Test for the Posterolateral Rotary Instability of Knee

• This test is apply by the therapist or doctor for the check the instability of knee.
• This test is apply when the patient is complain of Knee pain around to knee area .
• Test is do the during of the examination part of the assessment.

• Two test for this instability:
• Active posterolateral drawer sign
• Dynamic posterior shift test

Purpose of the both test:

• This both test are used to for to check the posterolateral rotary instability of the knee.

Some instruction for both test:

• During to performing of both test examiner is must looking for the abnormal posterior of the lateral side of the tibia .
• As with to posteromedial rotation , the examiner must always be aware that positioning the leg because gravity may cause the lateral tibia to drop back.
• So that this condition is lead to false – positive ALRI means anterolateral rotary instability.
• But in fact the problem is actually a PLRI means posterolateral rotary instability.

Active posterior lateral drawer sign:

Technique of performance of test:

• Patient position for to test is sitting .
• In the sitting foot is on the floor in neutral position .
• Then do the knee flex up to 80′ to 90′.
• After that asked to patient do the isometrically contract to hamstring muscles mostly of lateral one means biceps femoris muscle .
• On this time examiner is stabilizes the foot .

Interpretation of the test :-

• A positive test is indicate to posterolateral rotatory instability .
• It is also indicate to posterior sublaxions of the lateral tibial plateaus .

Dynamic posterior shift test:

Technique of performance of test:

• Patient position for the test is supine .
• Then the examiner is flex the hip &knee of the test leg to 90 ‘ with the femur in neutral rotation .
• With the one hand of examiner is stabilizes the anterior thigh while the other hand is extended to knee .

Interpretation of the test:

• A positive test is indicate to posterolateral rotatory instability.
• It is also indicate to posterior instability of knee.

• If the patient complain to pain around of knee before to accomplished of the knee extension, so decreases to hip flexion but must be keep to hamstring tight.