Local Administration of Enriched Mononuclear Cells, Platelets and Zoledronic Acid for Preventing Collapse of the Femoral Head in the Early Stage of Osteonecrosis: a Prospective, Randomized, Parallel-controlled Clinical Trial

Osteonecrosis of the femoral head (ONFH) is a common degenerative disease caused by a variety of factors, such as trauma, alcoholism, use of corticosteroids, and systemic lupus erythematosus. In ONFH, the overall mechanical properties of the femoral head change over time, and collapse of the femoral head results in severe pain and disability.

Although there are numerous strategies for treating ONFH, conservative treatments are often ineffective. Once collapse of the femoral head occurs, hip replacement is the only option for ONFH patients. Therefore, it is important to reduce osteonecrotic weakening of the femoral head in the early stage of ONFH to prevent subsequent head collapse. Studies have shown that bisphosphonates inhibit osteoclast activity, reduce bone resorption, retain bone trabeculae, reduce apoptosis of osteoblasts and osteocytes, and promote new bone formation. Therefore, investigators have chosen to use bisphosphonates for preventing collapse of the osteonecrotic femoral head. Zoledronic acid is the most potent bisphosphonate for the treatment of ONFH. It can reduce bone resorption and preserve the shape of the femoral head. In most cases, bisphosphonates are given intravenously or orally. However, systemic administration is associated with many complications, including osteonecrosis of the mandible and atypical femur fractures. As previously reported, poly(lactic-co-glycolic acid) acts as a drug carrier to facilitate the local release of zoledronic acid, and it has been found to promote bone formation and help avoid the complications caused by systemic administration. Using this method of administration, zoledronic acid can reach locally therapeutic levels, thereby preventing femoral head collapse.

ONFH reduces the viability of bone marrow hematopoietic cells and bone cells to varying degrees, and can even induce cell death. Adult red bone marrow has two distinct parts; a hematopoietic section containing hematopoietic stem cells, and a mesenchymal section containing mesenchymal stem cells that promote bone regeneration. Core decompression technology can reduce intraosseous pressure, improve venous return, promote revascularization of the femoral head, and effectively reduce the symptoms of osteonecrosis; however, clinical efficacy is currently unsatisfactory, probably because of insufficient bone formation and repair. In recent years, the use of bone marrow mononuclear cells (BMMCs) has shown good short-term clinical efficacy in the treatment of ONFH. However, the long-term outcome is unknown, and it is not known whether combined therapy with platelet-rich plasma may be effective for the treatment of femoral head collapse in the early stage of ONFH.

Here, investigators propose a prospective, randomized controlled trial to assess the clinical efficacy of local administration of enriched BMMCs, platelets and zoledronic acid for preventing femoral head collapse in the early stage of ONFH.

Safety assessment During the trial, inspectors will be responsible for monitoring adverse reactions in the patients. If any adverse reaction is observed during the follow-up, the patient will be urged to call their doctor for assistance. Predicted complications include fever, joint pain, joint snapping, joint noise, joint swelling, limited mobility, and itchy skin. Patients will be urged to inform their family members or close friends to observe for these symptoms and that they are participating in a clinical trial. If a patient has questions about participating in this trial, they will be informed how to contact their doctor. All serious adverse events will be recorded in detail-including the date of occurrence, duration, treatments, and possible relationships with the therapeutic procedures-and reported to the research director and the ethics committee within 24 hours.