With the tibial drop back sign, one relies on gravity with the knee flexed to 90° to compare if there is any “dropping back” of the tibia on the injured side compared to the normal contralateral knee. In this test, one compares the prominence of the proximal tibia to the femoral condyles with the knee flexed to approximately 80°-90°. In the normal knee, the tibial plateau is located approximately 1 cm anterior to the femoral condyles. In a patient with a PCL tear, this prominence is diminished and there may be subluxation of the tibial plateau posterior to the femoral condyles in a severe PCL injury.
About the Author: Robert LaPrade, MD
Robert LaPrade, MD, PhD has specialized skills and expertise in diagnosing and treating complicated knee injuries. He has treated athletes at all levels, including Olympic, professional and intercollegiate athletes, and has returned numerous athletes back to full participation after surgeries. Recognized globally for his outstanding and efficient surgical skills and dedication to sports medicine, he has received many research awards, including the OREF Clinic Research Award considered by many a Nobel Prize in orthopedics. Dr. LaPrade is one of the most published investigators in his field, and many of the surgeries that he has developed are now performed worldwide and recognized as the “gold standard” for the treatment of complex knee injuries.