S. Murakami et al., IMMUNOHISTOLOGIC ANALYSIS OF SYNOVIUM IN INFRAPATELLAR FAT PAD AFTER ANTERIOR CRUCIATE LIGAMENT INJURY, American journal of sports medicine, 23(6), 1995, pp. 763-768
To clarify the natural course of synovitis after anterior cruciate lig
ament injury, we took synovial tissues at various periods after injury
and analyzed them immunohistologically. Twelve patients with isolated
anterior cruciate ligament injuries participated in the study. Inflam
mation intensity was graded semiquantitatively based on the following
parameters: :synovial lining cell depth, synovial hyperplasia, vascula
r hyperplasia, lymphocyte infiltration, and the expression of cell adh
esion molecules. The expression of fibrogenic cytokines and the degree
of fibrosis were also investigated to elucidate the mechanisms of art
hrofibrosis. The results demonstrated that synovitis in the infrapatel
lar fat pad subsides within 3 months after injury with the progression
of fibrosis. Fibrogenic cytokines, platelet-derived growth factor and
transforming growth factor-p, were detected at fibrotic sites, sugges
ting their involvement in arthrofibrosis. An increased incidence of ar
throfibrosis recently has been recognized to occur when anterior cruci
ate ligament reconstruction is performed within several weeks after in
jury. We speculate that when anterior cruciate ligament reconstruction
is performed during the stage of acute synovitis, the operation may f
urther promote the synovitis, accelerating the arthrofibrotic reaction
. Waiting to perform the anterior cruciate ligament reconstruction unt
il the synovitis resolves may possibly decrease the motion problems se
en postoperatively.