Knee osteoarthritis is a condition that affects young or middle-aged patients with high functional demands. Knee replacement surgery in patients under 65 years of age is associated with a high risk of failure and the need for revision. For this reason, it becomes crucial to identify treatment alternatives aimed primarily at resolving symptoms but also at slowing down the joint degenerative process, with the goal of delaying the need for prosthetic treatment as much as possible. The medical device BB-02 (IGEA SpA, Carpi, Italy) is a certified medical device according to Regulation (EU) 2017/745 (MDR) for the treatment of inflammatory and degenerative tissue pathologies and represents an effective tool in the treatment of early and intermediate osteoarthritis. To date, the demonstration of the efficacy of BB-02 therapy has been measured through the evaluation of clinical endpoints, using both objective and subjective assessment scales. So far, there is a lack of instrumental measurement of the ability of BB-02 therapy to preserve the integrity of the articular cartilage. The primary objective of the study is to evaluate, through magnetic resonance imaging (MRI), the effect of pulsed electromagnetic fields administered via BB-02 therapy on cartilage damage in subjects with early-stage osteoarthritis. The BB-02 device was chosen based on promising results reported in the pre-clinical phase of experimentation. The secondary objective is to assess the effect of BB-02 therapy on pain resolution and clinical scores of knee functionality in the two different therapeutic regimens.