Fran Lowry
December 27, 2013

In patients with a degenerative medial meniscal tear and no knee osteoarthritis, arthroscopic partial meniscectomy is no better than sham surgery, Finnish researchers report in the December 26 issue of the New England Journal of Medicine.

“Arthroscopic partial meniscectomy is the most common orthopaedic procedure performed in the United States,” write Raine Sihvonen, MD, from Hatanpää City Hospital, Tampere, Finland, and colleagues for the Finnish Degenerative Meniscal Lesion Study (FIDELITY) Group. “[Y]et rigorous evidence of its efficacy is lacking.”

About 700,000 arthroscopic partial meniscectomies are done each year in the United States, at an estimated annual cost of $4 billion. Recently, a randomized trial showed that arthroscopic partial meniscectomy combined with physical therapy provides no better relief of symptoms than physical therapy alone in patients with a meniscal tear and knee osteoarthritis.

Therefore, the authors initiated this multicentre, randomized, double-blind, sham-controlled trial to determine the efficacy of the procedure in patients with a degenerative tear of the medial meniscus but no knee osteoarthritis.

After undergoing diagnostic arthroscopy to confirm eligibility for the trial, 146 patients aged 35 to 65 years were randomly assigned to receive arthroscopic partial meniscectomy or sham surgery.

During meniscectomy, the damaged and loose parts of the meniscus were removed with a mechanized shaver and meniscal punches until solid meniscal tissue was reached, the unstable meniscus was then resected, with as much of it as possible preserved. The sham surgery simulated partial meniscotomy but did not instill any medication into the knee during arthroscopy.

Patients in both groups received similar postoperative care, which included walking aids and instructions for a graduated exercise program. They also took over-the-counter analgesics as needed. The primary outcomes were changes in the Lysholm and Western Ontario Meniscal Evaluation Tool (WOMET) scores, each ranging from 0 to 100, with lower scores indicating more severe symptoms, and in knee pain after exercise, which was assessed on a scale ranging from 0 (no pain) to 10 (extreme pain) at 12 months after the procedure.

All patients in both groups showed marked improvement from baseline to 12 months in the 3 primary outcome measures, and there were no significant differences between the groups.

In the Lysholm score, the mean improvement was 21.7 points in the partial meniscectomy group vs 23.3 points in the sham-surgery group (between-group difference, −1.6 points; 95% confidence interval [CI], −7.2 to 4.0 points).

In the WOMET score, the mean improvement was 24.6 points in the partial meniscectomy group vs 27.1 points in the sham-surgery group (between-group difference, −2.5 points; 95% CI, −9.2 to 4.1 points).

For knee pain after exercise, the mean improvement score was 3.1 points for the partial meniscectomy group vs 3.3 points for the sham-surgery group (between-group difference, −0.1; 95% CI, −0.9 to 0.7 points).

Two patients in the partial meniscectomy group and 5 patients in the sham-surgery group required additional surgery, and a single partial meniscectomy patient suffered a serious adverse event.

The proportion of patients who guessed they had undergone a sham procedure was also similar in the 2 groups. This “indicates that the study-group assignments were concealed effectively,” the authors write.

They caution that their study results apply only to patients with nontraumatic degenerative medial meniscus tears. They also point out that some of the patients might have had knee osteoarthritis that was missed at the initial diagnostic arthroscopy before randomization.

They conclude that arthroscopic partial medial meniscectomy provides no significant benefit over sham surgery in patients who have a degenerative meniscal tear but who do not have knee osteoarthritis.

“These results argue against the current practice of performing arthroscopic partial meniscectomy in patients with a degenerative meniscal tear,” the authors conclude.