Admassie DanielGizaw Elias2018-10-232023-11-052018-10-232023-11-052017-09http://etd.aau.edu.et/handle/123456789/13077Introduction: The knee joint, the largest joint in the body, has several functions which are essential for human beings to walk, run and jump. Primarily, it enablesflexion-extension of the lower limb in the sagittal plane. Joint stability duringmovement is attained by the shape of the articular surfaces, the collateral andcruciate ligaments, the menisci and tendons and muscles crossing the knee joint.(1) The vulnerability of the knee, the largest joint in the body, to direct traumamakes knee injuries very common throughout life. (2)MRI visualizes most components of the knee joint, including articular cartilage,menisci, intra-articular ligaments, synovium, bone marrow, subchondral cysts, andother periarticular and intra-articular lesions that are not detectable by radiography.(4).The patterns of abnormalities of these different joint components as detected byMRI has been studied in different centers. Such types of studies, to date, have notbeen done in our country to our knowledge. The aim of this paper is to studyfrequency and the patterns of these abnormalities in the knee joint detected by kneeMRI. Objective: To assess the patterns of abnormalities in the knee joint detected by knee MRI. Methods: Hospital based prospective cross sectional study was conducted on 49patients who had knee MRI at Tikur Anbessa Specialized Hospital for a period of 7months from January 1 to August 2016. Patients included here are those who had knee MRI and no history of knee surgery. Results: A total of 49 patients were included in the study out of which 26(53.1%)were male and 23 (46.9%) were female, with a mean age of 43 years (range 17 to68 years). The three most common pathologies were joint effusion seen in32(65.3%), bone marrow edema in 22(45.8%) and osteophytes in 22(44.9%). ACLtear was the commonest ligament abnormality occurring in 5 (10.4%) patients. Ten(20.8%) patients had meniscal tear, all involving the medial meniscus with theposterior horn being involved in 8(80%) of these patients. Conclusion: The mean age of our study population was higher than most referenced papers suggestive of possible delay in health seeking. The commonestknee pathologies were similar to other studies. Features of osteoarthritis were seen in higher frequency in our study population. Even though the higher mean age could be the possible cause, further study is recommended to look into the causes.Bone fracture, tendon abnormality and ligament abnormality showed statistically significant association with trauma. These abnormalities which were seen with higher frequency in those with a history of trauma were also observed in higher frequency in the male population.en-USknee joint,cruciate ligamentsThesis