Toby M. Risko and William M. Ricci
DEFINITION
Bicondylar tibial plateau fractures involve both medial and lateral plateaus.
Schatzker type 5 fractures (FIG 1A,B) involve both condyles without complete dissociation from the shaft. Thus, a portion of the joint is still attached to the shaft. They are usually amenable to medial and lateral buttress plate fixation.
Schatzker type 6 fractures (FIG 1C,D) involve both condyles with complete dissociation of the articular segment from the shaft.
Lateral fractures with associated posterior medial 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
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 (FIG 2).
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.
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 re-establish 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 resists valgus force.
The medial collateral ligament originates on the medial femoral epicondyle and inserts on the medial tibial condyle.
The lateral collateral ligament resists varus force and external rotation of the femur.
The lateral collateral ligament originates on the lateral epicondyle of the femur and attaches to the fibular head.
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, while others feel that if the fracture can be reduced there is no need for early ligamentous repair.
NATURAL HISTORY
Joint incongruity can predispose to arthrosis.
Inadequate fracture stability can lead to varus–valgus collapse.
Joint stiffness
Joint instability can result from associated ligament injury.
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 or 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.
A complete examination is required to rule out other injuries. The vascular status of the limb proximal and distal to the injury requires evaluation.
If there is an abnormality on palpation 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.1,9The 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.
FIG 1 • A,B. AP and lateral views of a Schatzker type 5 bicondylar tibial plateau fracture. C,D. AP and lateral views of a Schatzker type 6 bicondylar tibial plateau fracture.
FIG 2 • AP (A) and axial (B) views of the tibia showing the relevant anatomy.
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 a stretch injury. Motor and sensory function of the nerve proximal and distal to the injury should be assessed.
A thorough ligament examination of the knee is needed, although this can be difficult preoperatively owing to difficulty differentiating ligamentous from bony instability.
Examination of the knee ligaments should therefore take place after operative stabilization and before the patient is awake in the operating room.
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).
CT scan with sagittal and coronal reconstruction is helpful to define complex fracture patterns and to plan surgical tactics (FIG 3D,E).
MRI is useful in evaluating ligament and meniscal injury around the knee.4
DIFFERENTIAL DIAGNOSIS
Unicondylar tibia fracture
Patella fracture
Ligament injury at the knee
Proximal tibial shaft fracture
Extensor mechanism disruption
NONOPERATIVE MANAGEMENT
A fracture brace, a long-leg cast, or both may be used to treat low-energy nondisplaced fractures.
These require close observation to ensure progressive malalignment (particularly varus) does not occur.
A long-leg cast, a fracture brace, or both can be used in treating low-energy, minimally displaced fracture patterns. It may also be used if patient factors (eg, comorbidities, functional status) would make operative intervention inappropriate.
FIG 3 • Bicondylar tibial plateau fracture including posterior medial fragment. A. AP view. B. Oblique view. C. Lateral view. D. CT sagittal reconstruction showing posterior medial fragment. E. Axial CT showing lateral and posterior medial fragments.
SURGICAL MANAGEMENT
Preoperative Planning
The surgeon should thoroughly review all preoperative imaging studies.
A surgical approach is planned that affords adequate exposure for reduction and stabilization of the fracture.
Single lateral, dual incisions and occasionally a posterior approach are most common.
Single anterior incisions with stripping should be avoided if medial and lateral exposure is required.
A tactic for fracture reduction is planned based on preoperative imaging.
Consideration should be given as to 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.
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.
Implant selection: single lateral locking plate or lateral locking and posteromedial plate.
The surgeon should consider whether a nonsterile or sterile tourniquet is required.
Imaging: The C-arm should be placed on the contralateral side of the patient for the lateral exposure. If the surgeon will start with the posteromedial exposure, the C-arm is on the ipsilateral side of the patient. The monitor is positioned for comfortable viewing, usually toward the head of the bed.
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 done when swelling has subsided.
FIG 4 • Supine positioning for fixation of bicondylar tibial plateau fractures should provide for unhindered AP and lateral fluoroscopic radiographs and both medial and lateral approaches.
Positioning
The patient is placed supine with the contralateral limb secured to a radiolucent or fracture table, with a bump under the ipsilateral hip (removed for medial approach) (FIG 4).
Nonsterile high thigh tourniquet
C-arm on contralateral side with the monitor near the head of the bed
Approach
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.
An anterolateral approach is the standard approach for most tibial bicondylar fractures. It allows for direct exposure of lateral meniscus and intra-articular fractures and for placement of lateral plates.
Metaphyseal fracture components are best treated indirectly, especially when comminuted, to maximally preserve biologic potential for healing.
The medial condyle can be stabilized with lateral locking plates, provided multiple locking screws engage the medial fragment.
Bicondylar fractures with displaced medial articular involvement require more direct reduction and stabilization, usually via a posteromedial exposure.
Soft tissue dissection should be limited with a dual incision technique.
A minority of fractures, those with a bicondylar posterior shearing injury pattern, may benefit from a direct posterior exposure.
TECHNIQUES
POSTEROMEDIAL APPROACH
The incision is started 1 cm posterior to the posteromedial edge of the tibial metaphysis (TECH FIG 1A).
The saphenous vein and nerve should be carefully avoided during the superficial dissection.
Deep dissection continues to expose the pes anserine tendons (TECH FIG 1B), which can be mobilized anteriorly and posteriorly.
If more proximal extension of the incision is needed, the surgeon can proceed posterior and parallel to the pes anserine tendons.
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 plate should be slightly undercontoured to help buttress the posteromedial fragment (TECH FIG 1C,D).
TECH FIG 1 • A. Skin incision for posterior medial approach to tibial plateau. B. Deep dissection for the posterior medial 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.
LATERAL EXPOSURE
The surgeon identifies and marks landmarks (tubercle of Gerdy, tibial crest, patella, fibular head).
The lower extremity is exsanguinated and the tourniquet inflated to about 300 mm Hg.
Tourniquet use is optional.
The skin incision is marked. The incision should begin distally about 2 cm lateral to the tibial crest, curving over the tubercle of Gerdy, then proceeding superiorly over the femoral epicondyle (TECH FIG 2A).
The skin is incised along the marked incision. The surgeon sharply dissects to fascia without detaching subcutaneous fat from the fascia (TECH FIG 2B).
The fibers of the iliotibial band are split longitudinally parallel to the skin incision without disrupting the capsule (TECH FIG 2C).
The iliotibial band is elevated from the tubercle of Gerdy anteriorly and posteriorly.
If required for lateral articular reduction, a lateral submensical arthrotomy is made by incising the capsule horizontally, including the coronary ligament (TECH FIG 2D).
The meniscus is elevated and inspected for tears.
The surgeon directly visualizes intra-articular fracture fragments laterally and obtains reduction.
The metaphyseal fractures should be indirectly reduced with fluoroscopic guidance.
Preliminary reduction may be held with Kirschner wire fixation or a large periarticular reduction forcep.
Simultaneous exposure of the medial side may be required if medial reduction is not obtained by indirect methods.
TECH FIG 2 • 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.Submensical arthrotomy provides direct access to the lateral articular surface.
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).
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 3).
Locking screws provide superior resistance to medial subsidence and are preferred to nonlocking screws for this application.
TECH FIG 3 • 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.
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 posterior medial fragments that are amenable to separate posteromedial buttress plate fixation.
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.
Once the articular surface has been reduced and final fixation achieved, then the meniscus may be repaired if needed.
Most of the meniscal injuries are peripheral rim tears and may be repaired in a horizontal mattress fashion to the capsule.
Layered closure of the lateral wound is done with a lateral drain.
POSTERIOR APPROACH (POSTERIOR SHEARING FRACTURE)
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,B).
The surgeon identifies and protects the common peroneal nerve, popliteal artery and vein, tibial nerve, and medial sural cutaneous nerve (TECH FIG 4C).
Full-thickness fasciocutaneous flaps are raised.
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.
The articular surface is elevated through the fracture site and the reduction assessed with fluoroscopy.
A 3.5-mm plate is contoured to buttress the fragments. Lag screw technique is used to compress the fragments (TECH FIG 4E,F).
TECH FIG 4 • A,B. Axial and sagittal CTs 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.
POSTOPERATIVE CARE
Use of a continuous passive motion (CPM) device should be started immediately after surgery 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 before hospital discharge.
Deep vein thrombosis prophylaxis is considered with lowmolecular-weight heparin, aspirin, or Coumadin and a sequential compression device on the contralateral limb.
Initial home physical therapy concentrates on restoring range of motion with closed-chain active range-of-motion exercises.
Toe-touch weight bearing is permitted for 6 to 12 weeks depending on radiographic and clinical healing response.
Weight bearing is advanced and strengthening exercises are initiated upon fracture healing, usually about 8 to 12 weeks postoperatively.
OUTCOMES
Satisfactory articular reduction (step-off or gap of 2 mm or less) in 62.1% of cases2
91.2% had satisfactory coronal plane alignment
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
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
1. 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.
2. 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.
3. Delamarter RB, Hohl M, Hopp E. Ligament injuries associated with tibial plateau fractures. Clin Orthop Relat Res 1990;250:226–233.
4. 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.
5. 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.
6. Kennedy J, Bailey W. Experimental tibial-plateau fractures. J Bone Joint Surg Am 1968;50A:1522–1534.
7. 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.
8. Morrison JB. The mechanics of the knee joint in relation to normal walking. J Biomech 1970;3:51–66.
9. Ottolenghi C. Vascular complications in injuries about the knee joint. Clin Orthop Relat Res 1982;165:148–156.
10. Paley D. Principles of Deformity Correction. Berlin: Springer-Verlag, 2002.
11. Rasmussen P. Tibial condyle fractures. J Bone Joint Surg Am 1973; 55A:1331–1349.