PATTERNS OF JOINT INVOLVEMENT IN FOOT OSTEOARTHRITIS: FINDINGS FROM THE CLINICAL ASSESSMENT STUDY OF THE FOOT

Rathod, T.; Marshall, M.; Thomas, M. J.; Myers, H.; Menz, H. B.; Thomas, E.; Peat, G.; Roddy, E.

Abstract

Purpose: The aetiology of foot osteoarthritis (OA) is poorly understood. OA most commonly affects the 1st metatarsophalangeal joint (MTPJ), followed by joints in the midfoot; the 2nd cuneo-metatarsal joint (CMJ), talo-navicular joint (TNJ) and navicular-first cuneiform (NCJ) joint. Patterning of OA joint involvement has been investigated at other sites, particularly the hands where a strong symmetrical patterning has been noted followed by clustering of joint groups. However, little is known about the patterning of OA in the joints of the feet. Examining the clustering and patterning of joint involvement, both within a foot and across feet could help identify distinct phenotypes and advance our understanding of the possible causal mechanisms of foot OA.
The aim of this study was to investigate the patterns of radiographic OA in ten joints across both feet among a sample of community-dwelling older adults.
Methods: The Clinical Assessment Study of the Foot is a population-based cohort of adults aged ≥50 years who reported foot pain in the last year. Participants attended a research clinic where weight-bearing dorso-plantar and lateral radiographs of each foot were taken. Using a validated atlas, radiographic foot OA was defined as scoring ≥2 for either osteophytes or joint space narrowing in the 1st MTPJ, 1st and 2nd CMJ, NCJ and TNJ on either view. Chi square tests determined whether radiographic OA affects multiple joints more than expected by chance within a foot and across both feet. Generalised estimating equations were used to examine pairwise associations between affected joints within a foot and to test for overall symmetry across the feet. Latent class analysis was used to investigate subgroups of radiographic foot OA.
Results: 560 participants attended research clinics and after exclusion for inflammatory arthritis (n = 24) and no radiographs (n = 3), 533 were eligible for the analyses (mean age 64.9 years (SD 8.4), 55.9% female). The 1st MTPJ was most frequently affected (287 feet, 27.2%) followed by the 2nd CMJ (184, 17.3%), TNJ (158, 14.8%), NCJ (86, 8.1%) and the 1st CMJ (50, 4.7%). Radiographic OA was found to cluster across both feet (p < 0.001) but not within each foot separately. Radiographic OA was also found to be highly symmetrical in the same joint in both feet even after adjustment for age, sex, total number of affected joints and the affected joint [adjusted odds ratio (OR) 2.96, 95% CI: 2.10, 4.18]. Clustering across both feet and symmetrical patterning was stronger in females than males. Within a foot, the strongest pairwise associations were found between the joints of the midfoot: the 2nd CMJ and NCJ [OR 6.12, 95% CI: 3.68, 10.17], the NCJ and TNJ [2.83, 95% CI: 1.68, 4.79] and the 2nd CMJ and TNJ [1.61, 95% CI: 1.05, 2.49]. Latent class analysis identified three distinct classes of foot OA: class 1 (64%) had low probability of OA in all joints; class 2 (21%) had high probability of bilateral 1st MTPJ OA; and class 3 (15%) had high probabilities of involvement across all ten foot joints in both feet. Increasing the number of classes preserved class 1 and class 2 however class 3 disaggregated. The 4 class solution showed class 3 splitting into two similar sized groups with high probabilities of either bilateral 2nd CMJ OA or bilateral TNJ OA. The 5 class solution then added a small group with high probability of OA in multiple midfoot joints including bilateral 2nd CMJ, NCJ and TNJ.
Conclusions: OA frequently involves multiple joints across both feet, has a strong symmetrical patterning, and subgroups into those with 1st MTPJ OA and those with midfoot OA which may be distinct subtypes of foot OA. These patterns may signify that certain foot joints have a predilection to OA and person-level risk factors. Further work to replicate these findings and to investigate distinctive causal mechanisms is warranted.

Citation

Rathod, T., Marshall, M., Thomas, M. J., Myers, H., Menz, H. B., Thomas, E., …Roddy, E. (2014). PATTERNS OF JOINT INVOLVEMENT IN FOOT OSTEOARTHRITIS: FINDINGS FROM THE CLINICAL ASSESSMENT STUDY OF THE FOOT. Osteoarthritis and Cartilage, 22, S206-S206. https://doi.org/10.1016/j.joca.2014.02.395

• Journal Article Type: Conference Paper
• Conference Name: 2014 World Congress (24-27 April 2014)
• Conference Location: Paris, France
• Online Publication Date: Mar 20, 2014
• Publication Date: 2014-04
• Deposit Date: Sep 6, 2023
• Journal: OSTEOARTHRITIS AND CARTILAGE
• Print ISSN: 1063-4584
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 22
• Pages: S206-S206
• DOI: https://doi.org/10.1016/j.joca.2014.02.395
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S106345841400435X
• Additional Information: https://www.oarsijournal.com/article/S1063-4584(14)00435-X/fulltext#articleInformation