Fracture, Proximal Tibia



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Fracture, Proximal Tibia
Steven G. Reece
Basics
  • Tibial plateau fractures occur as a result of:
    • Force directed either medially (valgus deformity) or laterally (varus deformity)
    • Axial compressive force
    • Combination of both
  • An axial compressive force, as with a fall from a height, landing on an extended knee, usually results in a bicondylar type of fracture.
  • Associated ligamentous injuries have been postulated to occur owing to continued deforming force after the fracture has been sustained.
    • 68% of tibial plateau fractures have posterolateral ligamentous corner injury (1).
    • These ligamentous injuries may not always occur after the fracture but may be coincident with the tibial plateau fracture.
Description
  • Fracture that includes the articular surface of the medial and/or lateral tibial condyles
  • Synonym(s): Tibial plateau fracture
  • First coined a “fender fracture” by Cotton in 1929
  • 40–60% of tibial plateau fractures involve an automobile hitting a pedestrian. Fracture results from a medially directed (valgus-deforming) force.
Epidemiology
  • Tibial plateau fractures account for ∼1% of all fractures and 8% of fractures in the elderly.
  • Lateral tibial plateau fractures account for 55–70%.
  • Bilateral plateau fractures account for 11–31%.
  • Medial plateau fractures account for 10–23%.
Risk Factors
  • Osteoporosis
  • Perioperative fracture associated with total or unicompartmental knee arthroplasty (2)
  • Sports: Skiing, football
Commonly Associated Conditions
  • Tibial plateau fractures often accompany a predictable pattern of associated soft tissue knee injury.
    • Medial tibial plateau fracture: Lateral collateral ligament and medial meniscus injuries
    • Lateral tibial plateau fracture: Medial collateral ligament and lateral meniscus injuries
    • Anterior cruciate ligament injuries can be seen with either medial or lateral plateau fractures.
  • Owing to brisk hemorrhage and swelling, tibial plateau fractures can be associated with acute compartment syndrome.
Diagnosis
  • X-ray: Anteroposterior (AP), lateral, oblique
  • MRI: Better assessment of associated ligamentous injury and osteochondral injury
  • CT scan: Best to assess bone deformity
  • Schatzker classification system for tibial plateau fractures (3):
    • Type I: Lateral split
    • Type II: Split with depression
    • Type III: Pure lateral depression
    • Type IV: Pure medial depression
    • Type V: Bicondylar
    • Type VI: Split extends to metadiaphysis.
  • Ancillary studies: Knee aspirate may help to reveal the presence of fat globules (indicating osteochondral injury) and to reduce pain.
History
  • An accurate history will help to determine the direction of the force, velocity (high vs low), and initial deformity produced.
  • Swelling can be an immediate effusion or delayed ± lower leg swelling.
Physical Exam
  • Signs and symptoms:
    • Painful swollen knee
    • Unable to bear weight
    • Also may have compartment syndrome signs and symptoms
    • Key to diagnosing compartment syndrome is pain out of proportion to physical examination findings.
  • Physical examination:
    • Most accurate way to evaluate the extent of the soft tissue injuries
    • Allows for evaluation of the vascular and neurologic status of the extremity
    • Gives insight into any associated ligamentous injuries and subsequent stability of the extremity
    • Pain and swelling about the knee may be associated with varus or valgus knee deformity.
    • Visible knee deformity indicates a severe injury.
    • Tenderness to palpation is noted over the medial and/or lateral tibial plateau.
    • Associated ligamentous injuries may show tenderness to palpation and instability of the collateral or cruciate ligaments.
    • Key finding is excursion of endpoint movement.
    • Large hemarthrosis usually is present.
    • If not present, it may indicate a torn capsule if the plateau is depressed.
    • Document distal pulses.
    • Check neurologic status with focus on the peroneal nerve and tendon function.
    • Check for abrasions or possible open fracture.
    • Watch for compartment syndrome findings:
      • Pain out of proportion to the physical examination findings
      • Pressure or tightness in the compartment
      • Pallor
      • Paresthesias
      • Paralysis: Sign of cell death and need for immediate compartment release
Diagnostic Tests & Interpretation
Imaging
  • Standard radiographs in anteroposterior (AP), lateral, and 2 oblique views;
    • Initial x-rays may miss a small tibial plateau fracture.
    • High index of suspicion must be maintained based on mechanism of injury, presence/absence of an effusion, and joint instability.
    • Series provides information allowing for accurate assessment of the fracture pattern.
      • Internal oblique view improves assessment of the lateral plateau.
      • External oblique view improves assessment of the medial plateau.
      • Tunnel view helpful if suspicious for intercondylar eminence fractures
      • Lateral view gives information on depression.
        • Medial side is concave.
        • Lateral side is convex.
    • Posterior collateral ligament injury may show avulsion fracture.
  • Tomography in the AP and lateral planes:
    • Reveals extent and position of the fracture lines.
    • Allows visualization of areas of depression.
  • CT scan:
    • Image of choice if negative films but high index of suspicion for fracture
    • Provides cross-sectional and sagittal assessment of the fracture pattern
    • If necessary, three-dimensional reconstructions can be provided to enhance the understanding of the fracture.
  • MRI: Allows for assessment of associated ligamentous injuries; may not show fracture well
  • Arteriography:
    • Should be considered in any tibial plateau fracture where the stability of the joint is in question.
    • Also may use ABI If <0.8, then indicates arterial insult.
    • Medial plateau fractures have a high incidence of vascular insult (owing to greater energy injuring force).
    • Arteriography/ABI should be seriously considered.
    • Presence of a palpable pulse does not exclude the possibility of intimal tear.
    • May lead to intraoperative occlusive thrombosis that could jeopardize the extremity
Differential Diagnosis
  • Intercondylar eminence fracture ± anterior cruciate ligament (ACL) tear: Segond sign on plain film indicates lateral capsule avulsion.
  • Collateral ligament avulsion
  • Tibial tubercle avulsion
  • Proximal fibular fracture
  • Patella fracture
  • Hemarthrosis from patellar dislocation, ACL tear, or meniscal tear (if in the red or red-white zone)

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Ongoing Care
Prognosis
  • High rate of arthritis associated with tibial plateau fractures (6)
  • Prognosis for full return of motion in the presence of OA is poor.
Codes
ICD9
823.00 Closed fracture of upper end of tibia


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