Foot Alignment in Symptomatic National Basketball Association Players Using Weightbearing Cone Beam Computed Tomography

Bernasconi, Alessio; Roberts, Lauren; Pontin, Pedro Augusto; Lintz, François; Saito, Guilherme Honda; Roney, Andrew; Elliott, Andrew; O’Malley, Martin J.

doi:10.1177/2325967119826081

Cited by 37 publications

(25 citation statements)

References 38 publications

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“…Negative measurements indicate varus alignment (center of the ankle positioned laterally to the bisecting line of the foot tripod), while positive values represent valgus alignment (center of the ankle joint located medially to the bisecting line of the foot tripod). 6,13,29,31,44 For this study, the mean FAO of included patients and 95% confidence intervals (95% CIs) were calculated. Patients with residual varus and valgus malalignment were identified as those with FAO values outside the 95% CI of the patient’s cohort, higher for valgus and lower for varus.…”

Section: Methodsmentioning

confidence: 99%

3D, Weightbearing Topographical Study of Periprosthetic Cysts and Alignment in Total Ankle Replacement

et al. 2019

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Background: We investigated the association between hindfoot residual malalignment assessed on weightbearing computed tomography (WBCT) images and the development of periprosthetic cysts (PPCs) after total ankle replacement (TAR). We hypothesized that PPCs would be found predominantly medially in the varus configuration and laterally in the valgus configuration. Methods: Cases of primary TAR with available WBCT imaging of the ankle were included in this retrospective study. The location of the PPC was marked and the following volumes were calculated: total (TCV), medial (MCV), central (CCV), and lateral (LCV) cyst volumes. Hindfoot alignment was measured as Foot and Ankle Offset (FAO), with 95% confidence intervals (95% CIs) calculated to define varus (<95% CI) and valgus (>95% CI) groups. Cyst volumes were compared between these 2 groups. The American Orthopaedic Foot & Ankle Society (AOFAS) score at the time of the WBCT was also retrieved. Receiver operating characteristic (ROC) curves were used to determine FAO thresholds for predicting an increased risk of PPC. Results: Forty-eight TARs (mean follow-up, 44.6 months) were included, 81% of which had at least 1 PPC. The mean FAO was 0.12% (95% CI, –1.12 to 1.36). Patients with greater residual malalignment ( P < .001) and those with longer follow-up ( P < .001) presented with increased TCV. In varus cases, the MCV was greater than the LCV ( P = .042), with a threshold FAO value of −2.75% or less predicting an increased MCV. In valgus cases, the LCV was greater than the MCV ( P = .049), with a FAO threshold value of 4.5% or more predicting an increased LCV. Conclusion: In this series, the PPC volume after primary TAR significantly correlated with postoperative hindfoot malalignment and longer follow-up. Level of Evidence: Level III, retrospective comparative series.

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Section: Methodsmentioning

confidence: 99%

3D, Weightbearing Topographical Study of Periprosthetic Cysts and Alignment in Total Ankle Replacement

et al. 2019

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“…1,8,10-12,14,15,22 Both measurements, PTS and FAO, were found to be reliably assessed in patients with AAFD. 1,7,8,10,11,14,15,22…”

Section: Discussionmentioning

confidence: 99%

Assessment of Posterior and Middle Facet Subluxation of the Subtalar Joint in Progressive Flatfoot Deformity

Silva

Mansur

et al. 2020

Foot Ankle Int.

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Background: Adult acquired flatfoot deformity (AAFD) is a complex 3-dimensional pathology characterized by peritalar subluxation (PTS) of the hindfoot. For many years, PTS was measured at the posterior facet of the subtalar joint. More recently, subluxation of the middle facet has been proposed as a more accurate and reliable marker of symptomatic AAFD, enabling earlier detection. The objective of this study was to compare the amount of subluxation between the medial and posterior facets in patients with AAFD. Methods: In this institutional review board-approved retrospective comparative study, a total of 76 patients with AAFD (87 feet) who underwent standing weightbearing computed tomography (WBCT) as a standard baseline assessment of their foot deformity were analyzed. Two blinded fellowship-trained orthopedic foot and ankle surgeons with >10 years of experience measured subtalar joint subluxation (as a percentage of joint uncoverage) at the both posterior and middle facets. One of the readers also measured the foot and ankle offset (FAO). PTS measurements were performed at the sagittal midpoint of the articular facets using coronal plane WBCT images. Intra- and interobserver agreement was measured for PTS measurements using the intraclass correlation coefficient (ICC). The intermethod agreement between the posterior and middle facet subluxation was assessed using Spearman’s correlation and bivariate analysis. Paired comparison of the measurements was performed using the Wilcoxon test. A multivariate analysis and a partition prediction model were used to assess influence of PTS measurements on FAO values. P values of <.05 were considered significant. Results: ICCs for intra- and interobserver reliabilities were 0.97 and 0.93, respectively, for posterior and 0.99 and 0.97, respectively, for middle facet subluxation. The intermethod Spearman’s correlation between subluxation of the posterior and middle facets was measured at 0.61. In a bivariate analysis, both measurements were found to be significantly and linearly correlated ( P < .0001; R2 = 0.42). Measurements of middle facet subluxation were found to be significantly higher than those for posterior facet subluxation, with a median difference (using the Hodges-Lehman factor) of 17.7% ( P < .001; 95% CI, 10.9%-23.6%). We also found that for every 1% increase in posterior facet subluxation there was a corresponding 1.6-fold increase in middle facet subluxation. Only middle facet subluxation measurements were found to significantly influence FAO calculations ( P = .003). The partition prediction model demonstrated that a middle facet subluxation value of 43.8% represented an important threshold for increased FAO. Conclusion: This study is the first to compare WBCT measurements of subtalar joint subluxation at the posterior and middle facets as markers of PTS in patients with AAFD. We found a positive linear correlation between the measurements, with subluxation of the middle facet being significantly more pronounced than that of the posterior facet by an average of almost 18%. This suggests that middle facet subluxation may provide an earlier and more pronounced marker of progressive PTS in patients with AAFD. Level of Evidence: Level III, retrospective comparative cohort study.

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“…Because traditional 2D radiographic measurements are heavily subjected to operator and rotational bias, and previous literature has shown that WBCT is more accurate, we believe there is need for a 3D modality that can reliably assess alignment of the foot and ankle in patients with flatfoot deformity. 11,12,31…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Specifically, studies have demonstrated the reliability and reproducibility of using WBCT in the evaluation of AAFD, highlighting its importance as a sensitive modality that can better quantify structural deformity compared to plain radiographs and nonweightbearing (NWB) imaging. 11,12,18,25,31,38 The foot and ankle offset (FAO) is a previously defined and validated WBCT biometric semiautomatic measurement that gauges the relative positioning between the foot tripod and the center of the ankle joint. 10,25,38 Previous studies have demonstrated its use in reliably characterizing hindfoot alignment with excellent correlation with clinical examination findings.…”

Section: Introductionmentioning

confidence: 99%

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Three-Dimensional Biometric Weightbearing CT Evaluation of the Operative Treatment of Adult-Acquired Flatfoot Deformity

et al. 2020

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Background: Assessment of operative correction of adult-acquired flatfoot deformity (AAFD) has been traditionally performed by clinical evaluation and conventional radiographic imaging. Previously, a 3-dimensional biometric weightbearing computed tomography (WBCT) tool, the foot ankle offset (FAO), has been developed and validated in assessing hindfoot alignment. The purpose of this study was to investigate the role of FAO in evaluating operative deformity correction in AAFD. Methods: In this prospective comparative study, 19 adult patients (20 feet) with stage II (flexible) flatfoot deformity underwent preoperative and postoperative standing WBCT examination at mean 19 months (range, 6-24) after surgery. Three-dimensional coordinates of the foot tripod and center of the ankle joint were acquired by 2 independent and blinded observers. These coordinates were used to calculate the FAO using dedicated software, and subsequently compared pre- and postoperatively. The FAO is a previously validated biometric measurement that represents centering of the foot tripod as well as hindfoot alignment, with a normal mean FAO of 2.3% ± 2.9%. In addition, Patient Reported Outcomes Measurement Information System (PROMIS) clinical outcomes scores were compared pre- and postoperatively with a mean follow-up of 22.6 months (range, 14-37). Results: There was significant correction of flatfoot deformity from a mean preoperative FAO of 9.8% to a mean postoperative value of 1.3% ( P < .001). Additionally, there was statistically significant improvement in all PROMIS domains ( P < .05), except depression, at an average follow-up of 22.6 months. Spring ligament reconstruction was the only procedure associated with a significant correction in FAO ( P = .0064). Conclusion: The FAO was a reliable and sensitive tool that was used to evaluate preoperative deformity as well as postoperative correction, with patients demonstrating both significant improvement in FAO as well as patient-reported outcomes. These findings demonstrate the role for biometric 3-dimensional WBCT imaging in assessing operative correction after flatfoot reconstruction, as well as the potential role for operative planning to address preoperative deformity. Level of Evidence: Level II, prospective comparative study.

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Foot Alignment in Symptomatic National Basketball Association Players Using Weightbearing Cone Beam Computed Tomography

Cited by 37 publications

References 38 publications

3D, Weightbearing Topographical Study of Periprosthetic Cysts and Alignment in Total Ankle Replacement

3D, Weightbearing Topographical Study of Periprosthetic Cysts and Alignment in Total Ankle Replacement

Assessment of Posterior and Middle Facet Subluxation of the Subtalar Joint in Progressive Flatfoot Deformity

Three-Dimensional Biometric Weightbearing CT Evaluation of the Operative Treatment of Adult-Acquired Flatfoot Deformity

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