ObjectiveTo design a new type of transarticular cuboid bone plate by measuring and collecting the anatomic data of the articular surface around cuboid, and to carry out comparative biomechanical study. MethodsThe angle α (between the fifth metatarsocuboid joint and the fifth metatarsal bone) and the angle β (between the fifth metatarsocuboid joint and the calcaneocuboid joint) were measured in 100 adults on medial oblique X-ray film and 30 adult foot specimens. Based on literature data, the transarticular cuboid bone plate was designed with an angle α of 70° and an angle β of 30°. Six adult cadaver feet were chosen and were transected approximately 15 cm proximal to the ankle. Five strain gauges were placed at the calcaneus, cuboid, and the fourth and fifth metatarsal bones. The vertical pressure was loaded on the foot at 0-600 N, the strain value was measured. Then the cuboid fracture model was established and 600 N load was given on foot to measure the strain value and compare with the strain value before fracture. The specimens were randomly divided into groups A and B (n=3). Fracture was fixed with transarticular cuboid bone plate and 9 screws in group A and with double plate and 8 screws in group B, then the 600 N load was given to measure the strain value and vertical displacement of the fracture fragments. ResultsAfter loads of 0-600 N on the foot, the strain value of the 5 points showed an increased trend. No significant difference was found in the strain value between pre- and post-fracture at a, d, and e points P>0.05), but it was significantly larger at post-fracture than pre-fracture at b and c points (P<0.05). After fracture fixation, no significant difference was shown in the strain value at 5 points between groups A and B when loads of 0-600 N was given P>0.05). The experimental data showed that the strain value change mainly focused on the fracture site under the same load, so the strain value after fracture fixation was similar to that before fracture at b and c points P>0.05). The vertical displacement values of medial and lateral fracture fragments in group A[(0.804±0.011) mm and (0.672±0.036) mm] were significantly less than those in group B[(1.126±0.083) mm and (1.007±1.103) mm] (t=-6.711, P=0.003; t=-5.307, P=0.006). ConclusionThrough biomechanical study, a new type of transarticular cuboid bone plate has better fixation effect.
ObjectiveTo observe the effectiveness of 360° internal fixation by anteromedial and posterior-lateral approaches for high-energy closed Pilon fractures. MethodsBetween February 2013 and February 2015, 18 cases of high-energy closed Pilon fractures were treated. There were 11 males and 7 females with an average age of 40.5 years (range, 20-65 years). The causes were falling injury in 10 cases and traffic accident injury in 8 cases. All fractures were RüediAllgower type Ⅲ Pilon fracture combined with ipsilateral fibula fracture. The average interval from injury to operation was 8 days (range, 5-13 days). Reduction of fracture was performed by anteromedial and posterior-lateral approaches and the fracture fragments were fixed by 360° internal fixation. The effectiveness was assessed by ankle X-ray film and Mazur score at last follow-up. ResultsTwo cases had skin necrosis and received flap surgery, the other cases obtained primary healing of incision. All the cases were followed up 11.2 months on average (range, 3-27 months). X-ray film showed that all fractures healed at 3-4 months after operation (mean, 3.6 months). No deep infection or plate exposure occurred. According to Mazur score, the results were excellent in 8 cases, good in 7 cases, fair in 2 cases, and poor in 1 case, and the excellent and good rate was 83.3%. ConclusionThe effectiveness of the 360° internal fixation for treatment of high-energy closed Pilon fractures has the advantages of reliable fixation, early functional exercise, and good functional recovery of the ankle joint.