Operative Techniques in Orthopaedic Surgery (4 Volume Set) 1st Edition

68. Open Reduction and Internal Fixation of the Bicondylar Plateau

Toby M. Risko and William M. Ricci

DEFINITION

images Bicondylar tibial plateau fractures involve both medial and lateral plateaus.

images 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.

images Schatzker type 6 fractures (FIG 1C,D) involve both condyles with complete dissociation of the articular segment from the shaft.

images 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

images In the loaded knee, the medial plateau bears about 60% to 75% of the load.7,8

images The medial plateau is larger than the lateral plateau (FIG 2).

images The medial plateau is concave, the lateral plateau convex.

images Stronger, denser subchondral bone is found on the medial side due to increased load.

images 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

images The proximal posterior tibial angle is 81 degrees relative to anatomic axis of the tibia (range 77 to 84 degrees).6

images The iliotibial band inserts on the tubercle of Gerdy.

images 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.

images 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.

images 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.

images The medial collateral ligament resists valgus force.

images The medial collateral ligament originates on the medial femoral epicondyle and inserts on the medial tibial condyle.

images The lateral collateral ligament resists varus force and external rotation of the femur.

images The lateral collateral ligament originates on the lateral epicondyle of the femur and attaches to the fibular head.

images 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.

images The medial meniscus is more C-shaped and the lateral meniscus is more circular in shape.

images The lateral meniscus is more mobile than the medial meniscus.

PATHOGENESIS

images Bicondylar tibial plateau fractures are typically caused by a high-energy mechanism with associated injury to surrounding soft tissue.

images The mechanism responsible for injury is primarily an axial force, which may be associated with a varus or valgus moment.

images With a valgus force, the lateral femoral condyle is driven wedge-like into the underlying lateral tibial plateau.5

images 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.

images Ligament injuries have been found to occur in 20% to 77% of tibial plateau fractures.3,4

images 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

images Joint incongruity can predispose to arthrosis.

images Inadequate fracture stability can lead to varus–valgus collapse.

images Joint stiffness

images Joint instability can result from associated ligament injury.

PATIENT HISTORY AND PHYSICAL FINDINGS

images 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.

images 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.

images The patient history should include details of the injury mechanism, preinjury ambulatory status, and any previous injury and disability.

images A complete examination is required to rule out other injuries. The vascular status of the limb proximal and distal to the injury requires evaluation.

images If there is an abnormality on palpation pulses, a vascular consult may be needed.

images 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.

images

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.

images

FIG 2 • AP (A) and axial (B) views of the tibia showing the relevant anatomy.

images 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.

images A thorough ligament examination of the knee is needed, although this can be difficult preoperatively owing to difficulty differentiating ligamentous from bony instability.

images Examination of the knee ligaments should therefore take place after operative stabilization and before the patient is awake in the operating room.

images 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

images Anteroposterior (AP) and lateral radiographs of the knee and tibia, and oblique views of the knee (FIG 3AC).

images CT scan with sagittal and coronal reconstruction is helpful to define complex fracture patterns and to plan surgical tactics (FIG 3D,E).

images MRI is useful in evaluating ligament and meniscal injury around the knee.4

DIFFERENTIAL DIAGNOSIS

images Unicondylar tibia fracture

images Patella fracture

images Ligament injury at the knee

images Proximal tibial shaft fracture

images Extensor mechanism disruption

NONOPERATIVE MANAGEMENT

images A fracture brace, a long-leg cast, or both may be used to treat low-energy nondisplaced fractures.

images These require close observation to ensure progressive malalignment (particularly varus) does not occur.

images 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.

images

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

images The surgeon should thoroughly review all preoperative imaging studies.

images A surgical approach is planned that affords adequate exposure for reduction and stabilization of the fracture.

images Single lateral, dual incisions and occasionally a posterior approach are most common.

images Single anterior incisions with stripping should be avoided if medial and lateral exposure is required.

images A tactic for fracture reduction is planned based on preoperative imaging.

images Consideration should be given as to whether a femoral distractor will be useful.

images 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.

images 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.

images 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.

images Implant selection: single lateral locking plate or lateral locking and posteromedial plate.

images The surgeon should consider whether a nonsterile or sterile tourniquet is required.

images 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.

images 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.

images

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

images 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).

images Nonsterile high thigh tourniquet

images C-arm on contralateral side with the monitor near the head of the bed

Approach

images A midline approach with medial and lateral exposure has been associated with high complication rates and should be avoided.

images When medial and lateral exposure is required, an anterolateral exposure with the addition of a posteromedial approach is therefore preferred.

images 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.

images Metaphyseal fracture components are best treated indirectly, especially when comminuted, to maximally preserve biologic potential for healing.

images The medial condyle can be stabilized with lateral locking plates, provided multiple locking screws engage the medial fragment.

images Bicondylar fractures with displaced medial articular involvement require more direct reduction and stabilization, usually via a posteromedial exposure.

images Soft tissue dissection should be limited with a dual incision technique.

images A minority of fractures, those with a bicondylar posterior shearing injury pattern, may benefit from a direct posterior exposure.

TECHNIQUES

POSTEROMEDIAL APPROACH

images The incision is started 1 cm posterior to the posteromedial edge of the tibial metaphysis (TECH FIG 1A).

images The saphenous vein and nerve should be carefully avoided during the superficial dissection.

images Deep dissection continues to expose the pes anserine tendons (TECH FIG 1B), which can be mobilized anteriorly and posteriorly.

images If more proximal extension of the incision is needed, the surgeon can proceed posterior and parallel to the pes anserine tendons.

images The medial gastrocnemius is easily dissected from the posteromedial tibia.

images Subperiosteal dissection should be limited to the fracture margins to aid in confirmation of the reduction.

images The plate should be slightly undercontoured to help buttress the posteromedial fragment (TECH FIG 1C,D).

images

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

images The surgeon identifies and marks landmarks (tubercle of Gerdy, tibial crest, patella, fibular head).

images The lower extremity is exsanguinated and the tourniquet inflated to about 300 mm Hg.

images Tourniquet use is optional.

images 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).

images The skin is incised along the marked incision. The surgeon sharply dissects to fascia without detaching subcutaneous fat from the fascia (TECH FIG 2B).

images The fibers of the iliotibial band are split longitudinally parallel to the skin incision without disrupting the capsule (TECH FIG 2C).

images The iliotibial band is elevated from the tubercle of Gerdy anteriorly and posteriorly.

images If required for lateral articular reduction, a lateral submensical arthrotomy is made by incising the capsule horizontally, including the coronary ligament (TECH FIG 2D).

images The meniscus is elevated and inspected for tears.

images The surgeon directly visualizes intra-articular fracture fragments laterally and obtains reduction.

images The metaphyseal fractures should be indirectly reduced with fluoroscopic guidance.

images Preliminary reduction may be held with Kirschner wire fixation or a large periarticular reduction forcep.

images Simultaneous exposure of the medial side may be required if medial reduction is not obtained by indirect methods.

images

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

images 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).

images 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).

images Locking screws provide superior resistance to medial subsidence and are preferred to nonlocking screws for this application.

images

images

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.

images When compression is required between the medial and lateral fragment, nonlocked lag screws should be used before placing locked screws across the fracture line.

images 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.

images This is most commonly the case with posterior medial fragments that are amenable to separate posteromedial buttress plate fixation.

images Subchondral defects should be grafted with allograft, autograft, or bone substitute.

images 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.

images A tamp is used to impact the graft along the inferior surface of the depressed fragment and elevate the fragment to its proper position.

images Once the articular surface has been reduced and final fixation achieved, then the meniscus may be repaired if needed.

images Most of the meniscal injuries are peripheral rim tears and may be repaired in a horizontal mattress fashion to the capsule.

images Layered closure of the lateral wound is done with a lateral drain.

POSTERIOR APPROACH (POSTERIOR SHEARING FRACTURE)

images 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).

images The surgeon identifies and protects the common peroneal nerve, popliteal artery and vein, tibial nerve, and medial sural cutaneous nerve (TECH FIG 4C).

images Full-thickness fasciocutaneous flaps are raised.

images 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.

images The lateral gastrocnemius is retracted medially (TECH FIG 4D).

images The popliteus and soleus origin are elevated off the posteromedial aspect of the proximal tibia.

images The articular surface is elevated through the fracture site and the reduction assessed with fluoroscopy.

images A 3.5-mm plate is contoured to buttress the fragments. Lag screw technique is used to compress the fragments (TECH FIG 4E,F).

images

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.

images

POSTOPERATIVE CARE

images 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.

images Deep vein thrombosis prophylaxis is considered with lowmolecular-weight heparin, aspirin, or Coumadin and a sequential compression device on the contralateral limb.

images Initial home physical therapy concentrates on restoring range of motion with closed-chain active range-of-motion exercises.

images Toe-touch weight bearing is permitted for 6 to 12 weeks depending on radiographic and clinical healing response.

images Weight bearing is advanced and strengthening exercises are initiated upon fracture healing, usually about 8 to 12 weeks postoperatively.

OUTCOMES

images Satisfactory articular reduction (step-off or gap of 2 mm or less) in 62.1% of cases2

images 91.2% had satisfactory coronal plane alignment

images 72.1% had satisfactory sagittal plane alignment

images 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

images Decreased arc of motion compared to the uninvolved extremity

COMPLICATIONS

images Compartment syndrome

images Infection (7% to 8.4%)1

images Superficial and deep wound complications

images Residual knee joint instability

images Removal of hardware due to local discomfort

images Deep vein thrombosis

images Arthrosis

images 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.



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