Pivot-shift test

Pivot-Shift Test

Illustration of the pivot-shift test being performed on a knee.

The pivot-shift test is a clinical examination technique used to assess the integrity of the anterior cruciate ligament (ACL) in the knee joint. It is a dynamic test that evaluates the knee's stability and is particularly useful in diagnosing ACL injuries. The test is considered positive if it reproduces a sensation of instability or "giving way" in the knee, which is indicative of an ACL tear.

Anatomy of the Knee

The knee joint is a complex hinge joint that connects the femur (thigh bone) to the tibia (shin bone). It is stabilized by several ligaments, including the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL), and lateral collateral ligament (LCL). The ACL is crucial for preventing anterior translation and rotational instability of the tibia relative to the femur.

Performing the Pivot-Shift Test

To perform the pivot-shift test, the patient is positioned supine with the hip flexed to approximately 30 degrees and the knee extended. The examiner holds the patient's foot with one hand and places the other hand on the lateral aspect of the knee. The examiner then applies a valgus force to the knee while internally rotating the tibia and flexing the knee. A positive test is indicated by a palpable "clunk" or "shift" as the tibia reduces on the femur, suggesting an ACL deficiency.

Clinical Significance

The pivot-shift test is an important tool in the clinical assessment of ACL injuries. A positive pivot-shift test is highly suggestive of an ACL tear and is often used in conjunction with other tests such as the Lachman test and the anterior drawer test to confirm the diagnosis. The test is also used post-operatively to assess the success of ACL reconstruction surgery.

Limitations

While the pivot-shift test is a valuable diagnostic tool, it requires skill and experience to perform accurately. Factors such as patient muscle guarding, pain, and examiner technique can affect the test's reliability. Additionally, the test may be less reliable in the presence of other knee injuries, such as meniscal tears or collateral ligament injuries.

Related Pages

• Anterior cruciate ligament injury
• Knee examination
• Lachman test
• Anterior drawer test