Investigations
1st investigations to order
no initial test
Test
Result
clinical diagnosis
Investigations to consider
knee x-ray
Test
Diagnosis of patellofemoral pain syndrome depends mainly on history and physical examination, with radiography as an adjunctive test where examination indicates patellar alignment abnormalities. Radiography should be the initial imaging study performed.[42]
The following views should be included: 1) weight-bearing anterior-posterior view: allows evaluation of joint arthritis; 2) weight-bearing true lateral view: allows the measurement of patella alta (the Blackburne-Peel measurement is the most accurate, reliable, and reproducible); and 3) Merchant axial view: with 45° of knee flexion.[23]
Result
trochlear dysplasia with the sulcus angle, patellar displacement with the bisect offset angle, and patellar tilt with the lateral tilt angle
MRI
Test
MRI without intravenous contrast is indicated when radiography findings are negative and/or further information is needed to evaluate for meniscal tear, synovial plica, fat pad inflammation/impingement, and patellar tendonitis. It can also grade degrees of chondromalacia or osteochondral defect.[5][42][43]
Result
abnormal knee morphology
kinematic MRI or CT
Test
Kinematic MRI or computed tomography may also be appropriate, for example, to more accurately define patellar tracking abnormalities.[42]
The patient should be supine or standing upright in a weight-bearing, closed-chain position while performing continuous knee flexion and extension movements.[5][43]
Result
patellar tracking abnormalities
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