Uncommon Knee Injury Easily Missed on Diagnosis
Feb. 3, 2000 (Lake Worth, Fla.) -- Most commonly found in runners who stop
short after running at full sprint, or after a fall on the knee which pushes
the tibia, the front leg bone, into the ligament, posterior cruciate ligament
(PCL) injuries are often difficult for physicians to diagnose. Therefore, it's
important for doctors to take a detailed patient history and perform a specific
in-office test to make an accurate diagnosis.
The posterior cruciate ligament is a cross-like ligament located at the back
of the knee. "Some of the disability that relates to the PCL injury
oftentimes is just misconstrued as having a sore knee or an achy knee,"
Robert S. Gotlin, MD, tells WebMD.
A study appearing in a recent issue of Sports Medicine and Arthroscopy
Review points out the importance of an accurate diagnosis. "The most
important thing is to learn to recognize [PCL injuries], and that means doing a
good history and physical examination, which would include the posterior drawer
test," study co-author K. Donald Shelbourne, MD, tells WebMD. Shelbourne
and a colleague, John J. O'Shea, MD, studied 133 patients who came through the
Methodist Sports Medicine Center in Indianapolis, where Shelbourne is a knee
specialist. Through their experience, they determined that the most important
diagnostic test used to diagnose this injury is the "posterior drawer
In the posterior drawer test, the physician looks at both of the patient's
knees held in a 90-degree position and applies force on the shin (tibia) with
both thumbs to determine if there is any amount of step-off, or misalignment of
position, between the tibia and the femur (thigh bone) in the injured leg. It
is important to compare the affected knee with the normal knee.
The important outcome of the study was that these injuries rarely need
surgery, and most of the patients returned to their pre-injury activity -- half
of them at the same level and a third at a lower level of activity. Only
one-sixth of the patients did not return to their pre-injury activity.
Gotlin, director of orthopaedic and sports rehabilitation in the department
of orthopaedic surgery at Beth Israel Medical Center in New York, provided
WebMD with an objective analysis of the study. He explains that the way the PCL
is injured is involved with its primary function, which is to prevent the knee
from going backward. When a person is running full out and stops short, that
momentum tries to push the knee backward. Sometimes, this is when most people
realize they've injured their knee. Also, falling on the knee can push the
tibia into the PCL and cause injury.
What often happens with the PCL is that, once it tears, "it scars and
scars the structures around it, and it almost self-heals, if you will,"
Gotlin explains. "People who have loose knees or tight knees with the PCL
do equally well, and [this] study shows that."