Is early osteoarthritis associated with differences in joint congruence?

Area of Science:

• Orthopedics
• Rheumatology
• Anatomy

Background:

• Osteoarthritis (OA) is linked to abnormal articular contact stress.
• Joint congruence, influenced by articulating surface shape and orientation, affects peak pressure.
• Anatomical variations, including joint congruence, are hypothesized OA risk factors.

Purpose of the Study:

• To investigate if first carpometacarpal (CMC) joint congruence differs in individuals with early OA or by sex.
• To analyze the relationship between joint congruence, OA onset, and sex.

Main Methods:

• Computed tomography (CT) scans of 59 healthy and 38 early OA first CMC joints.
• Measurement of joint congruence, considering both shape and size.
• Correlation analysis of congruence with OA and sex, before and after size normalization.

Main Results:

• A significant correlation between joint congruence and sex was found, attributed to sex-related size differences.
• This correlation disappeared after normalizing for joint size.
• Joint congruence increased with joint size but did not significantly correlate with early OA onset.

Conclusions:

• Joint congruence differences may not be a primary cause of first CMC joint OA.
• Sex-related differences in CMC joint congruence are likely due to size variations, not OA predisposition.
• Further research may be needed to fully understand OA etiology in the CMC joint.