Objective To investigate ideal screw implant angle in reconstruction of tibiofibular syndesmosis injury by using a biomechanical test. Methods A total of 24 ankle specimens from adult cadavers were used as the tibiofibular syndesmosis injury model. According to the angle of screw placement, the tibiofibular syndesmosis injury models were randomly divided into groups A (0°), B (10°-15°), C (20°-25°), and D (30°-35°), and the screws were placed at a level 2 cm proximal to the ankle joint. The displacement of fibula was measured by biomechanical testing machine at neutral, dorsiflexion (10°), plantar flexion (15°), varus (10°), and valgus (15°) positions, with axial load of 0-700 N (pressure separation test). The displacement of fibula was also measured at neutral position by applying 0-5 N·m torque load during internal and external rotation (torsional separation test). Results In the pressure separation test, group C exhibited the smallest displacement under different positions and load conditions. At neutral position, significant differences were observed (P<0.05) between group A and group C under load of 300-700 N, as well as between group B and group C under all load conditions. At dorsiflexion position, significant differences were observed (P<0.05) between group A and group C under load of 500-700 N, as well as between groups B, D and group C under all load conditions, and the displacements under all load conditions were significantly smaller in group A than in group B (P<0.05). At plantar flexion position, significant differences were observed (P<0.05) between group D and group C under all load conditions. At valgus position, significant differences were observed (P<0.05) between group A and group C under load of 400-700 N, as well as between groups B, D and group C under all load conditions. In the torsional separation test, group C exhibited the smallest displacement and group B had the largest displacement under different load conditions. During internal rotation, significant differences were observed (P<0.05) between group B and group C under all load conditions, as well as between group D and group C at load of 3-5 N·m. During external rotation, significant differences were observed between groups B, D and group C under all load conditions (P<0.05). No significant difference was detected between groups at the remaining load conditions (P>0.05). ConclusionThe ideal screw implant angle in reconstruction of tibiofibular syndesmosis injury was 20°-25°, which has a small displacement of fibula.
Objective To explore the morphological characteristics of the postero-superior protuberance of the calcaneus and to explore its relationship with Haglund malformation. MethodsAnkle lateral X-ray films of 391 hospitalized patients between May 2021 and June 2024 were retrospectively collected. The morphological parameters of the postero-superior protuberance of the calcaneus were measured, including the length of the base, the height of the base, and the tip angle of the postero-superior protuberance of the calcaneus, and the morphological types were classified according to the above parameters, including the peak type, the hill type, and the flat type. The related parameters of Haglund malformation were measured, including Fowler-Philipp angle (FPA), calcaneal pitch angle (CPA), parallel pitch line (PPL), Chauveaux-Liet angle (CLA), and X/Y ratio (total calcaneal length/length of greater tuberosity of calcaneus). The differences of the morphological parameters of the postero-superior protuberance of the calcaneus and the related indicators of Haglund deformity among the three types and between the males and the females were compared and analyzed, and the differences of the positive numbers of the related indicators of Haglund deformity among the three types were compared. ResultsAccording to the morphological parameters of the postero-superior protuberance of the calcaneus, there were 64 cases of peak type, 245 cases of hill type, and 82 cases of flat type. There was no significant difference in the length of the base of the postero-superior protuberance of the calcaneus, CPA, CLA, and X/Y ratio among the three types (P>0.05). Among the three types, the peak type had the largest FPA and the flat type had the smallest (P<0.05); the peak type had the smallest tip angle of the postero-superior protuberance of the calcaneus and the flat type had the largest (P<0.05); the positive rate of PPL in the hill type was significantly higher than that in the peak type and flat type (P<0.05); the height of the base of the postero-superior protuberance of the calcaneus in the flat type was the smallest (P<0.05). FPA, CPA, CLA, PPL, and X/Y ratio were positive in 2, 42, 172, 142, and 77 patients, respectively. There was no significant difference in the number of positive Haglund deformity indicators among the three types (P>0.05). There was no significant difference between male and female patients in the tip angle of the postero-superior protuberance of the calcaneus, FPA, the positive rate of PPL, and X/Y ratio (P>0.05). The length and the height of the base of the postero-superior protuberance of the calcaneus, CPA, and CLA in male patients were significantly higher than those in female patients (P<0.05). ConclusionThe postero-superior protuberance of the calcaneus can be divided into three types: the peak type, the hill type, and the flat type. The peak type is more likely to suffer from Haglund deformity, and the males are more likely to suffer from Haglund deformity than the females.