Lelli Test (Lever Sign Test): How to Perform It and Interpret ACL Results

Published July 25, 2026 Read time 5 min read Readers 37
Lelli Test (Lever Sign Test)

The Lelli test, also called the lever sign test, is a bedside physical examination maneuver used to assess the integrity of the anterior cruciate ligament (ACL) of the knee. It is quick to perform, needs no equipment beyond the examiner’s hands, and works in a clinic, on a sports field, or in the emergency department. Because ACL tears are among the most common knee injuries in active people, clinicians value any simple test that adds information to the Lachman, anterior drawer, and pivot shift tests.

What Is the Lelli Test (Lever Sign Test) Used For?

The test evaluates anterior stability of the knee. It helps the examiner judge whether the ACL is intact or whether it is partially or completely torn. It works by showing whether the tibia can behave as a rigid lever against the femur, which depends on a functioning ACL.

How to Perform the Lelli Test (Lever Sign Test)

Patient position: The patient lies supine on the examination table with the knee fully extended and the muscles relaxed.

Step-by-step technique:

  1. The examiner makes a closed fist and places it under the proximal third of the patient’s calf. This lifts the calf and flexes the knee slightly.
  2. The examiner’s other hand rests over the distal third of the quadriceps, just above the knee (the distal femur).
  3. The examiner slowly applies a moderate downward force to the distal thigh.
  4. The examiner watches the heel and the relationship of the tibial plateau to the femoral condyles.

Practical tips:

  • Keep the patient relaxed. Hamstring or quadriceps guarding can alter the result.
  • Apply force gradually rather than abruptly.
  • Compare both knees when possible.
  • Interpret the result alongside history and other ligament tests.

How to Interpret the Result

Negative (Normal) Test

When the ACL is intact, the downward force on the femur makes the tibia act as a lever. The heel lifts off the examination table. This indicates normal anterior stability of the knee.

Positive Test

When the ACL is partially or completely torn, the tibia slides anteriorly relative to the femur. The lever mechanism fails and the heel does not rise from the table. This is a positive Lelli test and suggests ACL insufficiency.

Accuracy of the Lelli Test: What Does the Evidence Show?

Accuracy figures for the lever sign vary considerably between studies. The values reported in the reference cited by this article are a sensitivity of 38% and a specificity of 72% (1). Sensitivity is the proportion of ACL tears the test detects. Specificity is the proportion of intact ACLs the test correctly identifies.

Other studies differ:

  • An independent comparison against MRI reported an overall accuracy of 77%, with 63% sensitivity and 90% specificity. It also found similar performance in awake patients and patients under anesthesia (2).
  • A systematic review and meta-analysis in the International Journal of Sports Physical Therapy concluded that the test is comparable to other clinical tests for ACL rupture. It found that a positive or negative result produces a moderate shift in post-test probability, and it suggested using the test together with other examinations (3).
  • A separate systematic review concluded that, based on limited evidence of heterogeneous methodological quality, the lever sign can moderately change post-test probability to rule in an ACL tear (4).
  • A later meta-analysis of more than 3,000 observations reported very good to excellent accuracy (5).

The original description of the test reported near-perfect values, but independent studies have not consistently reproduced them (2).

Clinical Takeaways

  • The Lelli test is simple, fast, and reproducible, and it can be learned easily.
  • A positive result raises suspicion of ACL insufficiency, but it does not replace a full knee examination.
  • A negative result does not reliably exclude an ACL tear, particularly given the lower sensitivity values reported in some studies.
  • Combine the test with the Lachman test, anterior drawer test, pivot shift test, and the patient’s history. Confirm with MRI or arthroscopy when clinically indicated.

Frequently Asked Questions (FAQ)

What is the Lelli test?
It is another name for the lever sign test, a physical examination maneuver for assessing the integrity of the ACL.

Is the Lelli test the same as the lever sign test?
Yes. The test is named after the clinician who described it, and both names refer to the same maneuver.

What does a positive Lelli test mean?
The heel stays on the table when downward force is applied to the distal thigh. This suggests the ACL is partially or completely torn.

What does a negative Lelli test mean?
The heel lifts off the table, indicating that the ACL is likely intact and anterior knee stability is normal.

How accurate is the lever sign test?
Reported accuracy varies widely between studies. The reference cited here gives 38% sensitivity and 72% specificity (1). Other studies report higher figures (2,5).

Can the Lelli test be used on its own to diagnose an ACL tear?
No. It should be combined with the Lachman test, anterior drawer test, pivot shift test, clinical history, and imaging when needed.

Can the test be performed on an acutely injured, painful knee?
Often yes, because it is gentle and does not require knee flexion or rotation. Pain and guarding can still affect the result, so interpret it with caution.

Is imaging needed after a positive result?
MRI is commonly used to confirm an ACL injury and assess associated meniscal or cartilage damage, depending on the clinical picture.

Research Limitations

Published studies on the lever sign differ in design, patient populations, examiner experience, reference standards, and whether testing was done awake or under anesthesia. These differences explain much of the variation in reported sensitivity and specificity. The test should be read as one piece of the clinical picture, not as a stand-alone diagnostic.

References

  1. Mulligan EP, Anderson A, Watson S, Dimeff RJ. The diagnostic accuracy of the lever sign for detecting anterior cruciate ligament injury. Int J Sports Phys Ther. 2017;12(7):1057–1067. PubMed
  2. Accuracy of the Lever Sign Test in the Diagnosis of Anterior Cruciate Ligament Injuries. PubMed
  3. Diagnostic accuracy of the lever sign in detecting anterior cruciate ligament tears: a systematic review and meta-analysis. Int J Sports Phys Ther. 2019;14(1):2–13. PubMed
  4. Accuracy of the lever sign to diagnose anterior cruciate ligament tear: a systematic review with meta-analysis. PMID 30276010. PubMed
  5. Lever sign test shows high diagnostic accuracy for anterior cruciate ligament injuries: a systematic review and meta-analysis of 3299 observations. Knee. Amsterdam UMC record