Commentary & Perspective

Commentary & Perspective on
"The Clinical Importance of Meniscal Tears Demonstrated by Magnetic Resonance Imaging in Osteoarthritis of the Knee"
by Bhattacharyya et al.
and on
"Effect of Arthroscopic Débridement for Osteoarthritis of the Knee on Health-Related Quality of Life"
by Dervin et al.

Commentary & Perspective by
William Garrett Jr., MD, PhD*,
Department of Orthopaedic Surgery, University of North Carolina School of Medicine, Chapel Hill, NC

This issue of The Journal contains two articles that are relevant to the evaluation and treatment of the arthritic knee. The studies have important implications for orthopaedic practice, but we must be cautious in interpreting the authors' findings. In both studies, the subjects were chosen from groups of patients with symptomatic osteoarthritis of the knee. Specific symptoms of a meniscal tear were not included in the patient data. Certainly, it is unlikely that the subjects had primary symptoms of a meniscal tear and a secondary diagnosis of low-grade osteoarthritis.

In the study by Bhattacharyya et al.¹, magnetic resonance imaging and plain radiography were performed in a group of 154 patients with symptomatic knee osteoarthritis and in a group of forty-nine age-matched asymptomatic controls. A meniscal abnormality, seen on magnetic resonance imaging, was considered to be a tear if an intrasubstance signal extended to the articular surface. No attempt was made by the authors to define instability or to determine whether any aspect of the meniscus was displaced. By these criteria, they found a medial or lateral meniscal tear in 91% of the patients with symptomatic osteoarthritis. While patients in the control group weighed significantly less than those with symptomatic osteoarthritis (an average difference of 12 kg; p < 0.001), thirty-seven (76%) of the forty-nine controls had a medial or lateral meniscal tear and twelve (24%) had radiographic evidence of low-grade osteoarthritis.

These data clearly indicate that a meniscal tear found on a radiograph or magnetic resonance imaging study does not reliably predict clinical symptoms, and they show that radiographic evidence of low-grade osteoarthritis may not be associated with the clinical findings.

However, we do not know whether any of the patients with osteoarthritis had signs or symptoms suggestive of a meniscal tear. Additionally, if symptoms of an unstable meniscal tear later developed in the asymptomatic patients who had radiographic evidence of low-grade osteoarthritis, it might be difficult to determine whether their symptoms were due to osteoarthritis or to a meniscal tear. Therefore, these data raise questions about whether magnetic resonance imaging provides any diagnostic benefit to a patient with primary symptoms of a meniscal tear and concurrent radiographic evidence of osteoarthritis.

In the second article on osteoarthritis of the knee in this issue of The Journal, Dervin et al.² selected 126 patients with persistent symptomatic primary osteoarthritis for treatment with arthroscopic débridement. Interestingly, >50% of the patients who were found to have an unstable meniscal tear at the time of arthroscopy had improvement in the pain score at two years. The authors reported significantly better results in patients with signs of an unstable meniscal tear (p = 0.01), joint-line tenderness (p = 0.04), and a positive Steinman test (p = 0.01). Fifty-six patients (44%) obtained clinically important pain reduction, a health-related quality-of-life benefit. The authors stated that partial meniscectomy is an effective treatment for mild-to-moderate osteoarthritis and that "clinical criteria to predict the presence of unstable meniscal tears would be desirable."

Relating the findings of the study on magnetic resonance imaging of the knee by Bhattacharyya et al. to those of the arthroscopic outcome study by Dervin et al., it seems that the use of imaging techniques for the detection of an unstable meniscal tear would be highly desirable. Magnetic resonance imaging may reveal displaced fragments indicating the presence of an unstable meniscal tear even if it cannot be used to predict whether the fragments will be displaceable at surgery.

The study by Dervin et al. should be compared and contrasted with the study by Moseley et al.³, which involved 180 patients who were selected because they had osteoarthritis of the knee as defined by the American College of Rheumatology, reported moderate knee pain despite maximal medical treatment for at least six months, had had no knee arthroscopy, and were not more than seventy-five years old. The authors did not record meniscal signs preoperatively, and an unstable meniscal tear was not noted intraoperatively as in the study by Dervin et al. The patients in the study by Moseley et al. were randomly assigned to undergo arthroscopic débridement, arthroscopic lavage, or a placebo procedure. With use of outcomes instruments other than the Short Form-36 and Western Ontario and McMaster Universities Osteoarthritis Index, which were used by Dervin et al., Moseley et al. did not find any clinically important difference in outcomes among the three groups.

In the study by Moseley et al., only fifty-nine patients underwent arthroscopic débridement. In that group, there was no attempt to evaluate meniscal symptoms and only 31% of those patients had mild osteoarthritis. Patients who have mild osteoarthritis of the knee and a symptomatic meniscal tear may be most likely to have improvement of their symptoms after arthroscopic treatment.

Ultimately, the studies by Bhattacharyya et al. and Dervin et al. suggest that we should attempt to determine whether the signs and symptoms in patients with degenerative arthritis of the knee are caused by a meniscal tear, arthritis alone, or both. In the absence of symptoms and signs of a meniscal tear, a magnetic resonance imaging scan may be misleading; its use may result in an inappropriate focus on the presence of a meniscal tear, which was revealed in 76% of the asymptomatic controls and in 91% of those with symptomatic osteoarthritis in the study by Bhattacharyya et al. Dervin et al. found that even patients with symptomatic primary osteoarthritis had improvement of their symptoms when an unstable meniscal tear was resected. Neither study addressed the question of how to treat patients who present primarily with symptoms and signs indicative of a meniscal tear and who also have radiographic evidence of degenerative osteoarthritis. Hopefully, these papers demonstrate that arthroscopic surgery for the treatment of osteoarthritis alone does not predictably provide good results. It remains to be determined in future studies whether arthroscopic surgery can benefit patients who have mechanical symptoms primarily and symptoms of osteoarthritis secondarily.

*The author did not receive grants or outside funding in support of the research or preparation of this manuscript. He did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the author is affiliated or associated.

References

1. Bhattacharyya T, Gale D, Dewire P, Totterman S, Gale ME, McLaughlin S, Einhorn TA, Felson DT. The clinical importance of meniscal tears demonstrated by magnetic resonance imaging in osteoarthritis of the knee. J Bone Joint Surg Am. 2003;85:4-9.
2. Dervin GF, Stiell IG, Rody K, Grabowski J. Effect of arthroscopic débridement for osteoarthritis of the knee on health-related quality of life. J Bone Joint Surg Am. 2003;85:10-9.
3. Moseley JB, O'Malley K, Petersen NJ, Menke TJ, Brody BA, Kuykendall DH, Hollingsworth JC, Ashton CM, Wray NP. A controlled trial of arthroscopic surgery for osteoarthritis of the knee. N Engl J Med. 2002;347:81-8.