Calcifications of the Knee’s Medial Compartment: A Case Report and Literature Review on the Adductor Magnus Tendon as an Uncommon Location and the Role of Ultrasound-Guided Lavage

<b>Background:</b> This paper examines the diverse etiologies of medial knee pain, emphasizing the prevalence of calcification-related pathologies, such as Pellegrini-Stieda Syndrome (PSS), particularly in the medial collateral ligament (MCL) and adjacent structures. Furthermore, we present a case of calcification of the distal adductor magnus tendon (DAMT) insertion into the femoral condyle of the knee and describe its treatment using ultrasound-guided percutaneous lavage (UGPL). A narrative review was conducted based on a single case; it underscores the importance of accurate diagnosis using magnetic resonance imaging (MRI) to differentiate between various calcific conditions, guiding appropriate treatment strategies. <b>Case Presentation:</b> A 70-year-old patient presenting with severe medial knee pain, with a duration of 4 days, and functional impotence underwent X-ray, ultrasound, and magnetic resonance imaging (MRI) examinations, revealing calcification in the DAMT. Treatment consisted of UGPL. The patient's pain level was assessed using the visual analog scale (VAS) initially and after 30 days of treatment. Upon initial assessment, the patient reported a VAS score of 9 out of 10. After 30 days of completing the treatment, the symptoms ceased. Follow-up imaging (X-ray, ultrasound, and MRI) showed only very tiny fragments of calcification remaining. <b>Conclusions:</b> UGPL is an effective technique for treating calcific tendinopathy of the DAMT insertion into the medial femoral condyle of the knee, offering significant pain relief and functional improvement. This case highlights the importance of considering this rare condition in the differential diagnosis of medial knee pain.