Signe Brinch, Philip Hansen, Peter Lavard, Mikael Ploug Boesen & Michael Rindom Krogsgaard
Ugeskr Læger 2021;183:V01210025
Trochlear dysplasia is the most common cause of objective patellofemoral instability (OPI). This review summarises the present knowledge on the diagnostics. On true lateral knee X-rays, it is possible to detect the crossing sign, which is the most important imaging marker for trochlear dysplasia of all types. This sign should be identified in relation to examinations in the emergency room, and if OPI is suspected, the patient should be referred to the orthopaedic department for further diagnosis. Increased attention to signs of trochlear dysplasia on X-rays may lead to earlier treatment of OPI patients.