Elbow Transcondylar Fractures

Definition: Transcondylar fractures are fractures of the distal humerus occurring at the level of the condyles, passing transversely through the olecranon and coronoid fossae. They are essentially distinct from supracondylar fractures because they are lower and intra-capsular.

Epidemiology:

• Typically unexpected in adults (unless high energy).
• Bimodal distribution:
  1. Young males (High energy trauma).
  2. Elderly females (Osteoporotic falls) - much more common.
• The "Silver Tsunami": Incidence of fragility distal humerus fractures is rising.

The Distal Humerus Triangle: The distal humerus is a triangle composed of two columns (Medial and Lateral) supporting the articular block (Trochlea and Capitellum). The columns diverge distally to form the supracondylar ridges. This structure is analogous to a suspension bridge or a tie-beam construct.

• Medial Column: Diverges at an angle of 45 degrees. Terminates in the medial epicondyle. It is easier to plate because it has a broad crest ("Medial Crest").
• Lateral Column: Diverges at an angle of 20 degrees. Terminates in the lateral epicondyle. It is flat posteriorly, accommodating a posterior plate.
• Transcondylar Pattern: Both columns are separated from the articular block at the lowest level, passing through the fossae. This is the thinnest part of the distal humerus ("The Wafer"), often measuring only a few millimeters in AP dimension.

Articular Block (The "Tie Beam"): The trochlea and capitellum form a spool-shaped articular surface.

• Trochlea: Covered by hyaline cartilage over 300 degrees of its surface. Acts as a tie-beam connecting the two columns. It has a sulcus that articulates with the ulnar ridge.
• Capitellum: Spheroidal structure articulating with the radial head. It projects anteriorly.
• Olecranon Fossa: Posterior fossa accomodating the olecranon tip in extension.
• Coronoid Fossa: Anterior fossa accomodating the coronoid process in flexion.
• Radial Fossa: Anterolateral fossa accommodating the radial head in flexion.

Muscle Attachments (Deforming Forces):

• Triceps: Inserts on the Olecranon. Pulls the proximal ulna proximally. If the fracture is very low (Transcondylar), the triceps does not de-rotate the distal fragment, but if the fracture involves the epicondyles, the extensors/flexors rotate them.
• Brachialis: Inserts on the Coronoid. Pulls the forearm distally.
• Common Flexor Origin: Medial Epicondyle. Flexes and pronates the medial fragment.
• Common Extensor Origin: Lateral Epicondyle. Extends and supinates the lateral fragment.

Ligamentous Attachments:

• MCL (Ulnar Collateral Ligament): Anterior bundle attaches to the inferior aspect of the medial epicondyle. Essential valgus stabilizer.
• LCL (Lateral Collateral Ligament): Component of the LCL complex (LUCL) attaches to the lateral epicondyle. Essential varus/rotatory stabilizer.
• Capsule: The anterior and posterior capsule is thin but reinforced by the brachialis and triceps respectively.

Neurovascular Anatomy:

• Ulnar Nerve: Runs in the cubital tunnel posterior to the medial epicondyle. It is at high risk during fixation of the medial column.
• Radial Nerve: Runs in the spiral groove and pierces the lateral intermuscular septum 10cm proximal to the joint line to enter the anterior compartment.
• Median Nerve: Runs medial to the brachial artery, well protected by the brachialis muscle anteriorly.
• Vascularity: The trochlea is supplied by terminal branches of the ulnar and collateral arteries. The capitellum has a precarious retrograde supply. Transcondylar fractures are intra-capsular and disrupt this intra-osseous supply, relying on capsular vessels for healing.

History:

• Fall on outstretched hand (FOOSH) or direct blow.
• Immediate pain, swelling, inability to move.

Exam:

• Deformity: Gross instability ("floppy elbow").
• Skin: Check for open wounds (posteriorly especially).
• Nerves:
  • Ulnar Nerve: Most commonly injured (contusion/stretch). Check intrinsic strength and sensation (little finger).
  • Radial Nerve: Check wrist extension/thumb extension.
  • AIN: Check "OK sign" (FPL/FDP).

Plain X-rays:

• Views: AP and Lateral views of the elbow are standard. Hand and Shoulder views if indicated.
• Signs:
  • Fracture Line: Transverse line at the supracondylar level but passing through the fossae.
  • Fat Pad Sign: The posterior fat pad is always pathological in adults. If visible, there is a fracture until proven otherwise. The anterior fat pad ("Sail Sign") may be elevated.
  • Alignment: Check for varus/valgus Angulation and Rotational Malalignment.
  • Drop Sign: Increase in the distance between the ulna and humerus (distraction) may indicate gross instability or ligament injury.
• Traction View:
  • Technique: Performed by the surgeon in the ED or under anaesthesia.
  • Value: Neutralizes the deforming forces of the triceps/brachialis. Allows better assessment of the comminution and whether the articular block is one piece (Simple A3) or split (C-type).

CT Scan:

• Role: Essential for almost all adult distal humerus fractures. Defines the "personality" of the fracture.
• 2D Views:
  • Coronal: Shows the "Tie Beam" integrity (trochlea calcified arch).
  • Sagittal: Shows the capitellum ("Headless Ghost" due to osteopenia).
  • Axial: Best for assessing rotation of the columns.
• 3D Reconstruction:
  • Subtract Humerus: Remove the shaft to see the articular surface from above ("Bird's eye view").
  • Subtract Ulna/Radius: Remove the forearm to see the Articular surface from below.
• Bone Stock Assessment:
  • Look for the "Wafer" - the thin shell of bone between the fracture line and the joint. If this is less than 5mm or very osteopenic, screw purchase is unlikely to be sufficient for ORIF, pushing the decision towards TEA.

MRI:

• Rarely indicated for acute fractures unless ligament injury (LCL/MCL) is suspected in a simple dislocation masking as a fracture-dislocation.
• May be used for late assessment of Ulnar collateral ligament in high-demand athletes (unlikely in this demographic).

Early Complications:

• Ulnar Neuropathy (15-20%):
  • Causes: Contusion at injury, stretch during reduction, hardware irritation (medial plate), scar tissue formation.
  • Management: Release in situ or Anterior Transposition.
• Wound Dehiscence:
  • Posterior skin is thin. Hematoma can cause tension.
  • Prevention: Full thickness flaps, sub-muscular drains, careful closure, prevent flexion greater than 90 degrees if skin under tension.
• Infection (2-6%):
  • Higher in revision cases or TEA.
  • Management: Debridement. If stable, retain hardware. If unstable/loose, remove and place antibiotic spacer (Spacer to Stage 2 TEA).

Late Complications:

• Stiffness (Arthofibrosis):

  • Most common complaint. Loss of terminal extension (30 degrees) is tolerated functionally.
  • Prevention: Early Active Motion (The "Motion" in ARM).
  • Treatment: Static progressive splinting (Turnbuckle) to Surgical release (capsulectomy).

• Heterotopic Ossification (HO):

  • Risk Factors: Head injury, delayed surgery, forceful passive stretching.
  • Prophylaxis: Indomethacin (75mg sustained release daily for 6 weeks) or Radiation (700 cGy single dose).

• Nonunion (2-10%):

  • Risk: Higher in Transcondylar (A3) due to lack of extensive soft tissue attachment to distal fragment.
  • Treatment: Revision ORIF with bone graft + Plate augmentation (90-90 or quad plating) OR Conversion to TEA in elderly.

• Hardware Failure:

  • Screw pullout from distal fragment.
  • Plate breakage (fatigue failure) due to nonunion.

• TEA Complications:

  • Loosening: Aseptic loosening of stems (10-15% at 10 years).
  • Bushing Wear: The polyethylene bushing wears out, causing metal-on-metal contact and osteolysis.
  • Triceps Insufficiency: Failure of triceps repair leads to inability to extend against gravity.

• Bag of Bones: Collar and cuff for comfort, move as tolerated. Ignore the X-ray, treat the patient.

• ORIF: Good to Excellent in 75-80% of young patients. Stiffness is main complaint.
• TEA: 90% 10-year survival. Happiness rate high in elderly.
• Non-Union: 5-10% in ORIF group.

• Elderly Care: Geriatric Orthopaedic services (Orthogeriatrics) co-management is standard for these falls risks patients.
• Implants: Typically use pre-contoured locking plates (Stryker VariAx, Synthes LCP, Acumed) or Coonrad-Morrey/Discovery arthroplasty systems.
• Rehab: Public hospital waitlists for elective TEA conversion of nonunion can be long; acute trauma TEA is prioritized.