Search Results
Examining the Validity of Selected Measures of Foot Type
A Preliminary Study
The rationale that subtalar joint position, reflected by calcaneal alignment, determines foot morphology was used to formulate an approach to examination of the validity of three measures of “foot type”: the Staheli Arch Index, the Chippaux-Smirak Index, and navicular height. Each measure was calculated in five positions, progressively inverting from a reference position of maximal comfortable eversion. Pearson product moment correlations (Staheli Arch Index: r = 0.5; Chippaux-Smirak Index: r = 0.6; and navicular height: r = 0.8) indicated that each measure progressively increased with inversion. The change in calcaneal position required to produce significant changes in each measure was investigated using analysis of variance with Scheffé post hoc analysis. This analysis revealed that changes of 15° and 20° were required to produce significant differences in Chippaux-Smirak Index and Staheli Arch Index scores, respectively, threatening their validity. Navicular height was sensitive to smaller changes of 10° and thus displays greater sensitivity to changes in calcaneal position than the footprint parameters tested. (J Am Podiatr Med Assoc 94(3): 275–281, 2004)
The purpose of this study was to determine the reliability and validity of two center-of-pressure quantification methods. One hundred five individuals (33 men and 72 women) with a mean age of 26.7 years participated in phase 1 of the study. Two measures of the center-of-pressure pattern, the lateral-medial area index and the lateral-medial force index, were calculated from plantar pressure data collected on all subjects. Between-trial reliability of the two measurements was assessed using intraclass correlation coefficients. In phase 2, frontal plane motion of the rearfoot was recorded in 30 individuals. Pearson correlation coefficients were then calculated between the two center-of-pressure indices and the magnitude of rearfoot eversion obtained from each subject during walking. Intraclass correlation coefficient values ranged from 0.374 to 0.889 for the lateral-medial area index and from 0.215 to 0.905 for the lateral-medial force index. Pearson correlation coefficients between the two center-of-pressure indices and the rearfoot kinematic variables ranged from 0.050 to 0.165. The lateral-medial area index and the lateral-medial force index may have adequate between-trial reliability but are not related to the magnitude of frontal plane rearfoot eversion during the stance phase of walking. (J Am Podiatr Med Assoc 93(2): 142-149, 2003)
The purposes of this study were to develop an instrument to assess the validity of randomized controlled trials and to report on the differences in the validity of randomized controlled trials between two podiatric medical journals and a mainstream medical journal. The study demonstrated that after adequate training, there can be agreement among reviewers evaluating the quality of published randomized controlled trials using an established instrument and guidelines. The results of the study indicate that randomized controlled trials published in podiatric medical journals are less credible than those published in a mainstream medical journal. (J Am Podiatr Med Assoc 93(5): 392-398, 2003)
Background
Several sophisticated methods of footprint analysis currently exist. However, it is sometimes useful to apply standard measurement methods of recognized evidence with an easy and quick application. We sought to assess the reliability and validity of a new method of footprint assessment in a healthy population using Photoshop CS5 software (Adobe Systems Inc, San Jose, California).
Methods
Forty-two footprints, corresponding to 21 healthy individuals (11 men with a mean ± SD age of 20.45 ± 2.16 years and 10 women with a mean ± SD age of 20.00 ± 1.70 years) were analyzed. Footprints were recorded in static bipedal standing position using optical podography and digital photography. Three trials for each participant were performed. The Hernández-Corvo, Chippaux-Smirak, and Staheli indices and the Clarke angle were calculated by manual method and by computerized method using Photoshop CS5 software. Test-retest was used to determine reliability. Validity was obtained by intraclass correlation coefficient (ICC).
Results
The reliability test for all of the indices showed high values (ICC, 0.98–0.99). Moreover, the validity test clearly showed no difference between techniques (ICC, 0.99–1).
Conclusions
The reliability and validity of a method to measure, assess, and record the podometric indices using Photoshop CS5 software has been demonstrated. This provides a quick and accurate tool useful for the digital recording of morphostatic foot study parameters and their control.
Background: This literature review was undertaken to evaluate the reliability and validity of the orthopedic, neurologic, and vascular examination of the foot and ankle.
Methods: We searched PubMed—the US National Library of Medicine’s database of biomedical citations—and abstracts for relevant publications from 1966 to 2006. We also searched the bibliographies of the retrieved articles. We identified 35 articles to review. For discussion purposes, we used reliability interpretation guidelines proposed by others. For the κ statistic that calculates reliability for dichotomous (eg, yes or no) measures, reliability was defined as moderate (0.4–0.6), substantial (0.6–0.8), and outstanding (> 0.8). For the intraclass correlation coefficient that calculates reliability for continuous (eg, degrees of motion) measures, reliability was defined as good (> 0.75), moderate (0.5–0.75), and poor (< 0.5).
Results: Intraclass correlations, based on the various examinations performed, varied widely. The range was from 0.08 to 0.98, depending on the examination performed. Concurrent and predictive validity ranged from poor to good.
Conclusions: Although hundreds of articles exist describing various methods of lower-extremity assessment, few rigorously assess the measurement properties. This information can be used both by the discerning clinician in the art of clinical examination and by the scientist in the measurement properties of reproducibility and validity. (J Am Podiatr Med Assoc 98(3): 197–206, 2008)
Background:
Abnormal foot posture and deformities are identified as important features in rheumatoid arthritis. There is still no consensus regarding the optimum technique(s) for quantifying these features; hence, a foot digitizer might be used as an objective measurement tool. We sought to assess the validity and reliability of the INFOOT digitizer.
Methods:
To investigate the validity of the INFOOT digitizer compared with clinical measurements, we calculated Pearson correlation coefficients. To investigate the reliability of the INFOOT digitizer, we calculated intraclass correlation coefficients, SEMs, smallest detectable differences, and smallest detectable difference percentages.
Results:
Most of the 38 parameters showed good intraclass correlation coefficients, with values greater than 0.9 for 30 parameters and greater than 0.8 for seven parameters. The left heel bone angle expressed a moderate correlation, with a value of 0.609. The SEM values varied between 0.31 and 3.51 mm for the length and width measures, between 0.74 and 5.58 mm for the height data, between 0.75 and 5.9 mm for the circumferences, and between 0.78° and 2.98° for the angles. The smallest detectable difference values ranged from 0.86 to 16.36 mm for length, width, height, and circumference measures and from 2.17° to 8.26° for the angle measures. For the validity of the INFOOT three-dimensional foot digitizer, Pearson correlation coefficients varied between 0.750 and 0.997.
Conclusions:
In this rheumatoid arthritis population, good validity was demonstrated compared with clinical measurements, and most of the obtained parameters proved to be reliable. (J Am Podiatr Med Assoc 101(3): 198–207, 2011)
Background:
Monitoring footprints during walking can lead to better identification of foot structure and abnormalities. Current techniques for footprint measurements are either static or dynamic, with low resolution. This work presents an approach to monitor the plantar contact area when walking using high-speed videography.
Methods:
Footprint images were collected by asking the participants to walk across a custom-built acrylic walkway with a high-resolution digital camera placed directly underneath the walkway. This study proposes an automated footprint identification algorithm (Automatic Identification Algorithm) to measure the footprint throughout the stance phase of walking. This algorithm used coloration of the plantar tissue that was in contact with the acrylic walkway to distinguish the plantar contact area from other regions of the foot that were not in contact.
Results:
The intraclass correlation coefficient (ICC) demonstrated strong agreement between the proposed automated approach and the gold standard manual method (ICC = 0.939). Strong agreement between the two methods also was found for each phase of stance (ICC > 0.78).
Conclusions:
The proposed automated footprint detection technique identified the plantar contact area during walking with strong agreement with a manual gold standard method. This is the first study to demonstrate the concurrent validity of an automated identification algorithm to measure the plantar contact area during walking.
Background: People with Down syndrome present skeletal abnormalities in their feet that can be analyzed by commonly used gold standard indices (the Hernández-Corvo index, the Chippaux-Smirak index, the Staheli arch index, and the Clarke angle) based on footprint measurements. The use of Photoshop CS5 software (Adobe Systems Software Ireland Ltd, Dublin, Ireland) to measure footprints has been validated in the general population. The present study aimed to assess the reliability and validity of this footprint assessment technique in the population with Down syndrome.
Methods: Using optical podography and photography, 44 footprints from 22 patients with Down syndrome (11 men [mean ± SD age, 23.82 ± 3.12 years] and 11 women [mean ± SD age, 24.82 ± 6.81 years]) were recorded in a static bipedal standing position. A blinded observer performed the measurements using a validated manual method three times during the 4-month study, with 2 months between measurements. Test-retest was used to check the reliability of the Photoshop CS5 software measurements. Validity and reliability were obtained by intraclass correlation coefficient (ICC).
Results: The reliability test for all of the indices showed very good values for the Photoshop CS5 method (ICC, 0.982–0.995). Validity testing also found no differences between the techniques (ICC, 0.988–0.999).
Conclusions: The Photoshop CS5 software method is reliable and valid for the study of footprints in young people with Down syndrome.
Background: Foot dimension information is important both for footwear design and clinical applications. In recent years, non-contact three-dimensional foot digitizers/scanners became popular as they are non-invasive and are both valid and reliable for the most of measures. Some of them also offer automated calculations of basic foot dimensions. The study aimed to determine test-retest reliability, objectivity, and concurrent validity of the Tiger full foot 3D scanner as well as the relationship between the manual measures of the medial longitudinal arch of the foot and its alternative parameters obtained automatically by the scanner. Methods: Intraclass correlation coefficients and the values of minimal detectable change were used to assess the reliability and objectivity of the scanner. Concurrent validity and the relationship between the arch height measures were determined by the Pearson's correlation coefficient and the limits of agreement between the scanner and the calliper method. Results: Both the relative and absolute agreement between the repeated measurements obtained by the scanner show excellent reliability and objectivity of linear measures and only good to nearly good test-retest reliability and objectivity of the arch height. Correlations between the values obtained by the scanner and the calliper were generally higher in linear measures (rp{greater than or equal to}0.929). The representativeness of state of bony architecture by the soft tissue margin of the medial foot arch demonstrate the lowest correlations among the all measurements (rp{less than or equal to}0.526). Conclusions: The Tiger full foot 3D scanner offers both excellent reliability and objectivity in linear measures, which correspond to those obtained by the calliper method. However, values obtained by the both methods shouldn't be used interchangeably. The arch height measure is less accurate, which could limit its use in some clinical applications. Orthotists and related professions probably appreciate scanner more than other specialists.
Background: Clinical diagnosis of pediatric flexible flatfoot is still a challenging issue for health-care professionals. Clarke’s angle (CA) is frequently used clinically for assessing foot posture; however, there is still debate about its validity and diagnostic accuracy in evaluation of static foot posture especially in the pediatric population, with some previous studies supporting and others refuting its validity. The present study aimed to investigate the validity and diagnostic accuracy of the CA using radiographic findings as a criterion standard measure to determine flexible flatfoot between ages 6 and 18 years.
Methods: A cross-sectional study of 612 participants (1224 feet) with flexible flatfoot aged 6 to 18 years (mean ± SD age, 12.36 ± 3.39 years) was recruited. The clinical measure results were compared with the criterion standard radiographic measures and displayed on the receiver operating characteristic curve, and the area under the curve was computed. Intrarater reliability, sensitivity, specificity, predictive values, and likelihood ratios were calculated for the CA. A Fagan nomogram was used to detect post-test probability.
Results: The CA demonstrated higher intrarater reliability (intraclass correlation coefficient = 0.997), sensitivity (98.4%), specificity (98.8), positive predictive value (97.3), negative predictive value (99.3), positive likelihood ratio (84), and negative likelihood ratio (0.02). The area under the curve was 0.98. The positive likelihood ratio yielded a post-test probability of 97%, and the negative likelihood ratio yielded a post-test probability of 0.02.
Conclusions: The CA is a valid measure with high diagnostic accuracy in the diagnosis of flexible flatfoot between ages 6 and 18 years.
