Thumb carpometacarpal joint osteoarthritis is one of the most common forms of osteoarthritis in the hand. The underlying causes are multifactorial. We investigated whether increased trapezial slope could be a causal factor.
We measured trapezial slope and 1st metacarpal slope in 37 patients with early thumb carpometacarpal joint osteoarthritis and compared results with 41 patients without osteoarthritis, using computer-supported 3D-analysis based on CT scans.
There was a significant intergroup difference in trapezial slope (111° in patients with osteoarthritis, and 107° in patients without) and in 1st metacarpal slope (17° versus 14°).
Steeper trapezial slope seemed to be a risk factor for thumb carpometacarpal joint osteoarthritis. Therefore, correction of trapezial slope by trapezium osteotomy could be a valuable surgical approach in early thumb carpometacarpal joint osteoarthritis.