Am Fam Physician. 2008;78(3):331-332
Author disclosure: Nothing to disclose.
Clinical Scenario
A 53-year-old man presents for follow-up of knee pain. Examination and plain radiography confirmed osteoarthritis. After little relief with analgesics and a corticosteroid injection, he inquires about arthroscopic surgery.
Clinical Question
Is arthroscopic debridement an effective therapy for improving pain and function in patients with osteoarthritis of the knee?
Evidence-Based Answer
Compared with other modalities of treatment such as sham surgery, joint lavage, and joint washout, arthroscopic debridement does not improve outcomes for patients with osteoarthritis of the knee.1
Cochrane Abstract
Background: Knee osteoarthritis is a progressive disease that initially affects the articular cartilage. Observational studies have shown benefits for arthroscopic debridement on the osteoarthritic knee, but other recent studies have yielded conflicting results that suggest arthroscopic debridement may not be effective.
Objectives: To identify the effectiveness of arthroscopic debridement in knee osteoarthritis on pain and function.
Search Strategy: The authors searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 2, 2006), Medline (1966 to August 2006), CINAHL (1982 to 2006), EMBASE (1988 to 2006), and Web of Science (1900 to 2006), and screened the bibliographies, reference lists, and cited Web sites of papers.
Selection Criteria: The authors included randomized controlled trials (RCTs) or controlled clinical trials assessing effectiveness of arthroscopic debridement compared with another surgical procedure (including sham or placebo surgery and other nonsurgical interventions) in patients with a diagnosis of primary or secondary osteoarthritis of the knee who did not have other joint involvement or conditions requiring long-term use of nonsteroidal anti-inflammatory drugs. The main outcomes were pain relief and improved function of the knee.
Data Collection and Analysis: Two review authors independently selected trials for inclusion, assessed trial quality, and extracted the data. Results are presented using weighted mean difference for continuous data and relative risk for dichotomous data, as well as the number needed to treat (NNT) and the number needed to harm (NNH).
Main Results: Three RCTs, with a total of 271 patients, were included. They had different comparison groups and a moderate risk of bias. One study compared arthroscopic debridement with lavage and with sham surgery. The study found no significant difference when compared with lavage. Compared with sham surgery, the study found worse outcomes for arthroscopic debridement at two weeks (weighted mean difference for pain = 8.7; 95% confidence interval [CI], 1.7 to 15.8; function = 7.7; 95% CI, 1.1 to 14.3; NNH = 5) and no significant difference at two years. The second trial, at higher risk of bias, compared arthroscopic debridement with arthroscopic washout and found that arthroscopic debridement significantly reduced knee pain compared with washout at five years (relative risk = 5.5; 95% CI, 1.7 to 15.5; NNT = 3). The third trial, also at higher risk of bias, compared arthroscopic debridement with closed-needle lavage and found no significant difference.
Authors’ Conclusions: There is high-quality evidence that arthroscopic debridement has no benefit for typical osteoarthritis of the knee (mechanical or inflammatory causes).
These summaries have been derived from Cochrane reviews published in the Cochrane Database of SystematicReviews in the Cochrane Library. Their content has, as far as possible, been checked with the authors of the originalreviews, but the summaries should not be regarded as an official product of the Cochrane Collaboration; minorediting changes have been made to the text (http://www.cochrane.org).
Practice Pointers
Various factors that contribute to degradation of articular cartilage include age, anatomy, genetics, obesity, and trauma. Arthroscopic surgery has been used for decades for the treatment of osteoarthritis of the knee and is common practice for meniscal or ligamental tears.2 However, its current role in the treatment of osteoarthritis of the knee is controversial.3
The authors of this Cochrane review found three studies that were too dissimilar to undergo meta-analysis calculations. Two of the studies were of poor quality. One 1993 study of 32 patients was inadequately powered, single-blinded, and did not describe concealment. A 1996 study of 76 patients was not blinded at all.
The best study was from 2002. It was a large double-blinded randomized controlled trial (RCT) of moderate quality. Participants were randomized into three groups: arthroscopic debridement, lavage, and sham surgery. Arthroscopic surgery was not shown to be beneficial. This study has been criticized.4 Participants were younger, more likely to be white, and more likely to have severe arthritis than those who chose not to participate; 44 percent of eligible patients declined to participate. The same surgeon performed all of the surgeries. Despite these limitations, this is the highest quality RCT to date of this common surgical procedure.
Sixteen international experts from four medical disciplines met to devise consensus guidelines for osteoarthritis of the knee and hip.3 Ranked by increasing “effect size” (the weighted mean difference or measurement of effectiveness used when comparing outcomes from different studies), the following treatments are beneficial for osteoarthritis pain of the knee: encouraging weight loss, acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDS) with gastroprotection, hyaluronate injections, topical NSAIDs or capsaicin, glucosamine sulfate (not glucosamine hydrochloride)5, acupuncture, aerobic exercise, thermal modalities (ice or heat), and steroid injections. Four patients need to be treated with steroid injections for one of them to have moderate pain relief at two and three weeks (number needed to treat [NNT] = 4), but evidence for relief of pain at four weeks and beyond is lacking. No serious adverse events were reported.6 Knee braces, lateral wedged insoles, transcutaneous electrical nerve stimulation units, and chondroitin supplements have less discernible benefit, but are thought to be safe. The guidelines published in BMJ Clinical Evidence generally agree with the above stated modalities, with the exception that acupuncture, capsaicin, and glucosamine are labeled as having unknown effectiveness.7
Regarding surgical treatments, high tibial osteotomy for young and active patients with severe unicompartmental knee osteoarthritis may prolong time until joint replacement. Total knee joint arthroplasty is reasonable and cost-effective for severe, debilitating osteoarthritis. About 10 percent of patients will need a revision at 10 years.3