The Knee Exam Basics

 

Anterior Cruciate Ligament

  • Lachman test

    • Technique​​

      • Patient supine

      • Examiner to the affected side of the patient with the near hand grasping the proximal tibia and the far hand stabilizing the distal femur.  The knee is passively flexed to 20-30° and the proximal tibia is then pulled forward while stabilizing the distal femur.

      • A positive result occurs when there is increased anterior translation of the tibia and no firm endpoint when compared to the uninjured knee

      • A negative result occurs when there is no increase in anterior translation of the tibia and a firm endpoint

  • Anterior drawer

    • Technique​

      • Patient supine with both feet flat on the table

      • Examiner to the affected side of the patient with a knee or hip resting on the patient's foot to stabilize the extremity.  The thumbs are placed on either side of the patellar tendon in the medial and lateral sulci ("dime spaces"), with the fingers grasping the proximal tibia.  The tibia is then pulled anteriorly.

      • A positive result occurs when there is increased anterior translation of the tibia compared to the uninjured side.  Tip: use the pads of the thumbs to gauge how much of the tibia plateau can be translated when pulling forward.

      • A negative result occurs when there is no increase in anterior translation compared to the uninjured side.​

Posterior Cruciate Ligament

  • Posterior drawer

    • Technique​

      • Patient supine with both feet flat on the table

      • Examiner to the affected side of the patient with a knee or hip resting on the patient's foot to stabilize the extremity.  The thumbs are placed on either side of the patellar tendon in the medial and lateral sulci ("dime spaces"), with the fingers grasping the proximal tibia.  The tibia is then pushed posteriorly.

      • A positive result occurs when there is increased posterior translation of the tibia compared to the uninjured side.  Tip: use the pads of the thumbs to gauge how much of the femoral condyles protrude into the thumb pads when pushing posteriorly.

      • A negative result occurs when there is no increase in posterior translation compared to the uninjured side.

  • Sag sign

    • Technique​

      • Patient supine on the table

      • Examiner to the affected side of the patient and passively flexes the patient's hips and knees to 90° supporting under the heels or ankles.  Evaluate the height of the tibial tubercles.

      • A positive result occurs when there is a tibial "sag" or increased posterior translation of the injured knee tibia tubercle compared to the uninjured side.

      • A negative result occurs when the tibial tubercle position is symmetric.

Medial Collateral Ligament

  • Valgus stress test

    • Technique​

      • Patient supine with the legs resting in extension

      • Examiner to the affected side of the patient with the near hand grasping the patient's ankle and the far hand at or just above the lateral joint line.  With the inside hand pull the ankle away from the body while pushing toward the body at the knee with the outside hand.  This should be done with the knee at 0° and passively flexed to ~30°.

      • A positive result occurs when there is increased medial opening at the knee or an increase the amount that the ankle can be pulled out.  This can also be assessed by the feel of the knee when the pressure is let off and the knee reduces alignment.  Pain with no increased laxity can indicate a mild ligament injury.

      • A negative result occurs when there is no increase in laxity or pain.

Lateral Collateral Ligament

  • Varus stress test

    • Technique​

      • Patient supine with the legs resting in extension

      • Examiner to the affected side of the patient with the near hand grasping the patient's ankle and the far hand wrapped over or under the knee and placed at or just above the lateral joint line.  With the inside hand push the ankle toward the body while pulling away from the body at the knee with the outside hand.  This should be done with the knee at 0° and passively flexed to ~30°.

      • A positive result occurs when there is increased lateral opening at the knee or an increase the amount that the ankle can be pushed inward.  This can also be assessed by the feel of the knee when the pressure is let off and the knee reduces alignment.  Pain with no increased laxity can indicate a mild ligament injury.

      • A negative result occurs when there is no increase in laxity or pain.

Meniscus 

  • McMurray's test

    • Technique​

      • Patient supine with the legs resting in extension

      • Examiner to the affected side of the patient with the near hand cupping the patient's heel and the foot resting on the forearm.  The far hand is placed on the knee with the index finger across the medial joint line and the thumb across the lateral joint line.  The knee is passively fully flexed and forcefully internally and externally rotated using the hindfoot as a lever.

      • A positive result occurs when there is increased pain and a palpable click in the joint line, although if the meniscus tear is stable, only pain would be elicited. 

      • A negative result occurs when there is no recreation of symptoms.

  • Apley's compression (grind) and distraction test

    • Technique​

      • Patient prone with the knee flexed

      • Part 1 -  Examiner to the affected side of the patient with the near hand cupping the patient's heel   An axial load is applied and the knee is forcefully internally and externally rotated using the hindfoot as a lever.  Part 2 - Grasping the patient's ankle with one hand and pressing down on the patient's posterior thigh with the other, the lower leg is distracted and rotated.

      • A positive result occurs when there is increased pain with compression and rotation, and relieved pain with distraction.

      • A negative result occurs when there is no recreation of symptoms.

Patella Instability

  • Patella apprehension sign

    • Technique​

    • Patient supine with the legs resting in extension

    • Examiner to the affected side of and facing the patient with one hand fingers and thumb forming a "C" around the inferior pole of the patella and the other doing the same superiorly.  The examiner then uses his/her fingers to pull the patella laterally, as if trying to sublux the patella.

    • A positive result occurs when there is increased pain and/or patient apprehension with the maneuver.

    • A negative result occurs when there is no recreation of pain or patient apprehension.