Knee Examination

The routine

Begin

• Introduce and expose the patient in their underwear
• Gait: antalgic (painful), trendelenburg (weakness of abductor muscles, gluteus medius and gluteus minimus)

Look

• Inspect whilst standing
• Valgus/varus deformity. Valgus = bow-legged, varus = knees come together
• Foot arches. Pes planus = flattened, pes cavus = arched
• Quadriceps wasting, scars, effusions
• Check the back of their legs
• Ask patient to lie down and inspect the knee again

Feel

• Temperature: compare sides with the back of your hand
• Stroke test for effusions: empty the medial compartment with your hand by massaging fluid up and into the lateral side. Then apply pressure over lateral side whilst holding your other hand above the patella. Watch the medial gutter whilst doing this: it will balloon if there is an effusion.
• Bend knee to 90 degrees with foot on bed. Palpate joint line for tenderness (meniscal pathology), and the medial/lateral collaterals
• Examine popliteal fossa for cysts, aneurysm
• Move patella from side to side (knee slightly flexed)

Move

• Patient to lift leg into air (with knee extended): if leg lifted straight quadriceps are working, if there is a lag and the knee flexes then weak quads or fixed flexion deformity
• Range of motion
• Flexion: bend their leg whilst putting a hand on their knee and feeling for crepitus. Their heel should be able to touch their buttocks
• Extension: Lift the patients leg in the air with your hand on their ankle (ask the patient to let you take their weight). If the leg extends fully then there is no fixed flexion

Special Tests

• Collateral ligaments: flex knee to 20 degrees and apply varus/valgus stress
• Anterior/posterior draw test: With the knee at 90 degrees, look from the side for sag of tibia in relation to femur (tear of posterior cruciate). Now anchor the foot by sitting on the end of the toes (be very careful not to hurt the patient). Grab the leg below the knee with both hands and push it back (posterior draw for posterior cruciate tear) and pull forward (anterior draw test for anterior cruciate tear). The angle you should be drawing is parallel to the line of the femur. There should be slight but not excessive draw in each direction.
• Lachman's Test for anterior cruciate injury: bend the patient's leg to 30 degrees and grasp above the knee with one hand and below with the other. Apply slow presssure to the back of the proximal tibia (below the knee), increased laxness indicates injury.
• Pivot shift test for anterior cruciate rupture Probably best to avoid in an exam as it can be painful. Flex the knee fully with the foot internally rotated. Apply slight valgus strain to the knee as it is slowly extended. A positive test is indicated by a click as the tibia shifts anteriorly on extension.
• McMurray's test for meniscal tears: is painful, rubbish, and best avoided
  

Common OSCE stations

1. Osteoarthritis
2. Replacement

Anatomy