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

69. Lateral Tibial Plateau Fractures

Philipp Kobbe and Hans Christoph Pape

DEFINITION

images 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

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

images 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.

images 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.

images 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.

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

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

images 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

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

images 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

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

images 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.

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

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

images 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

images 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.

images 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.

images 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

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

images 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.

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

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

images Such findings require immediate fasciotomy.

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

images 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.

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

images Palpation of peripheral pulses

images Doppler ultrasound

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

images Impaired sensorimotor status may indicate compartment syndrome; impaired dorsal flexion may indicate direct peroneal nerve injury.

images 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

images 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.

images 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

images 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.

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

DIFFERENTIAL DIAGNOSIS

images Ligamentous injuries of the knee

images Knee dislocation

images Meniscal injury

images Bone bruise

images Compartment syndrome

NONOPERATIVE MANAGEMENT

images 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

images Nondisplaced or minimally displaced tibial plateau fractures with stability of the knee joint can be managed nonoperatively, provided that the patient is compliant.

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

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

images 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

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

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

images 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.

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

images 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

images Review of radiographs, CT, MRI

images Surgical approach and placement of implants

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

images 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.

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

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

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

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

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

images 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).

images Schatzker's classification distinguishes between lateral and medial plateau fractures (Table 2).

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

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

Positioning

images Supine position

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

images

images

images Tourniquet to minimize blood loss and to improve fracture visualization

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

images Contralateral leg placed in leg carrier

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

Approach

images 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:

images Elevation of the meniscus

images Reduction of the fracture

images Temporary retention with Kirschner wire or small fragment lag screw

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

images 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).

images 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.

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

images

FIG 1  Leg position to reduce collateral ligament tension.

images

FIG 2  Landmarks for skin incision.

TECHNIQUES

ANTEROLATERAL APPROACH

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

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

images 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).

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

images 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.

images

TECH FIG 1  Anterolateral approach.

POSTEROLATERAL APPROACH

images  A longitudinal incision is made along the proximal fibula (TECH FIG 2).

images  The extensor muscles are mobilized from the tibial plateau.

images  After exposure of the peroneus nerve, osteotomy of fibula head is performed.

images  At the end of surgery the fibular head is refixated by tension band wiring or screw fixation.

images

TECH FIG 2  Posterolateral approach.

REDUCTION

images  Careful treatment of soft tissue and periosteum is mandatory.

images  Reduction is aided by ligamentotaxis and careful manipulation. An external fixator or a distractor may be a helpful tool.

images  Displaced fragments are reduced with reduction tools.

images  Reduction is temporarily maintained with Kirschner wires or lag screws (TECH FIG 3).

images

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

images  Impression fractures need to be elevated with a pestle, which may be inserted through a distal tibial bone window (TECH FIG 4).

images  Elevation is achieved by carefully exerting punches on the pestle (eg, with a hammer) under fluoroscopy until the contour of the articular surface is re-established.

images  In cases of severe bone loss, the defect must be filled with bone graft or bone substitute.

images

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

MENISCAL REPAIR

images  Meniscal integrity is important for stability and to avoid posttraumatic arthritis.

images  Peripheral longitudinal lesions of the anterior and intermediate part of the meniscus are fixated using the “outside-in suture” technique.

images  Peripheral longitudinal lesions of the posterior meniscus are fixated using the “all-inside” technique to avoid injury to the neurovascular structures in the popliteal area.

images  Complex meniscal lesions in the avascular area require resection.

OSTEOSYNTHESIS

Implants

images  Implants may include cancellous screws, conventional plates, or, most recently, angular stable plates.

images  If the lateral metaphyseal shell is intact, a lag screw with a washer or a three-hole conventional plate in the antiglide position is usually sufficient.

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

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

images  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.

Locking Plates

images  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.

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

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

images The stability of angular stable plates does not depend on friction between the plate and the bone, so less compression of the periosteum, with consequent better blood supply to the fracture area, is achieved.

Pure Split Fractures of the Lateral Plateau (AO-41-B1 or Schatzker I)

images  For fixation, two large partially threaded cancellous bone screws with washers can be used (TECH FIG 5).

images

TECH FIG 5  Stabilization of B1 or Schatzker I fracture with two lag screws and two-hole plate in antiglide position.

images  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)

images  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.

images

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.)

images  In osteopenic patients, a third cancellous bone screw with washer is recommended in an antiglide position, whereas in case of fragmentation a lateral buttress plate is used (TECH FIG 6).

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

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

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

images

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

images

POSTOPERATIVE CARE

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

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

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

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

images 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

images The outcome depends mostly on knee stability, joint congruity, meniscal integrity, and correct axis.

images 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

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

images 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

images Early complication.

images 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

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

images Late complication.

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

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

images 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 twoand 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/percutaneous fixation of tibial plateau fractures: arthroscopic versus fluoroscopic 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 arthroplast1y 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.



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