Posterior drawer test

How the test is done

You lie on your back with both knees bent and feet flat. Before touching the knee, the surgeon looks at both shins from the side. If the PCL is torn, the top of the shin on the injured side sags backwards, called the posterior sag sign.

The surgeon then steadies your foot and pushes the shin back. It feels like a firm push with a sliding sensation, and is usually not painful.

What it tells the surgeon

A healthy PCL stops the shin with a firm end point, with the front of the shin sitting slightly ahead of the thigh bone. As the PCL injury becomes more severe, the shin moves further back, and the test is graded from mild to complete. A high grade, especially with abnormal rotation, raises concern for an injury to the posterolateral corner as well.

PCL tears commonly happen when the shin hits a car dashboard or when someone falls onto a bent knee. Symptoms can be vague, such as aching at the front of the knee or discomfort on stairs, so the examination is important.

Next steps

An MRI usually confirms the injury and checks other ligaments. Stress X-rays may measure the backward shift. Many isolated PCL injuries are treated with a brace and physiotherapy; higher-grade or combined injuries may need reconstruction.