Pushed Quadriceps Active Test

Original Editor - Pacifique Dusabeyezu
Top Contributors - Pacifique Dusabeyezu

Purpose

The Pushed Quadriceps Active Test is modification of the traditional Quadriceps Active (QA) test which is also known as Muller's Test. This modification aims to improve the accuracy of diagnosing posterior cruciate ligament (PCL) deficiencies, particularly for those with subtle signs. As the diagnosis of PCL deficiency is difficult even for experienced professionals, this test improves both the accuracy of diagnosis of PCL tears and the sensitivity of the classical QA test.

Technique

The pushed quadriceps active test (PQA) involves two parts in which the examiner pushes the proximal tibia backward with the knee bent <90 degrees, similar to the posterior drawer test, and the patient actively reduces the translation by contracting the quadriceps, as in the QA test.

• With the patient lying on their back, their affected knee is bent slightly to less than 90°, similar to the position for the posterior drawer test. The patient should relax the muscles around the knee. The examiner holds the foot and then pushes the upper part of the tibia bone backward, as with the posterior drawer test. If the PCL is impaired, the tibia bone will move backward.
• At the point when the tibia bone is pushed back the most, the patient is asked to contact their quadriceps muscles actively. At the same time, the examiner reduces the amount of force pushing the tibia bone backward. This causes the proximal part of the tibia bone to move anteriorly, as seen in the QA test. However, in that test, the knee is more bent, and there is only an active component.

In the Pushed QA test (PQA), there is a passive component that moves the tibia maximum posteriorly, while the active component restores the rotation to the normal position. This has the added advantage that the examiner can perceive the posterior movements in the posterior drawer test, as well as perceive the anterior translation during the QA component visually as well as by tactile feedback from the hand.

The examiner's visual and tactile feedback are used to detect a positive test. Tactile feedback from the examiner could be crucial for detecting the translation of the proximal tibia, especially in very obese individuals where it may be missed by visual input.

Evidence

The posterior force applied in the PQAT eliminates any anterior sliding that might occur in an ACL-impaired knee. Therefore, a positive PQAT indicates a PCL issue, not an ACL problem. However, this test might be difficult to perform in some cases where there is limited flexion and significant bleeding (hemarthrosis) in the joint.

Conclusion

The PQA test is a useful test for the accurate diagnosis of PCL deficiency. However Further studies are needed to clarify its sensitivity and specificity and its role in the clinical evaluation of PCL and other injuries.