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-trapez ium joint (ST osteoarthritis) is associated with calcium pyrophosphate depo sition 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. Cas es and controls were identified from a clinical registry, The case ascertai nment process included: (1) chart review for evidence of pyrophosphate crys tals from arthrocentesis and/or cartilage calcifications and (2) blinded re ading of hand X-rays by three observers for calcification of the triangular fibrocartilage and/or cartilage calcification around the spatium triangula re. Osteoarthritis was graded from 0 to 4 according to the Standard Atlas o f Radiographs. The association of ST osteoarthritis with the diagnosis was examined using chi(2) tests or the Wilcoxon rank sum test as appropriate. F rom 65 potential cases,30 fulfilled the inclusion/exclusion criteria wherea s from 185 potential controls, 81 fulfilled the inclusion/exclusion criteri a. Thirty controls were matched to cases for gender and age. ST osteoarthri tis 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; CT 3.4-59.8). Definite; ST osteoarthritis identified CPDD with a sensiti vity 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 cartilag e or fibrocartilage calcification of the wrist, ST osteoarthritis may point to thr:correct diagnosis.