Clinical examination of a knee with a suspected ACL tear

The professional looks for the mechanism, rapid swelling, weight-bearing resumption, and episodes of instability. Sports, work, and goals give meaning to the findings.

The examination compares both sides while taking natural differences into account.

The Lachman test assesses anterior translation and the quality of the end-point. The anterior drawer and pivot shift explore other positions and components.

Pain and muscle contraction can reduce reliability in the acute phase. No test should be interpreted in isolation.

• Inspection and effusion.
• Range of motion, especially extension.
• Palpation and meniscal/ligamentous examination.
• Neurovascular assessment if necessary.

The diagnosis combines history, examination, and, when relevant, imaging. Measured laxity is not synonymous with felt instability.

Re-evaluation sometimes allows for a better assessment when the knee is less painful and swollen.

In the first few days, pain, hemarthrosis, and muscle guarding can make certain tests difficult. A cautious or incomplete result is not necessarily an error.

Ask what could be tested, what remains to be clarified, and at what sign a re-evaluation should be brought forward. This avoids turning a first consultation into a definitive verdict.

• Bring the timeline of the swelling.
• Report any known hyperlaxity or past surgery.

The evaluation is not limited to the ACL. It checks in particular mobility, effusion, the menisci, collateral ligaments, weight-bearing control, and, after severe trauma, the neurological and vascular state. Comparison with the other knee is useful but imperfect: some people naturally have more laxity. The professional's experience and the patient's relaxation also influence interpretation.

You can ask which test was the most informative, if pain limited the examination, and why imaging is—or is not—proposed. If you have had a dislocation, surgery, hyperlaxity, or a similar injury on the other side, report it explicitly.

These benchmarks are used to prepare a clinical discussion and to understand the possible choices. They do not allow for a remote conclusion on a lesion, treatment, or schedule: the context, the examination, and any associated gestures remain decisive.

To delve deeper into 'Clinical examination of a knee with a suspected ACL tear', revisit the elements of the sections 'History guides the examination' and 'Lachman, anterior drawer, and pivot shift' with your own timeline. It is useful to separate what is certain—date of trauma, report, triggering activity—from what remains an impression, such as the feeling of weakness or giving way. This distinction makes the information easier for the team to interpret.

The cited publications describe populations and trends; they do not replace the instructions of the team that knows the file. During the consultation, ask how general information applies or does not apply to your situation, what limitations it contains, and what sign would justify making contact before the scheduled follow-up.

After the discussion, note the next step, the person to contact, and the symptoms to watch for. If a response seems contradictory to a report or written instruction, ask for clarification rather than changing weight-bearing, activities, or medications on your own.

• AAOS 2022. Management of Anterior Cruciate Ligament Injuries — Clinical Practice Guideline.
• JOSPT 2017. Knee Stability and Movement Coordination Impairments: Knee Ligament Sprain Revision.
• Panther Symposium 2020. Treatment After Anterior Cruciate Ligament Injury — ACL Treatment Consensus Group.
• Benjaminse 2006. Clinical diagnosis of an anterior cruciate ligament rupture: a meta-analysis.