[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Clinical exam](https://durgical.com/en/clinical-exam/) › [Musculoskeletal system](https://durgical.com/en/clinical-exam/#a-musculoskeletal) › Lachman test and anterior drawer [Clinical exam](https://durgical.com/en/clinical-exam/) · [Musculoskeletal system](https://durgical.com/en/clinical-exam/#a-musculoskeletal) # Lachman test and anterior drawer - Maneuver Pulling the shin forward with the knee bent shows whether the anterior cruciate ligament is torn: the tibia slides too far and without a firm stop. Updated 2026-11-01 **See it in 3D:** [ACL](https://durgical.com/en/anatomy/anterior-cruciate-ligament/) · [Tibia](https://durgical.com/en/anatomy/tibia/) · [Femur](https://durgical.com/en/anatomy/femur/) · [PCL](https://durgical.com/en/anatomy/posterior-cruciate-ligament/) ## Key points - Lachman: knee at 20-30 degrees, pull the tibia forward; increased translation with a soft end point = ACL tear. - The Lachman is more useful than the anterior drawer, especially in acute injuries. - Before the anterior drawer, look for posterior sag of the tibia, which means a posterior cruciate ligament injury. - Typical ACL story: a pop, rapid swelling and giving way after a twist on a planted foot. ## What it is The Lachman test and the anterior drawer measure how far the tibia slides forward on the femur. The anterior cruciate ligament (ACL) is the main restraint; when it tears, the tibia moves further and without a firm end point. The Lachman, done with the knee almost straight, is the most useful bedside test for ACL tear, a common injury in pivoting sports. ## The anatomy it tests - The ACL runs from the inner side of the lateral femoral condyle to the front of the tibial plateau and stops the tibia sliding forward on the femur. - At 20-30 degrees of flexion the ACL is almost the only restraint to forward translation, which is why the Lachman is more reliable. - At 90 degrees the menisci and tense hamstrings also hold the tibia and can hide a tear on the drawer test. - The posterior cruciate ligament stops the tibia moving backward. ## How to do it - Patient supine and relaxed; examine the healthy knee first to learn its normal laxity. - Lachman: knee at 20 to 30 degrees of flexion; one hand holds the thigh just above the knee and the other grips the proximal tibia from behind. - Pull the tibia forward with a firm, brief movement, without rotating it, and feel the translation and the end point. - Positive Lachman: the tibia moves further forward than on the healthy side and the end point is soft or absent. - Anterior drawer: hip at 45 degrees and knee at 90 degrees with the foot flat; the examiner sits on the foot to fix it. - Before pulling, look at the knee from the side: if the tibia sags backward, the posterior cruciate ligament is injured. - Wrap both hands around the proximal tibia, thumbs on the joint line, check that the hamstrings are relaxed and pull forward. - Positive anterior drawer: increased forward translation without a firm stop; pushing backward in the same position tests the posterior cruciate. ## What a positive result means - Positive Lachman: ACL tear very likely. - Typical mechanism: a twist or sudden stop on a planted foot, an audible pop, swelling within hours (hemarthrosis) and a knee that gives way. - Posterior drawer or posterior sag of the tibia: posterior cruciate ligament injury. - A negative Lachman makes ACL tear unlikely; a negative anterior drawer does not rule it out. - In the acute knee, pain, effusion and hamstring guarding can cause false negatives. ## Usefulness and limits - The Lachman is the most useful bedside test for ACL tear; the anterior drawer is the least useful. - The pivot shift test is very specific but hard to do in an awake patient in pain. - MRI confirms the tear and shows associated meniscal and ligament injuries. ## Test yourself Think of the answer, then tap the question to see it. ## At what knee flexion angle is the Lachman test done? Between 20 and 30 degrees of flexion. ## Why is the Lachman more reliable than the anterior drawer? Because at 20-30 degrees the ACL is the main restraint and the menisci and hamstrings interfere less than at 90 degrees. ## What should be checked before reading an anterior drawer? Whether the tibia sags backward: it means a posterior cruciate injury and can mimic a positive anterior drawer. ## What does a knee effusion that appears within a few hours of a twist suggest? Hemarthrosis, whose most common cause is an anterior cruciate ligament tear. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/clinical-exam/lachman-test-and-anterior-drawer/) ## See it in 3D The structures of Durgical's 3D anatomy where it is found. - [ACL](https://durgical.com/en/anatomy/anterior-cruciate-ligament/) - [Tibia](https://durgical.com/en/anatomy/tibia/) - [Femur](https://durgical.com/en/anatomy/femur/) - [PCL](https://durgical.com/en/anatomy/posterior-cruciate-ligament/) ## Related - [Meniscal tests: McMurray and Apley](https://durgical.com/en/clinical-exam/meniscal-tests-mcmurray-and-apley/) - [Knee effusion: patellar tap and bulge sign](https://durgical.com/en/clinical-exam/knee-effusion-patellar-tap-and-bulge-sign/) - [Ottawa ankle and knee rules](https://durgical.com/en/clinical-exam/ottawa-ankle-and-knee-rules/) - [Joint examination: inspection, palpation and range of motion](https://durgical.com/en/clinical-exam/joint-examination-inspection-palpation-and-range-of-motion/) ## Related conditions - [ACL Tear](https://durgical.com/en/conditions/acl-tear/) - [PCL Injury](https://durgical.com/en/conditions/pcl-injury/) [← All of the clinical exam](https://durgical.com/en/clinical-exam/) Educational content on the clinical exam; it is learned and practised under supervision. It does not replace assessment by a health professional and is not for self-diagnosis. Sources: [Evaluating the Patient with a Knee Injury](https://www.aafp.org/pubs/afp/issues/2005/0315/p1169.html) (American Family Physician (American Academy of Family Physicians), 2005); [Musculo-Skeletal Examination – Knee Exam](https://sites.ucsd.edu/clinicalmedguide/musculo-skeletal-examination-the-knee-exam/) (UC San Diego School of Medicine, Practical Guide to Clinical Medicine, 2026). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/clinical-exam/lachman-test-and-anterior-drawer/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/clinical-exam/lachman-test-and-anterior-drawer/