Arthroscopic Knee Surgery Shows No Long-term Benefit

Tara Haelle

June 17, 2015

The potential harms of arthroscopy to treat pain and poor functioning of a degenerative knee may outweigh the procedure's small pain relief benefits, which last less than 1 to 2 years after surgery, according to a systematic review and meta-analysis published online June 16 in the BMJ.

"Arthroscopic surgery in the middle aged and older population with knee pain represents most arthroscopies and is routinely performed on the basis of a suspected meniscal tear by clinical examination or as diagnosed by magnetic resonance imaging, the reasoning being that the pain is associated with the meniscal tear," write Jonas Bloch Thorlund, PhD, from the Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, and associates. The available evidence, however, supports reversing this common medical practice, they add, while acknowledging the challenges of doing so, including surgeon confirmation bias, financial aspects, and administrative policies.

"Supporting or justifying a procedure with the potential for serious harm, even if this is rare, is difficult when that procedure offers patients no more benefit than a placebo," writes Andy Carr, ChM, DSc, FRCS, FMedSci, from the Botnar Research Centre, Oxford University Institute of Musculoskeletal Sciences, National Institute for Health Research Oxford Musculoskeletal Biomedical Research Unit, United Kingdom, in an accompanying editorial. Surgeons perform more than 700,000 knee arthroscopies in the United States, and more than 150,000 in the United Kingdom, he notes. Yet the imaging abnormalities often used to justify these procedures are common in the general population, and the findings of this meta-analysis suggest that "a substantial number of lives could be saved and deep venous thromboses prevented each year if this treatment were to be discontinued or diminished."

The researchers identified all randomized controlled trials that appeared in five databases through August 2014 and assessed the benefits of arthroscopic surgery for patients, regardless of whether they had X-ray evidence of osteoarthritis. The studies had to include surgery with partial meniscectomy, debridement, or both, and the researchers included additional cohort studies, register-based studies, and case series studies from 2000 onward to determine harms.

The nine trials they found included 1270 patients, with mean ages from 49.7 to 62.8 years, and follow-ups ranging from 3 to 24 months. The studies compared arthroscopy with control treatments such as exercise and sham surgery for patients whose mean baseline pain ranged from 36 to 63 mm on a 0- to 100-mm visual analogue scale. All participants in two trials, none in two others, and some in the remaining five had osteoarthritis determined by radiography.

Using each study's end point, the analysis revealed a combined 2.4-mm (95% confidence interval [CI], 0.4 - 4.3 mm) improvement in pain compared with control treatments. The effect size for pain relief (0.14; 95% CI, 0.03 - 0.26) was similar to that for acetaminophen (0.14) and less than that seen from nonsteroidal anti-inflammatory drugs (0.29) and exercise therapy (0.50 regardless of dose or 0.68 for three times weekly). The pain relief seen at 3 and 6 months, ranging from 3 to 5 mm, also did not last to 24 months, and the analysis revealed no improved physical functioning (effect size, 0.09; 95% CI, −0.05 to 0.24).

The most common harm identified from two randomized controlled trials and seven observational studies was deep vein thrombosis, occurring at a rate of 4.13 per 1000 arthroscopic meniscectomy procedures (95% CI, 1.78 - 9.60). Other harms included pulmonary embolism (1.45 per 1000 procedures; 95% CI, 0.59 - 3.54), infection (2.11 per 1000 procedures; 95% CI, 0.80 - 5.56), and death (0.96 per 1000 procedures; 95% CI, 0.04 - 23.9).

Because some previous research has found surgeries to provide no greater benefit than placebo surgeries, "[t]he treatment effect associated with arthroscopic surgery of the knee may well have a placebo component," Dr Carr writes. Similar to the authors, he suggests that confirmation bias may be among the factors contributing to the continued use of arthroscopic surgery, despite the weak evidence base.

"We may be close to a tipping point where the weight of evidence against arthroscopic knee surgery for pain is enough to overcome concerns about the quality of the studies, confirmation bias, and vested interests," he writes. "When that point is reached, we should anticipate a swift reversal of established practice."

One coauthor reported receiving funding from the Swedish Research Council funded and personal fees from Össur, Flexion Therapeutics, Medivir, Teijin, Merck Serono, Allergan, and Galapagos, as well as being the editor-in-chief of Osteoarthritis and Cartilage. Another coauthor reported receiving fees for lectures and royalties for books from Össur, the Finnish Orthopedic Society, Studentlitteratur, and Munksgaard, and being an associate editor of Osteoarthritis and Cartilage. Dr Carr reported receiving funding from the National Institute for Health Research Oxford Biomedical Research Unit and research grants from the National Institute for Health Research and Arthritis Research UK.

BMJ. 2015;350:h2747, h2983. Article full text, Edtiorial full text

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