Objective To investigate the effectiveness of osteotomy of non-core weight-bearing area of the lateral tibial plateau, reduction, and internal fixation in the treatment of tibial plateau fractures involving posterolateral column collapse. Methods A clinical data of 23 patients with tibial plateau fractures involving posterolateral column collapse, who had undergone osteotomy of non-core weight-bearing area of the lateral tibial plateau, reduction, and internal fixation between January 2015 and June 2021, was retrospectively analyzed. There were 14 males and 9 females with an average age of 42.6 years ranging from 26 to 62 years. The causes of injury included traffic accident in 16 cases, falling from height in 5 cases, and other injuries in 2 cases. According to Schatzker classification, there were 15 cases of type Ⅴ and 8 cases of type Ⅵ. The time from injury to operation was 4-8 days with an average of 5.9 days. The operation time, intraoperative blood loss, fracture healing time, and complications were recorded. The depth of articular surface collapse of posterolateral column and posterior inclination angle (PSA) of the tibial plateau were compared before operation and at 2 days and 6 months after operation; fracture reduction of tibial plateau fracture was evaluated by Rasmussen anatomic score. The recovery of knee function was evaluated by Hospital for Special Surgery (HSS) score at 2 days and 6 months after operation. Results All 23 patients were completed the operation successfully. The operation time was 120-195 minutes, with an average of 152.8 minutes; the intraoperative blood loss was 50-175 mL, with an average of 109.5 mL. All patients were followed up 12-24 months, with an average of 16.7 months. One patient had superficial wound infection after operation, and the incision healed after dressing change; primary healing of incision of other patients was obtained. The fracture healing time was 12-18 weeks, with an average of 13.7 weeks. No failure of internal fixation, varus and valgus deformity of the knee joint, and instability of the knee joint was found at last follow-up. One patient developed joint stiffness and the range of motion of the knee joint was 10°-100°; the range of motion of the knee joint of other patients was 0°-125°. At 2 days and 6 months after operation, the depth of articular surface collapse of posterolateral column, PSA, and Rasmussen anatomic scores significantly improved when compared with those before operation (P<0.05). There was no significant difference between the two postoperative time points (P>0.05). The HSS score at 6 months after operation was significantly higher than that at 2 days after operation (P<0.05). Conclusion For tibial plateau fractures involving posterolateral column collapse, reduction and internal fixation through osteotomy of non-core weight-bearing area of the lateral tibial plateau has the advantages of fully expose the posterolateral column fragment, good articular surface reduction, sufficient bone grafting, and fewer postoperative complications. It is beneficial to restore knee joint function and can be widely used in clinic.
Objective To compare the biomechanical differences among the five internal fixation modes in treatment of Day type Ⅱ crescent fracture dislocation of pelvis (CFDP), and find an internal fixation mode which was the most consistent with mechanical principles. Methods Based on the pelvic CT data of a healthy adult male volunteer, a Day type Ⅱ CFDP finite element model was established by using Mimics 17.0, ANSYS 12.0-ICEM, Abaqus 2020, and SolidWorks 2012 softwares. After verifying the validity of the finite element model by comparing the anatomical parameters with the three-dimensional reconstruction model and the mechanical validity verification, the fracture and dislocated joint of models were fixed with S1 sacroiliac screw combined with 1 LC-Ⅱ screw (S1+LC-Ⅱ group), S1 sacroiliac screw combined with 2 LC-Ⅱ screws (S1+2LC-Ⅱ group), S1 sacroiliac screw combined with 2 posterior iliac screws (S1+2PIS group), S1 and S2 sacroiliac screws combined with 1 LC-Ⅱ screw (S1+S2+LC-Ⅱ group), S2-alar-iliac (S2AI) screw combined with 1 LC-Ⅱ screw (S2AI+LC-Ⅱ group), respectively. After each internal fixation model was loaded with a force of 600 N in the standing position, the maximum displacement of the crescent fracture fragments, the maximum stress of the internal fixation (the maximum stress of the screw at the ilium fracture and the maximum stress of the screw at the sacroiliac joint), sacroiliac joint displacement, and bone stress distribution around internal fixation were observed in 5 groups. Results The finite element model in this study has been verified to be effective. After loading 600 N stress, there was a certain displacement of the crescent fracture of pelvis in each internal fixation model, among which the S1+LC-Ⅱ group was the largest, the S1+2LC-Ⅱ group and the S1+2PIS group were the smallest. The maximum stress of the internal fixation mainly concentrated at the sacroiliac joint and the fracture line of crescent fracture. The maximum stress of the screw at the sacroiliac joint was the largest in the S1+LC-Ⅱ group and the smallest in the S2AI+LC-Ⅱ group. The maximum stress of the screw at the ilium fracture was the largest in the S1+2PIS group and the smallest in the S1+2LC-Ⅱ group. The displacement of the sacroiliac joint was the largest in the S1+LC-Ⅱ group and the smallest in the S1+S2+LC-Ⅱ group. In each internal fixation model, the maximum stress around the sacroiliac screws concentrated on the contact surface between the screw and the cortical bone, the maximum stress around the screws at the iliac bone concentrated on the cancellous bone of the fracture line, and the maximum stress around the S2AI screw concentrated on the cancellous bone on the iliac side. The maximum bone stress around the screws at the sacroiliac joint was the largest in the S1+LC-Ⅱ group and the smallest in the S2AI+LC-Ⅱ group. The maximum bone stress around the screws at the ilium was the largest in the S1+2PIS group and the smallest in the S1+LC-Ⅱ group. Conclusion For the treatment of Day type Ⅱ CFDP, it is recommended to choose S1 sacroiliac screw combined with 1 LC-Ⅱ screw for internal fixation, which can achieve a firm fixation effect without increasing the number of screws.