Diagnosis and Surgical Treatment of Schatzker Type IV Variant Biplanar Medial Tibial Plateau Fractures in Alpine Skiers

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1 Techniques in Knee Surgery 6(1):17 28, 2007 Ó 2007 Lippincott Williams & Wilkins, Philadelphia j S P E C I A L F O C U S j Diagnosis and Surgical Treatment of Schatzker Type IV Variant Biplanar Medial Tibial Plateau Fractures in Alpine Skiers Mark L. Purnell, MD, Andrew I. Larson, BSME, Kent A. Schnetzler, MD, MS, N. Lindsay Harris, MD, and Tomas Pevny, MD Aspen Foundation for Sports Medicine, Education and Research Orthopaedic Associates of Aspen & Glenwood Aspen, Colorado, U.S.A. ABSTRACT Fractures of the tibial plateau frequently are associated with significant intraarticular injuries that generally require surgical treatment. The commonly used Schatzker classification of tibial plateau fractures first described in 1979 includes 6 types of fractures, I to VI. In the original description of this system, Type IV fractures involved the medial tibial plateau and were described as either (1) split-wedge types or (2) depressed and comminuted, and the prognosis for these fractures was reported to be poor. Frequently attributed to a highenergy injury, these fractures are commonly felt to be caused by a varus force. In our experience, some Type IV fractures found in injured alpine skiers neither fit this pattern of injury, are not adequately described by this system, nor is the surgical treatment well defined. These fractures can pose surgical treatment difficulties, especially if the complex, biplanar, or rotational nature of this variant is not recognized and adequately reduced and stabilized. This Schatzker Type IV variant found in alpine skiers is described with emphasis on recognition, diagnosis, and optimal surgical treatment of this serious complex intraarticular fracture. Keywords: Schatzker Type IV, bicondylar, posterior approach to the knee, medial tibial plateau fracture, skiing Fractures of the tibial plateau or tibial condyles can represent serious intraarticular injuries and constitute approximately 1% of all fractures. 1 The spectrum of injury extends from less severe fractures of an isolated plateau that may be treated nonsurgically with excellent results to devastating involvement of the entire plateau (and often the proximal tibial shaft) requiring extensive Address correspondence and reprint requests to Mark L. Purnell, MD, Orthopaedic Associates of Aspen & Glenwood, 100 E. Main St, Aspen, CO AFSMER@orthop.com. surgery. These severe injuries may result in premature arthritis, ligamentous injury, and lifelong pain and disability. 2,3 In 1979, Schatzker et al 4 described 6 tibial plateau fracture types. These types of tibial plateau fractures have markedly different incidences, although reported data are lacking. Hohl 1 noted that about 55% to 70% of tibial plateau fractures involve the lateral plateau, about 10% to 23% involved the medial plateau, and about 10% to 30% involved both tibial condyles (bicondylar). Other authors have reported higher percentages for lateral fractures with medial and tibial bicondylar fractures having correspondingly lower percentages. This low frequency of occurrence can lead to inexperience in recognizing and treating patterns such as the Type IV medial plateau fractures. Type IV fractures are uncommon and are typically classified as high-energy fractures involving the medial tibial plateau. 5 Classically described and usually illustrated as a split fracture of the medial plateau in the sagittal plane, the fracture has sometimes been called the medial counterpart to the Schatzker Type II fracture, especially as the partial plateau fracture form. Berkson and Virkus 6 however noted that medial plateau fractures were not the analogues of lateral fractures. Total plateau varieties are also described. Certain variations of plateau fractures may present especially difficult surgical treatment options. Unrecognized variations of previously described patterns that do not fit into commonly used classification systems may lead to suboptimal surgical treatment. We describe a variant of a medial tibial plateau fracture (Schatzker Type IV) found in skiers and discuss the optimal surgical treatment. ANATOMY The tibial plateau represents the entire proximal end of the tibia and is composed of medial and lateral weightbearing articular surfaces. The 2 articular surfaces are Volume 6, Issue 1 17

2 Purnell et al asymmetric both in size and concavity (as well as relative density and strength). The medial plateau is larger and stronger than the lateral plateau and is concave in both planes. The medial plateau carries about 60% of the knee s load and consequently has increased subchondral bone and a stronger, denser plateau when compared with the lateral. 6 The smaller and weaker lateral plateau is convex in the coronal and sagittal planes. As a result of this relative weakness combined with the natural valgus carry-angle of the lower extremity (the leg is often protected from varus forces by the contralateral leg), fractures of the lateral plateau are more common. Two additional dense bony prominences serve as attachment sites for tendonous structures and are located in close proximity of the tibial plateau: (1) the tibial tubercle located anteriorly and serving as the attachment of the patella tendon and (2) Gerdy tubercle located laterally and serving as the attachment of the iliotibial band. These structures usually remain intact in most fractures of the tibial plateau. On the medial side, the semimembranosis attaches to a ridge at the posteromedial corner of the medial plateau just below the joint line. The pes anserinus attaches more anteriorly and distally, closer to the level of the tibial tubercle. These tendons should be identified and protected when approaching the tibial plateau from the medial side. There are no ligamentous attachments to the lateral tibial plateau, whereas the medial plateau has a broad area of insertion for both the deep and superficial medial collateral ligament posing difficulties for plate placement on the proximal medial tibia. The posterior aspect of the tibial plateau serves as the insertion site for both the posterior cruciate ligament and the posterior oblique ligament. The entire plateau is set back from the longitudinal axis of the tibial shaft, leaving the posterior aspect of both the medial and lateral plateau cantilevered behind the posterior tibial cortex. When placing a posterior plate, this setback must be accommodated by appropriate contouring. The shape of the proximal tibia just distal to the tibial plateau is triangular, affecting the placement and type of any fixation device that might be used for stabilization. The orientation of the posterior and lateral walls is in their described direction, providing broad surfaces for plates and screws in the posterior to anterior and the lateral to medial directions. The medial wall, however, is at a more oblique angle and is oriented posteriorly as well as medially. Any plate placed on the broad medial surface of the proximal tibia will therefore be oriented in a posterior as well as a medial direction. This leaves only the narrow junction of this triangle as the most medial surface and only a small surface area for direct medial plate placement for support in the medial to lateral direction. MECHANISM OF INJURY Historically, motor vehicle or motorcycle crashes, pedestrian versus motor vehicle collisions, and falls have been the most common causes of tibial plateau fractures. Originally termed a Bcar bumper^ fracture, where the knee was struck from the lateral side by an automobile bumper, injuries of the lateral tibial plateau result from the natural valgus carry-angle of the lower extremity combined with a force directed. With varus and compressive injuring forces applied to the knee, medial tibial plateau fractures may be produced. Such injuries are less common, partly because of the valgus carry-angle of the leg, greater strength of the medial plateau, and some protection afforded by the contralateral leg. However, such medial injuries tend to require more energy to produce and, as a result, are more likely to have associated severe soft tissue injuries, including injury to the cruciate ligaments, peroneal nerve, popliteal vessels, and the lateral collateral ligament. 6,7 Posteromedial instability can cause the femoral condyle to dislocate posteromedially when the knee is flexed and the injury has been called a fracture dislocation. 8 CLASSIFICATION SYSTEMS Two common systems for classification of tibial plateau fractures, the Schatzker and the Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of Internal Fixation (AO/ASIF), are used to describe plateau fractures, with the Schatzker system probably the most accepted and widely used in the clinical setting. 4,9 Neither system, however, explicitly describes the variant fracture pattern we describe, although the AO/ASIF system would likely include it in one of its subdivisions (41-B). Other older classification systems include the Hohl and Luck, the Moore, and a later combination of the Hohl and Moore system. These systems are infrequently used today. Other systems have been proposed, some quite elaborate and inclusive, but are not commonly used in clinical practice. The Schatzker classification (Fig. 1) of tibial plateau fractures combines features of the previous systems and divides injuries into 6 types: 1. Type I or split fractures of the lateral plateau 2. Type II or split depression fractures of the lateral plateau 3. Type III or central depression fractures of the lateral plateau 4. Type IV or medial plateau fractures 5. Type V or bicondylar plateau fractures 18 Techniques in Knee Surgery

3 Special Focus: Type IV-Variant Tibial Plateau Fractures in Skiers FIGURE 1. Original Schatzker Classification System. Reprinted with permission from Schatzker J, McBroom R, Bruce D. The tibial plateau fracture. The Toronto experience 1968Y1975. Clin Orthop Relat Res. 1979;138:94Y Type VI or any plateau fracture in association with a proximal tibial shaft fracture (metaphyseal-diaphyseal separation) Implicit in the Schatzker system is an ever-increasing amount of energy involved to produce the injury corresponding to the higher types. Types I, II, and III are considered lower-energy, whereas Types IV, V, and VI are higher-energy fracture patterns, with correspondingly increasing incidence of injury to neurovascular and ligamentous structures about the knee. It is important to remember that all types may be associated with compartment syndrome. The AO/ASIF system, later adopted by the Orthopaedic Trauma Association, is part of a unified approach to classify fractures. Within the AO/ASIF system, Type IV fractures correspond to B1.2, B1.3, B2.3, B3.2, and B3.3 subgroups. 10 Most useful in research situations where the fracture can be very specifically described, classified, and catalogued, its use in the clinical setting is less practical. Khan et al 11 proposed a new comprehensive classification scheme that included posterior and anterior coronal split fractures, recognizing the significance of these atypical injury patterns not fully accounted for in the Schatzker system (Fig. 2). Posteromedial coronal split fractures were attributed to a combination of varus force and axial load on a hyperflexed knee. HISTORICAL REVIEW Few articles concern internal fixation of Type IV fractures, perhaps because of their rarity. Schatzker s original article illustrated fixation with a medial plate. Yang et al 12 used plain radiographs and computerized tomography (CT) to categorize Type IV fractures in 51 patients into 3 types: (1) split, (2) total condylar, and (3) depression. In both depression and total condylar injuries, buttress plate fixation was placed medially. In the split injury, the plate was placed posteromedial. De Boeck and Opdecam 13 reported on posteromedial tibial plateau fractures and recommended a posterior approach with partial division of the medial gastrocnemius tendon to obtain exposure. Several articles have described approaches to the posteromedial tibial plateau, usually for surgical treatment of Schatzker V bicondylar fractures. 14Y16 Some studies have noted that the division of the tendon of the medial gastrocnemius is not required for exposure. 15Y17 Bhattacharyya et al 18 reported on an uncommon posterior shearing tibial plateau fracture treated through FIGURE 2. Posterior shearing tibial plateau fracture similar to skier Type IV variant reported by Bhattacharyya et al. 18 Reprinted with permission from Bhattacharyya T, McCarty LP 3rd, Harris MB, et al. The posterior shearing tibial plateau fracture: treatment and results via a posterior approach. JOrthopTrauma.2005;19:305Y310. Volume 6, Issue 1 19

4 Purnell et al FIGURE 3. Partial description of a classification system by Khan et al. 11 Reprinted with permission from Khan RM, Khan SH, Ahmad AJ, et al. Tibial plateau fractures. A new classification scheme. Clin Orthop Relat Res. 2000;375:231Y242. a posterior approach in 13 patients, similar to the skier Type IV variant (Fig. 3). Such fractures defied classification as Schatzker Type IV, V, or VI fractures and did not fit fully into the system of Khan et al. 11 The authors noted the importance of coronal plane fractures visible only on lateral radiographs or CT. Such fracture planes, if not properly addressed and stabilized, may lead to inadequate reduction and the use of inappropriate or inadequate stabilization techniques. The article illustrated the need to recognize and address coronal plane fractures that coexist with more typical sagittal plane fractures in the variant Type IV fracture we describe. Hybrid fixation, with small-wire fixation, for complex tibial plateau fractures offer satisfactory fixation stability, but all studies show pin tract complications. 19Y21 More recently, Egol et al 22 and Stannard et al 23 reported on the benefits of a locked lateral plate (less invasive stabilization system, Synthes USA, Paoli, Pa) for the management of unstable complex tibial plateau fractures (Orthopaedic Trauma Association class 41C, Schatzker Type IV, V, and VI). They both reported excellent stabilization of medial fragments with this technique with low complication rates. INDICATIONS AND PREOPERATIVE PLANNING In an excellent review article, BArticular Fractures: Does an Anatomic Reduction Really Change the Result?^ Marsh et al 24 examined the factors that affect long-term outcome of periarticular fractures, including tibial plateau fractures. Age of the patient, extent of articular cartilage injury, step off of the articular surface, meniscal pathology and menisectomy, malalignment, and instability all play a role in long-term functional results. Of these factors, only the latter are affected by the decisionmaking process of the orthopedic surgeon. The degree of acceptable articular step off remains unresolved. Brown et al 25 using pressure-sensitive film in a human tibial plateau model demonstrated a 75% increase in local peak pressures with a 3-mm step off. Clinical follow-up studies, however, have shown little differences in outcome until step off exceeds 10 mm. 26Y28 Instability and malalignment on the other hand play an especially important role in long-term outcome with any residual varus being very poorly tolerated. 2,3,27,29 Because Type IV fractures by definition involve the medial tibial plateau and any displacement or instability will lead to a varus deformity, most of these fractures will require reduction and stable fixation. Soft tissue injury also plays a significant role in preoperative evaluation. Abdel-Hamid et al 30 used arthroscopy to evaluate soft tissue injuries in tibial plateau fracturesvfrequency of soft tissue injury was 71% (70/98 fractures). Although no association was noted between fracture type and presence of meniscal, cruciate ligament, collateral ligament, or neurovascular injury, significantly higher rates for anterior cruciate ligament injury were noted for Schatzker Type IV and VI injuries. Gardner et al 31 used magnetic resonance imaging (MRI) to evaluate soft tissue injury in 103 patients. The overall incidence of injury to soft tissue was higher than previously reported, and only 1 patient had no soft tissue injury. Stevens et al 32 noted peroneal nerve palsies and avulsions, multiligamentous injuries, and popliteal artery contusion in 8 Type IV fractures. Clearly, strict attention to neurovascular status and careful assessment of soft tissue injury are required, and because compartment syndromes can be associated with all Schatzker types, the tibial compartments should be carefully evaluated and monitored throughout the patient s hospitalization. 20 Techniques in Knee Surgery

5 Special Focus: Type IV-Variant Tibial Plateau Fractures in Skiers Plain radiographs in the anteroposterior (AP) and lateral views are routine but often are inadequate to understand the extent of displacement and nature of these fractures. 18,33 Radiographs of the normal side are often helpful for preoperative planning and are very useful as a template for intraoperative comparison (ie, the cover of a puzzle box). Computerized tomography or MRI is also highly recommended. In a study comparing the AO/ASIF to Schatzker system, Walton et al 34 found that the addition of CT to plain radiography increased both intraobserver and interobserver agreement of treatment plan. 35 Magnetic resonance imaging also increased the interobserver agreement on fracture classification and operative management of tibial plateau fractures. 36 Plain radiographs of the injured knee form the basis for evaluation, with MRI providing valuable information about soft tissue injury and axial CT scanning (with reconstructions) clearly demonstrating multiplanar fracture lines not apparent on plain radiographs. Computerized tomography or MRI should be routine, particularly for those fractures that are poorly seen on plain films and those fractures that are infrequently seen by the orthopedic surgeon. We prefer MRI because of its ability to evaluate soft tissue and subchondral injury as well as the fracture pattern. SKIER TYPE IV PATTERN After obtaining institutional approval, we retrospectively performed a chart review of all tibia and tibial plateau fractures seen by an orthopedist that occurred from FIGURE 4. Patient 1. Fracture initiation on the posterolateral articular surface of the proximal tibia. FIGURE 5. Patient 1. Comminution and inferior displacement on the posterolateral tibial plateau. skiing injuries at our institution (a level III hospital treating injuries from 4 major Colorado ski mountains) from November 2002 to April Overall, 641 patients sustained a tibia fracture (excluding the distal tibial pilon or plafond), 190 sustained a tibial plateau fracture, and 18 patients were classified with a Schatzker Type IV injury. Of those with Type IV fractures, 14 were the skier Type IV or biplanar variant fracture currently discussed. Eight of these were men (average age 43 T 9 years), and 6 were women (average age 43 T 15 years). Ten patients had an intact medial tibial plateau fragment, and 4 had an additional split of the medial plateau in the horizontal plane. All Type IV skier fractures occurred from relatively lower-energy noncontact trauma with the patient usually reporting a twisting-type fall while skiing. Three of 14 had a tear of the lateral meniscus; there were no other soft tissue or ligamentous injuries. No Type IV fracture patients had an associated neurovascular injury nor did any of the patients develop a compartment syndrome. All fractures were evaluated either by MRI or CT in addition to plain radiographs. Magnetic resonance imaging allowed evaluation of subchondral bony contusion on both the femur and tibia, and for some, CT allowed reconstructed, 3-dimensional evaluations of these complex fractures. All fractures demonstrated a very similar biplanar pattern: the fracture initiates proximally on the posterior articular surface of the lateral tibial plateau just lateral to the tibial eminences (Fig. 4). On MRI or CT imaging, the articular surface of the posterolateral tibial plateau typically shows comminution and varying degrees of inferior displacement (Fig. 5). Most of the articular damage is therefore on the Volume 6, Issue 1 21

6 Purnell et al lateral and not the medial tibial plateau. Propagating from the posterior aspect of the lateral tibial plateau, the fracture line extents anteriorly in the sagittal plane. From here, the fracture line extends inferiorly and medially in the sagittal plane through the tibial eminence (often with comminution involving the anterior cruciate ligament tibial insertion; Fig. 6). The fracture then rotates 90 degrees as it extends distally to exit posteriorly and medially in the coronal plane (Fig. 7) on the tibial shaft. With the pull of the semimembranosis and the posterior capsule still intact, displacement of the medial plateau is usually posterior and medial. The distal tibia shaft fragment, deprived of medial support, usually settles into a varus position. These displacements can be very subtle and poorly seen on plain AP radiographs (Fig. 8). Thus, MRI or CT is essential to understand the Bpersonality^ of these fractures and to determine fracture pattern and degree of displacement. The main medial tibial plateau fragment demonstrated 1 of 2 patterns. In most of the cases, 10 of 14 patients, the medial plateau fragment was 1 piece (Fig. 9). In 4 patients, the medial plateau fragment had another fracture in the coronal plane, splitting the medial plateau (Fig. 10). Whether the medial plateau was 1 fragment or split in 2 in the coronal plane, the pattern of articular injury of the posterolateral plateau and the changing plane from sagittal and lateral to coronal and posteromedial were always present. Magnetic resonance imaging also allowed for evaluation of femoral bony contusions which were noted anteriorly and laterally on the lateral femoral condyle in 10 of 14 cases. Assuming these contusions represent the area of maximal and initial stress on the femoral condyle and occurred by contact with the FIGURE 7. Patient 1. Rotation of the fracture 90 degrees as it exits posteromedial in the coronal plane. corresponding area of comminution on the posterolateral tibial plateau, then these injuries likely occurred with the knee in more extension than flexion. The initial articular injury laterally may also indicate that valgus may be a more likely force than varus. The pattern of changing fracture planes as the fracture propagates distally implies a rotational component of stress in addition to axial load. We had 3 nondisplaced fractures with the previous findings (Fig. 11). Notable in these fractures was the presence of nondisplaced tibial spine avulsion fracture. This pattern of femoral and tibial contusions and the comminution of the tibial spine demonstrate a very similar MRI pattern to what is seen in both tibial spine avulsions and anterior cruciate ligament (ACL) FIGURE 6. Patient 1. Fracture line extends inferiorly and medially through the tibial eminence. FIGURE 8. (A) Patient 1, (B) Patient 2. The personality of the fracture can be hardly seen on plain AP radiographs. 22 Techniques in Knee Surgery

7 Special Focus: Type IV-Variant Tibial Plateau Fractures in Skiers 4. reduction of any articular injury at the posterior articular surface of the lateral tibial plateau, if necessary; and 5. internal fixation of the fracture in first in the coronal plane, followed by fixation in the sagittal plane. FIGURE 9. Patient 2. Type IV variant with the medial plateau in 1 piece. ruptures. These fractures may therefore represent a similar mechanism of injury to an ACL rupture or spine avulsion with the addition of a higher axial load and a rotational fracture pattern extending medially, in other words, an ACL injury gone bad. SURGICAL TECHNIQUE This consistent fracture pattern and personality facilitates a systematic approach to open reduction and internal fixation of these Type IV variant fractures: 1. Reduction and fixation of any coronal split component of the medial tibial plateau; 2. reduction of varus displacement of distal tibia shaft fracture fragment; 3. reduction of flexion deformity of the medial plateau; Typically, the surgical approach and patient position are dependent on both fracture location and displacement. Minimally or mildly displaced fractures may be approached with the patient positioned supine and with the knee flexed over a support. Fractures with more articular comminution of the lateral plateau, a split medial fragment, and with significant displacement of the medial fragment are better managed through a posterior approach, with the patient in a prone position. 13,17,18,37 Anterior Approach The lower extremity is prepared and draped free and is usually supported with a fracture triangle. Restoration of length is first addressed by either manual traction or via use of a femoral distracter. Fluoroscopic evaluation is crucial at this point to assess residual flexion deformity of the medial plateau fragment. If no residual flexion is noted, then stabilization in the coronal plane can be obtained by simple interfragmentary fixation between the medial tibial shaft and the medial tibial plateau. This can be performed from either an anterior to posterior or posterior to anterior direction. However, if persistent flexion is noted, then a posterior medial incision is made to reduce and stabilize the distal spike of the medial fragment. An incision is first made along the posteromedial aspect of the proximal tibia at the level of the fracture. Deep dissection is performed bluntly to preserve the neurovascular structures. The tendons of the pes anserinus are identified and retracted proximally or distally, depending on need for access. The medial head of the gastrocnemius is lifted posteriorly to identify the FIGURE 10. (A and B) Patient 3. Type IV medial split variant. Volume 6, Issue 1 23

8 Purnell et al FIGURE 11. Patient 3. Nondisplaced Type IV fracture. medial fragment spike. The spike is then reduced and fixed either with interfragmentary screws or with plate and screw fixation. Typically, fractures that exist more medially than posteriorly are amenable to reduction and fixation from this approach. For those fracture that exit more posteriorly or are significantly displaced, then a posterior medial approach as described by De Boeck and Opdecam 13 or Burks and Schaffer 37 should be used, with the patient in the prone position. Once fracture stabilization in the distal coronal plain is obtained, comminution posterolateally and fixation in the sagittal plane can be addressed. Only rarely is posterolateral comminution displaced to the degree that open reduction fixation is required. Access to the posterior aspect of the tibial plateau through an anterior lateral approach is quite difficult because visualization is extremely limited. Arthroscopy can give excellent fracture visualization at this point, and reduction can be attempted through a bone window created anteriorly on the lateral tibial shaft distal to Gerdy tubercle. If significant posterolateral articular displacement is present, then a posterolateral approach, as advocated by Carlson, 17 will be more appropriate. At this point, the fracture can be stabilized in the sagittal plane. The medial plateau is reduced and secured to the stable lateral plateau. In minimally or nondisplaced fractures with good-quality bone, a simple percutaneous screw fixation may be adequate. Screws may be placed from either medial to lateral or lateral to medial, depending on bone quality. Typically, the lateral plateau has good lateral cortical bone for screw head or plate fixation, but very poor subchondral bone for screw thread purchase. The medial plateau, on the other hand, will usually have good subchondral bone for screw thread purchase, and therefore screws are usually place from lateral to medial. If more substantial fixation, such as a locked plate, is needed, a standard lateral approach is made through of slightly curving or hockey stick anterolateral incision. The incision is carried deep with sharp dissection incising the fascia and capsule between the iliotibial band and the patellar tendon. The iliotibial band is reflected off of the Gerdy tubercle, leaving its connection to the tibial facial intact. The anterior compartment musculature is dissected from the anterolateral tibia exposing the tibia for fixation. A locked plate in this location is ideal for unstable Type IV fractures, once reduction is obtained. Before fixation, the joint can be entered if necessary through this incision, and posterior comminution can be addressed through the anterolateral bone window, reducing the fragments with either a tamp or small elevator (Fig. 12). Posterior Approach If the medial plateau is significantly displaced, if the articular surface of the medial plateau has a split component in the coronal plane, or if the posterior articular surfaces are significantly displaced, a posterior approach is more appropriate. 13,17,18 The patient is placed prone on the operating table, and bony prominences are appropriately padded. The leg is then prepared and draped free. The knee is held in slight flexion with a trauma bump placed under the ankle. 18 An S-shaped or L-shaped (Fig. 13) incision is then made, centering the horizontal limb at the joint line on the posterior aspect of the knee. 13,17 The medial arm of the incision is made just posterior to the medial edge of the tibia. Sharp dissection is carried deep and the posterior fascia is incised, exposing the gastrocnemius. The gastrocnemius is then elevated posteriorly and laterally, FIGURE 12. Patient 4. Open reduction internal fixation AP screws medially and locked plate laterally. 24 Techniques in Knee Surgery

9 Special Focus: Type IV-Variant Tibial Plateau Fractures in Skiers FIGURE 13. Description of L-shaped incision described by Burks and Schaffer. 37 Reprinted with permission from Burks RT, Schaffer JJ. A simplified approach to the tibial attachment of the posterior cruciate ligament. Clin Orthop Relat Res. 1990;254:216Y219. exposing the posterior tibia. The neurovascular structures are safely protected deep to the gastrocnemius muscle, but overzealous retraction should be avoided to prevent traction injury to the tibial nerve. If more exposure is needed, the medial gastrocnemius tendon can be released near its insertion, leaving a small cuff for later repair. The soleus and popliteus muscles are then elevated from the medial edge of the tibia by sharp dissection, exposing the fracture site. The joint can then be entered posteriorly while carefully protecting the capsular and ligament insertions. If a coronal split is present, dissection is carried anteriorly and medially while retracting the pes anserinus tendons and the medical ligament. A split fragment can then be reduced using direct visualization and fluoroscopy and fixed with interfragmentary screws. The entire medial fragment can then be reduced to the tibia shaft using flexion of the knee to bring the distal tibial shaft to the medial plateau. Lateral plateau depression can be addressed through this incision, but if it is severe, it is probably best addressed through a posterolateral approach, as advocated by Carlson 17 and Bhattacharyya et al. 18 We currently have no experience with this exposure. Once the medial and posterior fragments are reduced, the medial fragment should be fixed with a contoured buttress plate. 18 This addresses stability in the coronal plane. The proximal sagittal plane of the fracture can now be addressed, fixing the medial to the lateral plateau. Interfragmentary screw fixation is usually sufficient. With a single medial fragment, a percutaneous screw is placed from the lateral tibial cortex into the medial tibial plateau (Fig. 14). If a split of the medial plateau is present, screw should be placed from medial to lateral. If more secure fixation is required, the patient must be turned to the supine position and a locked plate placed laterally through an anterolateral incision. Bone grafting is rarely necessary in these fracture types but can be performed in the usual fashion from the posterior approach. With the fracture reduced and fixed, the wound is closed. The soleus and popliteus are reduced, overlaying the plate and tacked in place. The medial gastrocnemius tendon is repaired with heavy suture. The subcutaneous tissues and skin are closed, leaving the fascia open. All patients were given perioperative antibiotics. Volume 6, Issue 1 25

10 Purnell et al FIGURE 14. Patient 2. Open reduction internal fixation from the posteromedial approach. Posteromedial buttress plate. The screws are inserted laterally to medially. Postoperative management followed standard protocols for intraarticular lower-extremity fractures. All patients were started on immediate passive range-of-motion exercises via a continuous passive motion machine and started on a physical therapy program while hospitalized. All patients were treated with pharmaceutical and mechanical deep venous thrombosis prophylaxis. The fractures were protected with either nonyweight bearing or touch down weight bearing, depending on the degree of comminution and security of fixation until fracture healing. Additionally, the knees were protected with postoperative bracing, allowing full range of motion as tolerated. There were no infections and no postoperative complications, although because of the transient nature of our patient population, the long-term outcome of these patients is not known. DISCUSSION Although no complications or associated soft tissue injuries occurred in our small series, the injuries we describe typically resulted from lower-energy ski trauma than reported for other studies of Type IV tibial plateau fractures. Bhattacharyya et al 18 reported on a similar type of fracture (12/147 surgically treated injuries or 8%), which they described as a posteriorshearing tibial plateau fracture. Most of those patients represented high-velocity, high-energy trauma: 5 injuries were from motor vehicle collisions, 3 from motorcycle collisions, and 5 from falls. One patient presented with a compartment syndrome. They reported only 2 complicationsv1 wound dehiscence managed with local wound care and 1 flexion contracture managed with dynamic splinting. All fractures healed, and there were no losses of reduction or failures of fixation. One patient underwent hardware removal for a prominent posteromedial plate. Eight of 9 responding patients stated that they were highly satisfied with their resultsv1 patient was dissatisfied. The functional outcome score and patient-related satisfaction seemed to be related to the quality of articular reduction; the 1 dissatisfied patient had a poor anatomical reduction, although 2 patients rated as Bhighly satisfied^ also had poor reductions. The other highly satisfied patients had either anatomical or near-perfect reductions. Carlson 17 also reported on a similar-sounding fracture which he termed the posterior bicondylar tibia plateau fracture. He reported on 8 patients with 6- to 24- month follow-up: 3 injuries resulted from a motorcycle crash or automobile collision, and the remaining 5 from either jumps or falls from height. Seven of 8 patients had complications or associated pathology; 1 patient died because of a medical comorbidity. All patients returned to near-full activities but reported aching with prolonged standing. Range of motion averaged 2 to 120 degrees of flexion and only 3 of 5 patients returned to their preinjury manual labor jobs. Chang et al 38 reported on a series of 107 tibial plateau fractures to evaluate the incidence of compartment syndromes. The overall incidence of compartment syndromes in all types was 10.3%, but the incidence in Schatzker Type IV, V, and VI was up to 30.4%. Stevens et al 32 prospectively studied 47 patients with tibial plateau fractures, 8 of whom had Type IV fractures. All 8 of these Type IV fractures resulted from high-energy trauma (motor vehicle accident, fall or pedestrian), 4 of 8 had significant neurovascular injuries (peroneal nerve and popliteal artery), and 2 had associated ligamentous injury to the ACL, medial collateral ligament, and lateral collateral ligament. Long-term functional analysis for all fracture patterns with the 36-item Short-Form Health Survery and Western Ontario and McMaster Osteoarthritis Index scores showed no significant difference between matched healthy controls or between fracture types, unless the patient was older than 40 years. Patients older than 40 years at the time of injury had similar Western Ontario and McMaster Osteoarthritis Index scores to matched controls only in 57% of the patients. They concluded that open reduction and internal fixation is a satisfactory technique for managing tibial plateau fractures, particularly in younger patients. CONCLUSION Schatzker Type IV fractures of the medial tibial plateau are rare and potentially difficult fractures to understand and treat. We have presented a description of a variant of 26 Techniques in Knee Surgery

11 Special Focus: Type IV-Variant Tibial Plateau Fractures in Skiers these fractures seen in skiing injuries. These patients usually describe a low-energy, twisting injury to the leg and present a fracture pattern consistent with rotational and axial stresses. These fractures initiate proximally on the posterior articular surface of the lateral tibial plateau and propagate anteriorly and medially in the sagittal plane. As the fractures extend distally, they rotate to the coronal plane and exit posteriorly on the tibial shaft. Left unsupported, the distal tibia settles into a varus position, and the plateau can fall into flexion. This displacement is poorly tolerated and should be reduced and stabilized. By understanding this pattern, the surgeon can plan appropriate steps for reduction and fixation. REFERENCES 1. Hohl M. Managing the challenge of tibial plateau fractures. J Musculoskel Med. 1991;8:70Y Honkonen SE. Indications for surgical treatment of tibial condyle fractures. 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