Physical Medicine and Rehabilitation for Posterior Cruciate Ligament Injury Clinical Presentation

Updated: Oct 21, 2016
  • Author: Jawad Bhatti, MD; Chief Editor: Consuelo T Lorenzo, MD  more...
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Presentation

History

Pain and limited range of motion (ROM) after an injury are the most common symptoms of posterior cruciate ligament (PCL) trauma with associated ligamentous injuries. The associated ligamentous injuries occur about 95% of the time. In isolated PCL injuries, patients may have symptoms of mild swelling, discomfort, and knee stiffness. Knee instability is uncommon in injuries isolated to the PCL. Patients with grade 2 injuries are able to perform gait and drop-landing activities. [3]

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Physical

The posterior drawer test performed with the knee at 90 º is the most sensitive test for detecting posterior cruciate ligament (PCL) injury. The change in the step off from 1 cm (normal) from the medial tibial plateau anterior to the medial femoral condyle is absent, as compared with the healthy knee. This test is 90% sensitive and 99% specific in the diagnosis of PCL injury. [4]

Grading the injury on examination may be performed by using the following scale:

  • Grade I injury - Step off present but decreased (ie, 0-5 mm)

  • Grade II injury - 5-10 mm of posterior translation

  • Grade III injury - Greater than 10 mm of posterior translation

Decreased ROM may be observed, as compared with the ROM of the other knee. The injured knee may lack only 10-20 º of flexion.

Adjuvant tests can increase the sensitivity for diagnosis of PCL injuries. These include the quadriceps active test, the dynamic posterior shift test, the posteromedial and posterolateral instability test, the posterolateral drawer test, the reverse pivot shift test, and the Godfrey, or posterior sag, test.

In the posterior sag test, the patient is asked to flex both knees and hips at 90 º while lying in the supine position. The examiner holds both heels and legs. Posterior tibial translation is an indication of an injured or insufficient PCL.

In the quadriceps active test, the knee is flexed at 60 º and the foot is secured by the physician. The patient is asked to extend the knee isometrically, and if the PCL is injured or absent, the tibia translates anteriorly from a subluxed position. This motion creates a medial tibial plateau step off. The sensitivity of this test was reported to be 58%, with a specificity of 97%. [5]

In the dynamic posterior shift test, the patient is asked to extend the knee from 90 º of flexion to full extension. The patient is asked to keep his/her hip at 90 º of flexion. A positive result occurs when the tibia reduces with a click near full extension.

In the reverse pivot shift test, a valgus load is applied to the knee. The foot is also externally rotated while the knee is extended from a flexed position. If the posteriorly subluxated tibial plateau abruptly shifts back to the reduced position, the result is positive. This test is 95% specific but is only 26% sensitive.

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Causes

In Schulz's study, the most common causes of posterior cruciate ligament (PCL) injury were motor vehicle accidents (45%) and athletic injuries (40%), with motorcycle accidents (28%) and soccer-related injuries (25%) making up the main specific causes of such trauma. Dashboard injuries (35%) and falls on a flexed knee with the foot in plantar flexion (24%) were the most common injury mechanisms. [1]

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