We performed a retrospective (EUREKA: Evaluation of Ultrasound guided non-invasive Rehabilitation for Knee Arthritis) analysis on patients treated for knee osteoarthritis with hyaluronic acid (HA) and/or platelet-rich plasma (PRP). Patients were stratified into reactive and non-reactive knees, based on their clinical response profile. Our findings suggest that this classification may help predict treatment outcomes and guide a more personalized approach to intra-articular regenerative therapies in knee osteoarthritis.