Prevalence of Clinically Relevant Findings on Magnetic Resonance Imaging in Middle-Aged Adults With Knee Pain and Suspected Meniscal Tear: A Follow-Up.

Objective: Radiographs are frequently obtained for patients with knee osteoarthritis (KOA), with magnetic resonance imaging (MRI) reserved for those with complex KOA. There are few data on how often subsequent MRI reveals clinically actionable but unanticipated findings. The purpose of this study is to estimate the prevalence of these findings on MRI for patients managed nonoperatively for suspected meniscal tears.

Methods: The Treatment of Meniscal Problems and Osteoarthritis (TeMPO) study enrolled patients aged 45 to 85 years with knee pain, osteoarthritis (Kellgren-Lawrence [KL] grades 0-3), and suspected meniscal tear. We reviewed baseline MRI and recorded notable findings, including subchondral insufficiency fractures of the knee (SIFKs), avascular necrosis (AVN), tumors, and nonsubchondral fractures. Other baseline data included demographic characteristics, Knee Injury and Osteoarthritis Outcome Score, duration of knee symptoms, and KL grade.

Results: Study-ordered MRI was performed on 760 patients, with 61 concerning findings identified (8.03%, 95% confidence interval 6.09%-9.96%). A total of 25 participants had SIFKs, 10 had nonsubchondral fractures, 4 had AVN, 8 had benign tumors, and 14 had other clinically relevant findings.

Conclusion: We estimated the prevalence of clinically relevant incidental findings on MRI to be 8.03% in middle-aged adults with mild to moderate KOA and suspected meniscal tear. These data may prompt clinicians to be more aware of the range of findings that can underlie knee symptoms, some of which could change management but may require different modalities of imaging to detect. Future research is needed to pinpoint factors associated with these concerning findings so that patients who are at risk can be identified and referred for advanced imaging.