In what has been described as a landmark study, scientists in Canada have found that a routine knee operation undergone by many patients with osteoarthritis does not relieve joint pain or improve knee function.
The study was the work of researchers at the The University of Western Ontario and Lawson Health Research Institute, both in London, Ontario, Canada, and appears in the September 11th issue of the New England Journal of Medicine, NEJM.
The study was designed by the late Dr Sandy Kirkley, orthopaedic surgeon and arthroscopy specialist, and was coordinated by the Clinical Trials Group of Robarts Research Institute. A research team comprising orthopaedic surgeons, rheumatologists and physiotherapists, carried out the study at the Fowler Kennedy Sport Medicine Clinic at London Health Sciences Centre (LHSC).
Co-author Dr Brian Feagan, Clinical Trials Director at the Robarts Research Institute at Western, and a professor in the Departments of Medicine, and Epidemiology and Biostatistics at Western’s Schulich School of Medicine & Dentistry, said:
“This study provides definitive evidence that arthroscopic surgery provides no additional therapeutic value when added to physical therapy and medication for patients with moderate osteoarthritis of the knee.”
Ten per cent of Canadians, and 27 million Americans are living with osteoarthritis, the most common type of arthritis.
Arthroscopic surgery is a minimally invasive surgical operation where the surgeon makes a small incision and inserts an arthroscope (long tube with a camera on the end and room to pass surgical instruments through as well) in the knee joint and them removes fragments of cartilage and smooths down the surfaces of the joints.
For the study, which ran from 1999 to 2007, the researchers treated 178 male and female patients of average age 60 who came from the London area and had moderate to severe arthritis of the knee.
The patients were randomly assigned to receive either surgical lavage and arthroscopic debridement together with optimized physical and medical therapy (92 treatment group patients) or to receive physical and medical therapy without surgery (86 control group patients).
The patients then completed symptom assessment questionnaires at various points post-treatment, for up to two years. One questionnaire was the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and another questionnaire was the Short Form-36 (SF-36) Physical Component Summary score.
The total WOMAC score ranges from 0 to 2400, with higher scores meaning more severe symptoms. This was the primary outcome measure. The SF-36 Physical Component Summary score can range from 0 to 100, with the higher scores indicating better quality of life. This was part of the secondary outcome measures.
The results showed that:
- Of the 92 patients assigned to surgery, 6 did not have it.
- All 86 patients in the control group had physical and medical therapy only, as planned.
- After 2 years of follow up, the mean (plus or minus standard deviation) WOMAC score for the surgery group was 874 plus or minus 624, compared with 897 plus or minus 583 for the control group.
- The absolute difference between the surgery group WOMAC score minus the control group WOMAC score at 2 years was a statistically insignificant -23 plus or minus 605 (95% confidence interval ranged from -208 to 161; P=0.22 after baseline and grade of severity adjustments).
- The SF-36 Physical Component Summary score for the surgery group was 37.0 plus or minus 11.4 and 37.2 plus or minus 10.6 for the control group at 2 years.
- The absolute difference in SF-36 Physical Component Summary scores in the surgery group minus the control group at 2 years was a statistically insignificant -0.2 plus or minus 11.1 (95% confidence interval ranged from -3.6 to 3.2; P=0.93).
- Analyses of WOMAC scores at interim visits and other secondary outcomes also failed to show better statistically significant results for the surgery group.
The authors concluded that:
“Arthroscopic surgery for osteoarthritis of the knee provides no additional benefit to optimized physical and medical therapy. “
“Based on the available evidence, we believe that the resources currently allocated towards arthroscopic surgery for osteoarthritis would be better directed elsewhere,” they said.
In other words, at several stages during the 2 year follow up, the researchers found both patient groups experienced comparable improvements in joint pain, stiffness, and function, but there was no significant benefit from surgery.
Co-author and orthopaedic surgeon Dr Bob Litchfield, who is also Medical Director of the Fowler Kennedy Sport Medicine Clinic, pointed out that the study only looked at knee problems that were arthritis related :
“Although this study did not show a significant therapeutic benefit of arthroscopic debridement in this patient population, knee arthroscopy is still beneficial in many other conditions affecting the knee, such as meniscal repair and resection, and ligament reconstruction.”
Litchfield is also a professor in the Department of Surgery at Schulich Medicine & Dentistry and a scientist with the Lawson Health Research Institute.
“As surgeons, we need to know when things are working and when they’re not. If this particular technique is not working for this subgroup of patients, we better come up with something else that does,” he added.
An earlier study (the “Moseley study”) published in 2002 showing similar results was considered methodologically flawed and rejected by the medical community and arthroscopic surgery is still routinely performed to treat joint pain and stiffness.
In 2006/2007, Ontario Health Insurance Plan (OHIP) spent 7.9 million dollars on this procedure alone, said the researchers in a press statement.
“A Randomized Trial of Arthroscopic Surgery for Osteoarthritis of the Knee.”
Kirkley, Alexandra, Birmingham, Trevor B., Litchfield, Robert B., Giffin, J. Robert, Willits, Kevin R., Wong, Cindy J., Feagan, Brian G., Donner, Allan, Griffin, Sharon H., D’Ascanio, Linda M., Pope, Janet E., Fowler, Peter J.
N Engl J Med 2008 359: 1097-1107.
Volume 359, Number 11, pages 1097-1107, September 11, 2008.
Source: The University of Western Ontario, Journal abstract.
Written by: Catharine Paddock, PhD