All patients treated for tibia plateau fracture involving the posterior column via a medial midline incision with posterior column fixation using a plate between 2017 and 2020 in our institution were included in this study. After obtaining institutional ethics committee approval (ID: B.10.1.TKH.4.34.H.GP.0.01/372) medical records of the patients were reviewed retrospectively. This study was conducted in accordance with principles for human experimentation as defined in the Declaration of Helsinki. Informed consent was obtained from all individuals prior to surgery.
Inclusion criteria were as follows: patients undergoing operations for tibia plateau fracture involving the posterior column via a medial midline incision with posterior column fixation or buttressing using a plate, patients with the necessary medical records, including radiographic images and follow-up data, at least 12 months of follow-up, and skeletal maturity (≥ 16 years of age). Exclusion criteria were as follows: posterolateral column fracture treated through a reverse L-shaped incision in the prone position, patients with pathological fractures, open fractures, lack of sufficient medical data, < 12 months of follow-up, and patients yet to reach skeletal maturity (< 16 years of age).
3D CT was performed preoperatively to evaluate the nature of the fracture and a CT was performed postoperatively to evaluate the success of the fixation in all patients. Fractures were classified using the three-column classification system as described by Zhu et al. [7]. An axial CT section at the plateau level showing the fibular head was evaluated for classification. In this classification, three lines intersecting at the midpoint between the two eminences divided the plateau into three columns. The first line started from the tibial tuberosities, the second started from the anterior cortex of the fibular head, and the third started from the medial-posterior ridge of the tibial plateau. Medial and lateral columns were separated by the first line, and the posterior column was separated from them by the second and third lines. Luo et al. [8] modified this classification, and referred to fractures medial to the posterior tibial sulcus and those lateral to the posterior tibial sulcus as posteromedial and posterolateral column fractures, respectively. Operations were guided by this classification and fixation of each column with an individual plate was performed. Fractures involving the medial, posteromedial, or posterior column (Schatzker type IV, V, and VI) were fixed with the same technique using the same single medial midline incision. For three-column fractures, patients were treated using the routine anterolateral and medial midline approach. However, patients with a posterolateral column fracture requiring separate fixation were treated through a posterior reverse L-shaped incision in the prone position. All patients underwent surgery when the periarticular edema at the knee was alleviated and skin was ready for incision. All patients received low-molecular-weight heparin (Clexane 4000 anti-Xa; Sanofi Aventis, Paris, France) starting from the first day of admission. Antibiotic prophylaxis (1 g cefazolin for patients < 70 kg, 2 g cefazolin for patients > 70 kg) was started 30 min prior to surgery, with two additional doses administered on the day after the operation. All operations were performed by the same senior surgeon.
Surgical technique
Operations were performed on a flat table, with the affected knee flexed to 30° and a padded pillow under the knee to allow clear lateral fluoroscopic imaging evaluation. A tourniquet was applied and inflated prior to starting the incision in all cases. For medial and lateral plateau fractures, separate medial midline and anterolateral incisions were performed. However, if the lateral plateau was not to be fixed, a single medial midline incision was used (Fig. 1a). An oblique medial midline incision was made, starting about 3 cm above the knee joint and extending 10 cm distal in the sagittal midline plane. After subcutaneous dissection, the pes anserinus was elevated from its insertion subperiosteally using a Z-shaped sharp periosteal incision (Fig. 1b). This subperiosteal deep incision enabled dissection of the posteromedial capsule from the plateau without disturbing the tibial insertion of the medial collateral ligament(MCL) (Fig. 1b–d). Moreover, using this incision, anatomical closure of the deep fascia and pes anserinus could be achieved (Fig. 1e). Subperiosteal dissection of the posteromedial capsule from the posterior tibial plateau enables a relatively safe zone for plate placement. After dissection of the posterior column fracture, a plate of suitable size was placed on the posterior and/or posteromedial plateau. Taking the knee in flexion and external rotation eased mobilization of the posterior skin flap and provided a sufficient field of view for both fixation and reduction. The choice of plate used for the surgery was made at the discretion of the operating surgeon. Either a 2.2 mm semitubular or a 3.5 mm dynamic compression plate (DCP) (TST Medical Devices, Istanbul, Turkey) was contoured to the shape of the posterior column and used for buttressing (Fig. 1d).
After placement of the plate, the knee was taken into extension to facilitate reduction of the posterior column. The first screw (3.5 mm cortical non-locking) was placed on the distal side of the fracture line and used to buttress the posterior plateau anteriorly. Two or three additional 3.5 mm cortical screws were placed distally to enhance stability. In 20 cases, plates were used for their buttressing effect and the posterior fragment was not fixed to the posterior plate. In five cases (three patients with isolated posteromedial column fracture, one with medial and posteromedial column fracture, and one with three-column fracture), the posterior fragment was also fixed to the posteromedial plate. The order of placement of the plates started with posterior column buttressing and proceeded with lateral column fixation and medial column fixation.
Postoperative care and evaluation
A hinged brace allowing 0°–90° flexion was applied postoperatively. Patients were mobilized allowing toe-touch walking without weight bearing. Quadriceps strengthening and hamstring flexing exercises were started on postoperative day 1. Clinical and radiographic assessments of the progress of healing and complications were carried out during follow-up visits. Two authors assessed the preoperative and postoperative images independently. The quality of reduction was evaluated in both coronal and sagittal CT planes. Displacement of 0 mm was defined as anatomical reduction, ≤ 2 mm was considered acceptable reduction, and > 2 mm was deemed poor reduction. All patients came for routine follow-up visits at 2 weeks, 6 weeks, 3 months, 6 months, and 1 year postoperatively. Weight bearing was allowed after 3 months of follow-up if callus was evident on at least three cortices. Flexion of 90°–120° was allowed after 6 weeks of follow-up. Duration of union and loss of reduction, if any, were recorded. Range of motion (ROM) and Knee Society score (KSS) were evaluated and recorded at the last follow-up after 1 year [9]. In addition, possible complications, including deep vein thrombosis (DVT), infection, nonunion, and delayed union, were recorded.
Data were analyzed using SPSS software (ver. 22.0; IBM Corp., Armonk, NY, USA). Interobserver reliability for qualitative data was assessed using the kappa coefficient (κ). The intraclass correlation coefficient (ICC) was used to assess reliability of quantitative data between two observers. Quantitative variables are expressed as the mean or median and standard deviation, and qualitative variables are expressed as the frequency or ratio.