Acute Knee Trauma Farhan Quader June 2013 Eliona Corrigan, MD

55 y/o female with hx of total knee arthroplasty presented to ED after fall – height of 3-5’ onto concrete – point of impact = left knee Could not ambulate after fall Endorsed tingling around the site which later resolved – +Pain around site, 10/10 H&P

PMH: – HTN, obesity, sickle cell trait PSH: – Total Knee Arthroplasty Physical exam: Left knee deformed, tibia anteriorly translocated. No ankle nor hip pain. Brisk cap refill, however, palpable dp/pt on right side with weakly palpable dp on left and non-palpable pt

Ddx: – Knee dislocation – Contusion – Ligament sprain/tear – Things to consider: arterial/venous insufficiency Screening: -Knee radiograph -Ultrasound -CT -MRI DDx and Screening

Screening Modality Patient falls under variant 2: inability to bear weight Procedure of choice is X-ray knee Ottawa Knee Rule: patients with acute knee pain with 1 or more should have X-ray: – Are 55 years of age or older – Have palpable tenderness over the head of the fibula – Have isolated patellar tenderness – Cannot flex the knee to 90 degrees – Cannot bear weight immediately following the injury, – Cannot walk in the emergency room (after taking four steps).

Left Knee Radiograph AP and Lateral Knee AP view unremarkable Lateral view remarkable

Left Knee Left Knee Radiograph AP and Lateral (previous)

Knee Knee Radiograph, Lateral view s/p reduction

Left Knee Xray Left Knee Radiograph AP and lateral s/p reduction

Left Knee Popliteal Ultrasound ultrasound

Left Popliteal artery Ultrasound longitudinal

Left Popliteal artery Popliteal arteriogram

Conclusion -Anterior dislocations are most common after knee trauma -Dislocations characterized in terms of tibial displacement with respect to femur (anterior, posterior, medial, lateral, and rotary) -Further characterized into high velocity and low velocity -High: violent force such as car accident; result in damage to the structures of the knee complex -Low-velocity: occur in sports settings and seen in athletic trainers; lower rates of neurovascular and associated soft- tissue damage -Predisposing factor = injury to ACL or MCL -Damage to neurovascular system is one of the greatest concerns -Popliteal artery is injured in approximately 20-40% of all knee dislocations -Peroneal nerve can still be injured due to it’s anatomical location as it passes around the fibular neck; 33% of knee dislocations