Jordy van Sambeeck

Chapter 1 16 Figure 5. Apprehension test (Insall Scott, Ch 65, Disorders of the PF joint) The patient lies supine with completely relaxed legs. The examiner pushes the patella gently laterally. The test is positive when the quadriceps muscle is activated involuntary or by reflex and this represents chronic patellar instability. This figure was published in Insall & Scott Surgery of the Knee, Sixth Edition, 2018, Chapter 65 Disorders of the Patellofemoral Joint, Figure 65.9, Page 848, Copyright Elsevier (2018). Imaging Radiographic imaging has an important role in the decision making for treatment of patients with patellofemoral instability. The radiographic imaging modalities that are used include conventional radiography (CR), computational tomography (CT) and magnetic resonance imaging (MRI). Conventional radiographs can provide the clinician with information on the current position of the patella, (osteochondral) fractures, patellar height and trochlear morphology 4 . Often additional imaging is required for an adequate assessment of injury and anatomy of the patellofemoral joint and surrounding structures. MRI scanning provides additional information on possible injuries such as (osteo)chondral injury, chondral damage and tear of the MPFL 7 . Anatomic risk factors such as trochlear morphology, lateralization of the tibial tubercle and