20ish year old and otherwise healthy male presents as the restrained driver in head-on MVC at low speed just prior to arrival. He has a large linear laceration to anterior aspect of R knee and is unable to fully extend the knee. Wound is hemostatic. No other injuries or complaints.
10cm linear, horizontal laceration to the anterior aspect of the patient’s R knee. Knee is held in slightly flexed positioning. Decreased ROM of the knee secondary to pain and injury, patient unable to actively extend extremity in straight leg raise. FROM of ankle. 2+ DP and PT pulses present. Sensation intact to light touch throughout. No erythema, swelling or significant tenderness present over RLE.
AP/Lateral/Sunrise/Oblique views of R knee:
Transverse fracture of the patella with 3mm of displacement present and surrounding soft tissue edema
Types of fracture:
C) Pole or sleeve (upper or lower)
D) Comminuted nondisplaced
E) Comminuted displaced
Evaluate with physical examination first
Severe knee pain and soft tissue swelling should raise suspicion for injury
Fracture displacement best viewed on lateral films, but obtain AP/Lat/Oblique/Sunrise to fully evaluate
Degree of displacement = degree of retinacular disruption
Early active ROM with hinged knee brace after 2-3 weeks
Watch out for patella sleeve fractures in peds – need high index of suspicion to diagnose
Bipartite patella = failure of bony fusion
Any lacerations present must be assumed to communicate with the knee joint until this assumption is disproved by a saline load joint challenge
A patellar fracture is problematic and requires intervention if extensor mechanism of knee is nonfunctional = unable to perform straight leg raise test
CMC ER Residents
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