, but did decreased significantly after sectioning of CFL. Peak pressures in the tibiotalar joint decreased significantly following CFL release compared to both the uninjured ankle and ATFL-only release. Mean contact area significantly increased following CFL release compared to both the uninjured ankle and ATFL release. There was a concentration of force in the anteromedial ankle joint during weight-bearing inversion. However, the center-of-force shifts 1.22 mm posteromedial after CFL release relative to an intact ankle. Motion capture showed a significant and sequential increase in inversion angle of both the calcaneus and talus, after release of each ligament. There was significantly more inversion in the subtalar joint than the tibiotalar joint with weight-bearing inversion. Conclusion: There is significantly lower stiffness and torque with weight-bearing inversion of the ankle joint complex following injury to both ATFL and CFL, and sequentially greater inversion of the talus and calcaneus with progressive ligament injury. This corresponds to a significant shift in the center of force in the tibiotalar joint. CFL contributes considerably to lateral ankle stability, and sprains that include CFL injury result in substantial alteration of contact mechanics at the ankle and subtalar joints. Repair of CFL may be beneficial during lateral ligament reconstruction, potentially mitigating long-term consequences (e.g., articular damage) of a loose or incompetent CFL.

Background: Acute inversion ankle sprains are among the most common musculoskeletal injuries. Higher grade sprains, including anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) injury, can be particularly challenging. The precise effect of CFL injury on ankle instability is unclear. Hypothesis: CFL injury will result in decreased stiffness, decreased peak torque, and increased talar and calcaneal motion and will alter ankle contact mechanics when compared with the uninjured ankle and the ATFL-only injured ankle in a cadaveric model. Study Design: Descriptive laboratory study. Methods: Ten matched pairs of cadaver specimens with a pressure sensor in the ankle joint and motion trackers on the fibula, talus, and calcaneus were mounted on a material testing system with 20° of ankle plantarflexion and 15° of internal rotation. Intact specimens were axially loaded to body weight and then underwent inversion along the anatomic axis of the ankle from 0° to 20°. The ATFL and CFL were sequentially sectioned and underwent inversion testing for each condition. Linear mixed models were used to determine significance for stiffness, peak torque, peak pressure, contact area, and inversion angles of the talus and calcaneus relative to the fibula across the 3 conditions. Results: Stiffness and peak torque did not significantly decrease after sectioning of the ATFL but decreased significantly after sectioning of the CFL. Peak pressures in the tibiotalar joint decreased and mean contact area increased significantly after CFL release. Significantly more inversion of the talus and calcaneus as well as calcaneal medial displacement was seen with weightbearing inversion after sectioning of the CFL. Conclusion: The CFL contributes considerably to lateral ankle instability. Higher grade sprains that include CFL injury result in significant decreases in rotation stiffness and peak torque, substantial alteration of contact mechanics at the ankle joint, increased inversion of the talus and calcaneus, and increased medial displacement of the calcaneus. Clinical Relevance: Repair of an injured CFL should be considered during lateral ligament reconstruction, and there may be a role for early repair in high-grade injuries to avoid intermediate and long-term consequences of a loose or incompetent CFL.

Directly measured strain patterns of the anterior talofibular and calcaneofibular ligaments after isolated ATFL repair in a combined ATFL and CFL injury: A cadaver study

Objectives: Magnetic resonance imaging (MRI) can complement clinical evaluation of ankle ligament injuries. This study aims to elucidate the relationship between lateral ligament injury and soft-tissue swelling in patients presenting with ankle injuries devoid of fractures, utilizing MRI. Materials and Methods: A retrospective analysis was conducted over a 1-year period, including 100 consecutive patients diagnosed with ankle injuries unaccompanied by fractures. All patients underwent MRI within 1 week of injury. Soft-tissue thickness surrounding the medial and lateral malleoli was measured on coronal proton density fat-suppressed MRI images. MRIs were further categorized based on the condition of ankle ligaments: normal ankle; isolated anterior talofibular ligament (ATFL) injury; isolated calcaneo-fibular ligament (CFL) injury; isolated anterior-inferior tibio-fibular ligament (AITFL) injury; combined ATFL and AITFL injury; and combined ATFL and CFL injury. Results: Analysis of the medial/lateral malleolar swelling ratio revealed an area under the curve of 0.636 (95% confidence interval [CI]: 0.500–0.773), indicating moderate discriminatory ability. Isolated lateral swelling exhibited a higher area under the curve of 0.842 (95% CI: 0.756–0.927). A lateral swelling measurement exceeding 2.5 mm demonstrated 91% specificity and 51% sensitivity. Statistical analysis revealed a highly significant association between lateral ligamentous injury and both lateral swelling ( P < 0.0001) and the swelling ratio ( P = 0.0001). Conclusions: Lateral malleolar soft-tissue swelling serves as a valuable predictor of ligamentous injury in ankle trauma cases. MRI provides complementary evidence to correlate the association between the size of lateral soft-tissue swelling and associated ligamentous injury.

ObjectiveTo quantitatively assess biochemical alterations in the cartilage of the subtalar and midtarsal joints in chronic lateral ankle instability (CLAI) patients with isolated anterior talofibular ligament (ATFL) injuries and combined calcaneofibular ligament (CFL) injuries using MRI T2 mapping.Materials and MethodsThis study was performed according to regulations of the Committee for Human Research at our institution, and written informed consent was obtained from all participants. Forty CLAI patients (26 with isolated ATFL injuries and 14 with combined ATFL and CFL injuries) and 25 healthy subjects were recruited for this study. All participants underwent MRI scans with T2 mapping. Patients were assessed with the American Orthopedic Foot and Ankle Society (AOFAS) rating system. The subtalar and midtarsal joints were segmented into 14 cartilage subregions. The T2 value of each subregion was measured from T2 mapping images. Data were analyzed with ANOVA, the Student's t test, and Pearson's correlation coefficient.ResultsT2 values of most subregions of the subtalar joint and the calcaneal facet of the calcaneocuboid joint in CLAI patients with combined CFL injuries were higher than those in healthy controls (all p < 0.05). However, there were no significant differences in T2 values in subtalar and midtarsal joints between patients with isolated ATFL injuries and healthy controls (all p > 0.05). Moreover, T2 values of the medial talar subregions of the posterior subtalar joint in patients with combined CFL injuries showed negative correlations with the AOFAS scores (r = −0.687, p = 0.007; r = −0.609, p = 0.021, respectively).ConclusionCLAI with combined CFL injuries can lead to cartilage degeneration in subtalar and calcaneocuboid joints, while an isolated ATFL injury might not have a significant impact on the cartilage in these joints.

ObjectiveTo investigate the differential biomechanical effects of injuries to the superior and inferior fascicles of the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL) on ankle stability and talar cartilage stress, providing a basis for the Fascicle-specific diagnosis and treatment of chronic ankle instability.MethodsA finite element model incorporating bones, articular cartilage, and nine sets of ligament spring elements was created based on CT data from the ankle of a 26-year-old male volunteer. Six conditions were simulated: 1. intact model; 2. superior ATFL Fascicle injury; 3. inferior ATFL Fascicle injury; 4. complete ATFL injury (superior + inferior Fascicles); 5. CFL injury; and 6. combined ATFL + CFL injury. Anterior drawer test (100 N anterior traction), varus stress test (1.7 N·m torque), and single-leg standing test (600 N axial load) were performed to measure talar displacement and cartilage stress distribution.Results1. In the anterior drawer test, talar displacement was greater in superior ATFL Fascicle injuries than in inferior ATFL Fascicle and CFL injuries. 2. In the inversion test, talar displacement was greater in CFL injuries than in superior, inferior, or complete ATFL injuries. 3. In the single-leg standing test, all five injury models altered the contact stress distribution on the talar cartilage compared to the intact model, shifting the peak stress from the anterolateral dome to the anteromedial dome and increasing pressure on the anteromedial talar dome. The peak stress magnitudes were ranked as follows: ATFL + CFL injury > complete ATFL injury > superior ATFL Fascicle injury > inferior ATFL Fascicle injury > CFL injury. 4. The combined ATFL + CFL injury model showed significantly greater displacement and peak stress than the other four injury models.ConclusionThe superior Fascicle of the ATFL is the primary restraint for anterior stability; the CFL dominates rotational stability; combined injuries trigger a biomechanical cascade failure; lateral ankle ligament injuries lead to increased contact stress on the anteromedial talar cartilage, contributing to the development of arthritis.

Background The roles of each ligament supporting the subtalar joint have not been clarified despite several biomechanical studies. The effects of ankle braces on subtalar instability have not been shown. Hypothesis The ankle brace has a partial effect on restricting excessive motion of the subtalar joint. Study Design Controlled laboratory study. Methods Ten normal fresh-frozen cadaveric specimens were used. The angular motions of the talus were measured via a magnetic tracking system. The specimens were tested while inversion and eversion forces, as well as internal and external rotation torques, were applied. The calcaneofibular ligament, cervical ligament, and interosseous talocalcaneal ligament were sectioned sequentially, and the roles of each ligament, as well as the stabilizing effects of the ankle brace, were examined. Results Complete sectioning of the ligaments increased the angle between the talus and calcaneus in the frontal plane to 51.7° ± 11.8° compared with 35.7° ± 6.0° in the intact state when inversion force was applied. There was a statistically significant difference in the angles between complete sectioning of the ligaments and after application of the brace (34.1° ± 7.3°) when inversion force was applied. On the other hand, significant differences in subtalar rotation were not found between complete sectioning of the ligaments and application of the brace when internal and external rotational torques were applied. Conclusion The ankle brace limited inversion of the subtalar joint, but it did not restrict motion after application of internal or external rotational torques. Clinical Relevance In cases of severe ankle sprains involving the calcaneofibular ligament, cervical ligament, and interosseous talocalcaneal ligament injuries, application of an ankle brace might be less effective in limiting internal-external rotational instabilities than in cases of inversion instabilities in the subtalar joint. An improvement in the design of the brace is needed to restore better rotational stability in the subtalar joint.

This study revealed the mechanism of transcutaneous electrical nerve stimulation (TENS) for improving the calcaneofibular ligament (CFL) injury rats by regulating the intestinal microbiota. After 1, 2, and 3 weeks of TENS treatment, the improvement of CFL injury rats model and the expressions of IL-1β/NF-κB/IL-17 signaling pathway were measured. Then the intestinal microbiota was analyzed by 16S rDNA sequencing and its functions related to improve CFL injury rat were analyzed. TENS could improved the athletic ability of CFL injury rats and reduced the expressions of IL-1β/NF-κB by regulating the IL-17 signaling pathway. By 16S rDNA sequencing analysis, the TENS treatment improved the intestinaldysbacteriosisof CFL injury rats and decrease pathogenic bacteria Ruminococcus and Dubosiella. The changed intestinal microbiota maybe relative with the ankle injury, whereas the increase in probiotics (Bacteroides and Lactobacillus) was relative with anti-inflammation. TENS could down-regulate the expressions of IL-1β/NF-κB to improve CFL injury rat. TENS could change the intestinal microbiota of CFL rats and the changed bacteria whose function related to anti-inflammation could improve CFL rat. The intestinal microbiota could become a potential treatment for CFL injury.

The classification of calcaneofibular ligament (CFL) injuries on magnetic resonance imaging (MRI) is time-consuming and subject to substantial interreader variability. This study explores the feasibility of classifying CFL injuries using deep learning methods by comparing them with the classifications of musculoskeletal (MSK) radiologists and further examines image cropping screening and calibration methods. The imaging data of 1,074 patients who underwent ankle arthroscopy and MRI examinations in our hospital were retrospectively analyzed. According to the arthroscopic findings, patients were divided into normal (class 0, n=475); degeneration, strain, and partial tear (class 1, n=217); and complete tear (class 2, n=382) groups. All patients were divided into training, validation, and test sets at a ratio of 8:1:1. After preprocessing, the images were cropped using Mask region-based convolutional neural network (R-CNN), followed by the application of an attention algorithm for image screening and calibration and the implementation of LeNet-5 for CFL injury classification. The diagnostic effects of the axial, coronal, and combined models were compared, and the best method was selected for outgroup validation. The diagnostic results of the models in the intragroup and outgroup test sets were compared with those results of 4 MSK radiologists of different seniorities. The mean average precision (mAP) of the Mask R-CNN using the attention algorithm for the left and right image cropping of axial and coronal sequences was 0.90-0.96. The accuracy of LeNet-5 for classifying classes 0-2 was 0.92, 0.93, and 0.92, respectively, for the axial sequences and 0.89, 0.92, and 0.90, respectively, for the coronal sequences. After sequence combination, the classification accuracy for classes 0-2 was 0.95, 0.97, and 0.96, respectively. The mean accuracies of the 4 MSK radiologists in classifying the intragroup test set as classes 0-2 were 0.94, 0.91, 0.86, and 0.85, all of which were significantly different from the model. The mean accuracies of the MSK radiologists in classifying the outgroup test set as classes 0-2 were 0.92, 0.91, 0.87, and 0.85, with the 2 senior MSK radiologists demonstrating similar diagnostic performance to the model and the junior MSK radiologists demonstrating worse accuracy. Deep learning can be used to classify CFL injuries at similar levels to those of MSK radiologists. Adding an attention algorithm after cropping is helpful for accurately cropping CFL images.

Intrinsic subtalar ligaments are primary varus stabilizers of the subtalar joint: A 3D cadaveric motion analysis.

Characteristic Bone Morphology Change of the Subtalar Joint in Severe Varus Ankle Osteoarthritis

Background: It is important to identify the location and pattern of lateral ligament injuries that are related to the development and prognosis of chronic ankle instability in athletes with ankle sprains. Purpose: To describe the location and pattern of lateral ligament injuries on magnetic resonance imaging (MRI) in elite-level or amateur athletes with acute ankle sprains and to further assess the risk of associated concomitant injuries. Study Design: Cross-sectional study; Level of evidence, 3. Methods: The anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) of 110 athletes with an ankle lateral ligament injury (mean age, 24.7 years) were evaluated. MRI scans were evaluated for the location and pattern of ATFL and CFL tears such as sleeve avulsions as well as concomitant deltoid ligament injuries, bone contusions, and osteochondral lesions of the talus (OLTs). Results: On MRI, 52 (47.3%) athletes had an isolated ATFL tear, 56 (50.9%) athletes had both ATFL and CFL tears, and 2 (1.8%) athletes had an isolated CFL tear. ATFL injuries occurred at the fibula, midsubstance, and talus in approximately equal numbers, whereas the majority of CFL injuries occurred at the calcaneal insertion. Concomitant deltoid ligament injuries were identified in 18 (16.4%) athletes. In addition, concomitant bone contusions and OLTs were identified in 38 (34.5%) and 6 (5.5%) athletes, respectively. Using linear-by-linear analysis, CFL injuries correlated with concomitant deltoid ligament and bone injuries ( P = .023 and P = .001, respectively) and a sleeve injury pattern ( P = .005). Conclusion: After an acute ankle ligament rupture, almost all athletes involved in this study had injured their ATFL, and approximately 50% had a concomitant injury to the CFL. The rate of sleeve-type CFL injuries at the calcaneal insertion was high, and concomitant deltoid ligament injuries and OLTs were associated with this pattern of injury.

Ankle sprains are prevalent in sports, often causing complex injuries to the lateral ligaments. Among these, anterior talofibular ligament (ATFL) injuries constitute 85%, and calcaneofibular ligament (CFL) injuries comprise 35%. Despite conservative treatment, some ankle sprain patients develop chronic lateral ankle instability (CLAI). Thus, this study aimed to investigate stress response and neural control alterations during landing in lateral ankle ligament injury patients. This study recruited twenty individuals from a Healthy group and twenty CLAI patients performed a landing task using relevant instruments to collect biomechanical data. The study constructed a finite element (FE) foot model to examine stress responses in the presence of laxity of the lateral ankle ligaments. The lateral ankle ligament was modeled as a hyperelastic composite structure with a refined representation of collagen bundles and ligament laxity was simulated by adjusting material parameters. Finally, the validity of the finite element model is verified by a high-speed dual fluoroscopic imaging system (DFIS). CLAI patients exhibited earlier Vastus medialis (p < 0.001) and tibialis anterior (p < 0.001) muscle activation during landing. The FE analysis revealed that with laxity in the ATFL, the peak von Mises stress in the fifth metatarsal was 20.74MPa, while with laxity in the CFL, it was 17.52MPa. However, when both ligaments were relaxed simultaneously, the peak von Mises stress surged to 21.93MPa. When the ATFL exhibits laxity, the CFL is subjected to a higher stress of 3.84MPa. Conversely, when the CFL displays laxity, the ATFL experiences a peak von Mises stress of 2.34MPa. This study found that changes in the laxity of the ATFL and the CFL are linked to shifts in metatarsal stress levels, potentially affecting ankle joint stability. These alterations may contribute to the progression towards CLAI in individuals with posterolateral ankle ligament injuries. Additionally, significant muscle activation pattern changes were observed in CLAI patients, suggesting altered neural control strategies post-ankle ligament injury.

AimTo determine the diagnostic value of high-frequency ultrasonography in the assessment of anterior talofibular ligament (ATFL) injury and concomitant lesions.MethodsWe retrospectively analyzed the data of 1005 patients with acute, unilateral ATFL injuries diagnosed using high-frequency ultrasonography in our hospital between January 2021 and December 2024. We analyzed ATFL and calcaneofibular ligament (CFL) thickness in patients with right vs. left ankle injuries and those with complete vs. incomplete ATFL rupture. We also analyzed the damage to other supporting structures of the ankle to provide an imaging basis for clinical diagnosis and treatment.ResultsIn patients with incomplete ATFL injury with concomitant CFL injury, the thickness of the left and right CFL was 1.75 ± 0.47 mm and 1.90 ± 0.58 mm, respectively (P < 0.01). The CFL thickness was 1.83 ± 0.54 mm and 2.13 ± 0.54 mm in patients with incomplete and complete ATFL injury, respectively (P < 0.001). The incidence of concomitant CFL and superior extensor retinaculum (SER) injuries significantly differed between patients with incomplete and complete ATFL rupture (P < 0.05).ConclusionHigh-frequency ultrasonography is valuable for diagnosing acute ankle ligament injuries. CFL thickness was greater in patients with complete ATFL injury than in patients with incomplete ATFL injury. A trend toward increase CFL thickness on the right was noted, possibly due to right-sided dominance, though this requires further validation. ATFL injuries are frequently associated with concomitant CFL and SER injuries, and these structures should be carefully assessed during ultrasound examinations of acute ankle injuries.