MRI Characteristics and Alterations in Patellar Height in Patients with Patellar Tendinopathy-A Retrospective Study.

(1) Background: Patellar tendinopathy (PT) is an overuse condition of the knee extensor mechanism characterized by ventral knee pain at the lower pole of the patella and limited functionality. (2) Methods: In this retrospective study, a group of patients with PT ( n = 41 ) was compared with a control group ( n = 50 ) in terms of patient-related data and magnetic resonance imaging (MRI) characteristics. (3) Results: Patellar height was higher in the PT patient group and there was a significant difference in Caton-Deschamps index (CD) compared to the control group ( p = 0.021). Patients with PT showed a lower patella-patellar tendon angle (PPTA) ( p = 0.011). The patellar tendon thickness (PTT) in the proximal (PTTprox), middle (PTTmid) and distal (PTTdistal) part of the tendon was significantly thickened ( p < 0.001). Increased signal intensity in MRI was detected in symptomatic tendons over 6 months compared to a duration of less than 6 months ( p = 0.025). A significant relationship between the PTTprox and an increased signal intensity was observed ( p < 0.001). (4) Conclusions: Patients with PT showed a significant difference in the patellar height and PPTA. With persistence of symptoms over 6 months, MRI seems suitable to detect the morphologic tendon changes and further identify patients suitable for surgical procedures.