Abstract
Meniscal pathology is an extremely prevalent problem, which inevitably leads to osteoarthritis
and associated pain, swelling, and disability. Relatively little data are available
regarding the molecular, biochemical, and histologic aspects of meniscal disease.
This study characterizes meniscal pathology in the presence of symptomatic osteoarthritis
and correlates clinical and basic science data in an attempt to delineate clinically
relevant mechanisms of disease. Twenty-seven knees from 23 patients who underwent
total knee arthroplasty comprised the affected group and 6 aged nonsymptomatic knees
were used as controls. All meniscal tissues were harvested and subjectively scored
for gross and histologic pathology. Biochemical analyses were performed to determine
glycosaminoglycan (GAG) content, collagen (hydroxyproline) content, and water content.
Real-time polymerase chain reaction analysis was conducted for genes involved in synthesis
(collagens [col] 1, 2, 3, and 6), degradation (matrix metalloproteinases [MMP-1, -2,
-3, -13]), and angiogenesis (vascular endothelial growth factor). Weight-bearing,
anterior-posterior radiographic views were used to determine joint space measurements
for lateral and medial compartments, and were subjectively scored for osteoarthritic
changes. Data were compared for statistically significant differences and to determine
the presence and strength of correlations among variables assessed. Affected menisci
had significantly higher gross and histologic pathology scores compared with control
menisci. Affected menisci had significantly higher water, proteoglycan, and collagen
content compared with control menisci. Col 1, 3, and 6 gene expression levels for
the affected group were significantly increased compared with controls. MMP-13 expression
was significantly increased for the affected group. MMP-2 and -3 expression levels
were significantly lower in the affected group compared with controls. The affected
group had significantly more joint space narrowing and higher radiographic scores
for medial compared with lateral compartments. Several strong and moderately strong
correlations were present between variables. These data suggest that in vitro measures
of meniscal pathology have potential value for understanding disease mechanisms and
predicting clinical disease.
Keywords
meniscus - pathology - osteoarthritis - knee
