REVERSE PIVOT SHIFT (JAKOB TEST)

TEST POSITIONING

The client lies supine with the test knee in 40 to 50 degrees of flexion.

The therapist stands with the proximal hand on the client's posterolateral leg, just distal to the patella, with the thumb on or anterior to the fibular head.

The distal hand grasps the client's midfoot and heel.

ALTERNATE TEST POSITIONING

Place the client's foot between the therapist's distal arm and body, with the same hand on the tibia.

The proximal hand should be placed on the posterolateral leg just distal to the knee, with the thumb on or anterior to the fibular head.

ACTION

The therapist externally rotates the tibia with one hand and applies a valgus force with the other hand while slowly extending the knee.

The same procedure applies for the alternate test position, except a slight axial load is applied as the knee is extended.

POSITIVE FINDING

This is first seen when the therapist flexes the client's knee if the lateral tibial plateau subluxes posteriorly.

Furthermore, this subluxation is reduced once the knee extends and approaches a position of approximately 20-degrees of flexion.

At this point, the lateral tibial plateau will return to a neutral position.

A palpable "clunk" or shift as it approaches extension (-20 to 30 degrees of flexion) is indicative of posterolateral rotary instability secondary to damage of primarily the posterior cruciate ligament (PCL), LCL posterolateral capsule and arcuate complex.

CONSIDERATIONS & COMMENTS

This test is very sensitive to the client who possesses an instability.

It should be done only with the client relaxed as a contraction of the surrounding musculature of the knee may prevent a subtle subluxation and indicate a negative test.