Jakob’s test is a clinical examination that tests for posteriolateral, instability of the knee joint.
- Patient standing with weight equally distributed on both feet
- Examiner applies a valgus force to involved knee while slowly flexing the knee.
If examiner observes some jerking of the knee, posterior shifting of the tibia, or proof of the “giving away” phenomenon then it can possibly mean Posteriolateral instability.
Damaged structures that may lead to positive test include; posterior cruciate ligament, medial collateral ligament, semimembranosus.