Persistent medial knee pain

Abstract

A 53-year-old patient presented with a 15-day history of persistent medial knee pain without preceding trauma and with insufficient response to oral analgesics. Imaging revealed a focal hydroxyapatite deposit at the origin of the medial collateral ligament, consistent with calcific peritendinitis. The acute symptoms are likely related to the inflammatory resorptive phase of hydroxyapatite deposition disease (HADD). Although HADD predominantly affects the shoulder, involvement of the knee is uncommon and may cause significant pain. Ultrasound-guided lavage and peritendinous infiltration may offer a minimally invasive treatment option for persistent symptoms.