Degeneration of the scaphoid-trapezium joint: a useful finding to differentiate calcium pyrophosphate deposition disease from osteoarthritis.

This study aimed to determine whether osteoarthritis of the scaphoid-trapezium joint (ST osteoarthritis) is associated with calcium pyrophosphate deposition disease (CPDD) in an elderly population with or without concomitant polyarthritis of the finger joints (FIPO). An age- and gender matched case-control study was performed at a university hospital outpatient clinic. Cases and controls were identified from a clinical registry. The case ascertainment process included: (1) chart review for evidence of pyrophosphate crystals from arthrocentesis and/or cartilage calcifications and (2) blinded reading of hand X-rays by three observers for calcification of the triangular fibrocartilage and/or cartilage calcification around the spatium triangulare. Osteoarthritis was graded from 0 to 4 according to the Standard Atlas of Radiographs. The association of ST osteoarthritis with the diagnosis was examined using chi2 tests or the Wilcoxon rank sum test as appropriate. From 65 potential cases, 30 fulfilled the inclusion/exclusion criteria whereas from 185 potential controls, 81 fulfilled the inclusion/exclusion criteria. Thirty controls were matched to cases for gender and age. ST osteoarthritis was much more severe in CPDD (median: 3.0) than in patients with FIPO (median: 0.3) and was strongly associated with the diagnosis (odds ratio 13.8; CI 3.4-59.8). Definite ST osteoarthritis identified CPDD with a sensitivity of 83% and a specificity of 73% with regard to FIPO. It was concluded that the presence of ST osteoarthritis is a helpful diagnostic finding for the diagnosis of CPDD in an elderly, predominantly female population with a high prevalence of FIPO. Especially in cases without radiographic cartilage or fibrocartilage calcification of the wrist, ST osteoarthritis may point to the correct diagnosis.