Tibia and fibula, proximal—introduction

10.1055/b-0034-87650

Tibia and fibula, proximal—introduction

Jong-Keon Oh

Introduction

Proximal tibial fractures can be divided into low- and high-energy injuries depending on the amount of energy applied at the time of injury. The management of high-energy proximal tibial fractures requires the surgeon to take very good care of the soft-tissue envelope as the anteromedial surface of the proximal tibia is covered only with skin and subcutaneous tissues. Even though these injuries are closed fractures, it is critical to understand and recognize the consequence of the dissipation of energy through the surrounding soft tissues ( Fig 19.1-1 ).

If the soft-tissue injury is not treated adequately according to the principles described in this chapter, there is a high risk of having devastating postoperative wound breakdown and infection ( Fig 19.1-2 ).

Incidence

Complete articular fractures (41-C) are often the result of high-energy injuries. Partial articular fractures, on the other hand, are usually caused by low-energy injuries. However, some of the 41-B fracture patterns are often associated with high-energy injuries and these fractures require special attention. Such fractures include isolated medial tibial plateau fractures (41-B1.3 and 41-B3.3). These types of isolated medial plateau fractures are frequently associated with subluxation or dislocation of the lateral plateau ( Fig 19.1-3 ). The importance of these fractures is that they are often associated with severe soft-tissue and neurovascular injuries as well as compartment syndrome. The recognition of these fractures should alert the surgeon to the need for careful assessment of neurovascular status. Moore separated these fractures into one of fracture-dislocation group, as shown in Fig 19.1-3 [ 1].

Axial MRI of a patient with a bicondylar tibial plateau fracture shows increased signal around the anteromedial and anterolateral surfaces of the proximal tibia.

a X-ray shows dual plating of proximal tibial fractures. b Single incision with skin necrosis along the anteromedial surface. Postoperative infection is inevitable in this setting.

A 42-year-old man sustained a 41-B3.3 fracture after falling from a height. Note the lateral plateau is completely dislocated and moved in a superolateral direction along with the entire shaft. This particular fracture pattern should alert a surgeon to possible compartment syndrome and neurovascular injuries to the common peroneal nerve and popliteal artery. Lateral meniscus injury is highly likely and the integrity of the posterolateral ligamentous structures must be carefully evaluated after stabilization. Initial reduction with bridging external fixation was performed to treat the surrounding soft-tissue injury.

Current methods of treatment

While the treatment of simple articular fractures is fairly standardized, this is not the case with complex fractures involving both condyles (41-C). For the past 10 years there have been two different strategies applied to the methods used to fix bicondylar fractures. The first technique is dual plating through two separate incisions (posteromedial and anterolateral), and the other is locked lateral plating using an anatomically preshaped locking plate. Both strategies embrace the concept of biological plating and have advantages and disadvantages. This chapter discusses a logical decision-making process for each technique based on the personality of the fracture pointing out the tips and pitfalls of each method.

Indications and role of temporary bridging external fixation

The injury to the surrounding soft-tissue envelope in high-energy proximal tibial fractures (most 41-C fractures, some 41-B fracture dislocations 41-B1.3/41-B3.3, many extraarticular fractures 41-A2 and 41-A3, and open fractures) should be treated before any attempt is made to treat these soft-tissue condition fractures with plating. Temporary bridging external fixation must be carried out as the initial step in those cases. Restoration of alignment and maintenance of length is the most important part. Bridging external fixation acts as a portable traction device, facilitating patient mobility while waiting for definitive fixation. At the same time the frame reduces further damage to the articular cartilage. Pins must be placed at a distance so that they will not interfere with definitive fixation. Following the application of a bridging external fixator additional investigations, such as a CT scan, should be done to allow proper planning of definitive fixation. It is not uncommon to have some amount of flexion contracture after 7–14 days of bridging external fixation. To minimize this problem it is recommended to keep the knee joint in full extension when the bridging external fixator is applied.

Indications and contraindications for MIPO

1.4.1 Extraarticular simple fractures (41-A2)

Simple metaphyseal fractures (41-A2) can be treated with conventional plating (compression or neutralization plating) technique ( Fig 19.1-5 ). However, when considering conventional plating, surgeons should be aware of the technical difficulties in gaining anatomical reduction and compression across the fracture surface because of the complex anatomical shape of the proximal lateral tibia and its bulky muscular coverage ( Fig 19.1-4 ). Thorough preoperative planning of the reduction technique and how to achieve compression of the fracture site is mandatory when conventional plating is used.

Even though MIPO is primarily indicated for wedge or complex fractures many surgeons are now trying to expand the indication of MIPO technique to simple metaphyseal fractures of the proximal tibia because conventional plating techniques carry many technical difficulties due to the anatomical shape of the proximal tibia. If MIPO technique is chosen for a transverse or short oblique fracture the surgeon must decide on the proper working length or bridging length by leaving preferably 3 holes empty centered around the fracture as the fracture span is very short ( Fig 19.1-5k, Fig 19.1-5l ).

a–c Postoperative x-rays show a gap along the medial and posterior cortices, which means compression across the main fracture was not achieved at the time of open reduction and internal fixation with a limited contact locking compression plate (LC-DCP). Failure to get compression in conventional plating resulted in almost no friction across the fracture surface and instability of the entire construct. Early failure with displacement of the fracture is visible 10 days postoperatively.

a–n A 62-year-old man sustained an injury to his left leg in a car accident (41-A2). a–b X-rays show a segmental fracture of the left tibia (arrows). The proximal fracture has multiple fracture lines and a wedge but they are nondisplaced or minimally displaced so this component may be classified as a simple metaphyseal fracture of the proximal tibia. The entire fracture could be stabilized with a single implant which would be an intramedullary nail. However, because of the high-level of the proximal tibial fracture it would be a technically challenging procedure, so MIPO was chosen. c–d Articular fractures were stabilized by in situ fixation with a raft of subchondral screws. Then the proximal metaphyseal fracture was reduced using a minimally invasive direct reduction technique by applying pointed reduction forceps percutaneously. A locking compression plate proximal lateral tibia (LCP-PLT) was slid in and provisionally positioned with two K-wires at each end of the plate. e–f The middle segment was reduced toward the plate using a unicortical screw. g–h The diaphyseal component was reduced by manual pressure over the medial aspect of the fracture site. i–j While drilling through hard cortex the shaft was pushed away. It was reduced again with a unicortical reduction screw. **k–n** Postoperative x-rays show acceptable alignment. Note that for each component of the fracture, a 3-hole plate span was chosen as a working length (double-headed arrows). The lag screw placed at the proximal fracture site was intended to hold the wedge fragment. In general it is recommended not to place a lag screw at the bridging zone as it may block the motion across the fracture site, hindering fracture healing. The distal medial plate is placed slightly more anterior than usual to avoid collision with the screws from the lateral side of the LCP-PLT. All fractures healed uneventfully.

Extraarticular multifragmentary fractures (41-A3)

MIPO is particularly advantageous for 41-A3 fractures as it bridges the component of metadiaphyseal comminution creating less soft-tissue damage to the surrounding soft-tissue envelope than occurs with conventional plating ( Fig 19.1-6 ). In high-energy injuries initial bridging external fixation is recommended to allow the soft-tissue injury to settle.

a–b X-rays show a 41-A3 fracture with meta-diaphyseal extension, Gustilo-Anderson type IIIC open injury. The proximal fracture and line extends into the tibial tuberosity, making nailing undesirable. Initial management constituted a bridging external fixator and vascular repair was done. The soft-tissue defect was treated by vacuum-assisted closure, then later with a skin graft. c–d MIPO was performed with good healing without bone graft 13 months after injury. Given the significant amount of energy applied, shaft fixation was performed over a 6-hole span with four locking screws. A 2 cm shortening was accepted to repair the vascular injury.

Partial articular fractures (41-B1.3, 41-B3.3)

MIPO is particularly advantageous for 41-A3 fractures as it bridges the component of metadiaphyseal comminution with less soft-tissue damage than occurs with conventional plating ( Fig 19.1-6 ). In high-energy injuries initial bridging external fixation is recommended to allow the soft-tissue injury to settle ( Fig 19.1-7 ).

a–b A 45-year-old man sustained a 41-B3.3 fracture in a motor vehicle accident. Because the lateral column is in continuity there is no metadiaphyseal dissociation. c CT scan after bridging external fixation shows articular comminution around the tibial spine and part of the lateral plateau. d Preoperative planning suggested that an anterior approach to the knee should be made where the main area for fracture reduction is located. Through this anterior approach, articular reconstruction under direct vision and repair of the meniscus were planned. The articular reduction was done through an anterior approach (white arrow indicates reduced tibial spine fragment; black arrow, suture used for meniscal repair; and asterisk, tibial tuberosity). Finally medial buttressing was planned using MIPO. e–g Metaphyseal fragment reduction with percutaneous placement of pointed reduction forceps. The direction of the positioning screw was chosen from lateral to medial so as not to hinder medial plating. h–i Reduction between the medial and lateral condyles was done with a collinear reduction clamp. **j–k** Medial buttressing using MIPO was done through separate incisions. l–m Postoperative x-rays show restoration of the articular surface and anatomical alignment. K-wires used for the support of articular fragments should have been bent closer to the bone to reduce irritation during rehabilitation.

Complete articular fractures/bicondylar fractures (41-C)

As mentioned previously there are two different strategies for the treatment of bicondylar fractures. There is a choice between the use of a single lateral locked plate applied using a MIPO technique and dual plating via two separate incisions according to the fracture pattern.

Indications for dual plating (type C to type A strategy)

Most 41-C1 and some C2 fractures (41-C2.1, 41-C2.2) involve a large fragment of medial condyle and a split depression of the lateral condyle without significant metaphyseal comminution especially along the medial column ( Fig 19.1-8 ). Restoration of a medial strut is usually technically not demanding due to the simple fracture pattern.

Bicondylar fractures that are associated with a small posteromedial fragment need a direct buttressing to achieve adequate stability ( Fig 19.1-9 ). In this strategy a type C fracture is converted into a type B fracture by restoring the medial column. Then the lateral articular depression is reconstructed against the medial column and buttress plating of the lateral condyle follows.

a–b A 54-year-old woman sustained a leg injury in a car accident. X-ray (a) and a coronal CT scan (b) show a 41-C bicondylar fracture, consisting of a large medial condyle fragment and an articular depression of the lateral condyle.

a–c X-rays and 3-D CT scan show a coronal split of the medial condyle creating a posteromedial fragment. Also note the significant articular depression on the lateral condyle. Direct support of the posteromedial fragment, converting a type C to a type B fracture, is required to produce a stable bone block upon which the lateral column can be reconstructed.

Indications for lateral locked plating/MIPO (type C to type A strategy)

Those 41-C3 fractures with metaphyseal/diaphyseal complex fracture patterns of the medial column may be the main indications for the type C to type A strategy with a single lateral locked plating ( Fig 19.1-10 ). In this fracture pattern, an attempt to reconstruct the medial column by means of open reduction is technically challenging and can lead to a significant stripping of soft tissue.

a–b AP x-ray and 3-D CT show a 41-C3 fracture with comminution (fragmented wedge) on the medial side of the metaphyseal area. Attempting to convert the type C fracture to a type B fracture in this fracture pattern would run a significant risk of soft-tissue stripping from the small wedge fragments. Moreover, anatomical reduction of all these small pieces is extremely challenging and risks devitalizing the wedge fragments.

41-C fractures that are associated with metaphyseal comminution and with minimal articular depression are also good candidates for a type C to type A (MIPO) strategy ( Fig 19.1-11 ).