Femur/Knee Case #7

History and Physical45 YOM pedestrian

struck by a vehicle backing rapidly out of the parking lot. Patient was hit on the lateral side of his right knee by the car’s bumper and immediately fell on the ground spinning towards the left and screaming in pain. No LOC. Unable to bear weight. Denies numbness or tingling to his lower extremities.

T 97.9 P 117 BP 134/76 RR 18 O2 97% on RA

Gen: Uncomfortable and in distress 2/2 pain, GCS 15.

Pulm: BS equal and CTA bilaterally. Trachea midline.

CV: S1S2 tachycardia, pulses equal throughout.

Pelvic: stable RLE: Contusion/abrasion noted

on the lateral aspect of knee, generalized swelling/effusion, extensor/flexion preserved with difficulty 2/2 pain, 20° instability upon Valgus, anterior/posterior drawers intact. Distal neurovascular intact

Image

Lateral Tibial Plateau Fracture with medial collateral ligament injury.

Note the depressed articular surface.

Diagnosis: Tibial Plateau Fracture

ABC’s of trauma resuscitationPain management.Open fractures: Type and Screen, IV fluids,

antibiotics and copious irrigation. Update Tetanus. Emergent Orthopedic consult.

Nondisplaced/stable fractures: Immobilization/Long-Leg posterior splint/RICE/Orthopedic referral within one week. Strict non-weight bearing

Displaced/unstable fractures: treat as non-displaced PLUS Emergent Orthopedic consult.

ED Management

Oblique views helpful in detecting subtle tibial plateau fractures.

CT of the knee crucial to determine the degree of the articular surface irregularity.

ACL and MCL injury associated with lateral plateau fractures.

PCL and LCL injury associated with medial plateau fractures.

Stability defined as <10° of movement upon Valgus and Varus at any point from full extension to 90° flexion.

Operative management can be delayed without significant consequences for up to 24-48 hours.

Pearls

Additional images

Medial Tibial Plateau Fracture.

Is there a fracture?

Additional images

Normal Radiograph. Criteria: No more than 5 mm of the tibial condyle should remain laterally to the line drawn from lateral femoral condyle to medial cortex of the fibular shaft.

Yes there is! Suspect subtle tibial plateau fracture in this radiograph that doesn’t meet the normal criteria. Arrow head shoes fracture.

Additional images

Axial CT showing lateral tibial plateau fracture.

3-D reconstruction of the CT images on the left.

Robert R. Simon, Steven J. Koenigsknecht, "Chapter 15. Knee" (Chapter).

http://www.imageinterpretation.co.uk/knee.html

Tintinalli's Emergency Medicine:A Comprehensive Study Guide, 7e . Chapter 271: Knee Injuries.

References