Figure. Sagittal MRI of right knee.
A 56-year-old man presents with right knee pain that has been present for the past few months. The patient does not recall any known injury and he feels the pain when he bends or pivots on the knee. On physical examination, the patient has a small effusion and pain to palpation over the posterior medial joint line. Sagittal magnetic resonance imaging (MRI) (Figure) shows a degenerative tear of the posterior medial meniscus with grade 3 arthritis of the medial compartment.
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The prevalence of meniscus tears increases with age, especially in men.1 Englund et al found that men older than 50 years have a 32% prevalence of meniscal tears compared with 19% of women. This prevalence increased among patients aged 70 and above, with a prevalence rate of 56%. Patients older than 70 years are also more likely to present with asymptomatic meniscus tears.1
The prevalence of meniscus tears also increases dramatically in the presence of arthritis. Among patients with moderate to severe arthritis (grade 3 and higher), 95% had meniscus damage.1 The take-home message is that incidental finding of a meniscus tear in patients with knee arthritis is very common. Clinicians should inform patients over 50 years of age of the high likelihood of finding an asymptomatic meniscus tear on MRI.1,2
Surgical treatment with an arthroscopic meniscectomy in the presence of knee arthritis has poor outcomes because arthroscopy can treat the meniscus tear but not underlying arthritis. The degenerative pattern of a meniscus tear in patients over 50 with underlying arthritis should be treated with a focus on arthritis and not with an arthroscopic meniscectomy.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopedics for Physician Assistants.
1. Englund M, Guermazi A, Gale D, et al. Incidental meniscal findings on knee MRI in middle-aged and elderly persons. N Engl J Med. 2008;359(11):1108-1115. doi:10.1056/NEJMoa0800777
2. Buchbinder R, Harris IA, Sprowson A. Management of degenerative meniscal tears and the role of surgery. BMJ. 2015;350:h2212. doi:10.1136/bmj.h2212