RESEARCH - Marginal osteophytes on x-ray indicate osteoarthritis

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Marginal osteophytes on x-ray indicate osteoarthritis

6/21/2006

By: Shalmali Pal

As the population ages, the incidence of osteoarthritis increases as well,

with nearly 75% of people over 65 years showing evidence of the disease in

the tibiofemoral joint. Osteoarthritis has several unique features on knee

x-ray, but how useful are they for detecting articular cartilage

degeneration, asked Wisconsin-based clinicians in a recent study.

" Characteristic radiologic features of osteoarthritis (are) marginal

osteophytes, joint space narrowing, subchondral sclerosis, and subchondral

cysts, " wrote Dr. Kijowski and colleagues from the departments of

radiology and statistics at the University of Wisconsin in Madison

(Radiology, June 2006, Vol. 239:3, pp. 818-824).

In this retrospective study, the group correlated x-ray findings of

osteoarthritis of the tibiofemoral joint with arthroscopic findings of

articular cartilage degeneration within the same joint. The patient

population consisted of 125 patients with osteoarthritis of the tibiofemoral

joint and 25 patients without the disease. All 125 patients had chronic knee

pain that lasted longer than two months with no history of recent knee

trauma.

All anteroposterior radiographs were done with the patient in the upright

standing position with the knee fully extended. Two musculoskeletal imaging

fellows reviewed all hard copies in consensus. All 150 patients also

underwent knee arthroscopy within two months after the x-ray.

The results showed that the majority of patients (90) had articular

cartilage degeneration within both the medial and lateral compartments of

the tibiofemoral joint. Thirty-five patients had articular cartilage

degeneration in either compartment.

The sensitivity of any radiographic feature of osteoarthritis for detecting

articular cartilage degeneration within the medial compartment was 69% and

the specificity was 68%. More specifically, radiographic sensitivity for

marginal osteophytes was 67% and the specificity was 73%. For joint space

narrowing, the sensitivity was 46% and the specificity was 95%. For

subchondral sclerosis, the sensitivity was 16% and the specificity was 100%.

Finally, for subchondral cysts the sensitivity was 10% and the specificity

was 100%.

" Our study has shown that marginal osteophytes are an important radiographic

feature of osteoarthritis of the tibiofemoral joint, " the authors wrote. " In

our study, marginal osteophytes were the most sensitive radiographic finding

for the detection of articular cartilage degeneration within the

tibiofemoral joint. " In addition, marginal osteophytes were the most common

finding in patients with early osteoarthritis.

Conversely, joint space narrowing was less sensitive, while subchondral

cysts and subchondral sclerosis were rarely seen in patients with articular

cartilage degeneration.

Osteoarthritis of the tibiofemoral joint should be diagnosed on the basis of

marginal osteophytes, while the other radiographic features should be

reserved for assessing disease process, the authors concluded.

By Shalmali Pal

AuntMinnie.com staff writer

June 21, 2006

http://www.auntminnie.com/index.asp?Sec=sup & Sub=ort & Pag=dis & ItemId=71471

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