Efficacy Study of Neridronate to Treat Painful Osteoarthritis of the Knee With Bone Marrow Lesions.

Inclusion Criteria: * Clinical diagnosis of knee Osteoarthritis (ACR criteria) * Radiographic diagnosis of knee Osteoarthritis (Kellgren/Lawrence scale \>=2) * \>4 weeks but \<3 months pain, reported as \>30 mm on a 100 mm VAS scale * bone marrow oedema of the affected knee on magnetic resonance Exclusion Criteria: * inflammatory arthritis * aseptic osteonecrosis of the knee * previous or current treatment with Bisphosphonates * serum calcium or creatinine abnormalities