MR-Based In Vivo Analysis of Joint Biomechanics and its Relevance in the Pathogenesis of Osteoarthritis

Alterations of joint biomechanics are known to play a pivotal role in the pathogenesis of osteoarthritis. Open MRI now allows one to assess important biomechanical parameters of diarthrodial joints in vivo during the entire range of joint motion, encompassing all clinically relevant joint positions, and to analyze in particular the influence of muscle activity and neuromuscular control. The current article reviews data of the authors on quantitative, open, functional MR imaging of in vivo joint biomechanics, with focus on the shoulder and knee and gives an overview of the literature on these topics. Further, the article summarizes technical descriptions of the methods used as well as studies on accuracy and reproducibility of the technique. We present normative data on subacromial space width, glenohumeral translation and scapulothoracic motion patterns in the human shoulder joint of young healthy volunteers, and describe their association with gender and body dimensions. Also, alterations of these parameters are reported in different disease entities of the shoulder. We present ongoing work on the functional changes of cartilage contact areas in healthy and pathologic knee joints and we describe how these biomechanical changes are related to alterations of cartilage morphology. Future perspectives of these methods are mentioned in which a combination of open MRI and qMRI of cartilage morphology should give a more detailed insight into the pathogenesis, progression and treatment of osteoarthritis in different joint pathologies.