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Purpose: To verify if indirect radiographic signs of first metatarsal pronation, determined by the head round sign, correspond to weight-bearing computed tomography (WBCT) measurements., Methods: In this case-control retrospective study, we analyzed 26 hallux valgus (HV) feet and 20 controls through conventional radiograph (CR) and WBCT images. Two blinded orthopaedic foot and ankle surgeons performed the measurements. Pronation classification (head roundness), head diameter (HD), traditional HV angles, arthritis, sesamoid positioning, and first metatarsal rotation angle (MRA) (alpha angle) were evaluated. Comparisons were performed by Student's T-test and a multivariate regression was executed. P-values less than 0.05 were considered significant., Results: Mean values were higher in HV patients than controls when evaluating MRA (11.51 [9.42-13.60] to 4.23 [1.84-6.62], 95%CI), HD (22.35 [21.52-23.18] to 21.01 [20.07-21.96]), and sesamoid rotation angle (SRA) (26.72 [24.09-29.34] to 4.56 [1.63-7.50]). The MRA had a low influence in head roundness classification (R 2 : 0.15). Changes in the pronation classification were explained chiefly by the sesamoid station (SS) (R 2 : 0.37), where stations 4 to 7 were found to be strong predictors of roundness classifications 2 and 3., Conclusion: Indirect signs of metatarsal pronation, determined by the head round sign, correlate weakly with the alpha angle measured in WBCT. The presence of arthritis and sesamoids displacement might modify the perception of first head roundness. The influence of MRA in the classification was low, where SS from 4 to 7 was strong predictors of a higher pronation classification., (© 2021. SICOT aisbl.)

Background: Malrotation of medial column bones of the foot has been advocated as an important factor in foot conditions such as hallux valgus and progressive collapsing foot deformity. Although stated as a deformity component, variances of normality in the general population are not completely understood. This study intended to describe the rotational profile of all medial column bones using weightbearing computed tomography (WBCT) images in a cohort of patients with different foot and ankle problems., Methods: In this retrospective study, 110 feet of 95 consecutive patients that received a WBCT for assessment of different foot and ankle pathologies were included. Measurements were performed by a blinded fellowship-trained orthopedic foot and ankle surgeon. Rotation of the navicular, medial cuneiform, proximal and distal first metatarsal as well as proximal phalanx of the first toe were recorded. Positive values were considered pronation and negative values were considered supination. Rotational profile of each bone/ segment was assessed by ANOVA and comparison between each segment was performed using Wilcoxon Each-Pair analysis. P-values of less than 0.05 were considered significant., Results: On average, a rotational positioning in pronation (internal rotation) was observed for all medial column bones. The navicular (43.2°, CI 41.1°-45.3°) and the proximal metatarsal (33.9°, CI 31.8°-36.0°) showed the highest mean rotation values. The medial cuneiform presented the lowest mean pronation (6.1°, CI 4.0°-8.3°). Comparison between each bone segment demonstrated statistically significant differences of rotational alignment for the different bones (p<0.0001), with the exception of the distal metatarsal and proximal phalanx, that had similar amounts of pronation. A zig-zag rotational pattern of alignment was observed from proximal to distal, with relative supination/pronation of adjacent medial column bones., Conclusion: The overall rotational profile of medial column bones was found to be in absolute pronation, most pronounced at the navicular and proximal first metatarsal, with significant differences in the amount of pronation when comparing most of the medial column bones. The presented data may be utilized as reference/ baseline values of medial column rotation, supporting future prospective, comparative and controlled studies. Level of Evidence: IV ., Competing Interests: Disclosures: Cesar de Cesar Netto-CurveBeam: Paid consultant; Stock or stock Options, Foot and Ankle International: Editorial or governing board, Nextremity: Paid consultant, Ossio: Paid consultant, Paragon 28: IP royalties; Paid consultant, Weightbearing CT International Study Group: Board or committee member, Zimmer: Paid consultant. Daniel Soares Baumfeld-Arthrex, Inc: Paid presenter or speaker, Merck: Paid presenter or speaker. John E. Femino Arthrex, Inc: Research support, Integra: Paid consultant, OnconRegen: Unpaid consultant. The other authors report no potential conflicts of interest related to this study., (Copyright © The Iowa Orthopaedic Journal 2021.)

Background: The outcomes of first metatarsal (M1) distal osteotomies in hallux valgus (HV) can be improved, especially for intermetatarsal angle (IMA) correction, which is mainly based on lateral displacement of the M1 head (i.e., translation) through the osteotomy. Conversely, there is a spontaneous reduction in the IMA in first metatarsophalangeal joint (MTP1) arthrodesis. But we do not know whether this can be applied to distal osteotomies. We propose a distal osteotomy, called 3D chevron, which combines supination and varization of the M1 head. This might realign soft tissues around the MTP1, potentially leading to a spontaneous reduction in the IMA by an analogous mechanism to MTP1 fusion. Therefore, our study aimed to assess whether spontaneous reductions in IMAs exist in distal M1 osteotomies in the absence of lateral translations of M1 heads. Methods: A prospective continuous series of 25 3D chevrons was performed. Two groups were formed during surgery. Patients requiring no M1 head lateral displacement were included in the "successful correction without translation" group, and patients requiring M1 head lateral displacement were included in the "failed correction without translation" group. Radiographic analysis was performed preoperatively and at 1 year postoperatively. Results: Twenty-two women and three men, with a mean age of 44.8 ± 14.2 years and a mean body mass index of 22.6 ± 4.1 kg/m2, underwent follow-up at one year after surgery. The "successful correction without translation" group was composed of HV with milder deformities (13/25 HVs, median preoperative IMA = 13 (IQR 2)) compared to the "failed correction without translation" group (median IMA = 16 (IQR 2.25) p < 0.001). Spontaneous reductions in IMAs were observed in the "successful correction without translation" group, with a median decrease in the IMA of 6 degrees (CI95%[5.5; 8.0]; p < 0.001) between preoperative and 1-year radiographs. Conclusion: Distal osteotomies allow for spontaneous reduction in the IMA in HV. First metatarsal head translation through an osteotomy should not be considered as the only procedure to correct IMAs in distal osteotomies. [ABSTRACT FROM AUTHOR]

Category: Midfoot/Forefoot; Bunion Introduction/Purpose: First ray or medial column instability has been linked to the development of hallux valgus deformity (HVD), in part due to potential instability of Lisfranc joints and ligamentous complex. However, no study has assessed the 3D weight- bearing (WB) relationship of the Lisfranc complex in patients with confirmed hallux valgus, particularly at the articulating surface of the first tarsometatarsal joint and the second metatarsal and medial cuneiform space, commonly described as the primary region- of-interest of the Lisfranc complex. In this case-control study, we aimed to assesses WB 3D volumetric measurements in the entire Lisfranc joint, as well as in between first and second rays, and to compare HVD patients and controls. We hypothesized that volumes would be increased in HVD patients. Methods: In this IRB-approved, retrospective case-control study, we analyzed weight-bearing Computed Tomography (WBCT) data of 20 consecutive HVD patients and 20 healthy control patients. Using an automated segmentation method (DISIOR Bonelogic 2.0, Paragon28, USA), 3D volumetric models of the bones of the foot were created from WBCT data. Opposing articular spaces in the Lisfranc joint were selected on the STL models of the bones. Interarticular distance mapping was then performed to characterize the joint space width (JSW) in each of the articulations. Interarticular volume was then assessed using an area-weighted volume measurement. Areas of each triangle from the triangulated surface were multiplied by the JSW at each triangle. The sum of individual volumes was then normalized by the total surface area. The final volume was estimated using the product of the normalized summation and average area of both surfaces. Comparisons were performed with independent t-tests. P-Values < 0.05 were considered significant. Results: Estimates of volumetric assessment of the Lisfranc Complex were obtained using the automated method written in MATLAB. These outputs are reported in Table 1. As expected, the first tarsometatarsal joint volumes were the highest for both HVD patients and controls. No significant differences in the volumes were observed when comparing HVD patients and controls for any of the joints or spaces assessed (Figure). Particularly, no differences in the volumetric analysis of the first tarsometatarsal joint, 1-2 intercuneiform space or Lisfranc space (medial cuneiform-second metatarsal) were confirmed. Conclusion: In this retrospective case-control study, we hypothesized that joint volumes of the articulating surfaces and spaces-of- interest within the Lisfranc complex would be higher in HVD patients, consistent with first ray/medial column instability. Our study results demonstrated however no significant volume increases in Lisfranc joints or spaces assessed, particularly with no increases in the volumetric measurements at the first tarsometatarsal joint or between first and second rays. Even though our study could be underpowered to demonstrate potential differences between HVD and controls, our results support that no significant first ray instability in present when volumetric WBCT assessment is used. [ABSTRACT FROM AUTHOR]

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: The first-ray and the medial column play a crucial role in preserving the tripod of the foot. Changes to structural properties of the first-ray, along with collapse of the medial-longitudinal-arch, have been associated with hallux valgus (HV). Thus, restoring the first-ray plays an important role when correcting the mechanical function of the foot tripod in the setting of HV combined with medial-longitudinal-arch collapse. The LapiCotton technique combines the mechanical advantages of Cotton osteotomy and modified Lapidus procedures by maintaining the length of the first-ray and preserving the medial- longitudinal-arch by plantar inclination of the distal part of first-ray. The aim of this study was to evaluate the effectiveness of the LapiCotton procedure in correcting selected radiographic parameters in patients with combined VH with medial-longitudinal arch collapse. Methods: Preoperative and postoperative Weight Bearing CT (WBCT) scans were obtained from HV patients who underwent unilateral LapiCotton procedure. Postoperative scans were obtained roughly three months after the date of surgery. Semi- automatic measurements were applied to 22 WBCT images across a total of 11 patients enrolled into the study using the Disior® Bonelogic® Software. Measurements of the hallux valgus angle (HVA), meary sagittal measurement, and intermetatarsal angles were taken from preoperative and postoperative scans. These scans were then compared using intraclass correlation coefficients and paired t-tests to evaluate the efficacy of the Lapicotton technique in treating HV with P-valus < 0.05 being significant. Results: HVA was found to be significantly larger (p=.026) in the preoperational group (Mdn = 27.52) than the postoperational group (Mdn = 20). In addition, the Meary sagittal measurement was found to be significantly different between groups (p=.033), with a larger value seen in the preoperational group (Mdn = -14.28) compared to the post-operational group (Mdn = -11.15). It was also observed that the IMA was significantly larger (p=.003) in the preoperative group (Mdn = 15.68) compared to the postoperative group (Mdn = 11.26). The sesamoid rotation was found to be higher in the preoperative group (Mdn = -17.71) than the post operative group (Mdn = -24.98), however, these values were not significantly different from one another (p=.203). Conclusion: The LapiCotton procedure proved to be effective in correcting radiographic parameters in patients with HV combined with collapse of the medial longitudinal arch. Reliable correction of HV, along with correction of medial longitudinal arch collapse, was quantified based on semi-automated WBCT measurements of HVA, IMA and Meary angle. LapiCotton produced significantly different measurements for both HVA and IMA postoperatively, providing evidence that the LapiCotton procedure can successfully correct medial longitudinal arch collapse in patients with HV, as well as radiographically reduce the severity of the deformity. [ABSTRACT FROM AUTHOR]

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: Evidence in the literature suggests the negative effects of using High Heels (HH), becoming a challenge for clinicians and researchers since they are welcomed by women worldwide, mainly due to the subjective power of attractiveness given to them. Although some people blame HH as one of the causes of Hallux Valgus (HV), until now, there are no studies in the literature that effectively prove a cause-effect relationship between HH and HV. The objectives of this study are: (1) to analyze whether the increase in heel height can lead to HV and (2) to evaluate whether HV can increase in severity with increasing heels. We hypothesized that an increase in heel height could cause and increase the severity of HV deformity radiographically. Methods: Comparative cross-section4-one feet from twenty-one participants (11 males and 10 females, aged 30.8 ± 8.9 years, and with Body Mass Index 25.5 ± 2.0 m kg2) were recruited. HH shoes were designed for this study with three heights for each participant: 3, 6, and 9 cm. The inclusion criteria were: no regular wearing of heels. The exclusion criteria were: Hallux Valgus diagnosis and/or any orthopedic conditions that affect the Foot and Ankle joints. Hallux Valgus Angle (HVA), Intermetatarsal Angle (IMA), First-Metatarsal Phalangeal Angle, 1st-to-5th Intermetatarsal Angle, First Tarsometatarsal Angle (axial), Second tarsometatarsal angle (axial), Hindfoot Moment Arm (HMA) (mm), Saltzman 45 angle and, Foot Ankle Offset (FAO) were measurement using semiautomated software analysis. Multiple comparisons were performed (Bonferroni's for normal distributions and Wilcoxon test for no normal distributions) when there was a main effect on an outcome (p < 0.05). Results: With the increase in HH, we noticed a progressive increase in HVA (p < 0.001), IMA (p < 0.001), First-Metatarsal Phalangeal Angle (p < 0.001), First Tarsometatarsal Angle (axial) (p < 0.001), and the Second tarsometatarsal angle (axial) (p < 0.001). The Hindfoot Moment Arm (HMA) (mm), Saltzman 45 angle, and Foot Ankle Offset (FAO) had hindfoot varus behavior. When we stratified the groups and compared them, we noticed that an increase of 3 cm in heels slightly increased HVA and IMA (p > 0.05). However, heel increases above 6 cm significantly increased HVA and IMA (p > 0.001). Based on Coughlin's classification, a 3 cm heel increase promoted a mild HV, and increases above 6 cm caused a moderate HV. Conclusion: Based on data from our study with patients without Hallux Valgus through analysis with WBCT versus High Heels, we conclude that increasing heel height can radiographically lead to Hallux Valgus deformity and progressively increase the severity. High heels above 6 cm can lead to radiographically moderate Hallux Valgus. These findings may be an essential step toward a better understanding the effects of increasing high heels on Hallux Valgus pathology. More studies are needed to support this data clinically. [ABSTRACT FROM AUTHOR]

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: Hallux valgus (HV) and progressive collapsing foot deformity (PCFD) are very common foot and ankle conditions in the adult population. Both could potentially disrupt the tripod construct of the foot which leads to chronic pain and arthritis. Several procedures were described to address HV deformity depending on deformity characteristics. PCFD could alter the management plan for HV if they occur simultaneously. The aim of this study was to detect the prevalence of PCFD in HV patients and study the frequency of individual PCFD classes. Methods: In this retrospective IRB approved study, patients > 18 years old who were evaluated for symptomatic hallux valgus and had a weight bearing computed tomography (WBCT) imaging were included. Patients were considered for further analysis if they have a hallux valgus angle (HVA) > 15° or inter-metatarsal angle (IMA) > 9°. All relevant demographic data were extracted. Two fellowship trained foot and ankle orthopaedic surgeon measured the following parameters: foot and ankle offset (FAO%) (Class A), talo-navicular coverage angle (TNCA) (Class B), Meary's angle (Class C) and middle facet subluxation (MFS%) (Class D). Cases that showed FAO% > 4.6% and MFS% > 28.7% were diagnosed as PCFD. The prevalence of PCFD classes (A,B,C and D) was calculated using threshold values for its respective radiographic marker. Descriptive statistics were performed. Results: Thirty-four cases were included. 16 cases were females (46.06%) and 16 (46.06%) were right side. The average age was 52.51 years (SD ± 17.75), the average BMI was 30.14 (SD ± 7.15). The average HVA was 26.82 (SD ± 9.98) and the average IMA was 15.41 (SD ± 3.53). 13 patients (38.24%) had MFS% and FAO% above the threshold values. The average FAO was 4.75% (SD ± 4.92) and the average MFS was 29.17% (SD ± 15.89). Prevalence of Class A (FAO%) was 20 (58.82%), Class B (TNCA) was 12 (35.29%), Class C (Meary's angle) was 15 (44.12%) and Class D (MFS%) was 16 (47.06%). Conclusion: Progressive collapsing foot deformity is prevalent in the hallux valgus population (38.24%). Class C which indicates medial column instability was prevalent in 44.12% of the cases. Given this high prevalence of PCFD, we believe that in addition to the classic hallux valgus parameters, PCFD classes evaluation could favor a surgical approach over another such as first tarsometatarsal joint procedures over isolated distal first metatarsal procedures to correct the HV deformity and simultaneously halt PCFD progression. [ABSTRACT FROM AUTHOR]

Category: Ankle; Trauma Introduction/ Purpose: Previous studies identified a link between increased hindfoot valgus and distal tibiofibular syndesmosis (DTFS) widening in patients with flatfoot deformity using foot-ankle offset (FAO). However, it is not known what the impact of 3D foot alignment is on the DTFS in the presence of a known syndesmotic injury, particularly in varus. Weight-bearing Computed Tomography (WBCT) has emerged as a highly precise tool for diagnosing deformities of the foot and ankle. Under weight-bearing, it is possible to precisely detect deviations in DTFS stability. The objective of this cadaveric study was to determine the relationship between hindfoot alignment, measured by FAO, and DTFS widening in specimens with complete DTFS ligamentous injury. We hypothesized that DTFS widening would be significantly greater in specimens with increased hindfoot valgus. Methods: Two WBCT scans of the foot and ankle were obtained for each of 17 matched pairs (34 legs) of through-knee cadaveric specimens in a radiolucent frame under 80lbs of load to simulate double legged stance, a baseline scan with intact syndesmotic ligaments and a second after surgical ligament sectioning. All syndesmotic ligaments were released through a direct lateral approach to the distal fibula. Models of the bones were created from scans using Disior Bonelogic. Distance mapping was used to evaluate DTFS widening over the entire DTFS interface, as well as the anterior/posterior sections, in the first 1cm, 3cm, and 5cm from the joint after injury. Post-injury distance maps were compared to the contralateral baseline normal scan as a control. FAO was measured post-injury and compared to the difference in DFTS widening between the injured leg and its contralateral, healthy control. Linear regression and Spearman's correlations were used to evaluate relationships. Results: Significant correlations between hindfoot alignment and DTFS widening were identified at every level in the syndesmosis. The Spearman's rho values for the entire DTFS interface at 1cm, 3cm, and 5cm were 0.393 (p = 0.0316), 0.458 (p = 0.0101), and 0.369 (p = 0.0446), respectively. Anterior Spearman's rho values at 1cm and 3cm were 0.453 (p = 0.0119) and 0.420 (p = 0.0209), respectively. Inter-observer variability of the FAO measurements showed no statistical difference (p = 0.4248). Extremely varus FAO measurements (FAO < -10%) showed negligible changes in syndesmotic opening. Linear regression also demonstrates a positive trend. The R2 values for the entire interface at 1cm, 3cm, and 5cm were 0.127, 0.213, and 0.158. Anterior R2 values at 1cm and 1cm were 0.133 and 0.1583. Conclusion: In this cadaveric study, we confirmed our hypothesis showing that valgus FAO was correlated with syndesmosis opening from an uninjured to an injured site. These data are in accord with prior findings relating FAO and DTFS opening in flatfeet and additionally demonstrate a stronger positive trend in the presence of known injury with smaller changes in tibiofibular distances after injury for extreme varus alignments. This study provides important context to the clinically relevant comparison of contralateral feet. The trend in our data allows for predictable results for the degree of injury in patients with valgus foot alignment. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: Kim et al.'s simulated weight-bearing CT (WBCT) investigation classifying first metatarsal (M1) pronation and its relationship to the metatarso-sesamoid complex suggested a high prevalence (87.3%) of M1 hyper-pronation in hallux valgus (HV). These authors' conclusions have prompted a marked increase in M1 derotation (supination) in HV surgical correction. No subsequent study confirms their M1 pronation values, and two recent WBCT investigations suggest lower normative M1 pronation values. The objectives of our WBCT study were to (1) determine M1 pronation distribution in HV, (2) define the hyperpronation prevalence compared to preexisting normative values, and (3) assess the relationship of M1 pronation to the metatarso-sesamoid complex. We hypothesized identifying a high HV M1 head pronation distribution, but not as high as suggested by Kim et al. Methods: We retrospectively identified 88 consecutive feet with HV in our WBCT dataset and measured M1 pronation with two previously validated methods, the Metatarsal Pronation (MPA) and α angles. Similarly, using two previously published methods defining the pathologic pronation threshold, we assessed our cohort's M1 hyper-pronation prevalence, specifically (1) the upper value of the 95% confidence interval (CI95) and (2) adding 2 standard deviations at the mean normative value (2SD).The position of the sesamoids relative to the crista on the axial plane (sesamoid grading) was assessed according to Talbot et al. classification secondarily adapted by Yildirim et al. on CT scan (Figure).Normality of different variables was assessed using the Shapiro-Wilk test and distribution histogram. Two groups were compared using Student's t-test for normal, and Mann-Whitney U test for nonnormal variables. P values less than .05 were considered significant. Results: The mean MPA was 11.4+/-7.4 degrees (IC95%:9.9-13.0; Range: -2.3-37.1) in our HV population and the α angle was 16.2+/-7.4 degrees (IC95%:14.7-17.7; Range: 2.8-43.2). A strong positive correlation was found between these two variables (ρ=0.82;r2=0.79;P<.001). According to the CI95 method, 69/88 HV (78.4%) were hyperpronated using the MPA, and 81/88 HV (92%) using the α angle. According to the 2SD method, 17/88 HV (19.3%) were hyperpronated using the MPA, and 20/88 HV (22.7%) using the α angle. There was a significant difference in M1 head pronation among sesamoid gradings (P=.025). Comparing HV sesamoid grade 3 to HV sesamoid grade 2 did not show any significant difference (P=.6). HV sesamoid grade 2 presented a decrease in MPA compared to HV sesamoid grade 1 (respectively 7.8+/-3.7 degrees for grade 2 and 10.8+/-4.9 degrees for grade 1,P=.026). Comparing HV sesamoid grade 1 to HV sesamoid grade 0 did not show any significant difference (P=.11). Conclusion: M1 head pronation distribution in HV was higher than in normative values, but threshold change demonstrated contradictory hyper-pronation prevalences (85% to 20%), calling into question the previously reported high prevalence of M1 hyper-pronation in HV. An increase in sesamoid subluxation was associated with a paradoxical decrease in M1 head pronation in our study. We suggest that a greater understanding of the impact of HV M1 pronation is warranted before routine axial plane M1 derotation (supination) is recommended for patients with HV. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: The presence of hyperpronation of the first metatarsal (M1) seems to have a clinically significant role in Hallux Valgus (HV). Some authors reported a decrease in recurrence rates after M1 hyperpronation correction in HV. However, when measuring the M1 head pronation relative to the ground, we are assessing and quantifying the aggregate coronal rotational profile of each bone and joint throughout the medial column. Therefore, we do not know the location of this hyperpronation. Moreover, studies showed a strong influence of the hindfoot alignment on coronal rotational measurements and Progressive Collapsing Foot Deformity (PCFD) is a condition frequently associated with HV. Our study aimed to assess and compare coronal plane alignment of medial column bones in HV, PCFD, PCFD HV and controls. Methods: We performed a retrospective IRB approved study. We collected 33 feet who consulted our center with combinations of symptomatic PCFD and HV. We then matched 33 HV, 33 PCFD, and 33 controls for BMI, Gender, and Age to this group. We assessed the coronal plane rotation of the navicular, medial cuneiform, M1 at its base and head, the Sesamoid Rotation Angle (SRA) with respect to the ground, and the hallux valgus angle (HVA) using Weight-Bearing CT images (Figure).The positions of the different joints (first naviculocuneiform (NC1), first tarsometatarsal (TMT1) and metatarsosesamoid rotation angle (MSRA)) were found by subtracting the adjacent angles. Intrinsic torsion of M1 was calculated by subtracting the M1 base angle from the M1 head angle.Normality of different variables was assessed using the Shapiro-Wilk test. Groups were compared using t test or ANOVA for normal and Mann Whitney or Kruskal Wallis for nonnormal variables. Results: HV, PCFD and PCFD HV presented higher M1 intrinsic torsion when compared to controls (respectively 7.3°[CI95%:2.9-11.7], p<0.001; 7.5°[CI95%:2.5-12.6], p<0.001; 7.5°[CI95%: 2.9-12],p<0.001).The navicular was more pronated in PCFD HV compared to controls (respectively 20+/-5.2° vs 12.5+/-3.9°,p<0.001) whereas it was not for PCFD and HV.NC1 was 6.8° significantly more supinated in HV (p<0.001) and 5.7° in PCFD HV (p<0.001) compared to controls whereas there was no significant difference between PCFD HV and Controls.TMT1 was 7.3° significantly more pronated in HV (p<0.001) and 4.9° in PCFD HV (p<0.001) compared to controls whereas there was no significant difference between PCFD HV and Controls. MSRA was significantly higher in HV (p<0.001) and PCFD HV (p<0.001) compared to controls whereas there was no significant difference between PCFD and Controls. In multivariate analysis, MSRA (β=0.95,[0.83;1.07], p <0.0001) were associated with higher values of HVA whereas NC1 (β=-0.24,[-0.42;-0.06], p= 0.0076) were associated with lower values of HVA. Conclusion: The intrinsic increase in M1 pronation appears to be a shared developmental abnormality in PCFD and HV. Combination of PCFD and HV seems to originate from the presence of a paradoxical supinatory malposition of the NC1 which was not present in PCFD without HV in our study. The presence of this compensatory supination malposition might explain the presence of HV by causing a metatarsosesamoid dislocation in HV and PCFD HV. In contrast, hyperpronation compensation in PCFD without HV might be proximal to the navicular because there was no difference between PCFD and control regarding the navicular position in our study. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: Little is known about the intersesamoid crista in Hallux Valgus (HV). However, this structure directly interfaces with the sesamoids and surrounding soft tissues and might play an important role in HV deformity. Our primary objective was to compare the angulation between the crista and first metatarsal (M1) longitudinal axis in HV and controls. Our secondary objective was to assess its correlation with the Distal Metatarsal Articular Angle (DMAA). We hypothesized that the longitudinal axis of the crista will be deviated in valgus in HV and that its position will be correlated with the DMAA. Methods: This IRB approved retrospective case control study evaluated 9 HV and 8 controls matched on age, BMI, and gender. The DMAA was measured as initially described on X-Rays, and then on weight-bearing CT images using a previously validated technique including pronation correction of the M1 called 3d-DMAA. To identify the angle of the inter-sesamoid crista relative to the shaft of the 1st metatarsal, CT scans were semi-automatically segmented to create 3D models of the forefoot. The crista was selected in Geomagic Design X and the resulting STL models were imported into MATLAB for analysis. Principal component analysis was used to identify the direction of both the crista and the 1st metatarsal shaft. The crista-shaft angle is the angle between the directions of greatest variation. Normality was assessed using Shapiro-Wilk tests. Comparisons were made using Student T-tests for normal variables and Mann-Whitney for non-normals. Correlations were assessed using Pearson's coefficients. Results: The crista deviated from the 1st metatarsal shaft in valgus in all the cases (HV and controls). There was a significant increase in valgus deviation of the crista in HV compared to controls (respectively 14.4+/-8.7 degrees and 5.5+/-3.2 degrees; p=0.017). Mean DMAA were respectively 25.1+/-7.9 degrees in HV and 7.4+/-2.9 in controls (p<0.001). Mean 3d-DMAA were respectively 12.5+/-5.6 degrees in HV and 3.1+/-2.4 in controls (p<0.001). There was a low positive non-significant correlation between the crista deviation and the DMAA (ρ=0.44; r2=0.193; p=0.078). There was a moderate positive significant correlation between Crista M1 Angle and 3D-DMAA (ρ=0.57; r2=0.326; p=0.017). Conclusion: The longitudinal axis of the inter-sesamoid crista deviates from the 1st metatarsal shaft in valgus in HV compared to controls. This follows the pattern of the 3d-DMAA which reflect the valgus deviation of the articular surface after exclusion of the pronation which is an important confounding factor of the original DMAA. The inter-sesamoid crista may play a role in HV pathophysiology as a possible lateral destabilizer of the surrounding soft tissues in HV. Surgically correcting the DMAA with a distal osteotomy might also correct the crista position in HV. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: The Distal Metatarsal Articular Angle (DMAA) has long been described as a valgus increase of the distal articular surface of the first metatarsal in Hallux Valgus (HV) deformity. Since then, several studies have reported a poor reliability of this measurement and some authors currently claim that DMAA is misinterpreted as just the rounded shape of the lateral part of the first metatarsal head reflecting pronation of the first ray and could also be biased by the first metatarsal plantarflexion angle. Our study aimed to compare the DMAA in HV and control populations after correcting, with a dedicated software, pronation and plantarflexion of the first metatarsal. We hypothesized that after correction, DMAA will be higher in the HV population, especially in juvenile cases. Methods: We performed a retrospective case-control study including 36 HV and 20 control feet. Patients under 15 or with surgery antecedent were excluded. DMAA1 was measured as initially described on X-rays by the angle between the distal articular surface and the longitudinal axis of the first metatarsal. DMAA2 was measured on Weight Bearing Computed Tomography (WBCT) without any corrections. DMAA3 was measured after correction of the first metatarsal plantarflexion in the sagittal plane. DMAA4 was measured after correction of the pronation of the first ray relative to the ground in the coronal plane using the alpha-angle. And DMAA5 after both corrections. Corrections in the coronal and sagittal planes were performed along the axis of the first metatarsal. Normality was assessed using Shapiro-Wilk tests. Comparisons were made using Student tests for normal variables and Mann-Whitney for non-normals. Correlations between age and angles were assessed by the Pearson correlation coefficient. Results: HV and Control groups were comparable on BMI (p=0.69), Age (p=0.58) and Gender (p=0.27). DMAA1 (25.9°+/-7.3 vs 7.6°+/-4.2; p<0.01), DMAA2 (19.1°+/-7.1 vs 3.3°+/-2.4; p<0.01), DMAA3 (16.1°+/-6.2 vs 2.9°+/-2.4; p<0.01), DMAA4 (14.4°+/-5.7 vs 2.6°+/-2.5; p<0.01) and DMAA5 (11.9°+/-4.9 vs 3.3°+/-2.9; p<0.01) were significantly higher in the HV group than in the Control group. Significant decreases in angles were present between DMAA1 and DMAA2 (Δ=-6.9; CI95[-8.6;-5.1]; p<0.01), DMAA2 and DMAA3 (Δ=-3; CI95[-4.1;-1.9]; p<0.01), DMAA2 and DMAA4 (Δ=-4.7; CI95%[-6.3;-3.1]; p<0.01), DMAA2 and DMAA5 (Δ=-7.2;CI95%[-8.8;-5.6]; p<0.01) and between DMAA3 and DMAA4 (Δ=-1.7;CI95%[-2.9;-0.5]; p<0.01) in the HV group. No significant correlation was found between the 5 different DMAA values and the age in the HV group (respectively Δ=0.1,p=0.55; Δ=0.31,p=0.07; Δ=0.19,p=0.28; Δ=0.1,p=0.56; Δ=0.04,p=0.83). Conclusion: Although overestimated with the 2-dimensional DMAA assessment, the valgus increase of the distal articular surface of the first metatarsal was present in the HV deformity, even after correction of pronation and plantarflexion of the first ray. DMAA overestimation was close to 14 degrees on X-rays and 7 degrees on WBCT without any correction and pronation of the first metatarsal seemed to play a more important role on this overestimation than plantarflexion. Age did not seem to influence this deformity. Increase of valgus of the distal articular surface of the first metatarsal should be considered in HV correction surgical planning. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: Subjective radiographic findings are commonly used in Hallux Valgus (HV) to dictate deformity aspects and surgical treatment. Head roundness, distal metatarsal metaphyseal angle (DMMA) and sesamoid positioning are being employed as predictors of ray pronation, intrinsic deformities, and soft tissue imbalance despite the lack of these observations' reliability. Estimation of first metatarsal rotation based on different head shapes has been proposed, including classifications for its severity. The objective of this study was to demonstrate if first metatarsal rotation measured by the alpha angle in weight-bearing computerized tomography (WBCT) images correlates with its head shape. We hypothesized that alpha angle values would not reliably reflect an indirect classification for rotation, and other variables would contribute to miscalculation. Methods: In this IRB-approved, case-control retrospective study, we analyzed 26 hallux valgus feet (19 patients) and 20 control feet (16 patients) through conventional radiographs (XR) and WBCT images. Two blinded fellowship-trained orthopedic foot and ankle surgeon performed the measurements. Head format, roundness classifications (0, 1, 2 or 3), head plantar surface diameter, hallux valgus angle (HVA), intermetatarsal angle (IMA), DDMA, sesamoid station, sesamoid rotation, sesamoid arthritis, and metatarsal rotation (alpha angle) were evaluated. Interclass Correlations Coefficients (ICC) were performed for interrater reliability. Normative data were analyzed by ANOVA and comparison among groups and methods by Student's T-test. A multivariate regression analysis was executed to evaluate which of the measurements influenced the rotation classification and a partition prediction model constructed to find how the variables contributed to the grading system. Statistical significancy was considered for p-values of less than 0.05. Results: All ICCs were found above 0.80 within both XR and WBCT readings. HV patients and controls were analogous regarding age and body mass index. Similarity was also found in WBCT and XR for traditional HV angles, considering both groups. Mean values were higher in HV patients than controls when evaluating alpha angle (11.51 [9.42-13.60] to 4.23 [1.84-6.62], 95%CI), head diameter (22.35 [21.52-23.18] to 21.01 [20.07-21.96]) and sesamoid rotation angle (26.72 [24.09-29.34] to 4.56 [1.63-7.50]). HVA and IMA were poorly correlated to alpha angles (values below 0.11). WBCT assessment downgraded the head roundness classification in comparison to XR. Changes in this classification were explained chiefly by the sesamoid station in the axial plane (R2: 0.37), where stations 4 to 7 were found to be strong predictors of roundness classification 2 and 3. The alpha angle had a low influence in head roundness classification (R2: 0.15). Conclusion: Metatarsal rotation cannot be reliably predicted through head roundness. Glenosesamoid arthritis and sesamoid subluxation alter the first metatarsal head format and diameter, blurring roundness evaluation. Sesamoid stations from 4 to 7 were strong predictors of higher roundness classifications. Measurements using different readers and methods (XR and WBCT) were reliable. First ray rotation (alpha angle) values did not influence head roundness classification strongly nor were correlated to HV severity. [ABSTRACT FROM AUTHOR]