Abstract
INTRODUCTION. Osteoarthritis (OA) is a complex chronic joint disease involvingdegeneration of articular cartilage, subchondral bone, and adjacent tissues, often affecting
multiple joints in an individual. This study aimed to determine whether OA severity and
spatial wear patterns are concordant across joints with distinct biomechanics and
ossification processes by comparing the temporomandibular joint (TMJ) and the distal
interphalangeal joint (DIPJ). While most OA studies rely on imaging, cadaveric
dissection enables direct assessment of articular surface wear and subchondral changes.
METHODS. Twenty TMJs and DIPJs from ten cadaveric donors were dissected to
determine degeneration severity and the distribution of osteoarthritic wear on the
mandibular condyle, glenoid fossa, head of the middle phalanx, and base of the distal
phalanx. Lesions were graded using a validated disease severity scale, and wear location
was categorized into three zones per surface. Age and sidedness were included as
covariates. Two mixed-effect models were used to evaluate osteoarthritic changes.
SUMMARY. The head of DIPJs demonstrated the highest predicted probability of severe
OA (p < 0.001). Individuals aged 76-85 showed the greatest probability of severe OA
across all joint surfaces (p < 0.001), whereas individuals younger than 75 were more
likely to exhibit mild OA (p < 0.001). Spatially, the central regions of the mandibular
condyle and radial surface of the DIPJ head showed the highest probability of OA
presence, compared to all other observed surfaces. CONCLUSIONS. OA severity and
spatial wear patterns differ between the TMJ and DIPJ, reflecting joint-specific
biomechanics and developmental processes. Cadaveric analysis provides a detailed
characterization of articular degeneration not captured by imaging and may help clarify
mechanisms underlying joint-specific OA progression. This study showed that DIP joints
are more likely to be severely affected by OA, and age is the best predictor of both OA
presence and disease severity. OA changes were not uniformly distributed across the joint
surface but instead followed consistent wear patterns in specific locations on the joint.