Knee pain is the most frequent symptom in osteoarthritis, a condition that is the leading cause of chronic disability in the elderly and one of the main sources of morbidity attributable to osteoarthritis in general. The causes of knee pain in individuals with osteoarthritis cannot be easily understood, and the knowledge of such causes is critical for determining future specific interventions. Bone attrition represents remodelling of the subchondral bone envelope in osteoarthritis, leading to a consequential change in bone shape and/or bone loss. However, bone attrition is not a feature that can be easily read, since it is hardly detected in the absence of clear defects of cortical bone integrity and because of overlap of bone structures at radiography. Bone attrition is associated not only with knee pain, but also with stiffness and disability. If attrition occurs prior to advanced osteoarthritis, this would suggest that changes in subchondral bone occur concurrently with cartilage loss and that treatments targeting cartilage loss alone are unlikely to be effective. Association with edemalike bone marrow lesions may be observed and constitute predictive factors for subchondral bone attrition. The present study was aimed at reviewing the literature, demonstrating the relevance of bone attrition and explaining how to diagnose this entity on imaging studies.

Keywords: Magnetic resonance imaging; Osteoarthritis; Knee pain; Bone attrition; Subchondral bone; Diagnosis.

Placental adhesion disorder encompasses the various types of abnormal placentation that occur when the chorionic villi penetrate the uterine wall. Placenta accreta has become more common, mainly because of the increasing rates of cesarean section. Although ultrasound is the first-line imaging modality for evaluation of the placenta, it plays a limited role in cases of posterior placenta accreta and inconclusive findings. In such cases, magnetic resonance imaging (MRI) is indicated, mainly because it is a more accurate means of identifying placental invasion of extrauterine structures in high-risk pregnant women. In this review article, we present the ten major and minor MRI features of placental adhesion disorder, as described in the international literature. In addition, we propose a template for structured reports of MRI examinations of the placenta. We have also devised a guided questionnaire in order to identify risk factors in patients scheduled to undergo such examinations, with the objective of facilitating the multidisciplinary treatment planning needed in order to minimize maternal morbidity and mortality.

Keywords: Placenta accreta; Placenta previa; Magnetic resonance imaging.