Surgical techniques 2022, Dec, 21 | 12:00 am

Lateral Tibial Plateau Fractures

 

 

 

DEFINITION

  • Tibial plateau fractures are intra-articular fractures that may result in a malalignment of the articular surface and bear the risk of subsequent arthritis.

    ANATOMY

  • The tibial plateau consists of three osseous structures: the lateral plateau, the medial plateau, and the intercondylar eminence.

    • The lateral plateau is smaller and convex, whereas the medial plateau is larger and slightly concave. Both plateaus are covered by a meniscus, which serves as a shock absorber and improves the congruency of the femorotibial joint.

    • The lateral plateau sits slightly higher than the medial joint surface, forming an angle of 3 degrees of varus with respect of the tibial shaft. This is helpful in identifying the lateral plateau on the lateral radiograph.

    • The anatomy of the tibial plateau leads to an eccentric load distribution in which the lateral plateau bears 40% of the knee’s load.1 This asymmetric weight bearing results in increased medial subchondral bone formation and a stronger, denser medial plateau.

    • The intermediate, nonarticular intercondylar eminence serves as the tibial attachment of the anterior and posterior cruciate ligaments.

    • The stability of the knee joint is based on the cruciate ligaments, the collateral ligaments, and the capsule.

  • The tibial tuberosity and the tubercle of Gerdy are bony prominences located in the subcondylar region for insertion of the patellar tendon and the iliotibial tract, respectively. These landmarks are important for planning surgical incisions.

    PATHOGENESIS

  • Several anatomic factors have been thought to contribute to the higher incidence of lateral as opposed to medial plateau fractures.

    • The relative softness of the subchondral bone of the lateral plateau, the valgus axis of the lower extremity, and the susceptibility of the leg to a medially directed force all lead to a prevalence of lateral plateau fractures in low-energy injuries.1

  • Tibial plateau fractures are due to either direct trauma to the proximal tibia and knee joint or to indirect axial forces.

    • The most frequent mechanism causing a lateral plateau fracture is a direct trauma to the proximal tibia and knee joint. This induces a valgus force and drives the lateral femoral condyle into the soft lateral tibial plateau.

    • Indirect axial forces often develop in high-energy injuries and may be associated with complex tibial plateau fractures.

    • Twisting injuries account for only 5% to 10% of tibial plateau fractures and are most commonly sports injuries (eg, skiing).

 

622

  • Split or wedge fractures occur in younger patients, whereas depression fractures occur more frequently in older patients with osteoporotic bone, which is less able to withstand compression.

    NATURAL HISTORY

  • The natural history of lateral tibial plateau fractures depends on the degree of articular depression and knee stability.8 Knee instability may result from the fracture itself but may also result from accompanying injuries like meniscal injuries or rupture of cruciate or collateral ligaments.

  • For nondisplaced or minimally displaced fractures, the prognosis is favorable,3,5,6,17,19,22 but displaced fractures, especially in combination with knee instability, tend to result in early posttraumatic arthritis.

  • Meniscal injuries have been reported in up to 50% of tibial plateau fractures. Meniscal injuries are a major determinant of prognosis because meniscal integrity is important for joint stability and may compensate for articular incongruity.

     

    PATIENT HISTORY AND PHYSICAL FINDINGS

  • The physical examination should always include a thorough assessment of the soft tissue envelope.

  • The marginal soft tissue envelope of the proximal tibia predisposes to open fractures and development of tissue necrosis. It is important to assess severe soft tissue injury because it may not allow primary plating of the fracture, requiring external fixation.

  • A compartment syndrome may result from continuous hemorrhage through the metaphysis into the area of the tibial shaft.

  • Clinical findings indicating a manifest compartment syndrome include pain, paresthesia, paresis, pain with stretch, intact pulses, and pink skin coloring.

    • Such findings require immediate fasciotomy.

  • An imminent compartment syndrome requires repeated or continuous compartment pressure monitoring.

    • A pressure difference between the diastolic pressure and the compartment pressure of less than 30 mm Hg is considered to be a manifest compartment syndrome,15 which requires fasciotomy.

  • The neurovascular status of the extremity must be carefully evaluated, although concomitant injuries of neurovascular structures are rare in proximal tibia fractures.

    • Palpation of peripheral pulses

    • Doppler ultrasound

    • An ankle-brachial index less than 0.9 indicates that vascular injury is very likely.

    • Impaired sensorimotor status may indicate compartment syndrome; impaired dorsal flexion may indicate direct per-oneal nerve injury.

  • Examination of knee stability is difficult because of pain, so it should be tested under anesthesia. Assessment of knee stability may be difficult on initial examination because of

     

     

     

    intracapsular hematoma and pain. Varus and valgus stress radiographs of the knee in near-full extension can be performed with sedation or under general anesthesia. Widening of the femoral–tibial articulation of more than 10 degrees indicates ligamentous insufficiency.

     

    IMAGING AND OTHER DIAGNOSTIC STUDIES

    • Plain anteroposterior (AP) and lateral radiographs should be centered on the knee, with the AP view angled 10 degrees in a craniocaudal direction to approximate the posterior slope of the plateau.

    • The standard tool in analyzing tibial plateau fractures is the three-dimensional CT scan, because the number and degree of isolated fractures are often underestimated on plain radiographs.13

    • Although MRI evaluates both osseous and soft tissue injuries, it has not yet become a standard tool in analyzing tibial plateau fractures. It may be helpful in identifying meniscal and ligamentous injuries.

    • In selected cases (eg, no CT diagnostics available), stress radiographs may be helpful in making decisions about surgical management.

      DIFFERENTIAL DIAGNOSIS

    • Ligamentous injuries of the knee

    • Knee dislocation

    • Meniscal injury

    • Bone bruise

    • Compartment syndrome

      NONOPERATIVE MANAGEMENT

    • For nondisplaced or minimally displaced fractures, the indications for surgical treatment are controversial and vary widely in the literature. The range of acceptance for articular depression varies from 2 mm to 1 cm.3,5,6,17,19,22

    • Nondisplaced or minimally displaced tibial plateau fractures with stability of the knee joint can be managed nonopera-tively, provided that the patient is compliant.

    • Partial weight bearing in a hinged fracture brace for 8 to 12 weeks with regular radiographic controls is recommended.

    • Isometric quadriceps exercises and progressive passive, active-assisted, and active range-of-knee motion exercises are recommended to avoid substantial muscle atrophy.

    • Failure to maintain reduction with nonoperative management is an indication for surgical fracture stabilization. Therefore, frequent surveillance radiographs are required for the management of these patients.

      SURGICAL MANAGEMENT

    • The primary management of tibial plateau fractures is usually dictated by the soft tissue injury and by the fracture type.

    • Absolute indications for surgery are displaced fractures, open fractures, fractures with vascular or neurologic lesions, fractures with compartment syndrome, and fractures with valgus instability.

    • The goals in the surgical treatment of tibial plateau fractures are restoration of articular surface, axis, meniscal integrity, and stability to avoid or postpone posttraumatic arthritis. Fracture stability allows early rehabilitation and supports long-term full recovery.

  • The degree of soft tissue injury and the general condition of the patient are important factors in surgical decision making.

    • If there is severe soft tissue damage, an open fracture, or a polytraumatized patient, a temporary external fixator is applied. Definitive fracture stabilization with open reduction and internal fixation is delayed until soft tissue damage or the patient’s critical condition has been resolved.

      Preoperative Planning

  • Review of radiographs, CT, MRI

  • Surgical approach and placement of implants

    • Depression fractures with continuity of the lateral cortex require only screw osteosynthesis.

    • Whether a cortical window is required depends on the degree and location of impaction. Condylar widening is a good radiologic sign for the requirement of articular elevation with a pestle via a cortical window.

    • Meniscal and ligamentous injuries require open joint or arthroscopic surgery.

  • The surgeon should consider the need of bone grafting (iliac crest bone graft, bone graft substitute) when severe depression of the plateau is obvious.

  • For surgical decision making, a separate classification of the fracture and degree of soft tissue injury is important.

    • Open fractures are classified according to Gustilo et al.4

    • The soft tissue injury is classified according to Tscherne and Oestern.21

  • The AO/OTA classification for proximal tibial fractures distinguishes between extra-articular, partial-articular, and complete-articular fractures, and further subdivides based on the level of comminution (Table 1).

  • Schatzker’s classification distinguishes between lateral and medial plateau fractures (Table 2).

    • In general, types I through III are low-energy injuries affecting the lateral plateau.

    • Types IV through VI involve increasingly higher-energy injuries mostly affecting the medial plateau in combination with ligamentous injuries.19

      Positioning

  • Supine position

  • Bolster under knee to improve internal rotation: the knee should be slightly bent (about 30 degrees) to reduce tension of collateral ligaments (FIG 1)

     

     

    Classification Description

    AO-41-A Extra-articular fractures

    AO-41-B Partial intra-articular fractures

    B1 Split fracture of the lateral plateau

    B2 Depression fracture of the lateral plateau

    B3 Split-depression fracture of the lateral plateau

    AO-41-C Complete articular fractures

    C1 Simple bicondylar fracture with simple metaphyseal fracture

    C2 Simple bicondylar fracture with comminuted metaphyseal fracture

    C3 Comminuted articular and metaphyseal fracture

    AO Classification for Proximal Tibial Fractures

    Table 1

     

     

     

    Type Description

    1. Split fracture of the lateral tibial plateau

    2. Split-depression fracture of the lateral tibial plateau

    3. Pure central depression fracture of the lateral tibial plateau

    4. Split (type A) or depression (type B) fracture of the medial plateau

    5. Bicondylar tibial plateau fracture

    6. Comminuted tibial plateau fracture with dissociation between the metaphysis and the diaphysis

    Schatzker’s Classification

    Table 2

     

     

    • Tourniquet to minimize blood loss and to improve fracture visualization

    • Radiolucent operating table to allow intraoperative use of fluoroscopy and image intensification

    • Contralateral leg placed in leg carrier

    • Ipsilateral iliac crest is prepared and draped if bone graft is needed.

      Approach

    • The surgical approach for lateral tibial plateau fractures demands good visualization of the lateral plateau, combined

      with preservation of all anatomic structures and minimal soft tissue and osseous devitalization. It can be summarized as:

      • Elevation of the meniscus

      • Reduction of the fracture

      • Temporary retention with Kirschner wire or small fragment lag screw

      • Final stabilization with lag screws, conventional plate, or angular stable plate

  • The incision must be planned to avoid implant location directly underneath the skin incision. Important landmarks are the joint line, the tubercle of Gerdy, the tibial tubercle, the fibula head, and the lateral femoral epicondyle (FIG 2).

  • The standard approach for lateral tibial plateau fractures is the anterolateral approach, which provides excellent exposure of the lateral plateau and allows good soft tissue coverage of the implant, especially after minimally invasive plate application.

  • The posterolateral approach is indicated for fractures of the lateral posterior plateau.

     

     

     

     

     

     

    FIG 1 • Leg position to reduce collateral ligament tension. FIG 2 • Landmarks for skin incision.

     

     

    TECHNIQUES

     

    ANTEROLATERAL APPROACH

    • A straight or a hockey-stick incision (about 10 cm) with the knee in 30 degrees of flexion is made.

    • The incision is extended down through the iliotibial band proximally and the fascia of the anterior compartment distally.

       

  • The tibialis anterior muscle is elevated off the proximal tibia to the level of the capsule and the coronary ligament is incised (TECH FIG 1).

  • To expose the lateral tibial plateau, the lateral meniscus is raised with holding sutures after incision of the coronary ligament.

    Iliotibial band

    Tibia

    Released

    extensor muscles

    Capsule of

    tibiofibular joint

     

     

  • The size of the fragment is crucial for the decision of whether soft tissue is stripped off. For small fragments not allowing compression, stripping the displaced fragment for buttress plating is indicated.

     

    TECH FIG 1 • Anterolateral approach.

     

    POSTEROLATERAL APPROACH

     

    Tibia

     

    Fibula

     

    Collateral ligament

    Attachment of

    biceps femoris m. TECH FIG 2 • Posterolateral approach.

    TECHNIQUES

    REDUCTION

    ful tool.

     

    A
    B
    C

     

    TECH FIG 3 • A. Temporary retention of fracture reduction with Kirschner wire. B. Alignment of angular stable plate.

    C. Final stabilization with angular stable plate.

    REDUCTION OF IMPACTED SEGMENTS

    the pestle (eg, with a hammer) under fluoroscopy until

    • A longitudinal incision is made along the proximal fibula ■ After exposure of the peroneus nerve, osteotomy of (TECH FIG 2). fibula head is performed.

    • The extensor muscles are mobilized from the tibial ■ At the end of surgery the fibular head is refixated by plateau. tension band wiring or screw fixation.

    • Careful treatment of soft tissue and periosteum is ■ Displaced fragments are reduced with reduction tools. mandatory. ■ Reduction is temporarily maintained with Kirschner

    • Reduction is aided by ligamentotaxis and careful manip- wires or lag screws (TECH FIG 3). ulation. An external fixator or a distractor may be a help-

    • Impression fractures need to be elevated with a pestle, the contour of the articular surface is re-established. which may be inserted through a distal tibial bone ■ In cases of severe bone loss, the defect must be filled window (TECH FIG 4). with bone graft or bone substitute.

    • Elevation is achieved by carefully exerting punches on

     

     

     

    TECHNIQUES

     

    TECH FIG 4 • Use of bone window to reduce articular impaction.

    MENISCAL REPAIR

    OSTEOSYNTHESIS

    Implants Pure Split Fractures of the Lateral

    plates, or, most recently, angular stable plates. ■ For fixation, two large partially threaded cancellous

    position is usually sufficient.

     

    Locking Plates

    quent better blood supply to the fracture area, is TECH FIG 5 • Stabilization of B1 or Schatzker I fracture with achieved. two lag screws and two-hole plate in antiglide position.

    • Meniscal integrity is important for stability and to avoid ■ Peripheral longitudinal lesions of the posterior meniscus posttraumatic arthritis. are fixated using the “all-inside” technique to avoid in-

    • Peripheral longitudinal lesions of the anterior and inter- jury to the neurovascular structures in the popliteal area. mediate part of the meniscus are fixated using the ■ Complex meniscal lesions in the avascular area require “outside-in suture” technique. resection.

    • Implants may include cancellous screws, conventional Plateau (AO-41-B1 or Schatzker I)

    • If the lateral metaphyseal shell is intact, a lag screw with a bone screws with washers can be used (TECH FIG 5). washer or a three-hole conventional plate in the antiglide

    • Multifragmentary fractures or fractures with severe bone loss usually require plate osteosynthesis.

    • Preformed locking or nonlocking plates allow an exact alignment and retention of the fracture.

    • A minimally invasive technique by sliding the plate with the aiming device underneath the muscle may be selected. The screws can be applied by stitch incisions.

    • In multifragmentary fractures or fractures with severe bone loss, an evidence-based advantage of locking plates versus nonlocking plates has not been reported in the literature.

    • However, locking plates in these types of plateau fractures are advisable for the following reasons:

      • Angular stable plates require less bone graft compared to conventional plates in fractures with severe bone loss.

      • The stability of angular stable plates does not depend on friction between the plate and the bone, so less compression of the periosteum, with conse-

     

     

     

     

     

     

    • In osteopenic patients a third cancellous bone screw with washer is recommended in an antiglide position; a lateral buttress plate is used in case of fragmentation.

      Pure Depression Fractures of the Lateral Plateau (AO-41-B2 or Schatzker III)

    • The depression is elevated through a cortical window and stabilized with two subchondral cancellous bone screws. In cases of severe bone loss, bone graft or bone graft substitute may also be needed for stabilization.

       

       

    • In osteopenic patients, a third cancellous bone screw with washer is recommended in an antiglide position,

 

TECH FIG 6 • Stabilization of B2 or Schatzker III fracture with lag screws and washers. (From Scheerlinck T, Ng CS, Handelberg F, et al. Medium-term results of percutaneous, arthroscopically-assisted osteosynthesis of fractures of the tibial plateau. J Bone Joint Surg Br 1998;80:959–964.)

whereas in case of fragmentation a lateral buttress plate is used (TECH FIG 6).

TECHNIQUES

 

Split-Depression Fracture of the Lateral Plateau (AO-41-B3 or Schatzker II)

  • The depression is elevated by working through the split component and deposition of bone graft (TECH FIG 7).

  • Three position screws are placed subchondrally to support the impacted joint surface (rafting) and a locking plate or buttress plate is applied.

     

     

     

    TECH FIG 7 • Stabilization of B3 or Schatzker II fracture with buttress plate.

     

    PEARLS AND PITFALLS

    Meniscal repair ■ Meniscal repair is crucial to reduce the incidence of degenerative changes after tibial plateau fractures.

    Even a failed meniscal repair that requires subsequent meniscotomy can be briefly protective to the underlying cartilage.19

    Articular depression ■ Articular depression is a major determinant of posttraumatic arthritis. After surgical management, no articular depression should be obvious. However, secondary articular depression may occur due to loss of fixation. To prevent secondary articular depression, sufficient bone graft or bone graft substitute

    should be used to stabilize tibial plateau depression fractures. However, tibial plateau depression fractures with a poor radiographic reconstruction may still be associated with a good functional outcome

    if meniscal integrity is preserved.

    • Excessive soft tissue stripping may increase the risk for infection and nonunion. Therefore, minimally invasive techniques with the least possible soft tissue stripping and soft tissue irritation should be used.

    Bone grafting ■ Iliac crest bone grafting is the treatment of choice to maintain the reduction of depressed tibial plateau fragments. Bone substitutes such as coralline hydroxyapatite and calcium-phosphate cements have also been successfully used.

    Soft tissue assessment ■ Soft tissue assessment is an easy but pivotal step in the management of tibial plateau fractures. An excellent reduction and fixation may be compromised by infection secondary to inadequate assessment of the surrounding soft tissue status. Fractures with severe soft tissue impairment benefit from external stabilization and secondary open reduction and internal fixation.

     

     

    POSTOPERATIVE CARE

    • Rehabilitation must be planned individually and depends on patient age, bone quality, type of osteosynthesis, and concomitant injury.

    • Ninety degrees of flexion should be achieved by 7 to 10 days.

    • Toe-touch weight bearing is recommended for 4 to 8 weeks, with progression thereafter according to radiographic findings.

    • Impression fractures of the lateral plateau managed with a minimally invasive angular plate are allowed weight bearing about 12 weeks after surgery.

    • Early mobilization and range-of-motion exercises are key to the successful treatment of proximal tibia fractures to avoid later knee stiffness and muscle wasting.

      OUTCOMES

    • The outcome depends mostly on knee stability, joint con-gruity, meniscal integrity, and correct axis.

    • A favorable outcome has been reported for surgically treated low-energy tibial plateau fractures.20 For split and split-depression fractures, adequate surgical techniques yield more than 90% good and excellent results.14

    • However, concomitant injuries of ligaments and menisci can compromise the outcome. Therefore, maintaining menisci and ligamentous stability is important.8

    • Satisfactory functional results can be obtained in the face of poor radiographic results, however, and may be due to preservation of the meniscus and its ability to bear the load of the lateral compartment.7,10

      COMPLICATIONS

    • Early complications

      • The incidence of wound infection appears to correlate with the amount of hardware implanted and ranges from 0% to 32% for fractures managed with the buttress technique.23

      • Deep vein thrombosis rates are reported to be 5% to 10%, and pulmonary embolus occurs in 1% to 2% of patients.2,12

    • Late complications

      • Loss of fixation with axial malalignment and valgus deformity11,19

      • Malunion as a consequence of inadequate reduction or loss of reduction9

      • Posttraumatic arthrosis, which may result from the initial chondral damage or may be related to residual joint incongruity8,18

REFERENCES

  1. Berkson EM, Virkus WW. High-energy tibial plateau fractures. J Am Acad Orthop Surg 2006;14:20–31.

  2. Blokker CP, Rorabeck CH, Bourne RB. Tibial plateau fractures: an analysis of the results of treatment in 60 patients. Clin Orthop Relat Res 1984;193–199.

  3. DeCoster TA, Nepola JV, el Khoury GY. Cast brace treatment of proximal tibia fractures: a ten-year follow-up study. Clin Orthop Relat Res 1988;196–204.

  4. Gustilo RB, Mendoza RM, Williams DN. Problems in the management of type III (severe) open fractures: a new classification of type III open fractures. J Trauma 1984;24:742–746.

  5. Hohl M. Tibial condylar fractures. J Bone Joint Surg Am 1967;49A: 1455–1467.

  6. Hohl M, Luck JV. Fractures of the tibial condyle; a clinical and experimental study. J Bone Joint Surg Am 1956;38A:1001–1018.

  7. Honkonen SE. Indications for surgical treatment of tibial condyle fractures. Clin Orthop Relat Res 1994;199–205.

  8. Honkonen SE. Degenerative arthritis after tibial plateau fractures. J Orthop Trauma 1995;9:273–277.

  9. Honkonen SE, Jarvinen MJ. Classification of fractures of the tibial condyles. J Bone Joint Surg Br 1992;74:840–847.

  10. Keogh P, Kelly C, Cashman WF, et al. Percutaneous screw fixation of tibial plateau fractures. Injury 1992;23:387–389.

  11. Koval KJ, Helfet DL. Tibial plateau fractures: evaluation and treatment. J Am Acad Orthop Surg 1995;3:86–94.

  12. Lachiewicz PF, Funcik T. Factors influencing the results of open reduction and internal fixation of tibial plateau fractures. Clin Orthop Relat Res 1990;210–215.

  13. Liow RY, Birdsall PD, Mucci B, et al. Spiral computed tomography with two- and three-dimensional reconstruction in the management of tibial plateau fractures. Orthopedics 1999;22:929–932.

  14. Lobenhoffer P, Schulze M, Gerich T, et al. Closed reduction/percuta-neous fixation of tibial plateau fractures: arthroscopic versus fluoro-scopic control of reduction. J Orthop Trauma 1999;13:426–431.

  15. McQueen MM, Court-Brown CM. Compartment monitoring in tibial fractures: the pressure threshold for decompression. J Bone Joint Surg Br 1996;78B:99–104.

  16. Morrison JB. The mechanics of the knee joint in relation to normal walking. J Biomech 1970;3:51–61.

  17. Rasmussen PS. Tibial condylar fractures: impairment of knee joint stability as an indication for surgical treatment. J Bone Joint Surg Am 1973;55A:1331–1350.

  18. Saleh KJ, Sherman P, Katkin P, et al. Total knee arthroplasty after open reduction and internal fixation of fractures of the tibial plateau: a minimum five-year follow-up study. J Bone Joint Surg Am 2001; 83A:1144–1148.

  19. Schatzker J, McBroom R, Bruce D. The tibial plateau fracture: the Toronto experience 1968–1975. Clin Orthop Relat Res 1979;94–104.

  20. Stevens DG, Beharry R, McKee MD, et al. The long-term functional outcome of operatively treated tibial plateau fractures. J Orthop Trauma 2001;15:312–320.

  21. Tscherne H, Oestern HJ. [A new classification of soft-tissue damage in open and closed fractures (author’s transl)]. Unfallheilkunde 1982;85:111–115.

  22. Whitesides TE, Heckman MM. Acute compartment syndrome: update on diagnosis and treatment. J Am Acad Orthop Surg 1996;4:209–218.

  23. Young MJ, Barrack RL. Complications of internal fixation of tibial plateau fractures. Orthop Rev 1994;23:149–154.?