Open Reduction and Internal Fixation of Bicondylar Plateau Fractures
DEFINITION
Bicondylar tibial plateau fractures involve both medial and lateral tibia plateaus. Schatzker type V and type VI fractures are both considered bicondylar fractures.
Schatzker type V fractures (FIG 1A,B) involve both condyles without complete dissociation from the shaft and are usually amenable to medial and lateral buttress plate fixation.
Schatzker type VI fractures (FIG 1C,D) involve both condyles with complete dissociation of the articular segment from the shaft. These fractures are typically treated with lateral locked plates or dual (lateral and medial) plating.
Lateral fractures with associated posteromedial fragments should be distinguished from other bicondylar types, as they often require posteromedial fixation independent from lateral fixation and may be representative of fracture-dislocation (see FIG 3).
ANATOMY OF THE PROXIMAL TIBIA
In the loaded knee, the medial plateau bears about 60% to 75% of the load.7, 8
The medial plateau is larger than the lateral plateau.
The medial plateau is concave, the lateral plateau convex.
Stronger, denser subchondral bone is found on the medial side due to increased load.
The lateral plateau is higher than the medial plateau. The medial proximal tibial angle is 87 degrees relative to the anatomic axis of the tibia (range 85 to 90 degrees).6
The proximal posterior tibial angle is 81 degrees relative to anatomic axis of the tibia (range 77 to 84 degrees).6 The iliotibial band inserts on the tubercle of Gerdy (FIG 2).
The anterior cruciate ligament attaches adjacent and medial to the tibial eminence. It acts to resist anterior translation of the tibia relative to the femur. Recognizing a fracture fragment that contains this attachment can be important to reestablish stability to the knee.
The posterior cruciate ligament attaches about 1 cm below the joint line on the posterior ridge of the tibial plateau and a few millimeters lateral to the tibial tubercle.
The function of the posterior cruciate is to resist posterior tibial translation of the tibia relative to the femur. This acts as the central pivot of the knee.
The medial collateral ligament (MCL) originates on the medial femoral epicondyle and inserts on the medial tibial condyle.
The MCL resists valgus force.
The lateral collateral ligament originates on the lateral epicondyle of the femur and attaches to the fibular head.
The lateral collateral ligament resists varus force and external rotation of the femur.
The menisci, medial and lateral, are crescent-shaped fibrocartilaginous structures that act to dissipate the load on the tibial plateau, deepen the articular surfaces of the plateau, and help lubricate and provide nutrition to the knee.
The medial meniscus is more C-shaped and the lateral meniscus is more circular in shape. The lateral meniscus is more mobile than the medial meniscus.
PATHOGENESIS
Bicondylar tibial plateau fractures are typically caused by a high-energy mechanism with associated injury to surrounding soft tissue.
The mechanism responsible for injury is primarily an axial force, which may be associated with a varus or valgus moment.
With a valgus force, the lateral femoral condyle is driven wedge-like into the underlying lateral tibial plateau.5
The size of the fracture fragments depends on multiple factors, including localization of the impact, the magnitude of the axial force producing the fracture, the density of the bone, and the position of the knee joint at the moment of trauma.
Ligament injuries have been found to occur in 20% to 77% of tibial plateau fractures.3, 4
Repair of ligament injuries at the time of fracture fixation is controversial. Some advocate ligamentous repair at the time of fracture fixation, whereas others feel that if the fracture can be reduced, there is no need for early ligamentous repair.
NATURAL HISTORY
Limb malalignment may predispose to adverse outcomes. Joint incongruity can predispose to arthrosis.
Inadequate fracture stability can lead to varus-valgus collapse, usually varus. Joint stiffness is common.
Joint instability can result from associated ligament injury. Acute compartment syndrome is not infrequently associated.
PATIENT HISTORY AND PHYSICAL FINDINGS
Generally, a bicondylar injury pattern is caused by a highenergy mechanism. It may also be seen with a low-energy mechanism, such as a fall from standing height in an older patient with osteoporosis.
The patient will complain of a painful swollen knee and will have difficulty bearing weight on the extremity. Hemarthrosis will be present if the capsule has not been disrupted.
The patient history should include details of the injury mechanism, preinjury ambulatory status, and any previous injury and disability.
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FIG 1 • A,B. AP and lateral views of a Schatzker type V bicondylar tibial plateau fracture. C,D. AP and lateral views of a Schatzker type VI bicondylar tibial plateau fracture.
FIG 2 • AP (A) and axial (B) views of the tibia showing the relevant anatomy.
A complete examination is required to rule out other injuries. The vascular status of the limb proximal and distal to the injury requires evaluation.
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If there is an abnormality on palpation of pulses, a vascular consult may be needed.
The ankle-brachial index of the extremity, along with ultrasound examination of the leg, can be helpful in fully evaluating the possibility of vascular injury, which occurs in about 2% of these fractures.1, 9
The patient is evaluated for compartment syndrome by palpating the lower extremity compartment for swelling and passively extending the muscles in the lower extremity, noting any increase in pain.
The strength of dorsiflexion and eversion will help evaluate the peroneal nerve. It is important to examine and document peroneal nerve function before surgery because of the possibility of injury from stretch or direct impact. Motor and sensory function of the nerve proximal and distal to the injury should be assessed.
A thorough examination of the knee ligaments and extensor mechanism is needed, although this can be difficult preoperatively owing to difficulty differentiating ligamentous from bony instability.
Examination of the knee ligaments and extensor mechanism should therefore take place after operative stabilization and before the patient is awake in the operating room.
FIG 3 • Bicondylar tibial plateau fracture including posteromedial fragment. A. AP view. B. Oblique view. C. Lateral view. D. CT sagittal reconstruction showing posteromedial fragment. E. Axial CT showing lateral and posteromedial fragments.
Soft tissues need careful inspection before definitive surgical intervention can take place. The surgeon should note where surgical incisions will be located when evaluating the soft tissue.
IMAGING AND OTHER DIAGNOSTIC STUDIES
Anteroposterior (AP) and lateral radiographs of the knee and tibia and oblique views of the knee (FIG 3A-C)
Computed tomography (CT) scan with sagittal and coronal reconstruction is helpful to define complex fracture patterns and to plan surgical tactics (FIG 3D,E).
Magnetic resonance imaging (MRI) is useful in evaluating ligament and meniscal injury around the knee.4
DIFFERENTIAL DIAGNOSIS
Multiligament injury at the knee Proximal tibial shaft fracture Unicondylar tibia fracture
Patella fracture
Extensor mechanism disruption
NONOPERATIVE MANAGEMENT
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A fracture brace, a long-leg cast, or both may be used to treat low-energy nondisplaced fractures. Nonoperative management may also be desired if patient factors (eg, comorbidities, functional status) would make operative intervention inappropriate.
These fractures require close observation to ensure progressive malalignment (particularly varus) does not occur.
OPEN REDUCTION AND INTERNAL FIXATION
Preoperative Planning
The patient is examined and imaging studies are reviewed.
The surgeon should consider a staged protocol with provisional spanning external fixation for high-energy bicondylar injuries with significant soft tissue swelling. Open reduction and internal fixation can be performed when swelling has subsided.
A surgical technique (eg, plating, nailing, or external fixation) is chosen.
A backup plan is considered.
A surgical approach is planned that affords adequate exposure for reduction and stabilization of the fracture.
Patient positioning should be planned to ease surgical exposure. It is usually supine, except when a posterior or posteromedial approach is required. If a posterior approach is required, the patient should be positioned prone.
The surgeon should consider whether a nonsterile or sterile tourniquet is required and the prep and draping procedure planned accordingly.
The C-arm location should be identified. It should be placed on the contralateral side of the patient's injured limb when a lateral exposure is planned. If the surgeon will start with the posteromedial exposure, the C-arm is ipsilateral to the injury. The monitor is positioned for comfortable viewing, usually toward the head of the bed.
A tactic for articular and metaphyseal fracture reductions are planned based on preoperative imaging and chosen method of fixation.
Consideration should be given whether a femoral distractor will be useful.
In bicondylar fracture patterns, joint distraction is marginal with use of a femoral distractor as distraction takes place through the fracture rather than across the joint.
The surgeon should decide which part of the bicondylar pattern to stabilize first. By approaching the posteromedial side first and obtaining the reduction on the medial side before approaching the lateral tibial plateau, the surgeon may help prevent stabilizing the knee in varus. If the medial side can be reduced percutaneously and the fracture pattern is amenable to lateral locked plating only, the surgeon may be able to avoid dual incisions. These decisions can be made in preoperative planning.
Required implants are inventoried and their availability confirmed. Additional equipment is identified, listed, and their availability confirmed.
Postoperative immobilization is considered and any supplies required are inventoried and their availability confirmed.
Choosing Approaches for Open Reduction and Internal Fixation
Single lateral, dual (lateral and posteromedial), and single posteromedial approaches are most common.
Single anterior incisions with medial and lateral stripping should be avoided if medial and lateral exposures are required.
A midline approach with medial and lateral exposure has been associated with high complication rates and should be avoided.
When medial and lateral exposure is required, an anterolateral exposure with the addition of a posteromedial approach is therefore preferred.
Metaphyseal fracture components are best treated indirectly, especially when comminuted, to maximally
preserve biologic potential for healing.
Lateral Approach Indications
An anterolateral approach is the standard approach for most lateral tibial bicondylar fractures.
It allows for direct exposure of intra-articular fractures, the lateral meniscus, and for placement of lateral plates.
The medial component of a bicondylar fracture can be stabilized with a lateral exposure and lateral locking plates, provided there is no medial articular incongruity and multiple locking screws engage the medial fragment.
Posteromedial Approach Indications
Isolated medial tibial plateau fractures are approached via a medial approach.
Coronal medial fractures with a posteromedial fragment, with or without associated lateral fractures, are common and are best managed with a posteromedial approach and posteromedial buttress plate.
Posterior Approach Indications
A minority of fractures, those with a posterior lateral shearing injury pattern, may benefit from a direct posterior exposure.
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TECHNIQUES
Techniques for Open Reduction and Internal Fixation of Tibial Plateau Fractures
Open Reduction and Internal Fixation via the Lateral Approach
Lateral Surgical Approach
The surgeon identifies and marks landmarks (tubercle of Gerdy, tibial crest, patella, fibular head).
The skin incision is marked. The incision begins distally about 2 cm lateral to the tibial crest, curving over
the tubercle of Gerdy, then proceeding superiorly over the femoral epicondyle (TECH FIG 1A). Optionally, the lower extremity is exsanguinated and the tourniquet inflated to about 300 mm Hg.
The skin is incised along the marked incision, and dissection is carried to the fascia without detaching subcutaneous fat from the fascia (TECH FIG 1B).
The facia is divided parallel with the skin incision.
Distally, the anterior compartment fascia is divided approximately 1 cm from the tibial crest.
Proximally, the fibers of the iliotibial band are split longitudinally without disrupting the capsule (TECH FIG 1C).
Centrally, the iliotibial band is elevated from the tubercle of Gerdy anteriorly and posteriorly.
TECH FIG 1 • A. Landmarks (patella, tibial tubercle, tubercle of Gerdy, and fibula) for the anterior lateral approach. B. Anterior lateral approach superficial dissection. C. Deep lateral exposure with iliotibial band incised parallel to its fibers centered over tubercle of Gerdy. D. Submeniscal arthrotomy provides direct access to the lateral articular surface.
If required for lateral articular reduction, a lateral submeniscal arthrotomy is made by incising the capsule horizontally (TECH FIG 1D).
The meniscus is elevated, inspected for tears, and repaired as needed.
Most of the meniscal injuries are peripheral rim tears and may be repaired in a horizontal mattress fashion to the capsule.
Reduction via Lateral Approach
Intra-articular fracture fragments are visualized directly (via the submeniscal arthrotomy) and indirectly (with the aid of fluoroscopy) while reduction is obtained.
Articular reduction is obtained with aid of reduction clamps, tamps, and joysticks and are provisionally held
with Kirschner wire fixation and/or a large periarticular reduction forceps. Condylar width is restored with aid of a large periarticular reduction clam
Metaphyseal fracture components should be indirectly reduced with fluoroscopic guidance such that the articular block is aligned relative to the shaft.
Simultaneous exposure of the medial side may be required if medial reduction is not obtained by indirect methods.
Lateral Fixation
A laterally applied plate is useful to support lateral split fragments and to support depressed articular fragments (via the raft effect of multiple proximal screws placed subchondrally).
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TECH FIG 2 • Bicondylar tibial plateau fracture. Preoperative AP (A) and lateral (B) radiographs and CT scan (C). D,E. AP and lateral radiographs after treatment with a single lateral locking plate.
Support of the medial side can be provided via a lateral plate when the medial fragment is of sufficient size and location that multiple screws from the lateral plate engage the medial fragment (TECH FIG 2).
Locking screws provide superior resistance to medial subsidence and are preferred to nonlocking screws for this application.
When compression is required between the medial and lateral fragment, nonlocked lag screws should be used before placing locked screws across the fracture line.
When the medial fragment is of such size and location that multiple locked screws from a lateral plate cannot engage this fragment, separate medial fixation is required.
This is most commonly the case with posteromedial fragments that are amenable to separate posteromedial buttress plate fixation.
Management of Lateral Subchondral Defects
Subchondral defects should be grafted with allograft, autograft, or bone substitute.
It may be helpful in some cases to use allograft bone croutons to help reduce depressed fracture fragments by impacting the graft through a cortical window inferior to the articular surface.
A tamp is used to impact the graft along the inferior surface of the depressed fragment and elevate the fragment to its proper position.
Lateral Closure
Layered closure of the lateral wound is done with a deep drain that can decompress the knee joint.
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Open Reduction and Internal Fixation via the Posteromedial Approach
Surgical Approach
The patient is positioned supine on a radiolucent or fracture table, with a bump under the contralateral hip considered.
Nonsterile high thigh tourniquet
C-arm on ipsilateral to side of injury with the monitor near the head of the bed
The incision is started 1 cm posterior to the posteromedial edge of the tibial metaphysis (TECH FIG 3A).
The saphenous vein and nerve should be carefully avoided during the superficial dissection. Deep dissection continues to expose the pes anserine tendons (TECH FIG 3B).
Dissection and mobilization of the tendons allow access to the fracture above, below, or between the tendons.
TECH FIG 3 • A. Skin incision for posteromedial approach to tibial plateau. B. Deep dissection for the posteromedial approach includes exposure of the pes anserine tendons, which are preserved. AP (C) and lateral (D) postoperative radiographs showing lateral plus posteromedial plate fixation of a bicondylar tibial plateau fracture.
The medial gastrocnemius is easily dissected from the posteromedial tibia.
Subperiosteal dissection should be limited to the fracture margins to aid in confirmation of the reduction. The fracture margins are exposed posterior and/or anterior to the MCL. The MCL is left intact.
Reduction
Fracture reduction is accomplished with a combination of traction, valgus stress, and appropriately positioned reduction clamps.
The weight of the leg often contributes to varus deformity and should be neutralized with valgus counterforce either manually or via a medial femoral distractor.
Articular fracture reduction is typically judged indirectly via cortical reduction and fluoroscopy. A submeniscal arthrotomy performed anterior to the MCL can provide a view of the anterior portion of the
medial plateau.
Fixation
Medial fixation depends on the fracture pattern.
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For the common coronal posteromedial fragment, a posteromedial plate that is slightly undercontoured to help buttress the fragment is used (TECH FIG 3C,D).
The plate location for isolated medial fractures that are complete may be either posteromedial or anteromedial. Some surgeons advocate direct medial plating over the MCL.
Medial plating is generally posteromedial when adjunctive to lateral plating in the case of comminuted bicondylar fractures.
Open Reduction and Internal Fixation via the Posterior Approach (Posterior Shearing Fracture)
Surgical Approach
The patient is positioned prone with a high thigh tourniquet.
An S-shaped incision starts midline superiorly and extends medial distally. The incision is centered on the popliteal fossa, with the transverse component made at the joint line (TECH FIG 4A-C).
TECH FIG 4 • A,B. Axial and sagittal CT scans demonstrating posterior shearing injury. C. Posterior S-shaped incision starting midline superiorly, transverse at the joint line, and extending to the medial side in the distal aspect of the incision. D. The lateral gastrocnemius is released after identification of
neurovascular structures and elevated medially. E,F. Postoperative AP and lateral radiographs demonstrating posterior plating.
The surgeon identifies and protects the common peroneal nerve, popliteal artery and vein, tibial nerve, and medial sural cutaneous nerve (TECH FIG 4C).
The lateral head of the gastrocnemius is dissected bluntly and its blood supply protected distally. The tendon is divided proximally, leaving a stump for repair.
The lateral gastrocnemius is retracted medially (TECH FIG 4D).
The popliteus and soleus origin are elevated off the posteromedial aspect of the proximal tibia.
Reduction
The articular surface is elevated through the fracture site and the reduction assessed indirectly with fluoroscopy and by the cortical reduction. Direct visualization of the articular surface is difficult.
Fixation
A relatively thin plate is contoured to buttress the fragments. Lag screw technique is used to compress the fragments (TECH FIG 4E,F).
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PEARLS AND PITFALLS
Do not rely on a lateral locked plate to prevent
varus collapse of bicondylar fractures with posteromedial articular components.
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A laterally applied plate is useful to support
lateral split fragments (via buttress effect) and to support depressed articular fragments (via a raft effect of multiple proximal screws placed subchondrally).
Posteromedial intra-articular tibial fragments
need buttress plates to prevent varus collapse even with newer locking plate technology.
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Support of the medial side can be provided via a
lateral plate when the medial fragment is of such a size and location that multiple screws from the lateral plate engage the medial fragment. Locking screws provide superior resistance to medial subsidence and are preferred to nonlocking screws for this application.
When the medial fragment is of such size and
location that multiple locked screws from a lateral plate cannot engage this fragment, separate medial fixation is required. This is most commonly the case with posteromedial fragments that are amenable to separate posteromedial buttress plate fixation.
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When compression is required between the
medial and lateral fragments, nonlocked screws should be used before placing locked screws across the fracture site.
Failure to recognize meniscal injury and repair
POSTOPERATIVE CARE
A drain to decompress any hemarthrosis facilitates obtaining early range of motion.
Use of a continuous passive motion (CPM) device should be considered immediately after surgery starting at about 0 to 40 degrees. Flexion is advanced 5 to 10 degrees during each of three 2-hour sessions per day, with the goal being 0 to 90 degrees within 24 hours.
Deep vein thrombosis prophylaxis is considered with lowmolecular-weight heparin, aspirin, or Coumadin; a sequential compression device is applied.
Initial physical therapy concentrates on restoring range of motion with closed-chain active range-of-motion exercises.
Toe-touch weight bearing is permitted immediately.
Weight bearing is advanced and strengthening exercises are initiated upon evidence of fracture healing, usually about 8 to 12 weeks postoperatively.
OUTCOMES
Satisfactory articular reduction (step-off or gap of 2 mm or less) is obtained in 62.1% of cases.2 There were 91.2% who had satisfactory coronal plane alignment.
Also, 72.1% had satisfactory sagittal plane alignment.
According to Barei et al,2 bicondylar tibial plateau fractures have a significant negative effect on leisure activities, employment, and general mobilization. Significant residual dysfunction was observed out to 51
months postoperatively when compared with the general population.2 Decreased arc of motion compared to the uninvolved extremity is common.
COMPLICATIONS
Compartment syndrome Infection (7% to 8.4%)1
Superficial and deep wound complications
Residual knee joint instability
Removal of hardware due to local discomfort Deep vein thrombosis
Arthrosis
Loss of motion
REFERENCES
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Barei DP, Nork SE, Mills WJ, et al. Complications associated with internal fixation of high energy bicondylar plateau fractures utilizing a two-incision technique. J Orthop Trauma 2004;18:649-657.
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Barei DP, Nork SE, Mills W, et al. Functional outcomes of severe bicondylar fractures treated with dual
incisions and medial and lateral plates. J Bone Joint Surg Am 2006;88A:1713-1721.
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Delamarter RB, Hohl M, Hopp E. Ligament injuries associated with tibial plateau fractures. Clin Orthop Relat Res 1990;250:226-233.
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Gardner MJ, Yacoubian S, Geller D, et al. The incidence of soft tissue injury in operative tibial plateau fractures: a magnetic resonance imaging analysis of 103 patients. J Orthop Trauma 2005;19:79-84.
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Hsu R, Himeno S, Coventry M, et al. Normal axial alignment of the lower extremity and load-bearing distribution at the knee. Clin Orthop Relat Res 1990;255:215-227.
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Kennedy J, Bailey W. Experimental tibial-plateau fractures. J Bone Joint Surg Am 1968;50A:1522-1534.
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Lachiewicz PF, Funcik T. Factors influencing the results of open reduction and internal fixation of tibial plateau fractures. Clin Orthop Relat Res 1990;259:210-215.
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Morrison JB. The mechanics of the knee joint in relation to normal walking. J Biomech 1970;3:51-66.
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Ottolenghi C. Vascular complications in injuries about the knee joint. Clin Orthop Relat Res 1982;165:148-156.