Management and Treatment for Post Knee Dislocation
Immediate vascular assessment is mandatory after knee dislocation, as vascular injury requires urgent intervention to prevent limb loss and long-term morbidity. 1
Initial Assessment and Management
Vascular Assessment
- Perform Ankle-Brachial Index (ABI) measurement:
- Apply cuff just above malleolus
- Compare systolic pressure at ankle to arm (reference) pressure
- ABI <0.9 indicates potential vascular injury (sensitivity 87%, specificity 97%) 1
- Normal ABI with no clinical signs virtually eliminates probability of vascular injury
Clinical Signs of Vascular Injury
- Strong signs (require immediate surgical exploration or rapid radiological examination):
- Absent pulses
- Pallor
- Neurological deficits (sensory or motor)
- Presence of a murmur/thrill 1
- Weak signs (require radiological examination with IV contrast):
- Externalizing bleeding
- Open or blunt trauma near main vascular axis
- Hematoma near arterial path
- Neurological deficit suggesting nerve compression 1
Imaging
- Initial imaging: Standard knee X-rays (AP, lateral, patellofemoral views) 2
- For suspected vascular injury: CT angiography or arteriography 1
- MRI without contrast for suspected internal derangement or multi-ligament injury 2
- Delaying MRI in multi-ligament injury can lead to missed diagnoses and poorer outcomes 2
Acute Treatment
Reduction
- If still dislocated, perform prompt reduction in emergency department setting 3
- For tourniquet application (if needed for hemorrhage control):
- Apply second tourniquet distal to first before loosening proximal one to avoid blood loss
- Reassess tourniquet necessity frequently 1
Vascular Management
- Abnormal ABI (<0.9) requires CT angiography 3
- Vascular repair should be performed urgently if injury is identified
- Delayed diagnosis of vascular injury significantly increases risk of amputation 4
Ligamentous Injury Management
- Multi-ligament knee injuries are common after dislocation
- Early one-stage or multiple staged ligament repair and reconstruction offer better outcomes 5
- Consider temporary external fixation or hinged bracing in severe cases
Rehabilitation and Long-term Management
Pain Management
- First-line: Acetaminophen/paracetamol
- Second-line: NSAIDs (topical preferred initially, then oral) 2
Exercise Therapy
- Joint-specific strengthening exercises
- General aerobic conditioning
- Hip and knee strengthening 2
- Progressive return to activities as tolerated
Prevention of Post-traumatic Osteoarthritis
- Moderate certainty evidence indicates increased risk of symptomatic knee OA after various knee injuries including dislocations 1
- Risk factors for post-traumatic OA:
- Cartilage injury (OR=2.31)
- Partial meniscectomy (OR=1.87)
- Total medial meniscectomy (OR=3.14) 1
Long-term Considerations
- Weight management for overweight patients to reduce OA progression 2
- Supportive measures: walking aids, knee bracing, prefabricated foot orthoses as needed 2
- Regular follow-up to monitor for complications and progression of symptoms
Prognosis
- Most patients have some long-term functional limitation despite appropriate treatment 5
- Follow-up studies show median Lysholm score of 83 and Tegner activity score of 5 at 2-9 years 6
- 87% of patients develop radiographic OA (Kellgren & Lawrence grade 2 or higher) 6
- Outcomes are worse in high-energy trauma compared to low-energy trauma 6
Common Pitfalls to Avoid
- Failing to perform vascular assessment even when pulses are present
- Delaying treatment of vascular injuries (increases amputation risk)
- Missing spontaneously reduced dislocations (50% reduce before ED arrival) 3
- Inadequate imaging for suspected multi-ligament injuries
- Neglecting long-term OA prevention strategies
Knee dislocation is a potentially limb-threatening injury requiring prompt diagnosis, vascular assessment, and appropriate management to optimize outcomes and minimize complications.