Is increased trapezial slope a cause of early trapeziometacarpal osteoarthritis?

Abstract

Objectives: 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.

Material and methods: 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.

Results: 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°).

Conclusion: 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.

Keywords: 1st metacarpal base slope; Carpometacarpal osteoarthritis; Trapezial slope; Trapeziometacarpal osteoarthritis.