This is a randomised study to assess the safety and efficacy of a combined drug and orthopaedic standard care compared to the standard orthopaedic care and treatment for Perthes Disease in children.

Exclusion Criteria7

• Diagnosis of Avascular Necrosis of the femoral head not due to Perthes Disease.
• Previous treatment of bisphosphonates.
• Current pregnancy or sexually active and not using a medically acceptable form of birth control.
• Untreated rickets within 1 year of enrolment.
• History of clinically significant organic or psychiatric findings on physical examination, which in the opinion of the investigator would prevent the patient from completing the study.
• History of using any of the following medications: regardless of dose, for at least one month, within 3 months of enrolment: Anabolic agents, Calcitriol, Calcitonin, Fluroide (except dental health products), Glucocorticoids (does not include inhaled Glucocorticoids), Growth Hormone, Parathyroid hormone (PTH), Strontium, anticonvulsant medication.
• At screening: aspartate aminotransferase (AST) or alanine aminotransferase (ALT) > 2 upper limit of normal, thyroid-stimulating hormone (TSH) outside of the normal reference range, Vitamin D < 50nmol/l or Glommerula Filtration Rate (GFR) < 60 ml/min as per the Schwartz formula.