A tear in the meniscus, the crescent-shaped cushion in the knee joint where the thighbone and shinbone of the leg meet that helps the joint carry weight, glide, and turn, is a common knee injury in older persons whether or not they exhibit osteoarthritis symptoms. However, osteoarthritic knees with a meniscal tear are not more painful than those without a tear, and the meniscal tear does not affect the function of the knee in older patients.
These are the results of an investigation conducted by Timothy Bhattacharyya, MD, and colleagues at the Clinical Epidemiology Research and Training Unit, Arthritis Center, and Department of Orthopaedics, Boston University Medical Center; and the Department of Radiology, VA Boston Healthcare system. The study, “The Clinical Importance of Meniscal Tears Demonstrated by Magnetic Resonance Imaging in Osteoarthritis of the Knee,” appears in the January 2003 issue of The Journal of Bone and Joint Surgery (JBJS).
The investigators used magnetic resonance imaging and plain X-ray radiography to examine 154 older patients with clinical symptoms of knee arthritis as well as a control group of 49 elderly persons with no symptoms of arthritis. Meniscal tears were commonly found in the knees of both groups but were more prevalent in the patients with arthritis symptoms (91 percent compared to 76 percent in the control group).
The investigators also found that although 12 of the 49 controls had X-ray evidence of low-grade osteoarthritis, there was more radiographic evidence of osteoarthritis in symptomatic patients than in the controls. For example, a medial meniscal tear was found in 86 percent of the patients with symptomatic osteoarthritis and in 67 percent in the control group. The rate of tears in other areas of the meniscus showed the same pattern with meniscal tears more common in men than in women. In summary, increasing severity of osteoarthritis as shown on radiographs was associated with increasing rate of meniscal tears.
The investigators then used a questionnaire and administered a function test to measure pain, stiffness, and function impairment. The function test scores were the same for patients with and without a meniscal tear, and the investigators found that meniscal tears do not affect function.
Bhattacharyya and his colleagues also evaluated the use of magnetic resonance imaging in diagnosing meniscal tears and concluded that a finding of a meniscal tear using this diagnostic procedure may be difficult to interpret because of the lack of data concerning the prevalence of meniscal tears in patients with arthritis and those without arthritis. In addition, if arthroscopy is recommended for a patient with arthritis, magnetic resonance imaging is not necessary; the arthroscopic procedure will detect a meniscal tear. Furthermore, a recent injury, joint tenderness, and other symptoms can point to the presence of a meniscal tear, and magnetic resonance imaging will not add any additional information nor contribute to a decision to treat a meniscal tear surgically. Thus, the investigators find that their data do not support routine use of magnetic resonance imaging in evaluating and managing meniscal tears in patients with osteoarthritis of the knee.