Transient lateral patellar dislocation: diagnosis with MR imaging.

The Measurement of Patellar Alignment in Patellofemoral Pain Syndrome: Are We Confusing Assumptions With Evidence?

“…9 and MRI 44,98 findings specific to patellar subluxation/dislocation have also been identified. However, a small number of investigators appear to consider PFPS as an umbrella term also including all forms of patellar instability.…”

Bone Contusion Patterns of the Knee at MR Imaging: Footprint of the Mechanism of Injury

“…Transient dislocation of the patella typically occurs in teenagers and young adults involved in athletic activities and results from a twisting motion of the knee while the knee is in a state of flexion (27). The femur rotates internally on a fixed tibia while the knee is flexed; contraction of the quadriceps occurs, resulting in lateral dislocation of the patella out of the trochlear groove (Fig 17).…”

Age-Related Differences in Medial Patellofemoral Ligament Injury Patterns in Traumatic Patellar Dislocation

“…5,7,38 During traumatic patellar dislocation (TPD), the MPFL is subjected to severe stretching forces, resulting in injuries of the ligament in most patients. 1,2,18,47,48 Posttraumatic insufficiency of the MPFL contributes to chronic medial patellar instability, which may lead to recurrent patellar dislocations (reported in 15%-44% of cases after a first TPD episode), 4,15,44 impairing the function of the patellofemoral joint and, in longer perspective, accelerating osteoarthritic changes. 11,12,21,28,29,32,44 Despite data currently emerging and questioning the long-term benefits from an acute MPFL repair as routine management of first-time TPD in every patient, z a complete ligament tear is still considered by many authors an indication for early surgery.…”