We conducted a prospective study of patients with recent-onset rheumatoid arthritis to determine the importance of carpal height ratio (CHR) or ulnar translation ratio (UTR) in predicting radiographic progression of rheumatoid arthritis in the wrist, especially with regard to stable or progressive wrist arthritis.
We evaluated 106 wrists with early rheumatoid arthritis. Radiologic misalignment was assessed by measuring CHR and UTR. The modified Schulthess classification of rheumatoid wrist involvement was used to classify the subtypes of wrist joint destruction radiographically types I, II, III, and IV, defined as ankylosing, osteoarthritis, disintegrating, and normal, respectively. We evaluated the wrist joints as stable or progressive by measuring the values of CHR and UTR indices. We also examined whether the modified Schulthess classification of rheumatoid wrist involvement subtypes are associated with radiographic progression over 10 years using the baseline CHR and UTR indices.
The mean CHR values of types I and III were 0.42 (95% confidence interval [CI], 0.40-0.43) and 0.37 (95% CI, 0.34-0.39), respectively. The mean UTR values of types I and III were 0.348 (95% CI, 0.336-0.360) and 0.351 (95% CI, 0.339-0.367), respectively. These values indicated that degradation was faster in types I and III than in other types. We then found type I and III wrists to have progressive arthritis, and type II and IV wrists stable arthritis. We also found that the baseline CHR index was a significant (p < .05) predictor of radiographic progression.
Our results indicated that type I and III wrists had radiographic progression and ultimately underwent deformation. This analysis also showed that the baseline CHR index was even more useful in predicting radiographic progression after 10 years.