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Knee Xray

Weight-Bearing P/A  
A/P Sunrise View
Lateral Merchant View
Tunnel (notch) View  
 CPT 73564 (Radiologic examination, knee;complete, four or more views. Includes professional and technical components. Requires a separate written report, signed by the interpretting physician. Interpretation must include views, anatomic location, diagnosis, reason for xray and interpretation.

CPT 73564-26 (Professional component only. Xrays must not have already been interpretted.)

CPT 73564-TC (Technical component only.)

Weight-Bearing P/A (Rosenberg) view Weight-Bearing P/A (Rosenberg)

Position: Standing with knees flexed 45° with grid in front of knees

Beam directed 10° caudal from the horizontal plane through the knee joint.

ap knee xray technique A/P Knee View

Position: supine with cassette under knee and femoral condyles parelll to cassette.

Beam directed to point 1-2cm distal to the patella.

lateral knee xray technique Lateral Knee View

Position: lateral with affected side down and flexed 30° at the knee. The contralateral leg is shifted posteriorly out of the way.

Beam directed at knee joint with 5°cephalad angulation.

Intercondylar notch view technique Tunnel View (Intercondylar notch view)

Position: prone, knee flexed 40°

Beam directed caudally toward the knee joint at a 40° angle from vertical.

sunrise view technique Sunrise View

Position: Prone; knee flexed 115°

Beam directed toward patella with 15° cephalad angulation

merchant view technique Merchant View

Position:supine knee flexed 45°;

Beam directed caudally toward patella at a 60° angle (30° from the horixontal plane).

(Merchant A, JBJS 1974; 56A:1391)

 patellar alta xray Patellar Alta, Patllar Baja
  • Insall-Salvati Ratio
  • Blackburne-Peel Ratio: <0.8=patella baja, >1.2=patella alta.

Image= lateral view of  patient with patellar tendon rupture demonstrating patella alta.

Insall-Salvati ratio

  • Lateral knee x-ray or sagittal MRI with knee flexed 30 degrees. 
  • Insall-Salvati ratio = TL/PL
  • TL = patellar tendon length (length of the posterior surface of the tendon from the lower pole of the patella the nsertion on the tibia 
  • PL = patellar length (PL)
  • Normal Insall-Salvati ratio = 0.8 to 1.2
  • patella baja: <0.8 (perhaps <0.74)
  • patella alta: >1.2 ( perhaps >1.5)
  Radiology References


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