Bone Marrow Edema and Osteonecrosis after Meniscectomy

Bone marrow edema and osteonecrosis are possible consequences following a meniscectomy. Magnetic resonance imaging (MRI) is a specific method to depict these changes at an early stage and in this case, fat-saturated T2 images are the most suitable. For diagnosis it is important to differentiate between bone marrow edema with and without signs of osteonecrosis. Etiological factors currently being discussed include the meniscus rupture itself, changes in the transmission of loads following meniscectomy, additive cartilage damage, thermal damage, the arthroscopic procedure itself, or preexisting spontaneous osteonecrosis of the knee joint (SONK). Osteonecrosis of the postoperative knee joint (ONPK) is an exceedingly rare but serious complication. Whether or not this can be attributed to the surgical procedure remains unclear. Preexisting SONK which is not diagnosed by MRI due to an inadequate time frame (<6 weeks) is the only differential diagnosis. Due to the forensic importance, arthroscopic surgeons should be well acquainted with both clinical pictures in order to have a line of reasoning at hand. © 2011 Springer-Verlag.