Treatment of Dislocated Knee
Immediate reduction and stabilization of the dislocated knee is the primary treatment priority, followed by thorough vascular assessment to prevent limb-threatening complications. 1, 2
Initial Management
Immediate Actions
- Perform immediate joint reduction and splinting to restore alignment 3
- Assess neurovascular status with particular attention to:
- Presence of distal pulses
- Ankle-Brachial Index (ABI)
- Signs of ischemia (pallor, paresthesia, pain, poikilothermia)
- Peroneal nerve function (dorsiflexion, sensation)
Vascular Assessment
- If pulses are abnormal or absent after reduction → immediate surgical exploration of popliteal artery 3, 4
- If pulses return to normal after reduction → obtain CT angiography or arteriogram to rule out intimal tears 1
- Vascular repair must be performed within 6-8 hours to prevent irreversible ischemic damage 3
Imaging
- Obtain radiographs (minimum two views: AP and lateral) to confirm reduction and rule out associated fractures 1, 2
- MRI is the preferred second-line imaging for assessment of ligamentous injuries once the patient is stabilized 2
- CT may be used when MRI is contraindicated to evaluate for occult fractures 1, 2
Stabilization Options
External Fixation
- Indicated for:
- Patients with vascular repairs
- Open dislocations
- Gross instability with inability to maintain reduction
- Multiple trauma patients who cannot tolerate mobilization 5
- Provides temporary stabilization while allowing wound care and vascular monitoring
Immobilization
- For stable reductions without vascular injury, immobilize in a hinged knee brace in slight flexion 2
- Avoid complete immobilization to prevent arthrofibrosis 2
Staged Treatment Approach
Stage 1 (Acute Phase: 0-24 hours)
- ATLS protocol for polytrauma patients
- Knee reduction and stabilization
- Vascular repair if needed
- Consider prophylactic fasciotomy after vascular repair to prevent compartment syndrome 4
- Thromboprophylaxis
Stage 2 (Subacute Phase: 1-3 weeks)
- MRI evaluation of ligamentous injuries
- Early range of motion exercises if stable
- Weight management and activity modification 2
- Pain management:
Stage 3 (Reconstruction Phase: 2-4 weeks)
- Definitive ligament reconstruction for persistent instability
- Selective repair of collateral ligaments and reconstruction of cruciate ligaments 3
- Consider one-stage versus multi-stage reconstruction based on patient status 6
Rehabilitation
- Begin early mobilization after acute phase (typically 3-7 days) 2
- Progressive rehabilitation program including:
- Joint-specific strengthening exercises
- General aerobic conditioning
- Range of motion exercises 2
- Avoid continuous passive motion machines as they show no benefit 1
Complications to Monitor
- Vascular compromise requiring amputation (up to 86% if arterial repair delayed >8 hours)
- Arthrofibrosis (particularly with prolonged immobilization)
- Venous thromboembolism
- Compartment syndrome
- Heterotopic ossification (reported in up to 44% of cases) 5
- Peroneal nerve injury (often requires ankle-foot orthosis) 4
Follow-up
- Reassess at 4-6 weeks for persistent instability
- Consider orthopedic referral if:
- Conservative management fails after 6-8 weeks
- Persistent mechanical symptoms
- Progressive instability despite rehabilitation 2
Knee dislocation represents a true orthopedic emergency with significant risk for limb-threatening vascular complications. The treatment approach must prioritize joint reduction, vascular assessment, and appropriate stabilization, followed by staged ligament reconstruction when indicated.