Abstracts & Commentary
Synopsis: Arthroscopic lavage or debridement is no better than a placebo procedure for improving pain and function in osteoarthritic knees.
Sources: Moseley JB, et al. N Engl J Med. 2002;347:81-88; Felson DT, et al. N Engl J Med. 2002;347:132-133.
In order to determine whether arthroscopic surgery benefits patients with osteoarthritis (OA) of the knee, Moseley and colleagues from Baylor recruited patients from the Houston Veterans Affairs Medical Center. They used the American College of Rheumatology’s definition of OA. Patients had to be younger than 75 and have pain severity at least 4 on a scale of 10. They assigned each subject a radiological severity score of 0-12; subjects with scores < 8 were included. From 324 consecutive patients who met criteria, 180 agreed to participate. The study participants differed from those that declined; they were younger, whiter, and more severely arthritic.
There were 3 arms to the study. In the first, the patients (61) underwent arthroscopic lavage. In the second, they (59) had lavage and debridement. The third group (60) had sham surgery. (The article goes on at great length to describe the sham surgery and the attempts to maintain blinding.) The patient characteristics were similar across the 3 groups; they were overwhelmingly male and in their early 50s. The groups were racially mixed, and there were similar numbers in the mild, moderate, and severe OA groups.
The clinical end points were pain and function. These were assessed at 2 weeks, 6 weeks, 3 months, 6 months, 12 months, 18 months, and 24 months postintervention. At all study points, the sham surgery group had less than or no greater pain than the arthroscopic groups and greater than or no worse function.
Comment by Allan J. Wilke, MD
Well, if there is no improvement in pain or function, who benefits from arthroscopic surgery? Moseley et al report that about 650,000 scopes at $5000 a pop are performed annually. It has become standard teaching that arthroscopic surgery is an option for patients who have OA of the knee.1 In this age of "let’s do it, because we can," it is sobering to read an article that demonstrates no improvement after a high-tech, high-cost procedure. (Not that we have a lot medically to offer patients who suffer from OA, beyond acetaminophen, NSAIDs, or COX-2s.)
This was not a perfect study. First, because this was conducted at a VA facility, the subjects were mostly men, despite the fact that most sufferers of knee OA are women. Would the results have been different if more of the participants were female? Next is the question of the exclusion criteria. Would patients with more radiographically severe OA have benefited? The size of the study groups was large enough to detect large therapeutic effects. Would an even larger study have detected small differences? All the surgeries (including the sham surgeries) were performed by one surgeon. Could a more skillful surgeon have produced better results? No subgroup analysis was done; maybe better patient selection would have produced results that are more favorable. Finally, would there have been a difference if the study had extended beyond 24 months?
In 1997, it is estimated that 43 million Americans had arthritis (not simply OA).2 Women suffer disproportionately (19.5% vs 12.5%). The incidence increases with age with over half of women older than 65 years having arthritis; for men it is slightly less that half. Eight million Americans reported that arthritis was a major limiting factor in their activity level. It accounted for 744,000 hospitalizations and 44 million ambulatory-care visits. It is the leading cause of disability in the United States and in 1992 cost an estimated $65 billion.3 Obesity and occupations that require frequent knee bending are preventable risk factors for OA. As primary care physicians, we need to help our patients forestall arthritis by weight control and injury prevention.
Dr. Wilke, Assistant Professor of Family Medicine, Medical College of Ohio, Toledo, OH, is Associate Editor of Internal Medicine Alert.
References
1. Wise C. Osteoarthritis. In: Dale DC, Federman DG, eds. Scientific American Medicine. 2002. Chapter 15, section X.
2. MMWR Morb Mortal Wkly Rep. 2001;50:334-336.
3. MMWR Morb Mortal Wkly Rep. 1999;48:349-353.
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