Research Review by Dr. Robert Rodine©


Sept. 2008

Study Title:

A Randomized Trial of Arthroscopic Surgery for Osteoarthritis of the Knee


Kirkley A et al.

Authors’ Affiliations: University of Western Ontario, London, Ontario, Canada.

Publication Information:

New England Journal of Medicine 2008; 359(11): 1097-1107.


Osteoarthritis (OA) of the knee is often associated with decreased function and quality of life due to joint pain and stiffness. Numerous interventions exist for the treatment of OA of the knee, including physical therapy, acupuncture, medication use and surgery. Despite its popularity as a treatment intervention for knee OA, the efficacy of surgery however has come into question due to the lack of supporting scientific evidence.

Surgery for OA of the knee, when complete joint replacement is not justified, typically consists of an arthroscopic procedure involving lavage (removal of particulate material) and debridement (smoothing of joint surfaces). A recent, commonly cited study1 showed no benefit from arthroscopic surgery for knee OA, but controversy remains in the literature2, as their conclusions have not been well accepted.

This randomized trial sought to compare arthroscopic knee surgery to physical and medical therapy. Patients were eligible for the study if they were over the age of 18 and had a Kellgren-Lawrence grade 2, 3 or 4 idiopathic or secondary osteoarthritis of the knee. Patients were excluded from the study if they:
  • had large meniscal tears (“bucket handle” type), or inflammatory or infectious arthritis
  • had previous arthroscopic surgery or 5 degrees or more of valgus/varus deformity
  • had Kellgren-Lawrence grade 4 OA in two compartments
  • were over the age of 60
  • had received intra-articular corticosteroid injections in the previous 3 months
  • had neurological deficit, serious medical illness, or pregnancy
The study began with 277 eligible patients with 188 undergoing randomization. In total, 94 were randomized to the surgical arm and 94 to the physical and medical therapy arm. When the data was compiled, 92 were included in the surgical arm and 86 were included in the physical and medical therapy arm. It should be noted that 6 patients in the surgical arm did not have surgery, however their data was included with the surgical arm, based on the intention-to-treat principle. Baseline characteristics were similar for both surgical and conservative treatment groups. The average age was 58.6 and 60.6 respectively in the two groups.

While the surgical group had a significantly higher average bodyweight, there was no significant difference in Body Mass Index (BMI) between the two groups. Severity of OA and initial WOMAC (Western Ontario and McMaster Osteoarthritis Index) and SF-36 scores were comparable between groups.

Surgical patients, who underwent mostly debridement of meniscal and articular cartilage lesions, also received physical and medical therapy which began within 7 days following surgery. Physical and medical therapy involved education regarding home exercise, instructions on performing activities of daily living and individual exercises tailored to the severity of the patients symptoms. Therapy consisted of a single one hour session each week for twelve weeks.

Upon successful completion of PT, patients continued an unsupervised home exercise program and received additional information from local Arthritis Society workshops. Medical treatment plans were also implemented by following evidence-based guidelines on the use of acetaminophen, NSAID’s and intra-articular injection of hyaluronic acid.

The outcome measures used in this study consisted of the WOMAC (primary outcome), SF-36, MACTAR (McMaster-Toronto Arthritis Patient Preference Disability Questionnaire), and the ASES (Arthritis Self-Efficacy Scale). Follow-up assessments were conducted at 3, 6, 12, 18 and 24 months.

Pertinent results of this study include:

Results of the study were compared between groups at the different follow-up points (3, 6, 12, and 24 months). In addition to calculating differences across the whole population, subgroups of OA severity, according the Kellgren-Lawrence grading system, were also calculated.
  • at the 3 month time point, the surgical group showed decreased total scores, decreased pain and improved physical function based on the WOMAC scale compared to the conservative therapy arm, but there were no significant differences between the groups thereafter
  • no benefit was conferred by surgery on those patients with mechanical symptoms of locking or catching
  • no significant differences were noted on any secondary outcome measures between groups
  • when treatment groups were subdivided into severity grades, patients with Kellgren-Lawrence grade 2 OA showed no difference from the conservative therapy arm (p = 0.91)
  • Grades 3 and 4 OA however showed the greatest difference from the conservative therapy arm (p < 0.001)
  • after three months, differences between the groups began to stabilize
  • at 24 months, there was no statistically significant difference on the WOMAC between the two groups, regardless of OA severity
  • mean SF-36 scores were comparable at 37.0 and 37.2 respectively at 24 months as well

Conclusions & Practical Application:

This RCT amply demonstrated that arthroscopic surgery in patients with osteoarthritis of the knee does not perform better than conservative therapy consisting of active rehabilitation and monitored medication use. It should be noted that subjects included in this study did meet strict inclusion/exclusion criteria, which resulted in only 68% of eligible patients being included in the study. However, this limitation serves dually to augment the management decision tree. The criteria in this study are likely to help guide clinicians towards directing the most appropriate patients towards less invasive and equally beneficial therapy.

It is most imperative that manual therapists are made aware of this trial given its implications on patient management within medical and orthopedic practices. If accepted as part of evidence-based practice, this study will likely result in an influx of patients to conservative therapy clinics seeking treatment for OA of the knee. In addition, it is important for clinicians to demonstrate leadership and educate each other on trials such as this.

Additional References:
  • Moseley JB, O’Malley K, Petersen NJ et al. A controlled trial of arthroscopic surgery for osteoarthritis of the knee. N Eng J Med 2002; 347: 81-88.
  • Felson DT, Buckwalter J. Debridement and lavage for osteoarthritis of the knee. N Eng J Med 2002; 347: 132-133.