منو منو

Capitellum Fractures


  • SUMMARY

    • Capitellum Fractures are traumatic intra-articular elbow injuries involving the distal humerus at the capitellum.

    • Diagnosis is made using plain radiographs of the elbow.

    • Treatment may be nonoperative for nondisplaced fractures but any displacement generally requires anatomic open reduction and internal fixation.

  • EPIDEMIOLOGY

    • Incidence

      • 1% of elbow fractures

      • 6% of all distal humerus fractures

  • ETIOLOGY

    • Pathophysiology

      • mechanism of injury

        • typically, low-energy fall on outstretched hand

        • direct, axial compression with the elbow in a semi-flexed position creates shear forces

      • pathoanatomy

        • radiocapitellar joint is an important static stabilizer of the elbow

        • capitellar fracture can cause potential block to motion and instability due to loss of the radiocapitellar articulation

    • Associated conditions

      • concomitant injuries to radial head and/or LUCL can occur up to 60% of the time

  • ANATOMY

    • Radiocapitellar articulation

      • essential to longitudinal and valgus stability of the elbow

        • can also lead to coronal plane instability with capitellar excision if medial structures are not intact

      • integral relationship with the posterolateral ligamentous complex of the elbow (i.e. LUCL)

  • CLASSIFICATION

      • Bryan and Morrey Classification (with McKee modification)

      • Type I

      • Large osseous piece of the capitellum involved

      • Can involve trochlea

      •  
      • Type II

      • Kocher-Lorenz fracture

      • Shear fracture of articular cartilage

      • Articular cartilage separation with very little subchondral bone attached

      •  
      • Type III

      • Broberg-Morrey fracture

      • Severely comminuted

      • Multifragmentary

      •  
      • Type IV

      • McKee modification

      • Coronal shear fracture that includes the capitellum and trochlea

      •  
  • PRESENTATION

    • History

      • fall on outstretched arm (typically fall from standing)

      • typically, elbow is in semi-flexed elbow position

    • Symptoms

      • elbow pain, deformity

      • swelling

      • wrist pain may also occur

    • Physical exam

      • inspection and palpation

        • ecchymosis, swelling

        • diffuse tenderness

      • range of motion & instability

        • may have mechanical block to flexion/extension and/or rotation

      • neurovascular exam

  • IMAGING

    • Radiographs

      • recommended

        • AP and lateral of the elbow

          • best demonstrated on lateral radiograph 

            • "double arc" sign created from subchondral bone of capitellum and lateral part of trochlea 

               

    • CT

      • delineates fracture anatomy and classification 

  • TREATMENT

    • Nonoperative

      • posterior splint immobilization for < 3 weeks

        • indications

          • nondisplaced Type I fractures (<2 mm displacement)

          • nondisplaced Type II fractures (<2 mm displacement)

    • Operative

      • open reduction and internal fixation

        • indications

          • displaced Type I fractures (>2 mm displacement) 

             

          • Type IV fractures

        • technique

          • ORIF with lateral column approach 

             

            • indications

              • isolated capitellar fractures

              • type IV fractures that can have trochlear involvement

          • ORIF with posterior approach with or without olecranon osteotomy

            • indications

              • capitellar fractures with associated fractures/injuries to distal humuers/olecranon and/or medial side of the elbow

      • arthroscopic-assisted ORIF

        • indications

          • isolated type I fractures with good bone stock

      • fragment excision

        • indications

          • displaced Type II fractures (>2 mm displacement)

          • displaced Type III fractures (>2 mm displacement)

      • total elbow arthroplasty

        • indications

          • unreconstructable capitellar fractures in elderly patients with associated medial column instability 

             

  • TECHNIQUE

    • ORIF with lateral column approach

      • approach

        • lateral approach recommended for isolated Type I and Type IV fx 

            

        • supine positioning 

        • lateral skin incision centered over the lateral epicondyle extending to 2cm distal to the radial head 

      • technique

        • headless screw fixation 

        • minifragment screw using posterior to anterior fixation

          • counter sink screw using anterior to posterior fixation 

        • mini-fragment or capitellar plates can be used to capture fractures with proximal extension 

        • avoid disruption of the blood supply that comes from the posterolateral aspect of the elbow

        • do not destabilize LUCL

    • ORIF with posterior approach with or without olecranon osteotomy

      • approach

        • indicated when more extensive articular work is needed 

        • can also be used when concomitant medial sided injuries and/or distal humeral fractures require more fixation

        • lateral decubitus positioning

        • long-posterior based incision along the elbow

          • radial and ulnar based flaps allow access to both medial and lateral sides of elbow

      • technique

        • fracture-pattern specific

          • independent headless compression/cannulated screws for capitellar component

          • supplemental fixation for concomitant pathology

            • parallel or orthoogonal distal humerus plates

            • radial head arthroplasty/ORIF

          • LUCL/UCL repair via bone tunnels or suture anchors

    • Arthroscopic-assisted ORIF

      • approach

        • definitive indications not fully known

        • experienced arthroscopists, indicated for isolated capitellar fractures

        • supine or lateral positioning (dependent on desire for anterior or posterior access) 

        • 70 degree scope can be helpful in gaining access

        • can be combined with limited open technique for fracture manipulation

      • technique

        • standard portals (anteromedial, anterolateral, posterolateral)

        • proximal anterolateral portal established under fluoroscopic guidance to place trocar to allow for reduction of fracture fragment 

          • extend elbow and push fragment with trocar for reduction

          • flex radial head past 90 to lock reduction

        • anteromedial and posterolateral portals allow for fracture debridement

        • freer elevator can help maintain reduction while cannulated/headless compression screws are placed under fluoroscopic guidance (typically posterior to anterior in direction) 

  • COMPLICATIONS

    • Elbow contracture/stiffness (most common) 

       

    • Nonunion (1-11% with ORIF)

    • Ulnar nerve injury

    • Heterotopic ossification (4% with ORIF)

    • AVN of capitellum

    • Nonunion of olecranon osteotomy

    • Instability

    • Post-traumatic arthritis

    • Cubital valgus

    • Tardy ulnar nerve palsy

    • Infection

  • PROGNOSIS

    • Most patients will gain functional range of motion but have residual stiffness

    • Surgical treatment results are generally favorable

      • reoperation rates as high as 48% (mostly due to stiffness)

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