Key points

Anatomy

Distal tibial metaphyseal fractures are those that extend within approximately 4 cm of the tibial plafond. The Orthopedic Trauma Association’s (OTA) fracture classification, similar to Muller’s definition, defines these fractures as those contained within a square with a side length equal to the widest portion of the epiphysis; extra-articular fractures are those with no or with simple extension of a nondisplaced fracture line into the plafond.

In an axial cross section of the tibia, moving distally from the diaphysis to the metaphysis, the shape of the tibia transitions from that of a triangle with an anterior apex to a more circular shape. Compared with that of the diaphysis, metaphyseal cortical bone is thinner and the central cortex is replaced by secondary spongiosa and cancellous bone, making screw fixation more challenging. However, the material properties of this cancellous bone vary based on the age and activity level of patients and can be quite dense in patients less than 50 years old, which allows for stronger screw purchase. The medullary canal of the tibia has an hourglass shape, with a narrow diaphyseal region and wider metaphyseal regions. This flaring out of the metaphyseal region poses a challenge for intramedullary (IM) fixation, as a tight endosteal fit with the nail is achieved only in the middle few centimeters of the diaphysis.

The fibula is situated posterolateral to the tibia and distally joins with the lateral surface of the distal tibial metaphysis at the inferior tibiofibular articulation. This articulation is composed of the lateral syndesmotic ligaments and the distal interosseous membrane and is the reason why the fibula is often injured in higher-energy fracture patterns. Conversely, the inferior tibiofibular articulation is important because an intact or repaired fibula may help maintain tibial alignment during fracture healing. The lateral malleolus and the lateral ligamentous complex are critical to maintaining stability at the ankle joint.

Blood supply to the distal tibia is derived from 2 sources. Perfusion to the outer one-tenth to one-third of the tibial cortex is extraosseous and arises from a network of periosteal vessels on the medial surface that are branches of the anterior and posterior tibial arteries. The inner two-thirds of the distal tibia are supplied by intraosseous nutrient arteries, which are branches of the posterior tibial artery. Segmental fractures can potentially obliterate this intraosseous supply, leaving only the extraosseous supply intact. As a result, significant periosteal stripping during fixation may destroy the remaining blood supply and cause avascular necrosis of the bone, with consequent complications in bone healing.

At the level of the distal tibia, the structures most at risk during medial fixation are the great saphenous vein and the saphenous nerve. This vein and the major branch of the saphenous nerve intersect at the posterior cortex of the tibia at an average of 10 cm from the tip of the medial malleolus and then pass the anterior cortex approximately 3 cm from the tip of the medial malleolus.

Anatomy

Distal tibial metaphyseal fractures are those that extend within approximately 4 cm of the tibial plafond. The Orthopedic Trauma Association’s (OTA) fracture classification, similar to Muller’s definition, defines these fractures as those contained within a square with a side length equal to the widest portion of the epiphysis; extra-articular fractures are those with no or with simple extension of a nondisplaced fracture line into the plafond.

In an axial cross section of the tibia, moving distally from the diaphysis to the metaphysis, the shape of the tibia transitions from that of a triangle with an anterior apex to a more circular shape. Compared with that of the diaphysis, metaphyseal cortical bone is thinner and the central cortex is replaced by secondary spongiosa and cancellous bone, making screw fixation more challenging. However, the material properties of this cancellous bone vary based on the age and activity level of patients and can be quite dense in patients less than 50 years old, which allows for stronger screw purchase. The medullary canal of the tibia has an hourglass shape, with a narrow diaphyseal region and wider metaphyseal regions. This flaring out of the metaphyseal region poses a challenge for intramedullary (IM) fixation, as a tight endosteal fit with the nail is achieved only in the middle few centimeters of the diaphysis.

The fibula is situated posterolateral to the tibia and distally joins with the lateral surface of the distal tibial metaphysis at the inferior tibiofibular articulation. This articulation is composed of the lateral syndesmotic ligaments and the distal interosseous membrane and is the reason why the fibula is often injured in higher-energy fracture patterns. Conversely, the inferior tibiofibular articulation is important because an intact or repaired fibula may help maintain tibial alignment during fracture healing. The lateral malleolus and the lateral ligamentous complex are critical to maintaining stability at the ankle joint.

Blood supply to the distal tibia is derived from 2 sources. Perfusion to the outer one-tenth to one-third of the tibial cortex is extraosseous and arises from a network of periosteal vessels on the medial surface that are branches of the anterior and posterior tibial arteries. The inner two-thirds of the distal tibia are supplied by intraosseous nutrient arteries, which are branches of the posterior tibial artery. Segmental fractures can potentially obliterate this intraosseous supply, leaving only the extraosseous supply intact. As a result, significant periosteal stripping during fixation may destroy the remaining blood supply and cause avascular necrosis of the bone, with consequent complications in bone healing.

At the level of the distal tibia, the structures most at risk during medial fixation are the great saphenous vein and the saphenous nerve. This vein and the major branch of the saphenous nerve intersect at the posterior cortex of the tibia at an average of 10 cm from the tip of the medial malleolus and then pass the anterior cortex approximately 3 cm from the tip of the medial malleolus.

Classification

Multiple classification systems have been developed to describe distal tibia fractures. Soft tissue injury can be evaluated with the Gustilo-Anderson or Tscherne-Gotzen classification systems for open or closed fractures, respectively. Robinson and colleagues developed a classification system after studying distal tibia metaphyseal fractures treated with IM nailing (IMN). Two distinct injuries were noted: type I fractures resulted from a direct bending force producing a transverse fracture pattern, and type II fractures resulted from a torsional force producing a spiral/helical fracture pattern of the tibia with an associated oblique fibular fracture at the same or different level. The Association for Osteosynthesis/Association for the Study of Internal Fixation (AO/ASIF) system was also developed primarily for use in research and describes all fractures in the form of an alphanumeric code. Distal tibial extra-articular metaphyseal fractures are 43-A (4 = tibia, 3 = distal metaphysis, A = extra-articular). Based on the degree of comminution of the fracture, 43-A1 are noncomminuted extra-articular fractures, 43-A2 are wedge fractures, and 43-A3 are comminuted extra-articular fractures. Simple extension of the fracture line into the tibiotalar joint without depression of the joint surface is classified as 43-B1 and can often be treated in the same manner as extra-articular (43-A) fractures.

Presentation and initial management

Distal tibia fractures are frequently caused by high-energy trauma and are often associated with life-threatening injuries. Management of these injuries should be initiated according to Advanced Trauma Life Support principles.

A thorough medical history should be obtained identifying patient factors associated with the risk of soft tissue complications, poor fracture healing, and fixation failure. Preexisting peripheral vascular disease, smoking, diabetes mellitus and associated neuropathy, alcoholism, malnutrition, and osteoporosis have all been associated with an increased risk of infection and nonunion and may affect the choice of fixation.

A complete physical examination should be performed, and it is critical to evaluate for neurovascular compromise of the lower extremity. In the event of vascular compromise, immediate fracture reduction should be attempted. A full evaluation for possible compartment syndrome is mandatory, especially in closed injuries; urgent 4-compartment fasciotomy should be performed if suspected.

The soft tissue envelope of the involved lower extremity should be closely examined. Early recognition of impending skin compromise and urgent fracture reduction reduces the risk of conversion to an open fracture and a compromised surgical approach. Soft tissue injury signs include edema, ecchymosis, fracture blisters, and open fracture wounds; injury is often greater with distal metaphyseal fractures than with diaphyseal fractures. Open distal tibia fractures occur with an approximate incidence of 20%; the medial surface of the tibia, covered by thin subcutaneous tissue, is the most common site of open injury. Prompt administration of antibiotics, tetanus vaccination, and urgent debridement and irrigation should be performed. The limb should always be splinted pending definitive management.

Radiography/imaging

Radiographic imaging is necessary for injury classification and determining surgical technique and approach. Imaging of the fracture should include orthogonal views of the distal tibia and ankle mortise. Full-length radiographs of the tibia and fibula and orthogonal views of the knee are routinely obtained. Computed tomography (CT) is also useful for preoperative planning as it has been shown to add information in 82% of patients and change the surgical plan in 64%. It is especially recommended if there is concern for intra-articular extension of the fracture.

It is important to define similar standards of radiographic outcomes that can be used by all studies, but this has not always been the case. Union can be defined as healing of at least 3 of 4 cortices on anteroposterior and lateral radiographs. Nonunion can be defined as a lack of healing within 6 months. Malunion is typically defined as fracture healing of greater than 5° of angular deformity in any plane or shortening greater than 10 mm.

Nonoperative management

Nonoperative management of distal tibia metaphyseal fractures involves the use of casting cast bracing and avoids the risks of surgery and postoperative complications. There are, however, few published studies examining nonoperative management of distal tibia fractures.

Sarmiento and Latta reviewed 450 cases of closed fractures of the distal tibia. Nonoperative management was chosen for fractures that were closed, with initial shortening less than 15 mm and angulation after manipulation less than 5° in any plane. A long leg cast was applied for these fractures, with the knee in 7° of flexion and the ankle in 90° of dorsiflexion. Patients were allowed to bear weight as tolerated and mobilize using walking aids. Early functional bracing demonstrated a longer healing time, with a mean time to union of 16.6 weeks and malunion of 13.1%. Of note, malunion was defined as greater than 7° angulation or 12 mm shortening, which is more forgiving than the accepted 5° angulation or 10 mm shortening.

Similarly, Böstman and colleagues reviewed 103 patients managed initially with a long leg cast and subsequent IMN if there was loss of reduction. A malunion rate of 26.4% was observed in the nonoperatively managed group. Approximately 4% of the patients developed nonunion and required bone grafting. The time to union was faster in those who underwent subsequent IMN than those who were managed by functional bracing alone.

Although surgical complications are minimized with nonoperative management, significant complications have been reported with its use. For axially unstable fractures, the risk of shortening is substantial. Loss of reduction with angular malunion is also an issue, with approximately 33% of patients healing with a deformity of greater than 5° in any plane. The increased occurrence of malunion leads to increased tibiotalar contact pressures, which can cause significant hindfoot and ankle stiffness in these patients. In fact, joint stiffness caused by conservative treatment has been reported to be as high as 40% in these cases. Because of these high rates of shortening, angulation, and malunion, nonoperative management should be used only for a select few patients with relatively stable fractures and the opportunity for close monitoring.

Operative management

Most distal tibial metaphyseal fractures necessitate operative management because of the potential for displacement and malunion with conservative treatment. After the initial reduction and stabilization in the emergency setting, patients should be medically optimized for definitive fixation. Classically, these fractures are treated with the use of IMN or plating, although the use of external fixation as the definitive management has also been described.

For open fractures, surgical debridement has historically been recommended within 6 hours of presentation; but the evidence for this time frame is weak, and multiple studies have failed to show any impact in infection rate with debridement occurring after 6 hours. Evidence does support the early administration of intravenous broad-spectrum antibiotics, and the Tscherne-Gotzen classification system can be used to guide surgical management in open wounds. Grade 0 and I fractures are amenable to definitive fixation within 24 hours, and grade II and III fractures are initially stabilized with external fixation until the soft tissue injury allows definitive fixation at a later date. With delays of 7 to 24 days for definitive treatment of the higher-grade injuries, a significant reduction in complication rates has been observed.

IMN

IM devices for diaphyseal tibia fractures have been implemented since the 1940s, allowing for sufficient movement at the fracture site to induce callus formation while minimizing the risk of pseudoarthrosis and malunion. In distal tibia fractures, IMN is associated with high union rates and minimally interferes with the soft tissue envelope at the time of surgery. Historically, this technique was reserved for fractures greater than 5 cm proximal to the ankle joint; but with newer nail designs, this limitation no longer exists.

Operative Technique

In comparison with plate fixation, IMN can be performed acutely without the need to wait for soft tissue stabilization. Initial reduction of the fracture may be achieved with gentle manipulation and traction by an assistant or with the use of percutaneously placed pointed reduction forceps ( Fig. 1 ). The use of gravity while flexing the knee over a support, such as a radiolucent foam wedge, may also assist reduction. Alternatively, a femoral distractor can provide length and alignment during traction and fracture reduction ( Fig. 2 A). Pins are placed proximally in the posterior metaphysis of the tibia and distally in the tibia (see Fig. 2 B), serving as an additional check to anatomic reduction (ie, the nail should be perpendicular to the pin and plafond; see Fig. 2 C). The use of a femoral distractor avoids the need for conventional fracture tables and provides complete control over the involved extremity. The importance of achieving and maintaining reduction of the fracture cannot be understated, as this is often the most difficult aspect of nailing distal tibial metaphyseal fractures.

AP ( A ) and lateral ( B ) fluoroscopic images showing percutaneous application of pointed reduction clamps. The near anatomic alignment achieved simplifies ball-tipped wire passage and initial reaming.

( A ) Clinical image of the tibia in preparation for nailing with femoral distractor in place ready for nail insertion. ( Inset ) Radiograph of typical fracture where this is of greatest utility; comminuted distal third fracture of tibia with associated fibula fracture at the same level. ( B ) Radiograph of proximal tibia with distractor pin in place. ( C ) Radiograph of the distal tibia with the distractor pin in place. Again the pin should be placed distal and posterior to the nail path, doing so will aid in confirming that restoration of alignment has been achieved. The distal pin, like the proximal pin, should be in line with the posterior cortex of the tibia. Note in the inset that the pin is posterior to the nail path and in line with the posterior cortex of the tibia.

The starting point of the IM nail is similar to that of diaphyseal tibial nails; however, the end point of the guidewire must be center-center to prevent deformity ( Fig. 3 ). The use of a guidewire with a minimal bend at the tip is helpful, and the wire should be kept perpendicular to the tibiotalar joint line during reaming to minimize deformity in the coronal plane. If intra-articular extension of the fracture line exists, lag screws should be placed before reaming and nailing to stabilize the fracture at the metaphysis and prevent propagation or displacement; but care must be taken to avoid blocking the passage of the subsequent nail.

Placement of the guidewire center-center and fully seated in the distal metaphysis is essential to avoiding final deformity. It is imperative that a true anteroposterior view ( A ) as well as a true lateral view ( B ) be obtained. Note the slight anterior bend at the terminal aspect of the wire allowing for precise positioning as well as matching the slight anterior bend of many commonly used nails.

Unlike diaphyseal fractures, the insertion of the nail in distal metaphyseal fractures does not result in fracture reduction; consequently, careful control of the distal fragment is critical to allow the nail to advance centrally into the distal fragment in both anteroposterior and lateral planes. Eccentric reaming or failure to control the distal fragment can lead to significant malalignment and deformity ( Fig. 4 ). Percutaneous bone reduction clamps are particularly helpful in spiral/oblique fractures in facilitating reduction. In the case of open fractures, the application of small fragment plates for provisional reduction has been described in combination with nailing. Distal locking of the nail with multiple distal fixation points and the use of at least 3 locking screws are recommended to facilitate reduction to healing ( Fig. 5 ).

Note the poor alignment established before reaming results in eccentric distal nail placement and significant malreduction. It is imperative that the alignment is confirmed on both anteroposterior and lateral views before reaming. In this case, reduction would have been facilitated by initial reduction and plating of the fibula.

This highly unstable distal tibia fracture has been stabilized with an IM fibular implant as well as multiple fixed-angle screws in 2 planes. In this case, the fixed-angle screws were chosen because of the extremely poor bone and concern for backing out of the interlock. Acceptable alignment has been achieved on both the anteroposterior ( A ) and lateral ( B ) views.

Approach

There are multiple surgical approaches to the proximal tibia for nailing, and these include the following:

• 1.
  

  Medial parapatellar tendon : This approach is the most common starting point but is prone to valgus malalignment when used to treat proximal tibial fractures.

  
  
• 2.
  

  Lateral parapatellar tendon : This approach aids in maintaining the reduction of proximal metaphyseal fractures but makes it more difficult to reach the correct starting point.

  
  
• 3.
  

  Patellar tendon splitting : This approach gives direct access to the starting point but can inadvertently damage the patellar tendon or lead to patella baja.

  
  
• 4.
  

  Semiextended medial or lateral parapatellar : The advantages include ease of positioning and imaging and aiding in the reduction of proximal and distal fractures. Inadvertent injury to femoral cartilage is possible as well as anterior nail migration during reaming.

  
  
• 5.
  

  Suprapatellar (trans quadriceps tendon) : This approach is similar to the semiextended technique but requires special instruments. Inadvertent trochlear damage to the patella and femur is possible, and deposition of reaming debris in the knee is a concern.

The use of one of the semiextended techniques, as described in the literature, can be extremely helpful when nailing distal shaft fractures, as it allows for surgical approach to the fibula as well as more intuitive control of the tibia and ease of fluoroscopic viewing ( Fig. 6 ).

( A ) The lateral view of an entry wire properly positioned in the proximal tibia during parapatellar extended nailing. Note the wire penetrates the proximal tibia behind the anterior cortex. ( B ) The anteroposterior view of the same entry site, showing the wire properly positioned and aligning with the lateral aspect of the tibial spine. ( C ) An intraoperative view showing a guidewire in place with the knee in the semiextended position.

Blocking (Poller) Screws

The use of Poller screws may be required to allow the passage of the nail into the desired location by blocking the nail passage into an undesirable location, and this is often done initially with a medium-sized Kirschner wire (K wire) ( Fig. 7 ). These wires can be inserted percutaneously in the sagittal or coronal plane adjacent to the nail along the concave side of an observed deformity to decrease the diameter of the medullary canal. Anteroposterior blocking screws placed medially in the distal fragment will help correct a varus deformity, whereas anteroposterior blocking screws placed laterally will help to correct a valgus deformity ( Fig. 8 ). In a clinical series of 21 tibial fractures managed with IM nails and blocking screws, blocking screws were shown to improve alignment with minimal risk or complications. Additionally, blocking screws help facilitate reduction, prevent nail translation, and increase the strength of the fixation construct. Still, blocking screws are more helpful in holding reduction than achieving it initially because the distal fragment is often short (ie, 3–4 cm) and the lever arm of the blocking screw construct makes angular correction challenging. Some surgeons choose to place smaller-diameter 2.0- to 2.5-mm wires as blocking pins as they allow easier passage of the reamers and the nail with the risk of fracture propagation, as discussed earlier. These pins can be easily changed to 3.5-mm screws after the nail is fully seated and all interlocks have been placed.

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