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Background: Flexible cavovarus deformity is prevalent and the Coleman block test is frequently used to assess the first ray plantarflexion malpositioning in the overall deformity as well as the flexibility of the hindfoot. The objective was to assess and compare the weightbearing computed tomography (WBCT) 3-dimensional (3D) changes in clinical and bone alignment in flexible cavovarus deformity patients when performing the Coleman block test when compared to normal standing position and to controls., Methods: Twenty patients (40 feet) with flexible cavovarus deformity and 20 volunteer controls (40 feet) with normal foot alignment underwent WBCT imaging of the foot and ankle. Cavovarus patients were assessed in normal orthostatic and Coleman block test positions. Foot and ankle offset (FAO), hindfoot alignment angle (HAA), talocalcaneal angle (TCA), subtalar vertical angle (SVA) and talonavicular coverage angle (TNCA) and a CT-simulated soft tissue envelope image, WBCT clinical hindfoot alignment angle (WBCT-CHAA), were evaluated by 2 readers. Measurements were compared between cavovarus nonstressed and stressed positions and to controls. P values of .05 or less were considered significant., Results: The intra- and interobserver intraclass correlation coefficient were good or excellent for all WBCT measurements. Cavovarus patients demonstrated significant correction of WBCT-CHAA (9.7 ± 0.4 degrees), FAO (2.6 ± 0.4%), and TNCA (8.8 ± 1.8 degrees) when performing the Coleman block test (all P values <.0001). However, WBCT-CHAA and FAO measurements were still residually deformed and significantly different from controls ( P values of .001 and <.0001, respectively). TNCA values corrected to values similar to healthy controls ( P  = .29). No differences were observed in cavovarus patients during Coleman block test for the coronal measures: HAA, TCA, and SVA measurements., Conclusion: In this study, we observed improvement in the overall 3D WBCT alignment (FAO), axial plane adduction deformity (TNCA), as well as CT simulated clinical hindfoot alignment (WBCT-CHAA) in flexible cavovarus deformity patients when performing a Coleman block test. However, we did not find improvement in measures of coronal alignment of the hindfoot, indicating continued varus positioning of the hindfoot in these patients., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. Disclosure forms for all authors are available online.

Background: The complex deformities in cavovarus feet of Charcot-Marie-Tooth (CMT) disease are difficult to evaluate. The aim of this study was to quantify the initial standing alignment correction achieved after joint-sparing CMT cavovarus reconstruction using pre- and postoperative weightbearing computed tomography (WBCT)., Methods: Twenty-nine CMT cavovarus reconstructions were retrospectively analyzed. Three-dimensional measurements were performed using semiautomated software (Bonelogic 2.1) to investigate changes in sagittal, axial, and coronal parameters. Pre- and postoperative data were compared, along with normative data. Correlation among the preoperative measurements and the amount of correction in sagittal, axial, and coronal parameters were analyzed., Results: The sagittal, axial, and coronal malalignment of the hindfoot, and the sagittal and axial malalignment of the forefoot, was significantly improved after corrective surgery ( P < .05). Sagittal Meary angle (from 14.8 to 0.1 degrees), axial talonavicular angle (TNA, from 3.6 to 19.2 degrees), and coronal hindfoot alignment (from 11.0 to -11.1 degrees) showed significant changes postoperatively ( P < .001). Hindfoot, forefoot sagittal, and forefoot axial parameters reached comparable outcomes compared with normative value ( P > .05). Regarding amount of correction, Spearman correlation demonstrated that axial Meary angle and TNA were most strongly related to improvement in sagittal Meary angle and coronal hindfoot alignment., Conclusion: Preoperative and postoperative WBCT measurements demonstrated that joint sparing CMT cavovarus reconstruction significantly improved sagittal, axial, and coronal deformities of CMT, and sagittal Meary angle was restored toward normative values. Apparent axial plane correction, the majority of which occurred at the talonavicular joint, had the strongest correlation with deformity correction in multiple planes. This suggests that soft tissue releases and correction of the talonavicular joint may be a key component of a cavovarus foot correction., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. Disclosure forms for all authors are available online.

Introduction: The goal of this study was to characterize the abnormal joint surface interaction at the ankle, hindfoot and midfoot joints of the cavovarus foot using distance mapping on weightbearing computed tomography (WBCT) images by comparing a series of cavovarus feet to a series of normally-aligned feet., Methods: In this case-control study, ten feet (10 patients) with asymptomatic cavovarus shape (cases; N = 10) were compared to 10 matched-paired (by age, gender and body mass index) normally-aligned feet (10 patients) (controls; N = 10). Three-dimensional models were produced from the images and distance maps representing joint surface configuration were generated for the ankle, hindfoot and midfoot joints. The distance maps for each joint were then compared between the two groups and between regions in the same group., Results: In the cavovarus group there was a significant increase in surface-to-surface distance at the posterior tibiotalar joint and a reduced distance at the anterior part, together with a greater distance at the posterior half of the medial gutter. Also, a decrease in surface-to-surface distance on the anterior half of the anterior facet and an increased distance on the posterior quadrants of the posterior facet of the subtalar joint were found. At the sinus tarsi, the lateral aspect of the talonavicular joint, the naviculocuneiform and the tarsometatarsal joints there was a statistically significant increase in surface-to-surface distance in cavovarus patients as compared to controls., Conclusion: Distance mapping analysis on WBCT images identified significant differences in surface-to-surface interaction at the foot and ankle joints between cavovarus and normally-aligned feet., Level of Evidence: Level III, case-control study., (Copyright © 2020 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.)