TIBIA/FIBULA SHAFT Fractures

EPIDEMIOLOGY

Fractures of the tibia and fibula shaft are the most common long bone fractures.

In an average population, there are about 26 tibial diaphyseal fractures per 100,000 population per year.

The highest incidence of adult tibia diaphyseal fractures seen in young males is between 15 and 19 years of age, with an incidence of 109 per 100,000 population per year.

The highest incidence of adult tibia diaphyseal fractures seen in women is between 90 and 99 years of age, with an incidence of 49 per 100,000 population per year.

The average age of a patient sustaining a tibia shaft fracture is 37 years, with men having an average age of 31 years and women 54 years.

Diaphyseal tibia fractures have the highest rate of nonunion for all long bones.

ANATOMY

The tibia is a long tubular bone with a triangular cross section. It has a subcutaneous anteromedial border and is bounded by four tight fascial compartments (anterior, lateral, posterior, and deep posterior) (Figs. 37.1 and 37.2).

Blood supply‌

• The nutrient artery arises from the posterior tibial artery, entering the posterolateral cortex distal to the origination of the soleus muscle. Once the vessel enters the intramedullary (IM) canal, it gives off three ascending branches and one descending branch. These give rise to the endosteal vascular tree, which anastomose with periosteal vessels arising from the anterior tibial artery.

• The anterior tibial artery is particularly vulnerable to injury as it passes through a hiatus in the interosseus membrane.

• The peroneal artery has an anterior communicating branch to the dorsalis pedis artery. It may

  therefore be occluded despite an intact dorsalis pedis pulse. The distal third is supplied by periosteal anastomoses around the ankle with branches entering the tibia through ligamentous attachments.

• There may be a watershed area at the junction of the middle and distal thirds (controversial).

• If the nutrient artery is disrupted, there is reversal of flow through the cortex, and the periosteal blood supply becomes more important. This emphasizes the importance of preserving periosteal attachments during fixation.

• The fibula is responsible for 6% to 17% of a weight-bearing load. Its major function is for muscle attachment.

• The common peroneal nerve courses around the neck of the fibula, which is nearly subcutaneous

  in this region; it is therefore especially vulnerable to direct blows or traction injuries at this level.

  MECHANISM OF INJURY

Direct

• High-energy bending: Motor vehicle accident

  • Transverse, comminuted, displaced fractures commonly occur.

  • Highly comminuted or segmental patterns are associated with extensive soft tissue compromise.

  • Compartment syndrome and open fractures must be ruled out.

• Penetrating: Gunshot

  • The injury pattern is variable but usually comminuted.

  • Low-velocity missiles (handguns) do not pose the same degree of problem from bone or soft tissue damage that high-energy (motor vehicle accident) or high-velocity (shotguns, assault weapons) mechanisms may cause.

• Low-energy bending: Three or four point

• Short oblique or transverse fractures occur, with a possible butterfly fragment.

  • Compartment syndrome and open fractures may still occur.

• Fibula shaft fractures: These typically result from direct trauma to the lateral aspect of the leg. Spiral fractures are seen proximally with rotational ankle fractures or low-energy twisting tibial injuries.

Indirect

• Torsional mechanisms

  • Twisting with the foot fixed and falls from low heights are causes.

  • These spiral, nondisplaced fractures have minimal comminution associated with little soft tissue damage.

  • Type 1 open fractures may be seen with this mechanism.

• Stress fractures

  • In military recruits, these injuries most commonly occur at the metaphyseal–diaphyseal junction, with sclerosis being most marked at the posteromedial cortex.

  • In ballet dancers, these fractures most commonly occur in the middle third; they are insidious

    in onset and are overuse injuries. “Dreaded black line” is pathognomonic (Fig. 37.3).

  • Plain radiographic findings may be delayed several weeks. Magnetic resonance imaging (MRI) is very sensitive for detecting these injuries.

     

     

     

    CLINICAL EVALUATION

Evaluation of neurovascular status is critical. Dorsalis pedis and posterior tibial artery pulses must be evaluated and documented, especially in open fractures in which vascular flaps may be necessary. Common peroneal and tibial nerve integrity must be documented.

Assess soft tissue injury. Fracture blisters may contraindicate early open reduction of periarticular fractures.

Monitor for compartment syndrome. Pain out of proportion to the injury is the most reliable sign of compartment syndrome. Compartment pressure measurements that have been used as an indication for four-compartment fasciotomy have been a pressure within 30 mm Hg of diastolic pressure (ΔP

<30 mm Hg). Deep posterior compartment pressures may be elevated in the presence of a soft superficial posterior compartment.

Tibial fractures may be associated with knee ligament injuries.

About 5% of all tibial fractures are bifocal, with two separate fractures of the tibia.

RADIOGRAPHIC EVALUATION

Radiographic evaluation must include the entire tibia (anteroposterior [AP] and lateral views) with visualization of the ankle and knee joints.

Oblique views may be helpful to further characterize the fracture pattern.

Postreduction radiographs should include the knee and ankle for alignment and preoperative planning.

A surgeon should look for the following features on the AP and lateral radiographs:

• The presence of comminution: This signifies a higher energy injury.

• The distance that bone fragments have displaced from their anatomic location: Widely displaced fragments suggest that the soft tissue attachments have been damaged and the fragments may be avascular.

• Osseous defects: These may suggest missing bone or open wounds.

• Fracture lines may extend proximally to the knee or distally to the ankle joints.

• The quality of the bone: Is there evidence of osteopenia, metastases, or a previous fracture?

• Osteoarthritis or the presence of a knee arthroplasty: Either may change the treatment method selected by the surgeon.

• Air in the soft tissues: These are usually secondary to open fracture but may also signify the

  presence of gas gangrene, necrotizing fasciitis, or other anaerobic infections.

Computed tomography (CT) and MRI are generally not necessary. CT may be useful in metaphyseal fractures if articular extension is suspected.

Technetium bone scanning and MRI scanning may be useful in diagnosing stress fractures before these injuries become obvious on plain radiographs.

Angiography is indicated if an arterial injury is suspected, based on ankle–brachial indexes (ABIs) or diminished pulses. (See Chapter 34.)

CLASSIFICATION

Poor sensitivity, reproducibility, and interobserver reliability have been reported for most classification schemes.

Descriptive

Open versus closed

Anatomic location: proximal, middle, or distal third

Fragment number and position: comminution, butterfly fragments

Configuration: transverse, spiral, oblique

Angulation: varus/valgus, anterior/posterior

Shortening

Displacement: percentage of cortical contact

Rotation

Associated injuries

Orthopaedic Trauma Association Classification of Tibial Fractures See Fracture and Dislocation Classification Compendium at http://www.ota.org/compendium/compendium.html.

Gustilo and Anderson Classification of Open Fractures (Final Grading Done after Debridement)

Type I: Clean skin opening of <1 cm, usually a “poke hole” from inside to outside; minimal muscle contusion; simple transverse or short oblique fractures

Type II: Laceration >1 cm long, with extensive soft tissue damage; minimal to moderate crushing component; simple transverse or short oblique fractures with minimal comminution

Type III: Extensive soft tissue damage greater than 10 cm in length, including muscles, skin, and neurovascular structures; often a high-energy injury with a severe crushing component

IIIA: Extensive soft tissue laceration, adequate soft tissue coverage; segmental fractures, gunshot injuries, minimal periosteal stripping

IIIB: Extensive soft tissue injury with periosteal stripping and bone exposure requiring soft tissue flap closure; usually associated with massive contamination

IIIC: Vascular injury requiring repair

Tscherne Classification of Closed Fractures

This classifies soft tissue injury in closed fractures and takes into account indirect versus direct injury mechanisms.

Grade 0: Injury from indirect forces with negligible soft tissue damage

Grade I: Closed fracture caused by low to moderate energy mechanisms, with superficial abrasions or contusions of soft tissues overlying the fracture

Grade II: Closed fracture with significant muscle contusion, with possible deep, contaminated

skin abrasions associated with moderate to severe energy mechanisms and skeletal injury; high risk for compartment syndrome

Grade III: Extensive crushing of soft tissues, with subcutaneous degloving or avulsion, with arterial disruption or established compartment syndrome

TREATMENT

Nonoperative

Fracture reduction followed by application of a long leg cast with progressive weight bearing can be used for isolated, closed, low-energy fractures with minimal displacement and comminution.

Cast with the knee in 0 to 5 degrees of flexion to allow for weight bearing with crutches as soon as tolerated by patient, with advancement to full weight bearing by the second to fourth week.

After 3 to 6 weeks, the long leg cast may be exchanged for a patella bearing cast or fracture brace.

Union rates as high as 97% are reported, although with delayed weight bearing related to delayed union or nonunion. The major limitation seen is hindfoot stiffness.

Acceptable Fracture Reduction

Less than 5 degrees of varus/valgus angulation is recommended.

Less than 10 degrees of anterior/posterior angulation is recommended (<5 degrees preferred).

Less than 10 degrees of rotational deformity is recommended, with external rotation better tolerated than internal rotation.

Less than 1 cm of shortening; 5 mm of distraction may delay healing 8 to 12 months.

More than 50% cortical contact is recommended.

Roughly, the anterior superior iliac spine, center of the patella, and base of the second proximal phalanx should be collinear.

Time to Union

The average time is 16 ± 4 weeks: This is highly variable, depending on fracture pattern and soft tissue injury.

Delayed union is defined as >20 weeks.

Nonunion: This occurs when clinical and radiographic signs demonstrate that the potential for union is lost, including sclerotic ends at the fracture site and a persistent gap unchanged for several weeks. Nonunion has also been defined as lack of healing 9 months after fracture, but more accurately as no change in radiographic appearance on successive radiographs.

Tibia Stress Fracture

A short leg cast may be necessary, with partial weight-bearing ambulation.

Use of adjuvants, such as bone stimulation, have yet to be proven.

Surgery is reserved for those refractory to nonoperative treatment or those that displace.

Fibula Shaft Fracture

Treatment consists of weight bearing as tolerated.

Although not required for healing, a short period of immobilization may be used to minimize pain.

Nonunion is uncommon because of the extensive muscular attachments.

Operative

Intramedullary Nailing

IM nailing carries the advantages of preservation of periosteal blood supply and limited soft tissue damage. In addition, it carries the biomechanical advantages of being able to control alignment, translation, and rotation. It is therefore recommended for most fracture patterns.

Locked versus unlocked nail

• Locked nail: This provides rotational control; it is effective in preventing shortening in comminuted fractures and those with significant bone loss. Interlocking screws can be removed at a later time to dynamize the fracture site, if needed, for healing.

• Nonlocked nail: This allows impaction at the fracture site with weight bearing, but it is difficult to control rotation. Nonlocked nails are rarely used.

Reamed versus unreamed nail

• Reamed nail: This is indicated for most closed and open fractures. It allows excellent IM splinting of the fracture and use of a larger diameter (allowing for larger locking bolts), stronger nail (to resist bending forces). Benefits of reaming include enhanced periosteal blood flow.

• Unreamed nail: This is thought to preserve the IM blood supply in open fractures where the periosteal supply has been destroyed. It involves quicker surgery without reaming. Recent studies have shown this to be acceptable in closed tibial fractures. Hardware failure is related to implant size, not reaming technique.

  Flexible Nails (Enders, Rush Rods)

Multiple curved IM pins exert a spring force to resist angulation and rotation, with minimal damage to the medullary circulation.

These are rarely used in the United States because of the predominance of unstable fracture patterns and success with interlocking nails.

They are currently only recommended in children or adolescents with open physes and in adults with exceptionally narrow canals.

External Fixation

Primarily used to treat severe open fractures, it can also be indicated in closed fractures complicated by compartment syndrome, concomitant head injury, or burns.

Its popularity in the United States has waned with the increased use of reamed nails for most open fractures.

Union rates: The rate is up to 90%, with an average of 3.6 months to union.

The incidence of pin tract infections is 10% to 15%.

Plates and Screws

These are generally reserved for fractures extending into the metaphysis or epiphysis.

Reported success rates are as high as 97%.

Complication rates of infection, wound breakdown, and malunion or nonunion increase with higher energy injury patterns.

Proximal Tibia Fractures

These account for about 7% of all tibia diaphyseal fractures.

These fractures are notoriously difficult to nail because they frequently become malaligned, the commonest deformities being valgus and apex anterior angulation.

Nailing may require use of special techniques such as blocking screws, unicortical plating, intraoperative external fixation, or a lateral starting point.

Use of a percutaneously inserted plate has been popularized recently.

Distal Tibia Fractures

The risk for malalignment also exists with the use of an IM nail.

With IM nailing, fibula plating or use of blocking screws may help to prevent malalignment.

Use of a percutaneously inserted plate has been popular recently.

Tibia Fracture with an Intact Fibula

If the tibia fracture is nondisplaced, treatment consists of long leg casting with early weight bearing. Close observation is indicated to recognize any varus tendency.

Some authors recommend IM nailing even if tibia fracture is nondisplaced.

A potential risk of varus malunion exists (25%), particularly in patients >20 years.

Fasciotomy

Evidence of compartment syndrome is an indication for emergent fasciotomy of all four-muscle compartments of the leg (anterior, lateral, superficial, and deep posterior) through one or multiple incision techniques. Following operative fracture fixation, the fascial openings should not be reapproximated.

COMPLICATIONS

Malunion: This includes any deformity outside the acceptable range. This is seen with nonoperative treatments and metaphyseal fractures.

Nonunion: This is associated with high-velocity injuries, open fractures (especially Gustilo grade III), infection, intact fibula, inadequate fixation, and initial fracture displacement.

Infection is more common following open fracture.

Soft tissue loss: Delaying wound coverage for greater than 7 to 10 days in open fractures has been associated with higher rates of infection. Local rotational flaps or free flaps may be needed for adequate coverage.

Stiffness at the knee and/or ankle may occur with nonoperative care.

Knee pain: This is the most common complication associated with IM tibial nailing.

Hardware breakage: Nail and locking screw breakage rates depend on the size of the nail used and the type of metal from which it is made. Larger reamed nails have larger cross screws; the incidence of nail and screw breakage is greater with unreamed nails that utilize smaller diameter locking screws.

Thermal necrosis of the tibial diaphysis following reaming is a theoretical complication. Recent basic science work has discounted use of a tourniquet as a cause of thermal necrosis.

Reflex sympathetic dystrophy: This is most common in patients unable to bear weight early and with prolonged cast immobilization. It is characterized by initial pain and swelling followed by atrophy of limb. Radiographic signs are spotty demineralization of foot and distal tibia and equinovarus ankle. It is treated by elastic compression stockings, weight bearing, sympathetic blocks, and foot orthoses, accompanied by aggressive physical therapy.

Compartment syndrome: Involvement of the anterior compartment is most common. Highest pressures occur at the time of open or closed reduction. It may require fasciotomy. Muscle death occurs after 6 to 8 hours. Deep posterior compartment syndrome may be missed because of uninvolved overlying superficial compartment and results in claw toes.

Neurovascular injury: Vascular compromise is uncommon except with high-velocity, markedly displaced, often open fractures. It most commonly occurs as the anterior tibial artery traverses the interosseous membrane of the proximal leg. It may require saphenous vein interposition graft. The common peroneal nerve is vulnerable to direct injuries to the proximal fibula as well as fractures with significant varus angulation. Overzealous traction can result in distraction injuries to the nerve, and inadequate cast molding/padding may result in neurapraxia.

Fat embolism is a complication.

Claw toe deformity: This is associated with scarring of extensor tendons or ischemia of posterior compartment muscles.