What is the management of sensory deficits from a posterior knee dislocation?

From the Guidelines

Management of sensory deficits from a posterior knee dislocation requires immediate neurovascular assessment and prompt orthopedic consultation, with a focus on reducing the dislocation, immobilizing the knee, and monitoring for any further complications, as vascular injury may be found in about 30% of patients following posterior knee dislocation 1. The initial management includes reduction of the dislocation under sedation, followed by a detailed neurovascular examination to document any sensory deficits, particularly in the distribution of the peroneal nerve which is commonly affected.

• Key steps in management include:
  • Reduction of the dislocation
  • Immobilization of the knee in slight flexion using a hinged knee brace or posterior splint
  • Serial neurovascular checks every 2-4 hours for the first 24-48 hours to monitor sensory deficits
  • Pharmacologic management for neuropathic pain, such as gabapentin or pregabalin
  • Physical therapy focusing on gentle range of motion exercises and proprioceptive training once stability is confirmed The mechanism of nerve injury typically involves stretching of the peroneal nerve as it wraps around the fibular head during dislocation, which can cause demyelination or axonal damage, and associated peroneal and tibial nerve injuries may cause significant morbidity and require an understanding of their pathophysiologic implications to maximize limb functionality 1.
• Important considerations include:
  • The potential for vascular injury, which may require prompt surgical intervention to help limb preservation
  • The role of angiography, CTA, and MRA in evaluating vascular injuries associated with knee dislocations
  • The possibility of permanent sensory deficits, and the need for ongoing monitoring and management to optimize outcomes.

From the Research

Sensory Deficits from Posterior Knee Dislocation

• Sensory deficits can occur due to damage to the peroneal nerve, which is a common complication of knee dislocation 2, 3.
• The peroneal nerve is at risk of injury, particularly in posterior or posterolateral dislocations, and can result in motor and sensory deficits 2.
• Studies have shown that patients with peroneal nerve injury after knee dislocation may experience worse function and outcomes, including persistent sensory deficits 3.
• The management of sensory deficits from posterior knee dislocation typically involves addressing the underlying nerve injury, which may require surgical intervention such as neurolysis, nerve transfer, or tendon transfer 3.

Associated Injuries and Complications

• Posterior knee dislocation can result in extensive disruption of the ligaments and surrounding soft-tissue structures, including the popliteal artery and peroneal nerve 2, 4.
• The mechanism of injury, such as a posterior or posterolateral dislocation, can increase the risk of peroneal nerve injury and subsequent sensory deficits 2.
• Early recognition and treatment of knee dislocation and associated injuries are crucial to prevent long-term complications and improve outcomes 4, 5.

Diagnostic and Treatment Considerations

• Plain radiographs and MR imaging can be useful in diagnosing knee dislocation and associated injuries, including peroneal nerve injury 6, 2.
• Surgical management, such as open reduction and ligament reconstruction, may be necessary to address the underlying injuries and prevent long-term complications 4, 3.
• Patients with peroneal nerve injury may require ongoing management and rehabilitation to address persistent sensory deficits and optimize functional outcomes 3.