Identification of radiographic foot osteoarthritis: are both dorsoplantar and lateral x-rays necessary?

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

Abstract

Purpose: The La Trobe radiographic atlas of foot osteoarthritis (OA), which was developed in 2009 to standardise the assessment of foot OA, incorporates observations of osteophytes (OP) and joint space narrowing (JSN) from dorsoplantar (DP) and lateral plain film x-rays. In some clinical and research contexts, two radiographic views may not be available, and this has the potential to affect the proportion of foot OA cases identified using this tool. Therefore, the purpose of this study was to compare the sensitivity of alternative case-finding approaches based on restricted x-ray views (DP or lateral only) or features (OP or JSN only). We also examined the intra- and inter-examiner reliability of each approach.

Methods: Participants were from a large population-based prospective cohort study, the Clinical Assessment Study of the Foot (CASF). All adults aged ≥50 years registered with four general practices in North Staffordshire, UK were invited to take part in a postal health survey. Those who reported foot pain in the previous 12 months were invited to attend a research clinic where weightbearing DP and lateral x-rays were taken of both feet. The La Trobe radiographic atlas was used to document the presence of OP and JSN (using scores ranging from 0 to 3) in five joints: the first metatarsophalangeal joint (1st MTPJ), the first cuneometatarsal joint (1st CMJ), the second cuneometatarsal joint (2nd CMJ), the navicular-cuneiform joint (NCJ) and the talo-navicular joint (TNJ). Radiographic OA at each individual joint was defined as a score of 2 or more for OP or JSN on either DP or lateral views. Prevalence of OA in each joint was then documented using both views and features in combination (the case definition recommended in the original atlas), and then by using (i) a single view (DP or lateral only) and (iii) a single feature (OP or JSN only). To determine intra- and inter-examiner reliability of each approach, x-rays from 60 randomly selected participants (120 feet) were rescored 8 weeks later by MM and scored by a second blinded examiner (HBM), and Gwet’s AC1 kappa (κ) statistics were calculated.

Results: Of the CASF clinic cohort (n=560), 27 participants were excluded (24 for inflammatory arthritis and 3 for missing x-rays), leaving a sample of 533 participants (1,066 feet) including 235 men and 298 women with a mean (standard deviation) age of 65 (8) years. The prevalence (n, %) of radiographic OA in each joint as defined by the original atlas was as follows: 1st MTPJ (294, 28%), 1st CMJ (50, 5%), 2nd CMJ (184, 17%), NCJ (86, 8%) and TNJ (158, 15%). Compared to the recommended case definition based on OP and JSN using both views, a DP only view identified between 15 and 77% of OA cases, while a lateral only view identified between 28 and 97% of OA cases (Figure). Compared to the recommended case definition of using both features, using only OP identified between 46 and 94% of OA cases, while using only JSN identified between 19 and 76% of OA cases. Intra- and inter-examiner reliability were similarly high across different combinations of views and features (κ ranging from 0.923 to 1.000 for intra-examiner reliability and 0.705 to 1.000 for inter-examiner reliability).

Conclusions: Applying the La Trobe radiographic atlas but using only one x-ray view (DP or lateral) or one feature (OP or JSN) in isolation misses a substantial number of OA cases, and the sensitivity of these approaches varies considerably between different foot joints. These findings indicate that, where possible, the atlas should be administered according to the original description to avoid underestimation of the prevalence of radiographic foot OA.

Citation

Menz, H., Marshall, M., Thomas, M., Peat, G., & Roddy, E. (2020). Identification of radiographic foot osteoarthritis: are both dorsoplantar and lateral x-rays necessary?. Osteoarthritis and Cartilage, 28(S1), S268-S269. https://doi.org/10.1016/j.joca.2020.02.430

• Journal Article Type: Conference Paper
• Conference Name: 2020 OARSI World Congress on Osteoarthritis; 30 April-3 May 2020
• Conference Location: Messe Wien Exhibition & Congress Center, Vienna, Austria
• Online Publication Date: Apr 20, 2020
• Publication Date: 2020-04
• Deposit Date: Jun 23, 2023
• Journal: Osteoarthritis and Cartilage
• Print ISSN: 1063-4584
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 28
• Issue: S1
• Pages: S268-S269
• DOI: https://doi.org/10.1016/j.joca.2020.02.430
• Keywords: Orthopedics and Sports Medicine; Biomedical Engineering; Rheumatology