PURPOSE:To compare the clinical and laboratory outcomes of intra-articular injections of culture-expanded bone-derived mesenchymal stem cells (MSCs) with or without platelet-rich plasma (PRP) to intra-articular corticosteroid injections for the treatment of knee osteoarthritis (OA). METHODS:Forty-seven patients with radiographic and symptomatic knee OA were randomized into three groups for intra-articular injec...