Decreased synovial fluid lubrication linked with cartilage damage

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Decreased synovial fluid lubrication linked with cartilage damage

A preclinical study suggests reduced synovial fluid lubrication may be

common in both acute and chronic inflammatory conditions.

June 2005

Inflammation resulting from knee injuries may lead to progressive loss

of joint lubrication, predisposing patients to arthritis, a new study

suggests.

D. Jay, MD, PhD, an associate professor of emergency medicine

at Brown University in Providence, R.I., conducted the study with

colleagues at the University of Rhode Island and at Case Western

Reserve University School of Medicine, Cleveland. They published their

results in Arthritis & Rheumatism.

Using a rabbit model, the researchers transected the anterior and

posterior cruciate ligaments of 10 knees. They then aspirated synovial

fluid from the affected knee joints weekly for three weeks. Analyses of

the synovial fluid included quantification of concentrations of

lubricin, Type II collagen peptides, C-terminal neopeptide 9A4 and

keratan sulfate epitope 5-D-4. The researchers also measured elastase

activity spectrophotometrically, according to the study.

The researchers found that the lubricating ability of synovial fluid as

well as concentrations of lubricin had both significantly decreased at

two and three weeks post injury compared to week one. Additionally,

Type II collagen peptide concentrations significantly increased at week

three, according to the study.

Elastase activity significantly increased at weeks two and three, which

significantly correlated with decreasing lubrication at all follow-up

points, the authors said. However, concentrations of keratan sulfate

epitope 5-D-4 showed no significant changes, they said.

“Loss of boundary-lubricating ability ... after injury is associated

with damage to the articular cartilage matrix. This can be attributed

to inflammatory processes resulting from the injury, particularly in

the early phases,” the authors said.

A retrospective evaluation of synovial fluid aspirated from emergency

room patients to alleviate swelling further supports their findings.

The researchers found injured patients had greater levels of friction

compared to uninjured patients. Injured patients also had increased

production of Type II collagen peptides, indicating early cartilage

damage, according to a press release.

The researchers found that patients with rheumatoid arthritis had no

lubricating ability. This suggests the possible association with

cartilage damage is not unique to early stages of a knee injury, “but

rather a common feature in inflammatory conditions, both acute and

chronic,” the authors said in the study.

“In this study, we were able to quantify loss of lubrication, which has

important implications for preventing osteoarthritis,” Jay said in the

press release. “If you’re walking on a nonlubricated joint, it’s likely

you’ll develop osteoarthritis or induce damage to other areas of the

knee,” he added.

For more information:

* Elsaid KA, Jay GD, Warman ML, et. al. Association of

articular cartilage degradation and loss of boundary-lubricating

ability of synovial fluid following injury and inflammatory arthritis.

Arthritis Rheum. 2005;52:1746-1755.