Tibia shaft fracture is a fracture of the proximal (upper) third of the tibia (lower leg bone). Due to the location of the tibia on the shin, it is the most commonly fractured long bone in the body.
Epidemiology Tibial shaft fractures are some of the most common long bone fractures in humans. They account for approximately 17% of lower extremity fractures. They also account for approximately 4% of fractures among Medicare patients. Tibial shaft fractures occur more often in males than females. The age distribution of these fractures is bimodal, with peaks in younger (20's) and older adults (50's-60's). Younger patients often sustain tibial shaft fractures from high energy trauma mechanisms such as motor vehicle accidents and sports injuries. In older adults, low-energy mechanisms like falls are most common. Tibial shaft fractures can be anatomically categorized by diaphysial location. Fractures of the midshaft are most frequent. Proximal and distal third fractures are less common.
Mechanism of injury Low energy tibial shaft fractures usually result from indirect torsional forces such as falls from standing heights, twisting injuries, or rotational forces applied to the leg. These mechanisms create rotational stress along the diaphysis. This typically results in a spiral fracture pattern. Spiral tibial fractures from these mechanisms are often associated with a fibular fracture at a different level. They also involve less severe soft tissue injury compared with high-energy mechanisms.
High energy fractures result from direct trauma such as motor vehicle accidents, falls from significant heights, or severe sports injuries. These mechanisms usually produce wedge or short oblique fractures with comminution. They are often associated with a fibular fracture at the same level. High energy fractures have a higher likelihood of severe soft tissue injuries, having associated compartment syndrome, and of being open fractures.
Anatomic location Proximal third fractures necessitate thorough assessment of the knee to exclude extension into the tibial plateau. Articular involvement may be difficult to detect on x-ray and in such instances may require a CT scan. Due to deforming muscular forces, proximal third fractures are prone to valgus and procurvatum malalignment during intramedullary nailing. In particular, the procurvatum results from the gastrocnemius pulling the distal fragment in to flexion while the patellar tendon pulls the proximal fragment in to extension. Valgus malalignment results from the per anserinus pulling the proximal fracture fragment in to varus. Spiral distal third tibial shaft are more commonly associated with posterior malleolar fractures. Extension to the posterior malleolus can affect syndesmotic stability. Careful evaluation of the ankle is thus required when such fracture patterns are present. CT scan may be warranted if X-ray findings are equivocal. Around 5% of all tibial fractures are bifocal, meaning there are 2 separate fractures of the tibia.
Clinical evaluation Clinical evaluation of tibial shaft fractures should begin with a thorough neurovascular assessment. This is essential in all cases and especially important in open injuries. Distal perfusion should be assessed by palpating the dorsalis pedis and posterior tibial pulses. Neurologic examination should include careful assessment of the common peroneal and tibial nerves. The soft tissue envelope should be evaluated. Fracture blisters may delay or contraindicate early operative reduction, particularly for periarticular fractures. Patients should be closely monitored for compartment syndrome with these fractures. Pain out of proportion to the injury serves as the most reliable clinical indicator. But compartment pressure measurements may assist in diagnosis. A differential between diastolic blood pressure and compartment pressure less than 30 mm Hg is indicative of compartment syndrome. Deep posterior compartment pressures can be elevated even when superficial compartments appear soft. There is an 8.1% risk of compartment syndrome in diaphyseal fractures, compared to proximal (1.6%) and distal (1.4%) fractures.
Classification Gustilo and Anderson Classification of open fractures Source:
Tscherne classfication of closed fractures source
classifies soft tissue injury in closed fractures
Treatment
Nonoperative treatment This may be appropriate for isolated, closed, low-energy injuries with minimal displacement and comminution, or for patients not able to undergo surgery. Treatment typically consists of fracture reduction followed by application of a long leg cast with progressive weight bearing. When casting, the knee should be positioned in approximately 0 to 15 degrees of flexion to facilitate early mobilization. Patients may begin weight bearing with crutches as tolerated. Progressing to full weight bearing should be considered by the second to fourth week. After three to six weeks, the long leg cast can often be transitioned to a patella-bearing cast or functional fracture brace. Union rates with nonoperative treatment are high, reaching up to 97%. But delayed weight bearing may occur in cases of delayed union or nonunion. Hindfoot stiffness is a notable limitation. Acceptable alignment following reduction includes less than 5 degrees of varus or valgus angulation, less than 10 degrees of anterior or posterior angulation (with under 5 degrees preferred), and less than 10 degrees of rotational deformity, with external rotation generally better tolerated than internal rotation. Shortening should be limited to less than 1 cm, as even 5 mm of distraction can significantly delay healing. At least 50% cortical contact is recommended. These are essentially the non-operative tolerances. Surgery is recommended for any fracture reduction that exceeds these parameters. Clinically, overall alignment can be assessed by ensuring collinearity of the anterior superior iliac spine, the center of the patella, and the base of the second proximal phalanx. Time to fracture union is approximately 16 ± 4 weeks but varies widely depending on fracture pattern and the degree of soft-tissue injury. Delayed union is typically defined as healing beyond 20 weeks. Nonunion is characterized by loss of healing potential, evidenced by persistent fracture gaps, sclerotic fracture ends, and lack of radiographic progression on serial imaging rather than time alone.
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