Abstract:

BACKGROUND: After femoral neck fracture, avascular necrosis of the femoral head occurs because of insufficient blood supply to the femoral head, resulting in increased difficulty in treatment, and greatly influencing the recovery of hip joint function. Core decompression and bone grafting is a common treatment method of avascular necrosis of the femoral head. A porous tantalum rod is a bone trabecula-like metal implant that is used to support weight-bearing area of necrotic bone, prevent further collapse of the necrotic area, and thereby exhibits favorable effects in the early treatment of avascular necrosis of the femoral head. Few randomized controlled studies are reported on porous tantalum rod implantation for treatment of avascular necrosis of the femoral head after femoral neck fracture surgery.
OBJECTIVE: To investigate whether porous tantalum rod implantation can improve the hip joint function of patients with avascular necrosis of the femoral head subjected to femoral neck fracture surgery.
METHODS: This is a prospective, single-center, randomized, controlled, open trial, which will be performed in the Department of Orthopedic Trauma, Qinghai University Affiliated Hospital, China. A total of 100 patients with avascular necrosis of the femoral head subjected to femoral neck fracture surgery will be randomly assigned to undergo core decompression and porous tantalum rod implantation (experimental group, n=50) or only core decompression (control group, n=50). All patients will be followed up for 1 year. Primary outcome measure is the percentage of patients whose hip joint function is graded as excellent as per Harris scores 12 months after surgery in total patient number in each group, which will be used to evaluate the recovery of hip joint function. Secondary outcome measures include (1) the percentage of patients with excellent hip joint function 1 and 6 months after surgery in total patient number in each group; (2) Visual Analogue Scale spine score prior to and 1, 6 and 12 months after surgery, which will be used to evaluate the severity of pain; (3) the percentage of patients presenting with femoral head collapse, prosthesis loosening and peri-prosthesis infection 6 and 12 months after surgery, which will be used to evaluate the biocompatibility of biomaterial with host; and (4) incidence of complications 6 and 12 months after surgery, which will be used to evaluate the safety of porous tantalum rod implantation. This study protocol has been approved by the Medical Ethics Committee of Qinghai University Affiliated Hospital of China (approval number: QHY1016B) and will be performed in accordance with the guidelines of the Declaration of Helsinki, formulated by the World Medical Association. Signed informed consent regarding trial procedure and treatment will be obtained from each patient. 
DISCUSSION: This study is powered to validate the biocompatibility and therapeutic effects of porous tantalum rods in the treatment of avascular necrosis of the femoral head after femoral neck fracture surgery, which hopes to provide a novel persuasive surgical treatment method for this disease.

Key words: tissue engineering, femoral neck fractures, hip joint