Hoffa Fractures

Letenneur Classification (based on fracture line relative to Blumensaat line)

Classification by Condyle:

Lateral condyle is more commonly affected due to its prominence and the typical mechanism of injury (direct blow to lateral knee).

Classification by Displacement:

Classification with Associated Injuries:

The Hoffa component should be fixed first when associated with supracondylar fracture to reconstitute condyle anatomy before addressing the metaphyseal component.

Indications for non-operative treatment:

• Truly undisplaced fractures (rare)
• Non-ambulatory patients
• Severe medical comorbidities precluding surgery
• Patient refusal of surgery

Non-operative protocol:

• Long leg cast or hinged knee brace
• Non-weight bearing for 6-8 weeks
• Very close follow-up with serial imaging
• CT at 2-4 weeks to assess displacement
• Low threshold for surgery if any displacement

Indications for operative treatment:

• All displaced fractures (any articular step-off)
• Undisplaced fractures (strong consideration)
• Associated supracondylar fracture
• Multiple fragments requiring stabilization

Timing of surgery:

• Semi-urgent (within 1-2 weeks)
• Earlier if open fracture or vascular compromise
• May delay if severe soft tissue injury

Goals of surgery:

1. Anatomic reduction of articular surface
2. Stable fixation allowing early motion
3. Restoration of condyle anatomy
4. Prevention of post-traumatic arthritis

Preoperative planning:

• Review CT images in detail
• Determine condyle(s) involved
• Plan approach based on fracture location
• Consider screw trajectories
• Prepare for possible plate fixation

Approach selection:

Equipment needed: Large fragment cannulated screws (6.5mm or 7.3mm), headless compression screws as an alternative, buttress plate if comminuted, K-wires for provisional fixation, and fluoroscopy.

Patient positioning:

• Supine with bump under ipsilateral hip
• Knee flexed to 20-30 degrees over bolster
• Leg free for intraoperative flexion/extension
• Tourniquet optional

Lateral approach (for lateral Hoffa):

• Incision along distal IT band to lateral epicondyle
• Develop interval between IT band and biceps
• Incise lateral capsule to expose condyle
• Protect common peroneal nerve posteriorly

Posterolateral approach:

• Incision posterior to lateral epicondyle
• Identify and protect peroneal nerve
• Split lateral gastrocnemius if needed
• Excellent access to posterior condyle

The posterolateral approach provides direct visualization of the posterior condyle and is often preferred for Hoffa fractures.

Reduction principles:

1. Expose the fracture:

   • Clear hematoma and debris
   • Visualize articular surface
   • Identify fracture margins

2. Reduce anatomically:

   • Use pointed reduction clamp
   • May use dental pick or small elevator
   • Reduce under direct vision

3. Assess reduction:

   • Palpate articular surface for step-off
   • Confirm with intraoperative fluoroscopy
   • No step-off or gap acceptable

Standard fixation: Posterior-to-anterior lag screws

Steps:

1. Achieve and confirm anatomic reduction
2. Place provisional K-wire from posterior to anterior
3. Measure screw length
4. Create gliding hole in posterior fragment
5. Insert lag screw (6.5mm or 7.3mm)
6. Countersink screw head posteriorly
7. Confirm compression and reduction on fluoro
8. Place additional screw(s) for rotational stability

Key technical points:

• Minimum 2 screws for rotational control
• Countersink heads to avoid posterior impingement
• Perpendicular to fracture for optimal compression
• Confirm articular reduction after fixation

Headless compression screws:

• Advantage: No prominent head to countersink
• Disadvantage: Less compression than headed screws
• Useful when fragment is small or articular damage concern

Buttress plate:

• Indicated for comminuted fractures
• Posterolateral or posteromedial plate
• Provides additional stability
• May be combined with lag screws

Anterior-to-posterior screws (second choice):

• May be needed if posterior access limited
• Countersink head anteriorly in non-articular zone
• Less ideal biomechanically
• Ensure threads purchase far cortex

When a buttress plate is needed, it is applied posteriorly to support the reduced fragments while lag screws provide interfragmentary compression.

Managing Hoffa with supracondylar fracture:

Surgical sequence:

1. Address Hoffa fragment FIRST
2. Reduce and fix condyle with lag screws
3. Then reduce supracondylar component to reconstituted condyle
4. Fix supracondylar with lateral locked plate or retrograde nail

Bicondylar Hoffa is rare but challenging. It may need combined medial and lateral approaches or posterior approach with patient prone. Fix both condyles before addressing metaphyseal injury.