Regional specificity in degenerative changes in finger joints: an anatomical study using cadavers of the elderly.

Rehabilitation therapists and orthopedists regard degenerative changes (DCs) of the articular cartilage or osteoarthritis in the finger joint as the major factors that interfere with normal grasp and pinch. However, previous research has concentrated on DCs in the carpometacarpal joint (CM) of the thumb. The present study revealed some general tendencies concerning the occurrence of DCs: (1) distal joint dominance between joints in a thumb or finger; (2) distal surface dominance in a joint; (3) radioulnar dominance in a joint; and (4) fifth-finger specificity (i.e., high incidences of both DCs and osteophytes). Moreover, according to our evaluation of multiple and solitary occurrences (i.e., how many segments carried DCs) we consider that DCs in the radioulnar segments advance not only to the complementary surface (i.e., mirror-image lesion formation) but also to other adjacent segments in the early stage before progression to cartilage defects occurs in the primarily affected segment. In addition, osteophytes were not associated with the cartilage defect in the adjacent segment, but, rather, occurred at opposite or distant segments in the joint. These results are discussed in relation to lateral pinch and precision grasping, with special reference to the hypothetical stress on these movements in the finger joint.