BACKGROUND:Ligament rupture and defect of the lateral or medial malleolus caused by high-energy injuries are common challenges in foot and ankle surgery.Their neighboring core tendons are often used as grafts to reconstruct the deficient ligaments.It is of paramount importance to investigate the mechanical properties of such tendons in the context of ligament defects to provide a suitable donor tendon.OBJECTIVE:To investigate the interactive dynamics and biomechanical alterations among their core tendons during ankle joint motions under varying degrees of lateral or medial malleolar ligament defect.METHODS:Based on CT imaging data of the left foot of a 50-year-old healthy male,a surface stereolithography model was extracted and constructed using MIMICS software.After Geomagic Wrap software was employed to fit the surfaces,a bone-cartilage-ligament-tendon ankle complex model incorporating varying degrees of ligament deficiencies was created within SOLIDWORKS software.Finite element analysis was then conducted using Ansys Workbench software,and the model's validity was verified through a simulated anterior drawer test.Following validation,the mechanical response of the ankle under the conditions of internal and external rotation,as well as inversion and eversion,was simulated.The variation and distribution patterns of the maximum Von-Mises stress in the peroneus brevis and longus tendons,as well as the anterior and posterior tibial tendons,were observed.RESULTS AND CONCLUSION:(1)In the anterior drawer test,the maximum talar displacement reached 5.208 5 mm,which was similar to the data in the previous literature,thereby the effectiveness of the model was validated.(2)Under four loading conditions,the defect of unilateral single-bundle ligaments exerted minimal influence on the maximum stress of adjacent core tendons,whereas the defect of unilateral multi-bundle ligament significantly increased the maximum tendon stress.Except for the consistently high stress across segments of the anterior tibial tendon,the high-stress regions in the long and short peroneal tendons and posterior tibial tendon were concentrated at their distal ends near the insertions.(3)Regarding the defect of the lateral malleolar ligament,the maximum stress and its variation in the peroneus brevis tendon during inversion and internal rotation were higher than those in the peroneus longus tendon.During inversion under the condition of the defect of the anterior talofibular ligament,the maximum stress in the short peroneal tendon increased by 0.951 2 MPa compared to that of normal condition,while that in the long peroneal tendon decreased by 0.065 1 MPa.Under the condition of the defect of the calcaneofibular ligament during internal rotation,the maximum stress in the short peroneal tendon increased by 2.352 9 MPa,while the maximum stress in the long peroneal tendon decreased by 0.269 2 MPa.(4)During eversion and external rotation under the defect of medial malleolar ligament,the variations in the maximum stress of the anterior and posterior tibial tendons were complex and depended on the type of ligament defect.Notably,full-thickness ligament defect significantly augmented the maximum stress in both tendons.

BACKGROUND:Ligament rupture and defect of the lateral or medial malleolus caused by high-energy injuries are common challenges in foot and ankle surgery.Their neighboring core tendons are often used as grafts to reconstruct the deficient ligaments.It is of paramount importance to investigate the mechanical properties of such tendons in the context of ligament defects to provide a suitable donor tendon.OBJECTIVE:To investigate the interactive dynamics and biomechanical alterations among their core tendons during ankle joint motions under varying degrees of lateral or medial malleolar ligament defect.METHODS:Based on CT imaging data of the left foot of a 50-year-old healthy male,a surface stereolithography model was extracted and constructed using MIMICS software.After Geomagic Wrap software was employed to fit the surfaces,a bone-cartilage-ligament-tendon ankle complex model incorporating varying degrees of ligament deficiencies was created within SOLIDWORKS software.Finite element analysis was then conducted using Ansys Workbench software,and the model's validity was verified through a simulated anterior drawer test.Following validation,the mechanical response of the ankle under the conditions of internal and external rotation,as well as inversion and eversion,was simulated.The variation and distribution patterns of the maximum Von-Mises stress in the peroneus brevis and longus tendons,as well as the anterior and posterior tibial tendons,were observed.RESULTS AND CONCLUSION:(1)In the anterior drawer test,the maximum talar displacement reached 5.208 5 mm,which was similar to the data in the previous literature,thereby the effectiveness of the model was validated.(2)Under four loading conditions,the defect of unilateral single-bundle ligaments exerted minimal influence on the maximum stress of adjacent core tendons,whereas the defect of unilateral multi-bundle ligament significantly increased the maximum tendon stress.Except for the consistently high stress across segments of the anterior tibial tendon,the high-stress regions in the long and short peroneal tendons and posterior tibial tendon were concentrated at their distal ends near the insertions.(3)Regarding the defect of the lateral malleolar ligament,the maximum stress and its variation in the peroneus brevis tendon during inversion and internal rotation were higher than those in the peroneus longus tendon.During inversion under the condition of the defect of the anterior talofibular ligament,the maximum stress in the short peroneal tendon increased by 0.951 2 MPa compared to that of normal condition,while that in the long peroneal tendon decreased by 0.065 1 MPa.Under the condition of the defect of the calcaneofibular ligament during internal rotation,the maximum stress in the short peroneal tendon increased by 2.352 9 MPa,while the maximum stress in the long peroneal tendon decreased by 0.269 2 MPa.(4)During eversion and external rotation under the defect of medial malleolar ligament,the variations in the maximum stress of the anterior and posterior tibial tendons were complex and depended on the type of ligament defect.Notably,full-thickness ligament defect significantly augmented the maximum stress in both tendons.

Objective:To exploring the uptake of fibroblast activation protein (FAP) inhibitor (FAPI) in pancreatic cancer through 68Ga-FAPI-04 PET/CT imaging, and provide a basis for the FAP-targeted imaging of pancreatic cancer. Methods:Pancreatic cancer-patient-derived tumor xenograft (PDX) mouse models ( n=8) were developed, then 68Ga-FAPI-04 and 18F-FDG microPET/CT imaging were performed (4 in each group). The differences of percentage activity of injection dose per gram of tissue (%ID/g) of 68Ga-FAPI-04 and 18F-FDG were analyzed by independent-sample t test. 68Ga-FAPI-04 and 18F-FDG PET/CT imaging were performed in 5 patients (4 males, 1 female, age: 46-74 (63.0±11.9) years) with pancreatic cancer, and the maximum standardized uptake value (SUV max) of 68Ga-FAPI-04 and 18F-FDG in primary pancreatic cancer and the SUV max ratio of liver metastases to liver tissue were compared by paired t test. Results:MicroPET/CT imaging showed that 68Ga-FAPI-04 was obviously uptaken at all time points in the tumor of PDX mice. The uptake of 68Ga-FAPI-04 in PDX mice 60 min after injection was significantly higher than that of 18F-FDG ((6.58±0.44) and (4.29±0.13) %ID/g; t=4.152, P=0.008 9). PET/CT showed that the SUV max of 68Ga-FAPI-04 in pancreatic cancer was significantly higher than that of 18F-FDG (16.82±3.08 and 5.14±2.20; t=6.893, P=0.000 1) and the SUV max ratio of liver metastases to liver tissue of 68Ga-FAPI-04 was also significantly higher than that of 18F-FDG (4.57±1.47 and 1.30±0.16; t=3.803, P=0.019 1). Conclusion:68Ga-FAPI-04 can be highly uptaken in pancreatic cancer, suggesting that FAP can be a potential target for PET/CT imaging of pancreatic cancer.