Tibial plateau fractures

Epidemiology

  • 1% of all fractures
  • Lateral tibial plateau 70%
    • More common as knees in valgus & forces usually cause valgus
  • Medial plateau is involved in isolation in around 15%
  • Bicondylar fractures occur in 15%

Aetiology

  • High violence injuries in young patients
    • Indirect forces
    • Axial loading
  • Age & bone quality determine fracture pattern
    • Younger patients develop split, older get depression
    • Younger patients have higher rate of ligamentous injury (i.e., on opposite side)
    • Older patients compact subchondral cancellous bone

Associated injuries

  • ligamentous injuries
  • popliteal artery injury
  • neurologic injury (esp peroneal nerve)
  • compartment syndrome

Anatomy

  • Medial tibial plateau
    • larger
    • concave from front to back & from side to side
    • medial plateau is stronger than lateral, so injury here is more rare & is accompanied by more soft tissue damage
  • Lateral tibial plateau
    • convex from side to side & front to back
  • Menisci
    • lateral meniscus covers larger area than medial

Classification

Schatzker classification

Schatzker Classification of Tibial Plateau Fractures
Type Description Features
I Split of lateral plateau
  • seen in young people with strong bone
  • Often associated with tear of lateral meniscus, which is trapped in fracture
II Split depression fracture
  • Caused by valgus blow with axial loading
  • Typically occurs in patients older than 40
III Pure depression (die punch) of lateral tibial plateau
  • Central depressions are usually more stable than lateral or posterior
IV Fracture of medial tibial plateau
  • Much less common, associated with large forces.
  • Often associated with lateral collateral ligament injuries
  • Many of these injuries represent knee dislocation that has reduced
  • fracture pattern most associated with vascular injury
V Bicondylar fracture
  • Usually result of pure axial load applied to knee
  • hallmark of this injury is that at least small part of metaphysis remains as part of joint
VI Plateau fracture with complete dissociation of metaphysis from diaphysis  

AO classification

  • A Extra-articular
  • B Unicondylar
  • C Bicondylar

Hohl and Moore Fracture Dislocation Classification

Hohl and Moore Tibial Plateau Fracture Dislocation Classification
Type Description
I Coronal split fracture
II Entire condylar fracture
III Rim Avulsion fracture
IV Rim Compression fracture
V Four part fracture

 

Assessment

  • Need to carefully assess soft tissue injuries:
    • Fracture blisters, skin wounds, tenting of skin, vascular compromise
    • detailed neurologic exam
    • look for associated injuries
    • more common with grades IV-VI
      • compartment syndrome
      • neurovascular injuries
      • ligamentous injuries

Imaging

XR

  • AP, lateral, oblique images
  • Opposite knee can serve as useful template
  • Look for subchondral bone below articular surface
  • Can do 15° caudal plateau views, obliques
  • Stress radiographs may be used if considering non-operative
  • ** the medial plateau is concave, the lateral plateau is convex (in both planes)
    • lateral plateau is also higher than medial

CT scans

  • mandatory

MRI

  • can help identify meniscal pathology
  • use particularly in type I fractures & or those in which percutaneous fixation is contemplated

Treatment

  • Depends on soft tissues
    • Skin compromised = Ext fix
      • open fractures require I & D
      • grade 2 & 3 open fractures probably best treated with temporary ex fix & late reconstruction of articular surface or ring fixator & mini-open arthrotomy to reduce articular surface
    • may require plastic surgery – usu rotational muscle flap in this location (gastroc)
  • Nonoperative
    • Hinged knee brace can be used for minimally displaced, or non-operative patients
    • Non/partial weight bearing for 8-12 weeks
  • ORIF
    • Absolute
      • open fractures
      • compartment syndrome
      • acute vascular injury
    • Relative
      • Joint depression
        • Acceptable amount not agreed upon
        • < 3-5mm are normally quoted
          • up to 1cm quoted
        • Long term followup has not demonstrated correlation between degree of depression & development of arthritis
      • Instability
        • of greater than 10° of nearly extended knee (varus /valgus) c.f. other side
        • joint depression severe enough to lead to instability is predictive of poor result
        • Tips & Tricks
          • Either immediate before significant swelling or delayed to allow soft tissues to heal
          • minimal stripping of comminuted fragments & careful soft tissue handling
          • use periarticular large fragment plate laterally (types I/II/V/VI)
          • use either anterior approach or 2 incision technique for bicondylar fractures
          • bicondylar fractures need 2 plates (medial buttress plate)
          • type IV fractures need buttress plate/screw rather than just interfragmentary screws
          • almost always use ICBG
          • use large fragment distractor to aid in reduction thru ligamentotaxis
          • risk of infection (10-40%) & wound slough
          • Submeniscal arthrotomy provides access to joint surfaces
  • Surgical treatment
    • Type I
      • percutaneous cannulated screws
    • Type II
      • ORIF with elevation, bone graft & lateral periarticular plate using hockey stick lateral incision
    • Type III
      • can attempt to elevate via cortical window, bone graft & stabilize with couple of screws
      • Use arthroscope to assess adequacy of reduction
    • Type IV
      • percutaneous or open techniques
      • Nonoperative management is associated with high rate of varus malunion
    • Types V & VI
      • Combined Anterolateral & posteromedial incision
        • Safest way to access bicondylar fractures
      • Extensile midline anterior incision
        • this can also be used in any subsequent knee replacement
      • Schatzker describes doing Z cut of patellar tendon( tubercle osteotomy may be almost impossible to fix) & division of medial & lateral capsule below menisci, flapping whole up; done via midline incision. At end of procedure tendon is protected by tension wire or heavy suture
  • Tips
    • In very severe fractures less injured condyle is fixed first
    • Can consider using one or two femoral distractors to help with indirect reduction of fracture
    • If hybrid external fixation is used wires should be placed no closer than 15mm to joint
    • Once bony parts of injury have been treated ligaments should be assessed. Any posterolateral injury should be addressed concurrently
  • external fixator
    • spanning ex fix from femur to tibia to hold soft tissues out to length & maintain reduction
    • half pins in femur & tibia
    • best to align the articular surface early, with limited fixation
    • once soft tissues have healed » ORIF
  • ring fixator:
    • mini-open reduction of articular surfaces using K-wires & small fragment screws
    • fine wires at level of articular surface (at least 2) & half pins in tibia
    • reduced deep infection rate & soft tissue complications

Complications

  • Nonunion
    • is very rare, except in Schatzker VI injuries
  • Stiffness
    • is common
    • If it is excessive & not responsive to aggressive physiotherapy adhesiolysis & MUA is indicated
  • Infection (6 to 12%)
    • Wound problems are the biggest problem in plateau fractures
    • Important to respect soft tissues, etc
    • Time surgery appropriately
    • Concern with large elevations of skin (bicondylar plates)
  • Loss of reduction
    • Should use buttress plates, unless bone quality is very good
  • Post traumatic arthrosis
    • Cartilage damage from initial injury
    • Also if residual joint incongruity
    • Important to preserve the meniscus
    • Avoid immobilization
  • Union at the metaphyseal – diaphyseal junction can be a problem

Outcomes

  • - 90% good/excellent results with ORIF (all types of fractures) – Lansinger et al., 1986 (seems too good to be true)
  • Minimally displaced are expected to do well, even with non-operative
  • Difficult to assess outcomes of displaced, as studies differ in classification, indications, etc
  • Helpful that the lateral meniscus covers most of the plateau
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