What is the appropriate management for a patient with a non-displaced tibial avulsion fracture when the knee is in full extension?

Management of Non-Displaced Tibial Avulsion Fracture with Knee in Full Extension

For a non-displaced tibial avulsion fracture when the knee is in full extension, conservative management with immobilization is the appropriate initial treatment, as these fractures typically heal well without surgery and maintain excellent functional outcomes. 1

Initial Assessment and Imaging

• Obtain standard radiographs first to confirm the diagnosis and assess displacement 2
• Consider CT imaging if there is uncertainty about fragment size, position, or to rule out additional occult fractures, as CT demonstrates 100% sensitivity for tibial fractures versus 83% for radiographs alone 3
• MRI may be indicated if you suspect associated meniscal or ligamentous injuries, particularly if there are clinical signs of instability or the patient cannot achieve full range of motion 2, 3

Conservative Management Protocol

Non-displaced and minimally displaced tibial avulsion fractures respond well to conservative treatment: 1

• Immobilize the knee in full extension using a hinged knee brace or above-knee cast 4, 5
• Maintain non-weight bearing status for the first 4-6 weeks 4, 5
• Begin passive range of motion exercises at 2 weeks postinjury with CPM (continuous passive motion) assistance while maintaining the brace 4
• Progress to partial weight-bearing at 4-6 weeks as tolerated with the brace locked in extension 4
• Remove the brace at 6 weeks and advance to full weight-bearing 4

Critical Pitfall to Avoid

The major risk with conservative management of displaced avulsion fractures is progression to nonunion and functional disability. In one series, 4 of 5 minimally displaced fractures treated conservatively progressed to nonunion with significant functional impairment 1. However, this applies primarily to displaced fractures, not truly non-displaced ones.

When to Consider Surgical Intervention

Surgical fixation is indicated if: 1

• The fracture shows any significant displacement on imaging
• The patient develops extension limitation or persistent instability
• Conservative management fails to achieve union by 6-8 weeks
• There is progression of displacement on follow-up radiographs

For displaced fractures requiring surgery, open reduction with screw fixation (for large fragments) or suture fixation through bone tunnels (for smaller fragments) provides stable fixation and excellent functional outcomes 6, 4, 1

Follow-Up Protocol

• Obtain repeat radiographs at 2,4, and 6 weeks to confirm maintenance of position and assess for healing 1
• Assess for full extension capability at each visit, as loss of extension suggests fragment displacement or impingement 7
• Evaluate posterior drawer test once immobilization is discontinued to ensure ligamentous stability 6