Arthroscopic Surgery for Osteoarthritis of the Knee

Introduction

Osteoarthritis of the knee is a leading cause of morbidity and disability in the United States. According to the Centers for Disease Control and Prevention (CDC), a person's average lifetime risk for symptomatic osteoarthritis of the knee is almost 50%.^[1] Knee arthroscopy has become one of the most commonly performed orthopaedic procedures to treat knee osteoarthritis. The latest National Health Statistics Report from the CDC states that approximately 985,000 knee arthroscopies were performed in 2006.^[2] Many of these procedures were performed to treat pain attributed to knee osteoarthritis.

A Randomized Trial of Arthroscopic Surgery for Osteoarthritis of the Knee

Kirkley A, Birmingham TB, Litchfield RB, et al.
N Engl J Med. 2008;359:1097-1107

Summary

Dr. Kirkley and colleagues sought to compare treatment outcomes in patients with knee osteoarthritis who underwent surgical intervention followed by postoperative conservative care with outcomes of patients who underwent non-operative, conservative treatment only. Those undergoing surgery had surgical lavage with at least one of the following procedures: synovectomy, debridement, or excision of degenerative meniscal tears, articular cartilage fragments, chondral flaps, and/or osteophytes that prevented full extension. Abrasion or microfracture surgery was not performed. Conservative care in both treatment arms consisted of a standardized physical and medical therapy program. Physical therapy was given for an hour per week for 12 weeks. Those who underwent surgery started the physical and medical therapy within 7 days of the operation.

This single-center, randomized trial conducted at the St. Joseph's Health Care London/University of Western Ontario included 188 patients diagnosed with moderate to severe knee osteoarthritis. There were 94 patients randomized to the surgical treatment arm and 94 patients assigned to the control treatment arm. Eleven patients withdrew consent from the trial (3 patients from the surgical group and 8 from the control group). There was no crossover noted in the control group. However, 6 patients in the surgical arm declined surgical intervention. Of those, 5 remained part of the study, while the sixth patient was lost to follow-up. A total of 8 patients were lost to follow-up; another patient died before completion of the study.

Primary study outcome was measured by the total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score at 2 years of follow-up. Secondary outcomes included the Short Form-36 Physical Component Summary survey, the McMaster-Toronto Arthritis Patient Preference Disability Questionnaire, the Arthritis Self-Efficacy Scale, and standard gamble (SG) utility scores. Greater improvements in the WOMAC score were initially seen in the surgical arm at 3 months. However, no statistically significant difference in WOMAC score was seen between the 2 treatment arms at any point after 3 months nor was any statistically significant difference seen for any of the secondary outcome measures.

Viewpoint

There is limited evidenced-based data that conclusively demonstrate the superiority of arthroscopy over conservative management in the treatment of osteoarthritis of the knee. The results of this study did not show long-term benefit of surgery in treating patients with moderate to severe knee osteoarthritis. These findings are consistent with results from a prior study by Moseley and colleagues^[3] in which surgery was compared with sham surgery in US male veterans. The author of an editorial accompanying the current article noted that knee arthroscopy is "not appropriate for patients with all knee conditions," and emphasized the use of clinical judgment together with evidenced-based care to decide whether a patient would benefit from surgery.^[4]

An important point to note from this study is the benefit of a standardized non-operative treatment program for patients with symptomatic osteoarthritis of the knee. Although there are conditions for which arthroscopic surgery would be indicated, such as the presence of a large meniscal tear or a loose body in the joint, patients in this study benefited just as much from regimented physical therapy with medical therapy optimization and they improved as much as those who underwent surgery and then conservative management.

Funding for this study was received from the Canadian Institutes of Health Research.

Abstract

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