M. Cameron et al., THE NATURAL-HISTORY OF THE ANTERIOR CRUCIATE LIGAMENT-DEFICIENT KNEE - CHANGES IN SYNOVIAL-FLUID CYTOKINE AND KERATAN SULFATE CONCENTRATIONS, American journal of sports medicine, 25(6), 1997, pp. 751-754
Restoring knee stability through reconstruction, while providing sympt
omatic relief, has not been shown to decrease the incidence of degener
ative changes after rupture of the anterior cruciate ligament. This su
ggests that posttraumatic osteoarthritis may not be purely biomechanic
al in origin, but also biochemical. To test this, we measured the leve
ls of seven cytokine modulators of cartilage metabolism in knee joint
synovial fluid after anterior cruciate ligament rupture. We also measu
red keratan sulfate, a product of articular cartilage catabolism, The
sample population consisted of patients with uninjured knee joints (N
10), and patients with acute (N = 60), subacute (N = 18), and chronic
(N = 8) anterior cruciate ligament-deficient knees, Synovial fluid sam
ples were analyzed by enzyme-linked immunosorbent assays. Normal synov
ial fluids contained high levels of the interleukin-l receptor antagon
ist but low concentrations of other cytokines. Immediately after ligam
ent rupture there were large increases in interleukins 6 and 8, tumor
necrosis factor alpha, and keratan sulfate, Interleukin-l levels remai
ned low throughout the course. As the injury became subacute and then
chronic, interleukin-6, tumor necrosis factor-alpha, and keratan sulfa
te levels fell but remained considerably elevated 3 months after injur
y, Concentrations of interleukin-1Ra fell dramatically. Granulocyte-ma
crophage colony-stimulating factor concentrations were normal acutely
and subacutely but by 3 months after injury were elevated IO-fold, Our
data reveal a persistent and evolving disturbance in cytokine and ker
atan sulfate profiles within the anterior cruciate ligament-deficient
knee, suggesting an important biochemical dimension to the development
of osteoarthritis there.