Open Reduction and Internal Fixation of Tibial Plateau Fractures
James A. Goulet, MD
Mark E. Hake, MD
Dr. Goulet or an immediate family member has received royalties from Zimmer and serves as a board member, owner, officer, or committee member of the American Orthopaedic Association. Dr. Hake or an immediate family member has stock or stock options held in Johnson & Johnson and Medtronic and has received research or institutional support from Zimmer.
INTRODUCTION
Fractures of the tibial plateau are challenging injuries. These fractures involve the joint surface and metaphysis of the proximal tibia and occur as a result of both high-energy and low-energy mechanisms. The severity of injury to the bone and surrounding soft tissue should be considered when deciding on the optimal course of treatment. Goals include anatomic reduction of the articular surface, restoration of the mechanical axis, stable fixation that allows early range of motion (ROM), preservation of the surrounding soft tissues, and avoidance of infection. Ligamentous repair or reconstruction also may be required to obtain a good outcome.
PATIENT SELECTION
Careful examination of the injured extremity is mandatory. Vascular injury, compartment syndrome, and open injuries should be noted and treated emergently. Knee stability and the condition of the soft-tissue envelope are vital in determining the imaging needed and timing involved in treatment.
Indications
Absolute indications for open treatment include fractures that are open or associated with compartment syndrome or vascular injury. Relative indications include fractures that cause joint instability or malalignment, medial condylar fractures, lateral plateau fractures with displacement greater than 3 mm, and condylar widening greater than 5 mm.1,2 Fractures in the patient with multiple traumatic injuries also are more likely to be treated surgically to facilitate mobility. In general, fractures with less than 2 mm of displacement at the joint surface and with normal alignment and a stable knee in extension can be considered for closed treatment.
Contraindications
With all fractures, the patient’s medical comorbidities and baseline activity level must be considered. Open treatment should be delayed until the surrounding soft tissues have been given adequate time to heal. Appropriate delay has been clearly shown to reduce the rate of wound breakdown and infection.3,4 Temporary early external fixation should be applied in cases of gross instability or severe soft-tissue injury until definitive fixation can be performed. The goals of treatment have evolved to prioritize maintaining the viability of the soft tissues and preserving vascularity surrounding the fracture. Using indirect reduction techniques to restore limb alignment while obtaining anatomic reduction of the articular surface has been shown to lead to favorable outcomes.
Alternative Treatments
Some debate exists regarding the optimal treatment of bicondylar fractures. Given historically poor outcomes due to high rates of infection, alternative techniques have been explored. Small-wire external ring fixators have been shown to be a potential alternative to traditional open reduction and internal fixation (ORIF). A recent Level I study that compared this method with ORIF showed comparable outcomes with fewer complications than with ORIF.5 The advent of locked plating led to the idea that bicondylar fractures could be stabilized by a single, laterally placed locked construct. Although several studies support this idea, a recent biomechanical study showed that dual plating allows less subsidence of the medial plateau than does a single, laterally based locked plate.6 Bicortical screw placement used with a locking construct provides a stiffer construct with a higher maximum load compared with unicortical placement.7
Closed reduction and percutaneous fixation is an option for minimally displaced lateral split fractures with minimal joint surface comminution. Injury or incarceration of the lateral meniscus should be ruled out preoperatively with MRI. The reduction is obtained with a varus force or a laterally based femoral distractor. The reduction is maintained with large reduction forceps while two to three screws are placed to provide compression across the fracture. A small antiglide plate may be used in the setting of metaphyseal comminution or in patients with poor bone quality.
Arthroscopically assisted reduction and internal fixation may be beneficial for certain types of tibial plateau fractures with an intact or restorable cortical envelope.
Although high-quality studies comparing outcomes of this technique with ORIF are lacking, cited benefits include minimal soft-tissue dissection, better visualization of reduction compared with open techniques, and the ability to diagnose and repair intra-articular soft-tissue injuries.8 Shorter hospital stays and faster rehabilitation times also have been reported.9
Although high-quality studies comparing outcomes of this technique with ORIF are lacking, cited benefits include minimal soft-tissue dissection, better visualization of reduction compared with open techniques, and the ability to diagnose and repair intra-articular soft-tissue injuries.8 Shorter hospital stays and faster rehabilitation times also have been reported.9
CLASSIFICATION
The fracture pattern and severity of the soft-tissue injury will guide the decision about the optimal approach to use for reduction and stabilization. The two main classification systems used today describe the fracture pattern but do not take into account ligamentous injury or damage to the soft-tissue envelope, nor are they predictive of outcomes. The system described by Schatzker et al10 divides fractures into six types. In general, types I, II, and III are low-energy injuries that involve the lateral plateau, and types IV, V, and VI involve a higher-energy mechanism and medial condyle or bicondylar injury. The AO/OTA system classifies these fractures into extra-articular, partial articular, and complete articular, with further subdivisions based on the severity of the fracture.
PREOPERATIVE IMAGING
Plain radiographs of the injured knee, including AP and lateral views, are obtained, along with internal and external rotation oblique views. An AP view with the beam directed 10° caudal shows displacement at the articular surface most clearly. CT with sagittal and coronal reconstructions has been shown to affect the surgical plan in many cases because articular depression can be difficult to evaluate on plain radiographs11 (Figure 1). Obtaining preoperative MRI to evaluate for soft-tissue injury has become more common. Meniscal and ligamentous injuries have been shown to be common even in low-energy injuries. In a recent series of closed fractures evaluated arthroscopically, soft-tissue injuries were found in 70 of 98 cases (71%).12 Meniscal injuries occurred with all fracture types, whereas anterior cruciate ligament tears were more common in Schatzker type IV and VI fractures. MRI is helpful to evaluate the need for ligamentous repair or reconstruction before hardware is placed.
VIDEO 76.1 Open Reduction and Internal Fixation of Tibial Plateau Fractures. Mark E. Hake, MD; James A. Goulet, MD (21 min)Video 76.1
PROCEDURE
Approaches
Many options have been described for treating low-energy and high-energy tibial plateau fractures. The anterolateral approach can be used for the most common types of these fractures. The anterolateral approach is used for ORIF of lateral plateau fractures (Schatzker types I, II, and III) as well as for fixation of the lateral plateau when using a dual-incision technique to repair bicondylar fractures. The Lobenhoffer posteromedial approach is used when fixation of the medial plateau is required. A posteromedial fragment has been shown to be present in approximately one-third of AO/OTA C-type bicondylar tibial plateau fractures.13 The Lobenhoffer approach, when used in combination with the anterolateral approach, leaves a wide skin bridge and provides sufficient soft-tissue coverage of the hardware, so later removal is rarely required.
Approaches that are required only rarely include the direct posterior approach, which is used for treating posterior shear-type injuries that are not accessible from the anterolateral or Lobenhoffer approaches.14 We recommend against using a direct anterior approach with tibial tubercle osteotomy because this approach is associated with a high rate of nonunion.
Room Setup/Patient Positioning
Most patients treated with a single-incision or dualincision technique can be placed supine on a radiolucent table. A high thigh tourniquet is placed. A radiolucent triangle is placed under the injured knee to facilitate access to the lateral plateau and aid in obtaining high-quality AP and lateral fluoroscopic images during the procedure. The C-arm is brought in from the contralateral side of the table. When using the Lobenhoffer approach, we prefer to place the patient prone, although a supine position also has been described.15
Special Instruments/Equipment/Implants
Several specialized instruments can be helpful when performing ORIF of tibial plateau fractures. A femoral distractor can prove useful for direct visualization of the joint surface, which is helpful when confirming adequate reduction. The distractor can be applied after a submeniscal arthrotomy is performed to confirm reduction of the fractured fragments. In many cases, the distractor provides axial traction to aid in reduction. If a femoral distractor is not available, a standard external fixator can be used in the same fashion to distract across the joint.
When an isolated depression of the joint surface is present, a cortical window is required to elevate the articular cartilage. This window can be created with a 2-mm drill and an osteotome. We have found that using a cannulated reamer from a hip compression screw set is useful for this purpose. The guidewire can be directed from the metaphysis directly at the depressed segment for accurate placement of the window. A curved bone tamp is used to reduce the displaced fragments. To fill the remaining defect, bone graft or a bone graft substitute is required to support the reduction. Autologous iliac crest bone graft was long considered the benchmark for this purpose,
although it is associated with significant donor-site pain.16,17 Alternatives such as allograft bone and calcium phosphate cement have largely supplanted autologous bone graft. Recent reports have shown that repairs with calcium phosphate cement have less subsidence and higher fatigue strength than autologous bone graft.18 We typically use crushed cancellous allograft for this purpose because of its availability and ease of use.
although it is associated with significant donor-site pain.16,17 Alternatives such as allograft bone and calcium phosphate cement have largely supplanted autologous bone graft. Recent reports have shown that repairs with calcium phosphate cement have less subsidence and higher fatigue strength than autologous bone graft.18 We typically use crushed cancellous allograft for this purpose because of its availability and ease of use.
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