Study finds, Sagittal Patellar flexion angle measurement det
The objective of this study was to compare patellar height and patella alta between a control cohort and patients with patellar tendinopathy by the sagittal patellar flexion angle (SPFA) measurement.

MRI scans of the knee were obtained from a sports imaging facility and screened to select patients with anterior knee pain. This symptomatic group was divided into two patient cohorts: those with and without MRI features of patellar tendinopathy. Lateral knee radiographs were reviewed and SPFA, knee flexion angle and Insall–Salvati ratio (IS) were measured from the radiographs by two independent reviewers.

--A total of 99 patients consisting of 48 patellar tendinopathy patients and 51 control patients were included.

--There was a significantly higher mean patellar height and a greater patella alta incidence in the patellar tendinopathy cohort (25.0%) compared to the controls (3.9%).

--Insall–Salvati ratio measurements showed no difference in patella alta incidence between tendinopathy and control cohorts. There was excellent inter- and intra-observer reliability of SPFA measurements (ICC 0.99).

A greater patella alta incidence amongst patellar tendinopathy patients as defined by SPFA was found to be clinically relevant, as it suggests these patients may comprise the recalcitrant patient subgroup who do not improve with current surgical intervention and may therefore benefit from a biomechanical surgical solution.