The proximal patellar tendon at its inferior patellar pole insertion is the specific zone that develops patellar tendinopathy (jumper's knee) from repetitive high-load eccentric quadriceps activity in jumping sports. The pathological process involves angiofibroblastic degeneration in the deep posterocentral fibres of the proximal tendon, invisible on plain radiograph but clearly demonstrable on ultrasound and MRI as an intratendinous hypoechoic region.
Proximal patellar tendon zone — first to load during eccentric quadriceps activity; site of jumper's knee
Patellar tendinopathy at the inferior pole is graded by the Victorian Institute of Sport Assessment scale (VISA-P) for monitoring. The decline squat — single-leg squat on a 25-degree decline board — specifically loads the patellar tendon in the mid-range where pain is most provoked and is the assessment and rehabilitation exercise standard. Platelet-rich plasma injection has the strongest evidence among injection options. Surgery (arthroscopic debridement or open tendon scraping) is reserved for tendons failing 6 months of progressive loading.
Inferior pole patellar tendon angiofibroblastic degeneration in jumping athletes managed with decline squat progressive loading and PRP injection.
