Coagulopathy Study

Osteonecrosis has been shown to be associated with systemic lupus erythematosus, sickle cell disease, Gaucher disease, corticosteroids, and alcohol use. What triggers the disease in a small percentage of individuals with these factors and/or diseases is not known. Furthermore, there is a group of patients where no obvious underlying factors have been identified. As recent reports in the medical literature have provided evidence that patients with osteonecrosis may have defects in their blood clotting system, we currently screen all of our osteonecrosis patients for coagulopathies. An initial review of the laboratory test results revealed that 22 of 26 (83%) of the patients with osteonecrosis had a coagulation abnormality. Although coagulopathies are also detected in the normal population, the frequency of these abnormalities is noticeably higher in patients with osteonecrosis. Larger numbers of patients and matched control subjects are needed to define the association between coagulopathies and osteonecrosis.

Animal Models

In many musculoskeletal diseases, animal models have been used to study the pathogenesis, i.e., the development, of the disease process as well as to study the effectiveness of different approaches to treatment. The investigation of the pathogenesis of osteonecrosis is hindered by the lack of an adequate animal model.

In 1996, Michael A. Mont, M.D. received a 2-year grant from the Orthopaedic Research and Education Foundation to study an animal model. This grant was entitled Femoral Head Collapse: Prevention with Strut Autografting With or Without Bone Morphogenetic Proteins. This model simulates the circumstances associated with one type of treatment for osteonecrosis, the "Trapdoor" procedure. In this procedure, diseased bone is removed through a trapdoor in the cartilage. The bone is then replaced with bone graft or a bone graft substitute. This study seeks not only to further characterize this model, but also to evaluate the use of bone graft with bone morphogenetic protein, a protein shown to stimulate bone formation.