Radiography of the knee

Veronica Lagos-Jaramillo, MS4September 2012

Knee Anatomy The knee is the largest joint in the body. The knee is stabilized by the collateral

ligaments. The lateral and medial menisci function as

shock absorbers. The bursae decrease friction of tendons

and muscles as they move over bones.

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Knee Anatomy

Knee Joint Anatomy

Am Fam Physician. 1999;60(9):2599-2608.

Imaging the kneePlain radiograph for:

Fractures Degenerative changes Osteochondral defects Effusions

CT for: Fractures in patients with knee trauma

MRI for: Damage to cartilage, menisci or ligaments

Cleveland Clinic Journal of Medicine 2008;75:377-384

AP view of the knee

Lateral view of the knee

Sunrise view of the kneeTo assess the patellofemoral articulationFemur and tibia are superimposed Medial condyle is more rounded and prominent

Identify the following . . .

femur

tibia

fibula

patella

lateral condyle

medial condyle

lateral epicondyle

medial epicondyle

intercondylar notch

Identify the following . . .

medial femoral condyle

lateral femoral condyle

Inferior patellar tendon

Quadriceps femoris tendon

Tibial tuberosity

femur

tibia fibula

patella

intercondylar notch

Knee injuries

Patellar fracturesThe patella can be fractured

through one of its poles or through its central body.

Patellar fractures can be simple or comminuted.

Transverse fractures are most common and are most likely to

be displaced.

Am Fam Physician. 1999;60(9):2599-2608.

Patellar fracturesDisplaced fracture of the lower pole of the

patella

Patellar fracturesWhere is the fracture?

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What type of fracture is this? Non-displaced patellar fracture

FracturesFemoral condyle fractures account for 4% of

femur fractures. Potential complications include: DVT, fat embolus syndrome, delayed union ort malunion, and osteoarthritis.

Tibial spine and tuberosity fractures usually result in cruciate ligament insufficiency.

Fractures of the tibial plateau are seen more commonly in the elderly. Lateral plateau is more often fractured. Potential complications include: popliteal artery injury, DVT and osteoarthritis.

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Lateral condylar split fracture

Usually the result of low impact trauma

Common in kids

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Where is the fracture?

Tibial intercondylar emminence fracture

The lipohemarthrosis (composed of blood and fat from the marrow) seen above is a specific sign of an intra-articular fracture although a fracture is not visualized.

Identify the lipohemarthrosis on the radiograph

Comminuted left tibial metaphysis and lateral plateau fracture

left tibial metaphysis fracture

Lateral plateau fracture

Fracture of the tibial eminence

Koplas M et al. Cleveland Clinic Journal of Medicine 2008;75:377-384

joint effusion

lateral tibial bone depressed posteriorly

fracture

An additional sign of a fracture includes a joint effusion

Epiphyseal platesEpiphyseal plates in children can be mistaken for

fractures

http://www.dartmouth.edu/~anatomy/Lowerextremity/leg-knee/radiology/APknee-child.htm

Child Adult

Knee dislocation Often associated with a fracture of the tibial plateau

Usually the result of motor vehicle crashes, falls, sports, and industrial injuries

Knee dislocations are associated with popliteal artery and common peroneal and tibial nerve injuries

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Posterior displacement of the tibia

Anterior knee displacement

Patellar tendon rupture

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Arthritis

Flow chart shows approach to radiographic evaluation of arthritis.

Jacobson J A et al. Radiology 2008;248:737-747©2008 by Radiological Society of North America

Osteoarthritis of the knee

Felson DT. N Engl J Med 2006; 354:841-848

Radiographic findingsOsteoarthritis: initially involves medial

sidejoint space narrowing subchondral cystsosteophytessclerosis

Basic Radiology, 2nd edition: http:accessmedicine.com

Osteoarthritis

Bone on bone contact

Patellar osteophyte

subchondral osteophyte

Radiographic findingsRheumatoid arthritis:OsteopeniaLoss of joint spaceLigamentous laxity Joint effusionBone erosion

Rheumatoid arthritis

Tibial erosion

Jointeffusion

Diffuse osteopenia

Symmetric joint space narrowing Bone

erosion

Identify the type of arthritis

What radiographic features do you see?

joint space narrowing medial or lateral side? medial

osteophyte

subchondral cyst

Osteoarthritis

ReferencesFelson DT. N Engl J Med 2006; 354:841-848.

Geisel School of Medicine at Dartmouth, Department of Anatomy. Introduction to Radiology. Retreived September 6, 2012 from http://www.dartmouth.edu/~anatomy/Intro-to-radiology/index.htm.

Glaspy J.N., Steele M.T. (2011). Chapter 271. Knee Injuries. In Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 7e. Retrieved September 6, 2012 from http://www.accessmedicine.com.

Gonzales R., Nadler P.L. (2013). Chapter 2. Common Symptoms. In M.A. Papadakis, S.J. McPhee, M.W. Rabow (Eds), CURRENT Medical Diagnosis & Treatment 2013. Retrieved September 6, 2012 from http://www.accessmedicine.com.

Jacobson J, Girish G, Jiang Y, et al. Radiographic evaluation of arthritis: degenerative joint disease and variations. Radiology. 2008; 248: 737-747.

Koplas M, Schils J and Sundaram M. The painful knee: choosing the right imaging test. Cleveland Clinic Journal of Medicine 2008;75:377-384.

Raukar N.P., Raukar G.J., Savitt D.L. (2010). Chapter 11. Extremity Trauma. In K.J. Knoop et al. (Eds), The Atlas of Emergency Medicine, 3e. Retrieved September 7, 2012 from http://www.accessmedicine.com.

Tandeter HB and P Shvartzman. Acute knee injuries: use of decision rules for selective radiograph ordering. Am Fam Physician. 1999 Dec 1;60(9):2599-2608.

Wasserman P.L., Pope T.L. (2011). Chapter 7. Imaging of Joints. In M.Y. Chen, T.L. Pope, D.J. Ott (Eds), Basic Radiology, 2e. Retrieved September 7, 2012 from http://www.accessmedicine.com.