Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

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Posterior Cruciate Ligament Injury

Basics
Description
  • Injury to the OSD, the primary stabilizer to posterior translation of the tibia on the femur at the knee
  • Classification (see Posterior drawer test under Physical Exam):
    • Grade 1: Tibial plateau is anterior to the femoral condyles.
    • Grade 2: Tibial plateau is level with the femoral condyles.
    • Grade 3: Tibial plateau is posterior to the femoral condyles.
Epidemiology
  • Young adults
  • Males affected more than females
Incidence
Uncommon
 
Risk Factors
  • Motor vehicle accident
  • Participation in collision sports
  • Hyperextension injury to the knee
Genetics
No Mendelian pattern is known.
 
Etiology
  • Direct blow to the anterior tibia with the knee flexed and the foot plantarflexed
  • Hyperflexion without a blow
  • Hyperextension
Associated Conditions
Popliteal artery injury
 
Diagnosis
Signs and Symptoms
  • Knee pain and swelling after the injury with gradual improvement in generalized pain symptoms
  • Minimal symptomatic instability, usually when climbing stairs
  • Recurrent effusion
  • Posterior knee pain
  • Knee recurvatum (late finding)
Physical Exam
  • Perform a complete neurovascular examination.
  • Tests for ligamentous stability:
    • Posterior drawer test:
      • Position the patient supine with the knee flexed 90° and the foot stabilized on the examination table.
      • Apply posterior force to the anterior tibia.
      • Note the excursion of the tibia underneath the femoral condyles.
      • Note the quality of the end point.
      • Compare the involved and contralateral sides.
      • The position of the affected knee can reveal a posterior sag of the tibia when the patient is supine with hips flexed 45°, knees flexed 90°, and feet flat on the examination table.
    • Lachman test:
      • Anterior drawer test at 30° of flexion
      • To rule out associated ACL rupture
    • Rule out collateral ligament injury
Tests
Lab
None indicated
 
Imaging
  • Radiography:
    • Plain film AP and lateral views of the knee:
      • To evaluate for fracture about the knee
      • May reveal an avulsion fracture off the proximal posterior tibia
    • Stress radiography
  • MRI is very sensitive for identifying PCL injury and associated injuries
Pathological Findings
Either midsubstance rupture or proximal or distal bony avulsion is noted.
 
Differential Diagnosis
  • ACL injury
  • Tibial plateau fracture
  • Meniscal tear
Treatment
General Measures
  • Patients may be partial weightbearing as tolerated.
  • History and physical examination for a provisional diagnosis
  • Radiography and MRI to confirm the diagnosis
  • Nonoperative treatment initially, except for high-grade injuries/knee dislocations
  • Knee immobilizer and crutch ambulation as tolerated until comfortable
  • Early ROM and strengthening
  • Knee braces are of questionable use.
Special Therapy
Physical Therapy
A specific OSD-insufficiency knee program is initiated.
 
Medication
First Line
  • NSAIDs
  • Acetaminophen
Second Line
Mild, as-needed narcotics for acute/severe pain
 
Surgery
  • Relative indications for surgery:
    • Grade 3 PCL injuries
    • Posterolateral corner injuries
    • Associated ligamentous, meniscal, or articular surface injuries
    • Giving-way of the knee
    • Pain
    • Radiographically documented progressive articular deterioration
  • Reduction and internal fixation of avulsion fractures
  • Reconstruction is reserved for patients with symptomatic swelling and activity-related pain.
    • The procedure entails reconstruction of the ligament with an autograft or allograft.
    • Arthroscopically assisted reconstructions are demanding technically but obviate wide surgical exposure.
Follow-up
Prognosis
  • Extremely good
  • Most patients do not require surgery.
Complications
  • Recurrent symptomatic giving-way of the knee
  • Failure of reconstruction
  • Progressive medial compartment arthrosis, followed by patellofemoral compartment arthrosis
Patient Monitoring
Patients are followed at 3-6 month intervals to check on their prognosis with ROM, muscle strength, and function.
 
Miscellaneous
Codes
ICD9-CM
717.84 Disruption of the posterior cruciate ligament
 
Patient Teaching
Isolated PCL injuries often are treated nonoperatively.
 
FAQ
Q: What is the natural history of nonoperatively treated isolated PCL injuries?
A: Most patients are able to return to functional activity in 6-8 weeks. Although progressive laxity is uncommon, patients can develop medial and patellofemoral compartment changes over the ensuing years of PCL laxity.
 
Q: Are other injuries associated with PCL injury?
A: Low-energy PCL injuries usually are isolated. However, high-energy PCL injuries usually are accompanied by collateral ligament injury and/or ACL injury. A patient with a high-energy PCL tear should be evaluated for concomitant vascular and neurologic injury.

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