History
Patients with acute posterior cruciate ligament (PCL) injuries have a presentation similar to that of patients with most other knee injuries. Patients with acute isolated PCL injuries often have minimal symptoms consisting of pain, swelling, and instability. In many cases, a near-normal gait pattern is seen. [36]
Physical Examination
PCL injury should be suspected at the time of physical examination of any acute knee injury. (See the image below.) Complete examinations of the contralateral and injured knees should be performed for comparison. If a PCL insufficiency is noted, care must be taken to evaluate the competency of the posterolateral corner.
Clinical examination photograph of a ruptured posterior cruciate ligament (PCL) confirmed on a posterior sagittal radiograph. Image courtesy of Mervyn J. Cross, MBBS, FRACS.
With acute isolated PCL injuries, patients typically do not have joint-line tenderness. An effusion may or may not be present. Varus, valgus, and rotational stressing reveal no instability.
The posterior drawer test is the most reliable indicator during physical examination for a PCL injury. [37, 38] Positive posterior drawer test results are graded as follows:
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Grade 1 - Laxity is noted compared with the contralateral knee, but the tibia remains anterior to the anterior aspect of the femoral condyles
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Grade 2 - The anterior tibia can be subluxated equal to the anterior aspect of the femoral condyles
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Grade 3 - The tibia subluxates posterior to the anterior aspect of the femoral condyles
With internal rotation, the posterior drawer test may elicit normal results for a PCL-insufficient knee because of the secondary restraint effect of the meniscofemoral ligaments. [39] If more than 10 mm of posterior tibial translation is noted at 90° of knee flexion, a combined PCL and posterolateral corner injury is present. The posterior drawer test result demonstrates more than 10 mm posterior translation at 30° of knee flexion when the posterolateral corner is disrupted, either in isolation or in combination with a PCL injury.
The dial test helps identify an associated or isolated posterolateral corner injury. Greater than 10° of increased external rotation of the leg compared with the contralateral leg at 30° and 90° of knee flexion is a positive finding signifying a posterolateral corner injury with a PCL injury. [2] A posterolateral corner injury has increased external rotation at 30º of flexion that (with PCL injury) stays the same or increases at 90º of flexion, whereas, at 90º of flexion without a PCL injury, less external rotation occurs.
Care must be taken in evaluating a knee with a positive dial test result to note that the lateral tibial plateau is subluxating posteriorly so that anterior subluxation of the medial tibial plateau secondary to an anterior cruciate ligament(ACL) and/or medial collateral ligament (MCL) disruption is not misinterpreted. [40]
The posterior sag, quadriceps active, external rotation recurvatum, and reverse pivot shift tests also aid in evaluating an acutely injured knee for PCL pathology. [41] (See the images below.)
The photo on the left demonstrates the clinical finding of the posterior tibia sag sign. A line drawn parallel to the patella accentuates the posterior tibia sag. The photo on the right demonstrates the quadriceps active drawer test described by Daniels; with the knee in 70-90° of flexion, the extensor mechanism is contracted, pulling the tibia anteriorly into a reduced position. Image courtesy of Janos P. Ertl, MD.
Close-up view of a posterior tibia sag with an incompetent posterior cruciate ligament (PCL). Image courtesy of Janos P. Ertl, MD.
Posterior sag of the left posterior cruciate ligament–deficient knee in comparison to the right knee. Note the posterior subluxation of the tibia relative to the femur of the left knee. Image courtesy of Robert Bronstein, MD.
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Lateral radiograph of a normal knee. In a normal knee, a line drawn along the posterior femoral condyle does not intersect the posterior tibial condyle. Image courtesy of Janos P. Ertl, MD.
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Lateral radiograph of a knee with a posterior cruciate ligament injury. Note that the same line as in the image above bisects the posterior tibial condyle due to a posterior sag and an incompetent PCL. Image courtesy of Janos P. Ertl, MD.
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The photo on the left demonstrates the clinical finding of the posterior tibia sag sign. A line drawn parallel to the patella accentuates the posterior tibia sag. The photo on the right demonstrates the quadriceps active drawer test described by Daniels; with the knee in 70-90° of flexion, the extensor mechanism is contracted, pulling the tibia anteriorly into a reduced position. Image courtesy of Janos P. Ertl, MD.
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Close-up view of a posterior tibia sag with an incompetent posterior cruciate ligament (PCL). Image courtesy of Janos P. Ertl, MD.
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A view of the broad origin of the posterior cruciate ligament (PCL) on the medial femoral condyle of a left knee. The anterior cruciate has been removed for surgical reconstruction. Image courtesy of Janos P. Ertl, MD.
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An additional view of the posterior cruciate ligament (PCL) broad origin and insertion in a knee pending anterior cruciate ligament (ACL) reconstruction. Image courtesy of Janos P. Ertl, MD.
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A right knee pending posterior cruciate ligament (PCL) reconstruction. A minimal notchplasty is completed. Two guide pins are advanced into the medial femoral condyle for tunnel placement to reconstruct the two bundles of the PCL. Image courtesy of Janos P. Ertl, MD.
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The two femoral tunnels are created by reaming from outside in; 8- to 9-mm tunnels are made depending on the patient size and graft used. Image courtesy of Janos P. Ertl, MD.
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Two red Robinson catheters are advanced through the femoral tunnels. Image courtesy of Janos P. Ertl, MD.
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The catheters have premade holes that are used for suture retrieval. Image courtesy of Janos P. Ertl, MD.
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The catheters are advanced and threaded out the posterior knee. In this case, a posterior tibial inlay graft from an Achilles tendon allograft is used. The two bundles are secured to the catheters and advanced into the joint through the tunnels. Image courtesy of Janos P. Ertl, MD.
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The two Achilles tendon bundles are secured with a baseball whipstitch, threaded through the catheter holes, and advanced into the femoral condyle tunnels. Image courtesy of Janos P. Ertl, MD.
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Additional view of the placement and advancement of the Achilles allograft. Image courtesy of Janos P. Ertl, MD.
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Completion and seating of the femoral allograft reconstruction. The two bundles are secured or stabilized by suturing over a post and washer. Note the re-establishment of the broad surface area for the reconstructed posterior cruciate ligament (PCL) origin. Image courtesy of Janos P. Ertl, MD.
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Completion of the tibial inlay two-bundle Achilles tendon allograft/posterior cruciate ligament (PCL) reconstruction. The bony calcaneus remnant is secured to the posterior tibia with one or two interfragmentary compression screws into a trough into the posterior tibia at the level of the PCL insertion. Care is taken not to penetrate the anterior tibial cortex with these screws. Note the intact original anterior cruciate ligament (ACL). Image courtesy of Janos P. Ertl, MD.
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Posterior sag of the left posterior cruciate ligament–deficient knee in comparison to the right knee. Note the posterior subluxation of the tibia relative to the femur of the left knee. Image courtesy of Robert Bronstein, MD.
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Clinical examination photograph of a ruptured posterior cruciate ligament (PCL) confirmed on a posterior sagittal radiograph. Image courtesy of Mervyn J. Cross, MBBS, FRACS.
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Radiograph depicting a chronic avulsed posterior cruciate ligament (PCL). Image courtesy of Mervyn J. Cross, MBBS, FRACS.
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An MRI showing a torn posterior cruciate ligament (PCL). Image courtesy of Mervyn J. Cross, MBBS, FRACS.
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Sagittal view radiograph showing a posterior cruciate ligament (PCL) rupture. Note the posterior positioning of the tibia in relation to the femur. Image courtesy of Mervyn J. Cross, MBBS, FRACS.
