Document Type: RESEARCH PAPER
Bone and Joint Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Department of Oral and Maxillofacial Pathology, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran
Background: One of the major challenges in orthopedic surgery is the prevention of arthrofibrosis, which can be
successfully alleviated in its early stages. Many studies suggest the administration of methylene blue (MB) as an
accessible and effective agent for the prevention of post-operation adhesions. The purpose of this study was to evaluate
the efficacy of MB in the prevention of arthrofibrosis.
Methods: This study was conducted on 18 New Zealand white female mature rabbits. The anterior cruciate ligament
of the left stifle joint of each animal was cut during aseptic surgery. In the next step, the rabbits were divided into three
groups based on their treatments. The rabbits in the first, second, and third groups were subjected to the injection of
normal saline, 1% MB solution, and 2% MB solution into their synovial space, respectively. The postoperative stifle
range of motion was measured every week. After 4 weeks, the animals were euthanized and all joints were dissected
Results: The histopathological evaluation of tissues indicated the presence of fibrotic connective tissue as a sign of
fibrosis in all groups. The fibrosis rate, inflammatory rate, tissue disarrangement, fibroblastic cellularity, and granulation
tissue formation were at their highest levels in the 1% MB group. The integrity of articular cartilage in the 2% MB group
was lower than the other groups. The level of bone degeneration was similar in both MB groups; however, it was more
than the control saline group. The range of motion was reduced during the first week, then increased in the second and
third weeks, and finally decreased in the fourth week.
Conclusion: The MB was not an effective method regarding the prevention or treatment of arthofibrosis and the
subsequent osteoarthritis. In contrast with previous studies, fibrosis was lower in the high dose MB group, compared
to the low dose MB group. The alterations in the range of motion were related to the reduced movement caused by the
pain and stiffness of the operated joints. The current study can be considered as the first report addressing the adverse
effect of MB on synovial components.