The Stanford 25

An Initiative to Revive the Culture of Bedside Medicine

Knee Exam

In addition to teaching and attending, Doctor Mark Genovese is involved in research including clinical trials and interventions in rheumatic diseases such as rheumatoid arthritis, psoriatic arthritis, & osteoarthritis. In the video below, he demonstrates examination of the knee; in the notes, he provides several clinical pearls.

 

 

Introduction: Careful examination of the knee can provide valuable information and help the physician determine when imaging studies may or may not be helpful.

Please note, the anterior & posterior drawer tests are not demonstrated in this, older video. Please see the notes below, the NEJM video, and the embedded videos at bottom for specifics.

Additionally, the NEJM “Videos in Clinical Medicine” series has an excellent segment on the knee exam. Click here for Stanford NEJM access to the video, here for all other institution access.

  • Unique aspects of the history include: +/- “pop” heard at time of injury, +/- pain decreasing w/ use, inability to bear weight, instability, and locking.
  • Inspection: Observe both knees together. Note any asymmetry of the joint or quadriceps muscles.
  • Ask patient to lie supine. Whenever possible, ensure patient can lie comfortably with head back, legs straight, and toes up.
  • Assess temperature by placing back of hand to shin then ipsilateral knee, repeated for both legs.
    • Commonly, the knee will feel cooler than the shin.
    • If knee feels warmer than shin, suspect inflammation.
  • Assess for fluid by gently pressing just medial of the patella, then moving hand in an ascending motion, press firmly on the lateral aspect of the knee.
    • Commonly, no fluid will be appreciated.
    • A medial aspect that ‘bulges’ out after lateral pressure (positive “bulge sign”) is consistent with a moderate amount of fluid.
    • A medial aspect that does not bulge but tensely reflects lateral pressure is consistent with a large amount of fluid.
  • Assess for fluid by placing one hand superior to the patella and applying slight downward pressure while using the other hand to periodically push on the patella (the so called ‘patella tap test’).
    • A palpated or audible tap indicates a “ballotable” knee and is consistent with at least a moderate amount of fluid.
  • Assess for ligament pathology by firmly palpating the superior pole of the patella and then the inferior to assess patellar femoral syndrome.
    • Tenderness at the superior insertion is consistent with quadriceps tendon pathology.
    • Tenderness at the inferior insertion is consistent with patellar tendonitis, “Jumpers knee.”
      • In the patient with direct patellar trauma & isolated patellar tenderness, an x-ray is indicated to evaluate for fracture.
  • Assess for patellar cartilage pathology by placing palm on patella and applying firm pressure while manipulating the patella in the sagittal plane (Apely’s grind test). Crepitus is significant only when accompanied by tenderness, in which case it is consistent with patellar cartilage pathology.
  • Assess for laxity
    • While supine, ask patent to flex knee and set foot on examination table. Sit on the foot to immobilize it and grasp the head of the tibia with both hands and pull anteriorly. (Not demonstrated in video above, please see NEJM video or embedded video below.)
      • Movement greater than 1cm (positive anterior drawer sign) is consistent with an ACL tear.
      • Do not attempt to elicit an anterior drawer sign with legs hanging; the extra degree of freedom will confound any findings.
    • Attempt to hyperextend knee by placing one hand superior to the patella and the other posterior to the heel. More than 2-3cm (i.e. able to place one or two fingers beneath the heel when leg is extended and flat) is abnormal.
    • With both hands, flex and extend the knee. Repeat while introducing medial and lateral rotation. Determine if any “locking” or “catching” is present.
    • With leg straight, apply valgus and varus stress to text deviation greater than a few centimeters.

Clinical Pearl: If a careful exam does not elicit significant pain or laxity imaging studies are extremely unlikely to provide further useful information.

Further Reading:

Solomon, DH; Simel, DL, et al., “Does This Patient Have a Torn Meniscus or Ligament of the Knee?” JAMA. 2001;286:1610-1620.

Embedded Videos & Links (Not produced by Stanford, click through for credit and source).

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Written by stanford25admin

June 7, 2010 at 3:37 pm

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