BOSTON, Massachusetts—Magnetic resonance imaging (MRI) commonly reveals meniscal tears or other damage in middle-aged or older subjects, but these changes are no more common in subjects with knee osteoarthritis (OA) than in those without OA, Martin Englund, MD, PhD, and colleagues report in The New England Journal of Medicine.1 Incidental meniscal findings on MRI are common in the general population, increase with increasing age, and should not be the basis for decisions about whether to undertake meniscal surgery, the authors say.

“Sixty percent of the subjects who had meniscal tears in their knees had not had any pain, aching, or stiffness during the previous month.”—Martin Englund, MD, PhD
“Of middle-aged and elderly persons with meniscal tear in their knee, 61% did not report any knee pain, aching or stiffness. But this does not mean that in the remaining 39% the meniscal tear is the cause of knee symptoms, [it means] only that they co-occur. The sheer high prevalence of meniscal tear in this age category, irrespective of knee joint symptoms, strongly suggests it being a frequent incidental finding on many routine MRIs. The cause of knee pain in this age category may instead often be due to knee osteoarthritis of various stages. A degenerative meniscal tear may be signaling early osteoarthritic disease,” Dr. Englund told Musculoskeletal Report. He is from the clinical epidemiology research and training unit at Boston University School of Medicine and also from the Department of Orthopedics at Lund University in Sweden.

The study assessed the integrity of the menisci in the right knee on 1.5-tesla MRI scans from 991 subjects randomly selected from Framingham, Massachusetts. Subjects were ambulatory and aged 50 to 90 years.

Prevalence of meniscal tear or destruction detected on MRI was
  • 19% among women 50 to 59 years of age
  • 56% among men 70 to 90 years of age
  • 63% among persons with radiographic evidence of OA who reported knee pain, aching, or stiffness on most days
  • 60% among persons with OA and no knee pain, aching, or stiffness
  • 32% among subjects without radiographic evidence of OA and with no knee symptoms
  • 23% among subjects with radiographic evidence of OA but no knee symptoms.

Translating research into practice

According to Dr. Englund, these data “absolutely” suggest that clinicians should be more cautious about using findings of meniscal tear in middle-aged or elderly patients as a reason to do arthroscopic knee surgery.

“There is yet no scientific evidence of a beneficial effect of meniscal resections in this age category. The results of the Moseley trial (NEJM 2002) and Kirkley trial (NEJM 2008), both high quality studies, show meniscal surgery to be noneffective at least in persons with knee OA (both studies included meniscal resections in the active treatment arm). However, randomized clinical trials of meniscal surgey including middle-aged patients with only early stage OA or no radiographic OA are needed. Even in absence of definite radiographic evidence of osteoarthritis, it may be hard to differentiate symptoms caused by a meniscal tear from symptoms of early OA disease,” Dr. Englund said.

He noted that the study confirms meniscal tears and or destruction as highly prevalent among persons with knee OA, which suggests that the menisci play an important role in the development and progression of the disorder, but are not directly responsible for symptoms. “Knee OA should not be viewed as a joint cartilage disease alone, but a whole joint disorder affecting several structures of the knee including the menisci,” Dr. Englund said.

Reference

1. Englund M, Guermazi A, Gald D, et al. Incidental meniscal findings on knee MRI in middle-aged and elderly persons. N Engl J Med. 2008;359:1108-1115.