Computer Code: P60 Credits: 1¼ To receive credit, relinquish attendance voucher at the end of the session.
PRESIDING Peggy J. Fritzsche, MD, San Bernardino, CA President, Radiological Society of North America
PRESENTATION OF THE GOLD MEDAL OF THE RADIOLOGICAL SOCIETY OF NORTH AMERICA TO:
Stanley Baum, MD Philadelphia, PA
William G. Bradley, Jr, MD, PhD San Diego, CA
David B. Fraser, MD Musquodoboit Harbor, NS
INTRODUCTION OF LECTURER George S. Bisset III, MD, Durham, NC
ANNUAL ORATION Donald L. Resnick, MD, San Diego, CA
INTERNAL DERANGEMENTS OF JOINTS: ANATOMIC-PATHOPHYSIOLOGIC-IMAGING CORRELATION
Understand essential functional anatomy of synovium-lined articulations.
Determine mechanisms of failure of structures within these articulations.
Elucidate the MR imaging findings associated with derangements of each
of the constituents of a synovium-lined joint.
The anatomy of a synovial-type joint is complex, typically consisting of apposed bone surfaces covered by a thin layer of hyaline cartilage and linked together by a fibrous capsule and subjacent vascular connective tissue, the synovial membrane. In certain of these joints, capsular and accessory ligaments or fibrocartilaginous annular lips (ie, labra), or both, provide stability; partial or complete articular discs (ie, menisci) distribute forces; and nearby muscles and tendons are essential for proper articular motion. Dysfunction, or derangement, of such a joint is a common clinical problem, analysis of which often requires application of imaging methods, especially magnetic resonance (MR). Although countless descriptions exist of the MR imaging abnormalities associated with classic internal derangements of synovial joints, details of the anatomic and pathophysiologic principles that govern these abnormalities are less readily available.
Articular surfaces of synovial joints differ in complexity, degrees of rotational freedom, and shape, and these differences account for variations in the normal range of joint motion, the extent of inherent stability, and the likelihood and pattern of subluxation or dislocation. Intrinsic ligaments (as in the glenohumeral joint and hip) exist as focal thickenings of the joint capsule that may be disrupted when one paired bone is displaced with respect to the other. Menisci and labra share many structural features that influence their pattern of failure and the strategies related to medical and surgical treatment for such failure.
Articular cartilage is of variable thickness and extent and is subject to both injury and degeneration. The subchondral bone plate, a thin layer of compact bone beneath the articular cartilage, may also be injured, often as an accompaniment to shearing and compressive forces applied to the end of the bone. Such forces may lead to hemorrhage and edema in the adjacent marrow. In many locations such as the glenohumeral joint, tendinous expansions are intimate with the joint capsule. Modifications in these tendons and corresponding muscles may be produced by injury or advancing age.
A firm understanding of structure and function is essential for proper interpretation of the MR imaging abnormalities that accompany internal derangements of synovial joints. Such understanding will promote a more meaningful interpretation of the clinical significance of the imaging findings and ensure improved communication between the radiologist and the referring physician.