Posteromedial Plate as Strategy for Fixation of Posterior Column of Tibial Plateau Fracture

INTRODUCTION

The fracture of the posteromedial column of the tibial plateau is one of the most challenging types of the tibial plateau fractures. ¹ This type of fracture is not rare, but it has been underappreciated previously. Attention to these types of fractures markedly increased with the advances achieved in computed tomography (CT) technology. ² These fractures are usually caused by high-energy trauma that commonly results in articular surface comminution, meta-diaphyseal dissociation, and soft-tissue injury. ³

Several surgical approaches like the anterolateral approach, the anteromedial approach and the posterior approach have been prescribed. However, each approach has its shortcoming including damage of the soft tissues caused by dissection, failure to expose the fracture site, impairment of the blood supply of the soft tissues, and risk of injuring the neurovascular bundles. ⁴

The posteromedial approach was first described in a German literature in 2003 and is usually used to access the posteromedial and posterior side of the tibial plateau. It allows for good visualization and reduction of the posteromedial fragment without exposure of the neurovascular bundle. ⁵

Our study is aiming to spot light on the posteromedial approach in managing the posteromedial tibial plateau fractures, and to evaluate the patients clinically and radiologically after fixation of the fracture with a buttress plate.

PATIENTS AND METHODS

This is a prospective study that included 15patients (13males & 2 females) with closed posteromedial tibial plateau fractures who had undergone surgery in the period between May 2019 and September 2019. The protocol was discussed and approved for clinical study by the Ethical Research Committee of Al-Azhar University and a written informed consent was obtained. All patients were informed about the pathology and the suggested treatment according to their diagnosis and also informed about the possible complications. All our patients underwent the same treatment of open reduction and internal fixation by a buttress plate and screws to fix the posteromedial tibial plateau fracture through a posteromedial approach at Bab AL-Sharia (Sayed Galal) university hospital and Dar El Shefa Hospital, Cairo, Egypt. The average patient age at the operation time was 34.8 years (age ranges from 20 to 48 years). Our follow up period extended from three to six months. According to the Schatzker classification, there were 6 cases (40%) with type lVfractureand9 cases (60%) with type Vfracture.

Inclusion Criteria were: Posteromedial Column Fracture, Schatzker Type IV and V Bicondylar Tibial Plateau Fracture, Moore Type 1 posterior Split Fracture. We excluded patients with Open fractures, Neurovascular Injury, Schatzker type VI

Indication for surgery in tibial plateau fracture was described by Honkonen suggesting that surgical treatment should be considered in all fractures of the medial condyle, medially tilted bicondylar fracture, all fractures of the lateral condyle and laterally tilted bicondylar fractures showing more than 5 degrees of lateral tilt, more than 3 mm of articular step-off, or condylar widening greater than 5 mm, in addition to all displaced axial bicondylar fractures.

Surgical procedure:

Patients were operated under general or spinal anesthesia. All Patients were placed in the prone position with the hip laterally tilted on a radiolucent operative table, with the other leg ex­tended on a leg holder or any other similar positioning device. The administration of preoperative antibiotic was done after sensitivity test, the leg is then ex­sanguinated and a tourniquet was inflated around the upper thigh.

Surgical landmarks in the posteromedial approach consist of the me­dial head of the hamstrings and gastrocnemius muscle, which are palpated on the medial and distal border of the popliteal fossa. We made an inci­sion about 10 cm along the border of the medial head of the gastrocnemius muscle.

Sharp dissection is done in the subcutaneous tissue and popliteal fascia using a blade knife (Figure 1A). After that we identified and bluntly dissected the medial head of the gastrocnemius muscle from distal to proximal and retracted it laterally. The insertion of the ham­strings (pes anserine tendons) is then retracted medially revealing the popliteus muscle underneath which is dissected completely or partially and detached from the proximal tibia subperi­osteally with a peri­osteal elevator.

Hohmann retractor is then placed subperiosteally and the periosteum is then incised carefully and elevated with caution to reveal the fracture site. Indirect reduction can be achieved through hyperextension with axial traction, compression on the fragment and applying a T-shaped buttress plate, with the first screw placed through the plate and into an oblong hole just distal to the fracture. this allowed the reduction of the fracture by approximating the plate to the bone (Figure 1B).

Wires can be used to temporary fix the plate in place. Using image intensifier in the lateral view ensured perfect proximal level of the plate. After that the rest of the screws are inserted through the plate (Figure 2).

The tourniquet was turned off slowly before wound closure, vascularity was checked and small vessels were cauterized. Closure of the wound was done by closing the deep fascia, subcutaneous tissue and skin. A 12 mm drain was inserted. The wound was then covered with a sterile dressing.

In patients with bicondylar fractures that needs fixation of the lateral tibial condyle, the leg is prepared and draped again for a standard approach to fracture fixation either by an anterolateral approach to apply an anterolateral plate or with percutaneous 6.5mm or 7.3mm cannulated lag screws (Figure 3).

Post-operative stage:

Proper analgesia was continued for the first 2 days, anti-edematous measures were done in the form of elevation of the operated limb and cold packs for 24 hours. Physiotherapy started on the first postoperative day in the form of chest exercise and cold therapy. In patients with unicondylar fractures, continuous passive motion was started on the first post-operative day. In cases with bicondylar fractures, posterior above knee splint was done and range of motion was delayed for 10 to 14 days. On the third post-operative day, all patients were allowed to walk using two crutches with no weight bearing to the affected limb. Hospital stay ranged from 2 to 5 days postoperatively

Follow up:

Two weeks follow up was done to evaluate the wound, remove stitches and check for complication like deep venous thrombosis and infection. Eight weeks follow up was done to check the fracture union and plan for the weight bearing. Twelve weeks follow up was done to assess the clinical and radiological outcome according to the Rasmussen system (Table 1).

Clinical score is considered Excellent with 18 points, good from 12 to 18 points, fair from 6 to 11 points and poor with less than 6 points.Radiological score is evaluated asexcellent with 18 points, good from 12 to 18 points,fair from 6 to 11 pointsandpoor with less than 6 points.

Statistical Analysis:

Data were collected, revised, coded and entered to the Statistical Package for Social Science (IBM SPSS) version 23. The quantitative data were presented as mean, standard deviations and ranges when their distribution found parametric and median, inter-quartile range (IQR) when data found non parametric. Also, qualitative variables were presented as number and percentages. So, the p-value was considered significant as the following: P > 0.05: Non significant, P < 0.05: Significant, P < 0.01: Highly significant.

Fig (1):posteromedial approach to the tibial plateau. (A) sharp dissection is done in the subcutanous tissue and poplteal fascia using a blade knife medial to the medial head of the gastrocnemius. (B) conventional nonlocking (4.5-mm) buttress T plate used to fix the posteromedial fragment.

Fig (2): bicondylar tibial plateau fracture fixed by double plating.

RESULTS

Our study included 15 patients, 2 of them were females and 13 were males with age ranged from 20 years to 48 years and a mean age at the time of the injury of 34.8 years. A total number of 8 patients (53.3%) presented by tibial plateau fracture in the right limb and 7 patients (46.7%) in the left limb.

Fig (3):posteromedial unicondylar tibial plateau fracture fixed by posteromedial plate.

There was significant correlation between the type of fracture and the total radiological score. A total of 6 patients with type IV fracture had a mean radiological score of 18 points while 9 patients with type V fracture had a mean radiological score of 14 points. Better radiological results were observed in patients with type IV fracture (Table 2).

In this study, we included 6 patients with fracture type IV, 4 of them (66.6%) had excellent score and 2 of them (33.4%) had good score. The other 9 patients had fracture type V, 4 of them (44.4%) had excellent score while 5 of them (55.6%) had good results (Table 3).

In this study, one case presented at the 3rd day postoperative with signs of compartment syndrome. The patient was managed by close observation and conservative treatment that included massive antiedematous, leg elevation and cold packs. On the 6th day, the same patient showed dehiscence and superficial infection on the distal 3 sutures. Culture and sensitivity tests were done and the proper antibiotic was administrated for two weeks. The patient improved with conservative treatment with no need for surgical intervention.

Table 1: Rasmussen Score (Criteria of Clinical and radiological assessment)

Table 2: Clinical and radiological outcome in relation to the Type of fracture

P-value > 0.05: Non significant; P-value < 0.05: Significant; P-value < 0.01: Highly significant

*: Chi-square test; ≠≠: Mann-Whitney test

Table 3: Percentage of the clinical outcome according to each fracture type.