Posterior Cruciate Ligament (PCL) Injury

Key Features

• Usually follows an anterior trauma to the tibia, such as a dashboard injury during a motor vehicle accident

• The knee may freely dislocate and reduce

• One-third of multi-ligament injuries involving the PCL have neurovascular injuries

• More than 70–90% of PCL injuries have associated injuries to the posterolateral corner, medial collateral ligament, and anterior cruciate ligament

Clinical Findings

• Most patients with acute injuries have difficulty with ambulation

• Patients with chronic PCL injuries

  • Can ambulate without gross instability but may complain of subjective "looseness"

  • Often report pain and dysfunction, especially with bending

• Pain, swelling, pallor, and numbness in the affected extremity may suggest a knee dislocation with possible injury to the popliteal artery

• Clinical examinations of PCL injuries include the sag sign (Table 41–7)

• The PCL ligament can also be examined using the posterior drawer test (90% sensitivity and 99% specificity) (Table 41–7)

Diagnosis

• Radiographs are often nondiagnostic but are required to diagnose any fractures

• MRI is used to diagnose PCL and other associated injuries

Treatment

• Isolated PCL injuries can be treated nonoperatively

• Acute injuries are usually immobilized using a knee brace with the knee extension; the patient uses crutches for ambulation

• Physical therapy can help achieve increased range of motion and improved ambulation

• Many PCL injuries are associated with other injuries and may require operative reconstruction