In the present study, soft x-ray and light microscopic examinations were carried out on 17 interphalangeal (IP) joints and 85 distal interphalangeal (DIP) joints with Heberden's nodes from 15 cadavers.
Microradiograms of the IP and DIP joints were analyzed as to the degenerative changes in the antero-posterior and lateral views according to our own criteria. Degenerative changes were more severe in females than in males.
Advanced degeneration was found in the index, middle and little fingers, while the thumb and ring fingers had less degeneration. In the hands with evident Heberden's nodes, all fingers showed extensive degenerative changes. This fact indicates that such individuals have a hereditary tendency to advance to finger joint degeneration.
Light microscopic observations were made on sectioned samples from articular cartilage, subchondral bone, synovium and tendon insertion. Degenerative changes in the articular cartilage from finger joints included irregular orientation of the tidemark (69%), cell cluster formation (66%), fissure formation (59%), splitting of the cartilage from the subchondral bone (48%), defect of the whole cartilage layer (28%) and fibrocartilage repair (17%).
In the subchondral bone, there was hypertrophy of bone trabeculae (82%), osteophyte formation (51%) and bone cyst formation (10%). Synovial membranes had villi formation with lining-cell proliferation, but no inflammatory cell infiltration was found in the subsynovial layer. Bony spur formation was sometimes found in the tendon insertion to the distal phalanx.
Microradiographic and histological observations of IP and DIP joints with Heberden's node disclosed degenerative changes similar to osteoarthritic alterations described in other reports.