Dorso-ventral osteophytes of interphalangeal joints correlate with cartilage damage and synovial inflammation in hand osteoarthritis: a histological/radiographical study.

OBJECTIVE: To detect dorsally located osteophytes (OP) on lateral x-ray views and to correlate their presence with the extent of structural joint damage, determined by histologic grading (cartilage damage and synovial inflammation) and radiographic scoring in hand osteoarthritis (HOA). METHODS: Distal interphalangeal (DIP) and proximal interphalangeal (PIP) joints were obtained from post mortem specimens (n = 40). Multiplanar plain x-rays were taken (dorso/palmar (dp) and lateral views). Radiographic OA was determined by the Kellgren and Lawrence classification. Joint samples were prepared for histological analysis and cartilage damage was graded according to the Mankin scoring system. Inflammatory changes of the synovial membrane were scored using the general synovitis score (GSS). Spearman's correlation was applied to examine the relationship between histological and radiographical changes. Differences between groups were determined by Mann-Whitney test. RESULTS: Bony proliferations that were only detectable on lateral views but reminiscent of OPs on dp images were termed dorso-ventral osteophytes (dvOPs). All joints displaying dvOPs were classified as OA and the presence of dvOPs in DIP and PIP joints correlated with the extent of histological and radiographic joint damage, as well as with patient age. Joint damage in osteoarthritic DIP and PIP joints without any dvOPs was less severe compared to joints with dvOPs. Synovial inflammation was mainly present in joints displaying dvOPs and correlated with joint damage. CONCLUSION: dvOPs are associated with increasing structural alterations in DIP and PIP joints and can be seen as markers of advanced joint damage. Detecting dvOPs can facilitate the diagnosis process and improve damage estimation in HOA.

Interphalangeal Osteoarthritis Radiographic Simplified (iOARS) score: a radiographic method to detect osteoarthritis of the interphalangeal finger joints based on its histopathological alterations.

OBJECTIVE: To develop a radiographic score for assessment of hand osteoarthritis (OA) that is based on histopathological alterations of the distal (DIP) and proximal (PIP) interphalangeal joints. METHODS: DIP and PIP joints were obtained from corpses (n=40). Plain radiographies of these joints were taken. Joint samples were prepared for histological analysis; cartilage damage was graded according to the Mankin scoring system. A 2×2 Fisher's exact test was applied to define those radiographic features most likely to be associated with histological alterations. Receiver operating characteristic curves were analysed to determine radiographic thresholds. Intraclass correlation coefficients (ICC) estimated intra- and inter-reader variability. Spearman's correlation was applied to examine the relationship between our score and histopathological changes. Differences between groups were determined by a Student's t test. RESULTS: The Interphalangeal Osteoarthritis Radiographic Simplified (iOARS) score is presented. The score is based on histopathological changes of DIP and PIP joints and follows a simple dichotomy whether OA is present or not. The iOARS score relies on three equally ranked radiographic features (osteophytes, joint space narrowing and subchondral sclerosis). For both DIP and PIP joints, the presence of one x-ray features reflects interphalangeal OA. Sensitivity and specificity for DIP joints were 92.3% and 90.9%, respectively, and 75% and 100% for PIP joints. All readers were able to reproduce their own readings in DIP and PIP joints after 4 weeks. The overall agreement between the three readers was good; ICCs ranged from 0.945 to 0.586. Additionally, outcomes of the iOARS score in a hand OA cohort revealed a higher prevalence of interphalangeal joint OA compared with the Kellgren and Lawrence score. CONCLUSIONS: The iOARS score is uniquely based on histopathological alterations of the interphalangeal joints in order to reliably determine OA of the DIP and PIP joints radiographically. Its high specificity and sensitivity together with the dichotomous approach renders the iOARS score reliable, fast to perform and easy to apply. This tool may not only be valuable in daily clinical practice but also in clinical and epidemiological trials.

Histopathological correlation supports the use of x-rays in the diagnosis of hand osteoarthritis.

OBJECTIVE: To correlate histopathological and radiographic features of distal and proximal interphalangeal (DIP and PIP) joints in order to test whether the use of an x-ray examination would be beneficial to the classification/diagnosis process of hand osteoarthritis (OA). METHODS: DIP and PIP joints were obtained from post mortem specimens (n=40). Plain x-rays of the DIP and PIP joints were taken and radiographic OA was determined by the Kellgren and Lawrence classification. Individual radiographic features were scored according to the method described by Altman. Joint samples were prepared for histological analysis; cartilage damage was graded according to the Mankin scoring system. Spearman's correlation was applied to examine the relationship between histological and radiographical changes. Differences between groups (bony swelling vs no bony swelling) were determined by Student t test. RESULTS: A highly significant correlation was found between histological (Mankin score) and radiographic (Kellgren/Lawrence score) changes in the investigated DIP (r(s)=0.87, p<0.0001) and PIP (r(s)=0.79, p<0.0001) joints. A subgroup of patients (37.5% for DIP and 18.8% for PIP joints) showed advanced radiographic changes (Kellgren/Lawrence score ≥2) in joints without clinical bony swelling. Histologically, the mean Mankin scores accounted for 11±1.66 for DIP and 9.67±2.4 for PIP joints. CONCLUSION: On the basis of histopathological changes of DIP and PIP joints, this investigation demonstrates the validity of x-ray examinations and supports the use of plain radiography in the diagnosis of hand OA and in the classification of hand OA in clinical trials.