Clinical recognition of symptomatic midfoot osteoarthritis: findings from the clinical assessment study of the foot

Purpose: Osteoarthritis (OA) is a common yet poorly understood cause of disabling foot pain. In the absence of radiographic confirmation of OA, clinical diagnosis in primary care is inhibited by lack of evidence informing clinical examination. This study aimed to determine whether the presence of symptomatic midfoot OA (SMOA) can be clinically identified in older adults with midfoot pain presenting to primary care.Methods: A diagnostic model using brief clinical assessments was developed using cross-sectional data from 274 adults aged ≥50 years who had self-reported midfoot pain in the last month and attended a research assessment clinic between 2010-2011. All clinical assessment data were collected by trained physiotherapy or podiatry assessors adhering to a standardised, quality-controlled protocol. Presence of radiographic midfoot OA in at least one of four scored joints (1st and 2nd cuneo-metatarsal joint, navicular-first cuneiform joint, and talo-navicular joint) was ascertained by a single reader using a validated atlas and scoring system, and who was blinded to the clinical assessment data. Radiographic OA was defined as a score of ≥2 for osteophytes or joint space narrowing on either weight-bearing dorso-plantar or lateral views. SMOA was defined as co-occuring radiographic OA and midfoot pain. One foot per participant was entered into the analysis. The selection of predictor variables was based on known associations with OA or mechanically-driven putative links to SMOA. Significant predictor variables (p<0.25 from likelihood ratio tests) from univariable analyses were simultaneously entered into a multivariable logistic regression model and backward elimination (p=0.05) was performed. The Hosmer-Lemeshow statistic assessed the calibration of the refitted model and the area under the curve (AUC) evaluated discrimination. Histograms visually summarised discrimination. Internal validation of the model was performed using 1000 bias-corrected bootstrap samples with replacement.Results: 274 participants without inflammatory disease comprised 125 men and 149 women (mean age 65 yrs, SD 9). Of these 155 had midfoot pain and 119 had SMOA. 16 univariable analyses identified 9 significant predictors and no collinearity was observed. In addition to force-entered variables (age, gender, body mass index (BMI)), only two independent predictors of SMOA were retained in the multivariable analysis: (i) reduced ankle dorsiflexion with the knee flexed and (ii) absence of a midfoot exostosis. Based on the strength of univariable association, the Foot Posture Index, subtalar inversion and ankle dorsiflexion with the knee extended appeared too weak to contribute to the final model, whereas the removal of the Arch Index and foot length-corrected navicular height was due to the stronger influence of age explaining these relationships. The final fitted model was well calibrated (p=0.79) but discrimination was poor (AUC, 0.69; 95%CI: 0.62, 0.75). Bootstrapping revealed a small degree of overfitting. The use of categorical predictor variables in continuous form did not identify any other predictors, nor did it improve model performance.Conclusions: Brief clinical assessments offer only marginal improvement to age, gender and BMI for identifying SMOA. Milder severity in a population sample, random and systematic error in the clinical assessment, and variable expression of SMOA disease manifestation may have contributed to poor diagnostic accuracy. A clinically defined SMOA phenotype based on modifiable joint loading characteristics may offer an alternative approach to facilitating the development of more targeted biomechanical interventions

Foot pain and inflammatory markers: a cross sectional study in older adults

Background: Foot disorders may limit independence and reduce quality of life for older adults. Obesity is a risk factor for foot conditions; both mechanical load and metabolic effects may contribute to these conditions. This study determined cross-sectional associations between inflammatory markers and foot disorders. Methods: Participants were drawn from the Framingham Foot Study (2002–2008). C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α) were each examined for associations with foot pain, forefoot pain, hindfoot pain, hallux valgus, hallux rigidus, and toe deformities (claw, hammer, or overlapping toes). Unadjusted and adjusted (age, body mass index, physical activity, smoking status) sex-specific logistic regression was performed. Results: Of 909 participants, 54% were women (mean age 65 ± 9 years), 20% had foot pain, 29% had hallux valgus, 3% had hallux rigidus, and 27% had toe deformities. In unadjusted models, higher CRP (OR [95% CI] = 1.5 [1.1, 2.0]) and IL-6 (OR [95% CI] = 1.8 [1.2, 2.6]) were associated with foot pain among men; higher CRP was associated with foot pain (OR [95% CI] = 1.3 [1.0, 1.5]) among women. Higher CRP (OR [95% CI] = 1.9 [1.1, 3.2]) and IL-6 (OR [95% CI] = 2.4 [1.2, 4.7]) were associated with forefoot pain in men. Higher CRP was associated with hindfoot pain ([95% CI] = 1.8 [1.2, 2.6]) in women. After adjustment, CRP ([95% CI] = 1.5 [1.1, 2.0]) and IL-6 ([95% CI] = 1.8 [1.2, 2.6]) remained associated with foot pain in men, and IL-6 with forefoot pain ([95% CI] = 2.9 [1.4, 6.1]) in men. No associations with structural foot disorders were observed. Conclusions: Inflammation may impact foot pain. Future work assessing whether inflammation is part of the mechanism linking obesity to foot pain may identify areas for intervention and prevention

HAPPi Kneecaps! Protocol for a participant- and assessor-blinded, randomised, parallel group feasibility trial of foot orthoses for adolescents with patellofemoral pain

BACKGROUND: Patellofemoral pain (PFP) is a common cause of knee pain in adolescents, but there are limited evidence-based treatment options for this population. Foot orthoses can improve pain and function in adults with PFP, and may be effective for adolescents. The primary aim of th

Reliability of the GAITRite® walkway system for the quantification of temporo-spatial parameters of gait in young and older people

The purpose of this study was to evaluate the test-retest reliability of an instrumented walkway system (the GAITRite® mat) for the measurement of temporal and spatial parameters of gait in young and older people. Thirty young subjects (12 males, 18 females) aged between 22 and 40 years (mean 28.5, S.D. 4.8) and 31 older subjects (13 males, 18 females) aged between 76 and 87 years (mean 80.8, S.D. 3.1) walked at a self-selected comfortable walking speed across the pressure-sensor mat three times and repeated the process approximately 2 weeks later. Intra-class correlation coefficients (ICC), coefficients of variation (CV) and 95% limits of agreement were then determined. For both groups of subjects, the reliability of walking speed, cadence and step length was excellent (ICCs between 0.82 and 0.92 and CVs between 1.4 and 3.5%). Base of support and toe in/out angles, although exhibiting high ICCs, were associated with higher CVs (8.3-17.7% in young subjects and 14.3-33.0% in older subjects). It is concluded that the GAITRite® mat exhibits excellent reliability for most temporo-spatial gait parameters in both young and older subjects, however, base of support and toe in/out angles need to viewed with some caution, particularly in older people

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

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