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The anterior drawer test for ACL injuries is one of the oldest exams in orthopedic medicine, and patients ask about it constantly. Someone pulls on your shin, writes a note in the chart, and sends you for imaging. Here is what that exam checks, how much weight it carries, and what your result actually means.
What is the anterior drawer test for ACL injuries?
The anterior drawer test is a physical exam that checks whether the anterior cruciate ligament (ACL) is still holding the shin bone back. The knee is bent to about 90 degrees, the foot is held down, and the examiner pulls the top of the shin forward. If the shin slides farther than it does on the healthy leg, the test is positive.
No equipment. No radiation. It takes less than a minute in the exam room.
The name comes from the motion itself: the shin bone opens forward like a drawer sliding out of a desk.
What does the ACL do?
The ACL is one of four main ligaments in the knee. It runs diagonally through the center of the joint and keeps the shin bone (tibia) from sliding forward under the thigh bone (femur).
Tear it, and the knee loses its front-to-back checkrein. ACL tears account for more than half of all knee injuries and affect over 200,000 people in the United States each year.
Most patients describe some version of the same story:
- A pop or snap at the moment of injury, often while pivoting or landing
- Swelling that builds within a few hours
- A knee that gives way or buckles on uneven ground
- Loss of full bending or straightening
- Pain and a sense of looseness when walking
How is the anterior drawer test performed?
The test is performed with the patient lying flat, the hip bent to roughly 45 degrees and the knee bent to 90 degrees. The examiner steadies the foot, cups both hands behind the upper shin, and draws it forward with a gentle back and forth motion.
The sequence looks like this:
- You lie on your back on the exam table with both legs relaxed
- The knee is bent to about 90 degrees, with the foot flat
- The examiner stabilizes the foot, often by sitting lightly on it
- Both hands wrap behind the upper shin, thumbs resting on the joint line
- A steady forward pull is repeated two or three times
- The same exam is done on the uninjured knee for comparison
Relaxation is the whole game here. Tight hamstrings can hold the shin in place and hide a torn ligament, which is the most common reason this exam reads falsely normal.
Here is what I tell my patients before I start: this should feel like pressure, not pain. If it hurts, say so, and we stop and try a different position.
What does a positive anterior drawer test mean?
A positive result means the shin translated forward farther than it should, generally more than about 6 millimeters compared with the uninjured side, and it stopped softly instead of hitting a firm end point.
That soft ending matters as much as the distance. A healthy ACL brings the shin to an abrupt stop; a torn one lets it drift and settle.
Grading is by comparison, never by an absolute number, which is why both knees always get examined.
How accurate is the anterior drawer test?
A 2022 systematic review and meta-analysis pooling eight studies and 620 patients found the anterior drawer test had 78 percent sensitivity and 91 percent specificity for ACL injury within six weeks of the injury.
In plain terms: when this test is positive, it is usually right. When it is negative, a tear can still be sitting there.
Accuracy improves once the acute phase passes. A separate study of 653 patients, 428 of whom went on to arthroscopy, reported 94.4 percent sensitivity for the anterior drawer test in clinic and 96.4 percent under anesthesia. Swelling, pain, and muscle guarding all fade with time, and a relaxed knee gives a truer reading.
The same 2022 review measured three other ligament exams for comparison:
- Lachman test: 79 percent sensitivity, 91 percent specificity
- Lever sign test: 82 percent sensitivity, 88 percent specificity
- Pivot shift test: 55 percent sensitivity, 96 percent specificity
No single exam wins outright. Combining two or three of them is what makes a bedside diagnosis reliable.
Why the Lachman test is usually done alongside the anterior drawer test
The Lachman test checks the same ligament with the knee bent only 20 to 30 degrees, and most surgeons trust it more in a freshly injured knee. At 90 degrees, the extra forward movement caused by an isolated ACL tear is smaller than at any other angle, so a torn ligament can slip past the anterior drawer test unnoticed.
Some knee specialists now treat this exam as more historical than decisive. It keeps its place for one specific reason: it can turn strongly positive when the back portion of the medial meniscus is damaged along with the ACL, and that combination changes the surgical plan.
After more than twenty years of knee work, I have learned to trust the pattern of several exams over any single result.
Does a positive result mean you need an MRI?
In almost every case, yes. Physical exam narrows the diagnosis; MRI confirms the tear and shows what else was hurt, including meniscus tears, cartilage damage, and bone bruising that no hands-on exam can detect.
Delay is the real risk. Two UK studies found ACL tears were correctly identified at first contact in only 28.2 percent and 14.4 percent of cases, with a median of six weeks from injury to diagnosis.
Every one of those weeks on an unstable knee raises the odds of a second injury inside the joint.
A knee that keeps giving way deserves another look, even after a normal first exam. That is the single most useful thing I can tell someone reading this.
Who should evaluate a knee injury in Franklin or Nashville?
Any knee with swelling, a pop at the time of injury, or a feeling of instability should be seen by an orthopaedic specialist within a few days rather than waited out for weeks.
I am a board-certified orthopedic surgeon and a founding partner at the Bone and Joint Institute of Tennessee, and I perform more than 700 hip and knee replacements a year. Judging ligament tension by hand is part of every one of those operations.
ACL reconstruction itself is sports medicine work. I refer those patients to my sports medicine partners so they see the surgeon who performs that operation every week.
What I do treat is the knee that hurts from cartilage wear rather than a torn ligament: arthritis, mechanical symptoms, and the full range of options from nonsurgical joint pain treatment through knee arthroscopy and total knee replacement. Patients travel to our Franklin office from Nashville, Brentwood, Spring Hill, Columbia, Nolensville, and Murfreesboro.
Bone and Joint Institute of Tennessee, 3000 Edward Curd Lane, Franklin, TN 37067. Call (615) 791-2630 or schedule a consultation with Dr. Calendine online.
You can also read more about Dr. Calendine’s training and background or browse the rest of the joint replacement blog.
This article is for educational purposes only and does not replace an in-person evaluation. Always consult a qualified orthopaedic provider about your own knee symptoms. Individual results vary based on injury pattern, activity level, and overall health.
References
- Tanaka S, Inoue Y, Masuda Y, Tian H, Jung H, Tanaka R. Diagnostic accuracy of physical examination tests for suspected acute anterior cruciate ligament injury: a systematic review and meta-analysis. International Journal of Sports Physical Therapy. 2022;17(5):742-752. PMC9340834
- Makhmalbaf H, Moradi A, Ganji S, Omidi-Kashani F. Accuracy of Lachman and anterior drawer tests for anterior cruciate ligament injuries. Archives of Bone and Joint Surgery. 2013;1(2):94-97. PMC4151408
- Arastu MH, Grange S, Twyman R. Prevalence and consequences of delayed diagnosis of anterior cruciate ligament ruptures. Knee Surgery, Sports Traumatology, Arthroscopy. 2015;23(4):1201-1205.
- Parwaiz H, Teo AQA, Servant C. Anterior cruciate ligament injury: a persistently difficult diagnosis. The Knee. 2016;23(1):116-120.
- Luan L, Ji W, Ganderton C, Farragher J, Pappas E, Adams RD, Wang S, Han J. Is the anterior drawer test still valuable for diagnosing mechanical ankle instability in clinical practice and research? Frontiers in Bioengineering and Biotechnology. 2025;13:1664779.
- American Academy of Orthopaedic Surgeons. Anterior cruciate ligament (ACL) injuries. OrthoInfo. orthoinfo.aaos.org. Accessed July 2026.
Watch: Why the ACL Exam Changes Once You Are Asleep
Here is the short version of why the same knee can read differently in clinic than it does in the operating room.
