Usually caused by sudden flexion and external rotation of tibia on femur, with simultaneous contraction of quadriceps muscle
Direct trauma to patella is a less common cause
History of feeling knee “go out”; popping, ripping, or tearing sensation
Inability to bear weight
Obvious lateral deformity of patella
Mild to moderate swelling
Patients with superior, medial, or intra-articular dislocation or in whom a lateral dislocation cannot be reduced require orthopedic consultation in the ED and p...
Lateral patella dislocations often reduce spontaneously prior to arrival in ED; do not dismiss patient's history of dislocation.
In patella tendon ruptures, tendon defect may not be...
Ahmad CS, McCarthy M, Gomez JA, et al. The moving patellar apprehension test for lateral patellar instability. Am J Sports Med. 2009;37(4):791–796.
Fithian DC, Paxton EW, ...
726.64 Patellar tendinitis
836.3 Dislocation of patella, closed
836.59 Other dislocation of knee, closed
822.1 Open fracture of patella
M76.50 Patellar tendinitis, unspecified knee
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