Basics
Description
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Injury to the OSD, the primary stabilizer to posterior translation of the tibia on the femur at the knee
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Classification (see Posterior drawer test under Physical Exam):
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Grade 1: Tibial plateau is anterior to the femoral condyles.
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Grade 2: Tibial plateau is level with the femoral condyles.
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Grade 3: Tibial plateau is posterior to the femoral condyles.
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Epidemiology
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Young adults
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Males affected more than females
Incidence
Uncommon
Risk Factors
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Motor vehicle accident
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Participation in collision sports
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Hyperextension injury to the knee
Genetics
No Mendelian pattern is known.
Etiology
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Direct blow to the anterior tibia with the knee flexed and the foot plantarflexed
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Hyperflexion without a blow
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Hyperextension
Associated Conditions
Popliteal artery injury
Diagnosis
Signs and Symptoms
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Knee pain and swelling after the injury with gradual improvement in generalized pain symptoms
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Minimal symptomatic instability, usually when climbing stairs
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Recurrent effusion
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Posterior knee pain
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Knee recurvatum (late finding)
Physical Exam
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Perform a complete neurovascular examination.
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Tests for ligamentous stability:
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Posterior drawer test:
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Position the patient supine with the knee flexed 90° and the foot stabilized on the examination table.
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Apply posterior force to the anterior tibia.
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Note the excursion of the tibia underneath the femoral condyles.
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Note the quality of the end point.
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Compare the involved and contralateral sides.
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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.
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Lachman test:
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Anterior drawer test at 30° of flexion
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To rule out associated ACL rupture
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Rule out collateral ligament injury
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Tests
Lab
None indicated
Imaging
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Radiography:
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Plain film AP and lateral views of the knee:
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To evaluate for fracture about the knee
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May reveal an avulsion fracture off the proximal posterior tibia
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Stress radiography
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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
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ACL injury
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Tibial plateau fracture
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Meniscal tear
Treatment
General Measures
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Patients may be partial weightbearing as tolerated.
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History and physical examination for a provisional diagnosis
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Radiography and MRI to confirm the diagnosis
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Nonoperative treatment initially, except for high-grade injuries/knee dislocations
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Knee immobilizer and crutch ambulation as tolerated until comfortable
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Early ROM and strengthening
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Knee braces are of questionable use.
Special Therapy
Physical Therapy
A specific OSD-insufficiency knee program is initiated.
Medication
First Line
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NSAIDs
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Acetaminophen
Second Line
Mild, as-needed narcotics for acute/severe pain
Surgery
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Relative indications for surgery:
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Grade 3 PCL injuries
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Posterolateral corner injuries
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Associated ligamentous, meniscal, or articular surface injuries
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Giving-way of the knee
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Pain
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Radiographically documented progressive articular deterioration
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Reduction and internal fixation of avulsion fractures
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Reconstruction is reserved for patients with symptomatic swelling and activity-related pain.
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The procedure entails reconstruction of the ligament with an autograft or allograft.
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Arthroscopically assisted reconstructions are demanding technically but obviate wide surgical exposure.
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Follow-up
Prognosis
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Extremely good
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Most patients do not require surgery.
Complications
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Recurrent symptomatic giving-way of the knee
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Failure of reconstruction
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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.