This was a retrospective case series in a single referral hospital. The study was approved by our institutional ethics committee (Approval#2016-005-1). The study group included 12 patients (8 men and 4 women) who had been treated for posterolateral tibial plateau fractures between 2016 and 2019. The average age at the time of trauma was 44.7 years (range, 31–66 years). The mechanism of injury was a motor vehicle accident in three patients and a fall from a height in nine patients. According to the Schatzker classification system, there were 2 cases of type I, 5 cases of type II, 2 cases of type III, 1 case of type IV and 2 cases of type V fractures. The preoperative imaging examinations included X-ray and CT scans and three-dimensional reconstruction. All operations were performed by the same experienced trauma surgeons after the soft tissue condition stabilized.
Methods
Approach
Under general anaesthesia or spinal anaesthesia, the patient was placed in the supine position, the affected limb was bent at the hip and knee by approximately 30°-40°, and the calf was placed in neutral rotation. All RSP fixation procedures were performed using the traditional anterolateral approach.
The incision we made started from the lateral joint line of the knee joint, arced forward and downward over the Gerdy tubercle, and extended to the distal end for approximately 6 cm. The subcutaneous tissue was separated, and the iliotibial band was incised subperiosteally along the outer edge of the tibia. The lateral joint capsule and the ligament between the meniscus and tibial plateau were incised. The meniscus was carefully dissected to expose the upper surface of the lateral tibial plateau, while its anterior and posterior attachment were preserved. The lateral meniscus, iliotibial band and superficial tissue were retracted proximally using sutures. The lateral collateral ligament, posterior iliotibial band, popliteal tendon and superficial tissue were posteriorly retracted using sutures (Fig. 3). After a Schanz nail was placed in the middle and lower sections of the femur and tibia and with slight internal rotation and varus of the lower leg while a femoral distractor was applied, the posterolateral tibial plateau articular surface was fully visualized.
Reduction and Plate Fixation
Through the oval hiatus of the interosseous membrane, a minitype elevator was used to peel back the periosteum to the posterior lateral aspect of the tibial plateau and lift the fracture block of the posterolateral tibial plateau (Fig. 4A). K-wire was used to maintain the reduction if necessary. This procedure led to initial reduction of the fracture and established a soft tissue path, which needed to be close to the periosteum to avoid injury to nearby neurovascular bundles, for the implantation of the RSP.
The straight part of the RSP was placed beneath the proximal tibiofibular joint anterolaterally, and the curved part was immediately adjacent to the posterolateral fragments (Fig. 4B). First, a screw was inserted through the sliding hole located at the junction of the straight and curved parts as a fulcrum. Then, the special pressurizer was placed close to the distal end of the straight part (Fig. 4C). At this time, by screwing in the screw, the L-shaped hollow frame of the pressurizer was squeezed, thereby pushing the distal end of the RSP so that the posterior lateral fracture could be further compressed and reduced (Fig. 4D). Finally, two or three consecutive locking screws were inserted in the distal screw holes before the pressurizer was removed (Fig. 4E-F). All reduction and fixation procedures were conducted under intraoperative fluoroscopic guidance. The ligaments and joint capsule were carefully sutured back to the attachment, and the subcutaneous tissue and skin were closed over suction drains.
For the patients with anterolateral tibial plateau fractures, the anterolateral tibial plateau was routinely reduced and then used as a reference to reduce the posterior lateral fracture; after reduction, the 3.5-mm lateral anatomic locking plate was used to fix the lateral fracture. For the patients with medial tibial plateau fractures, anteromedial incisions were made, and a 3.5-mm "T"-shaped locking plate or lag screws were used for fixation. Additionally performing the above internal fixation technique did not affect the placement of the RSP.
Evaluation index
A CT examination of the knee joint was performed after the operation to observe the state of fracture reduction and fixation. The knee X-rays were taken at 6, 12, 24, and 48 weeks after surgery to observe the level of bony union. The knee joint range of motion was recorded at the last follow-up. Knee joint function was evaluated using the American Hospital for Special Surgery (HSS) knee joint function assessment tool [9]. The highest score possible is 100 points; scores of >85 points are excellent, those of 70-84 are good, those of 60-69 are fair, and those of ≤59 are poor.