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Distal Humerus Fractures
Updated: Oct 4 2016

Hinged Elbow External Fixator

Preoperative Patient Care
Operative Techniques

Preoperative Plan


Template fracture

  • identify fracture pattern, displacement, comminution, and presence of dislocation


Execute surgical walkthrough

  • describe key steps of the operation verbally to attending prior to beginning of case.
  • description of potential complications and steps to avoid them

Room Preparation


Surgical instrumentation

  • hinged external fixation system


Room setup and equipment

  • c-arm perpendicular to OR table


Patient positioning

  • supine position
  • arm should be in 90 degrees of flexion
  • place bump under ipsilateral scapula

Construct Assembly


Identify the rotational axis

  • locate the rotational axis of the elbow for proper rotation of the external fixator


Construct the hinge block assembly

  • it is important in the preoperative preparation that the hinge block assembly for the humeral portion is set up so that the large block is on the medial aspect


Adjust the block height

  • accommodate the valgus of the distal humerus by adjusting the block height
  • the upper ring should be perpendicular to the distal humerus and the axis of rotation should still be aligned
  • the average valgus will be approximately 7 degrees

Medial Pin Placement


Make the skin incision

  • the most proximal portion of the incision should allow visualization of the upper humerus for placement of the medial pin


Identify and mobilize the ulnar nerve


Expose the joint of the elbow

  • expose the anterior and posterior elbow joint


Excise the intermuscular septum

  • this will expose the anterior distal humerus and capsule


Perform a capsular release


Excise any heterotopic ossification


Lengthen the muscle as needed and reduce the elbow joint


Create a fascial sling

  • before closure of the wound, transpose the ulnar nerve and hold it in position with a fascial sling
  • construct the fascial sling in a manner where it does not constrict the nerve during flexion or extension of he elbow


Determine the level of pin placement

  • place the compass hinge over the elbow to determine the level of the pin placement
  • place an appropriately sized Steinmann pin up to 3.1 mm across the axis of rotation of the elbow
  • place the compass hinge over the pin


Place the medial pin

  • under direct vision, place the medial pin into the humerus posterior to the anteriorly transposed nerve
  • make sure that the pin does not impinge on the vascular structures or the ulnar nerve
  • perfect placement of this pin is essential for alignment of the compass hinge at the elbow


Verify placement

  • take AP and lateral radiographic views to ensure the placement is correct
  • judge the superior ring and the relative distance from the medial to the lateral aspect of the elbow
  • it is better to have the arm closer to the medial side of the wheel in comparison to the lateral side of the wheel
  • this allows more adduction of the arm at the side of the patient once the hinge is placed

Half Pin Placement


Determine the position of the half pin

  • use the cube assembly for pin placement
  • attach the cube directly to a ring or a construct hinge by attaching a cube to a hinge or a post with a bolt
  • pass the drill guide through the large hole until it touches the skin


Appropriately place the incision

  • make an incision at this spot


Expose the bone

  • separate the soft tissues and the periosteum


Insert the drill guide until it rests on the bone

  • lock the drill guide in place with a set screw or bolt


Drill through the bone

  • use a drill bit of the appropriate size and drill though both cortices


Determine thickness of the bone

  • determine the bone thickness by reading the number in millimeters indicated on the drill shank on the top of the guide or by hooking the tip of the depth gauge onto the outside of the far cortex and reading the number of millimeters on the top guide
  • choose the appropriate length thread that is designated by the measurement of the cortical width and place the pin through the guide by use of the driver extractor


Place self tapping screws


Manual placement is recommended for self tapping screws

  • confirm that the pin is seated firmly in both cortices clinically and with image intensification


Remove the drill guide


Place the centering sleeve

  • slide a centering sleeve of the appropriate size over the pin and align the bold line on the head to point to the threaded hole that will be used to lock the pin
  • this allows the bolt or set screw to impinge on the pin directly
  • this ensures a more secure lock

Humeral Pin Placement


Place the superolateral pin

  • place the superolateral pin into the humerus just distal to the deltoid insertion and direct it medially
  • the radial nerve will be posterior to the pin at this level


Place the posterolateral pin

  • place the posterolateral humeral pin just anterior to the triceps pin
  • direct this pin from posterolateral to anteromedial
  • the radial nerve will be anterior to this pin


Check the alignment of the pins

  • once the pins are attached to the external fixator check that the alignment of the axis is appropriate
  • use the sliding 5/8 inch ring attachment assembly to modify any position from anterior to posterior if needed

Ulna Pin Placement


Position the elbow

  • place the elbow in 90 degrees of flexion when placing ulnar fixation
  • if the elbow is grossly unstable, reduce the elbow joint before placing the ulnar pins


Place the proximal ulnar pin

  • tighten the pin into place on the ring perpendicular to the ulna
  • place a second pin
  • it is advised to predrill the holes in the ulna due to the size and shape of the ulna


If reduction of the joint was performed, check the reduction

  • flex and extend the elbow to ensure there is adequate reduction of the joint


Apply distraction

  • after all of the pins are placed, apply distraction to the system by the distraction mechanism
  • loosen the three washer headed screws and apply distraction by adjusting the set screws on either wheel
  • the total distraction permitted is 6 mm


Once the humeral fixation is achieved, remove the axis pin

  • at this point evaluate elbow range of motion
  • apply a light dressing around the wounds with sponges over the pins and leave a hemovac drain in place

Elbow Stability Testing


Check elbow flexion and extension


Check stability in various rotations of the elbow

  • pronation
  • supination
  • neutral

Wound Closure


Irrigation and hemostasis

  • irrigate wounds thoroughly
  • deflate tourniquet (if elevated)
  • coagulate any bleeders carefully



  • apply a light dressing around the wounds with sponges over the pins and leave a hemovac drain in place
Postoperative Patient Care
Private Note

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