Knee Examination

1. Inspect
2. Palpate
3. Move
4. X-ray

Gait

• Does pt have a normal swing phase?
• Limp? Do they spend as much time on one foot as the other.

Standing

• Deformity.
• Knee alignment:
  • Varus [bow leg].
  • Valgus [knock-knee].

Inspect

• Skin:
  • Scars.
  • Inflammation.
  • Bruising.
• Swellings:
  • Normal is knee concavity should be bigger on medial side.
  • Normal is small suprapatellar pouch.
  • Swelling DDx:
    • Effusion [#1 cause].
    • Hemarthrosis.
    • Pus.   
    • Synovial proliferation [RA, etc]
• Deformity.
• Wasting:
  • Quads wasting: measure their diameter at fixed distance up from tibial tubercle.

• Abnormal fixed flexion when legs laid flat (flexion deformity).

Palpate

• Warmth.
• Tenderness:
  • Generalized.
  • Over joint line [apply firm pressure] (meniscal tear).
  • Over medial/lateral ligaments.
• Swelling.
• Bony prominences.
• Popliteal fossa for Baker's cyst [knee capsule hernia].

Move

• Do active, then passive movement. Note range, pain, and crepitus [grating sound]:
  • Flexion [normal: 135°].
  • Extension [normal: 5°].
• Stress the medial and collateral ligament for laxity:
  • Pt's leg should be flexed at 20°, so nice and loose as Dr wobbles it.

ACL: Lachman test

ACL: Anterior drawer test

PCL: Posterior drawer test

PCL: Posterior sag sign

• Pt. flexes knee and hip to 90°.
• Dr. looks at knees side-on.
• Normal is a convex part on the front of the knee.
• If see a concave instead, then it's a posterior sag from bone falling downwards with gravity. Dx is PCL tear.

Meniscus: McMurray's rotation test

• Pt flexes knee to 90°.
• Dr rotates knee externally [only about 6°], and as rotate, extend knee 10°.
• If hear a click/klunk, then possible Dx of meniscal tear.
• Then repeat again, rotating the other way.

Meniscus: Joint palpation

Bursa: Move

• Dr places hand on suprapatellar pouch and move it back and forth.

Bursa: Bulge sign

• If bulge positive, then Dx an effusion.
• Only for very small effusions.
• A patella tap is used for a moderate effusions [won't work if too much or too little].

Bursa: Fluid thrill

• Dr flicks finger on lateral of knee, feeling for thrill on medial side [or vice versa]
• If feel thrill, Dx an effusion.
• Good for small effusions.

Patella: compression

• Dr compresses patella against thigh.
• If painful, suggestive Dx is:
  • Young pt: chondromalacia patellae.
  • Old pt: arthritis.

Patella: apprehension test

• Purpose: DDx whether knee pain is subluxated or dislocated.
• Dr starts to apply sideways pressure to patella, looking at pt's face for apprehension.
• If pt apprehensive that patella will dislocate?? when continue, then the knee pain is from subluxation.