Weightbearing Computed Tomography (WBCT) Analysis of Subtalar Joint Dynamics in Hindfoot Valgus Malalignment

Background/Objectives: Hindfoot valgus malalignment, characterized by the lateral deviation of the calcaneus and medial tilting of the talus, disrupts hindfoot biomechanics and increases strain on subtalar joint. This study evaluates weightbearing and non-weightbearing imaging modalities to identify dynamic alignment changes and their diagnostic implications. This study aims to (1) quantify changes in subtalar joint parameters between non-weightbearing computed tomography (NWBCT) and weightbearing computed tomography (WBCT) in patients with hindfoot valgus; (2) evaluate correlations between WBCT and standard radiographic parameters; and (3) identify radiographic predictors of subtalar joint status during weightbearing. Methods: We reviewed 70 patients with confirmed hindfoot valgus malalignment (hindfoot valgus angle >5°), identified through radiographic measurements. Of these, 32 underwent both NWBCT and WBCT, while 38 underwent WBCT alone. Hindfoot alignment angle (HAA) and hindfoot alignment ratio (HAR) were measured on hindfoot alignment radiographs, while heel valgus angle (HVA), talocalcaneal distance (TCD), subtalar joint subluxation (SL) and calcaneofibular distance (CF) were assessed on CT. Results: WBCT revealed significant increases in HVA and SL (both, p < 0.001) and decreases in TCD and CF (p < 0.001 and p = 0.002, respectively) compared to NWBCT, reflecting dynamic subtalar joint changes under weightbearing conditions. Receiver operating characteristic (ROC) analysis identified hindfoot alignment angle (HAA) as the most reliable predictor of talocalcaneal osseous contact, with a cutoff value of >9.25° based on Youden's index, yielding a sensitivity of 73% and specificity of 81.8%. Inter- and intra-observer reliabilities for all parameters were excellent (ICC > 0.81). Conclusions: WBCT provides critical insights into subtalar joint dynamics under physiological loads, surpassing NWBCT in assessing weightbearing-induced alignment changes. Although standard radiographic parameters, particularly HAA, can serve as reliable, cost-effective predictors of subtalar joint pathology in resource-limited settings, WBCT should still be preferred when available, especially in patients with significant malalignment or when detailed dynamic evaluation is needed to guide clinical decision-making.

Different Positions of Weightbearing CT Images Can Influence the Hindfoot Alignment Evaluation Using 2-Dimensional Methodology

BACKGROUND

Three-dimensional weightbearing CT (WBCT) has been widely used to assess foot and ankle alignment. However, most current measurement methods are based on 2-dimensional concepts-distance, long axis, angulation, etc-and are sensitive to changes in orientation of the WBCT images. This study demonstrated how changes in positioning of the image can significantly influence the evaluation of hindfoot alignment.

METHODS

WBCT scans of 10 feet without deformities were used. In the horizontal view, the long axis of the foot image was aligned to a neutral position and then rotated 5, 10, 15, and 20 degrees both internally and externally to simulate malposition. The Calcaneal Moment Arm (CMA) was measured by 2 investigators independently in the above positions. An intraclass correlation coefficient (ICC) model was used to assess the intra- and interobserver reliabilities. The correlation between the CMA and the rotation angle of the foot images was analyzed using linear regression.

RESULTS

The CMA measurements demonstrated that internal rotation of the image changed the neutral hindfoot into valgus, whereas external rotation led to varus. A 1-degree internal or external rotation of the image correlated with 0.48 (±0.03) mm increase or decrease in the modified WBCT-CMA value (P < .0001, R2 = 0.6406).

CONCLUSION

This study demonstrated that although 3D WBCT provides the ability to observe the foot from different perspectives, current alignment evaluation tools are limited to 2 dimensions. Therefore, positioning the WBCT images in a consistent orientation is important to generate correct data.

Miodynamic and Radiographic Evaluation in Recreative Athletes with Patellofemoral Pain

Background and Objectives: Patellofemoral pain (PFP) is frequent in the young and active population. The effect of muscle strength in the lower extremities after aerobic activity in patients with this condition has yet to be detailed. Our objective was to determine if patients with PFP show alterations in lower extremity muscle strength measurements after performing a session of ten minutes of aerobic activity on a treadmill compared to people without patellofemoral pain. Materials and Methods: We conducted a prospective experimental study with a stratified, non-randomized, and non-blinded population sample with group matching, including an experimental group with PFP and a control group with no pain. Subjects completed self-reported functional questionnaires (IKDC, Kujala, KOOS, SF-12), underwent radiographic studies, and were evaluated by measuring the strength of hip and knee muscles and the Single-Leg Triple-Hop (SLTH) test before and after ten minutes of exercise on a treadmill. Results: Seventeen subjects diagnosed with PFP and seventeen control subjects were evaluated. Both groups were homogeneous and had no significant differences in the demographic variables. A wider sulcus angle at 30° (136.8 ± 3.8° vs. 132.5 ± 5.6°, p = 0.0140), a decrease strength post-exercise in the hip abductor (37.9 ± 7.1 N⋅m vs. 45.6 ± 7.7 N⋅m, p < 0.05) and knee extensor (36.0 ± 9.1 N⋅m vs. 47.7 ± 14.0 N⋅m, p < 0.05), and a shorter distance in the SLTH test (337.9 ± 74.9 cm vs. 438.6 ± 65.8 cm, p < 0.01) was recorded in subjects with patellofemoral pain. Conclusions: Subjects with PFP had an overall lower strength of hip and knee muscles, showing significant differences in the hip abductors and knee extensors between people with PFP and healthy matched controls after aerobic exercise.

Mechanical Ankle Joint Axis Point on a Hip-to-Calcaneus Long Leg View Correlates Significantly With SPECT/CT Activation in Symptomatic Asymmetric Ankle Osteoarthritis

BACKGROUND

Asymmetric joint load is the main cause of development of ankle osteoarthritis (OA). Realignment surgery aims to transfer ankle joint load from the degenerative area toward the uninvolved area. Determination of the optimal shift is still challenging. When the degenerative area is correlated to the ankle joint mechanical axis establishing an optimal target angle for corrective surgery may become more feasible. The primary aim of our study was to investigate if the area of ankle joint activation on single-photon emission computed tomography and conventional computed tomography (SPECT/CT) imaging correlates with the mechanical ankle joint axis point (MAJAP).

METHODS

In this cross-sectional study, patients 18 years or older with symptomatic asymmetric ankle OA and a hip-to-calcaneus long leg view with SPECT/CT of the affected ankle were eligible for inclusion. Primary outcome was MAJAP divided into 3 alignment categories (medial shift, neutral, lateral shift). SPECT/CT activation was determined in 8 different areas of the ankle joint. A Spearman rho correlation coefficient was calculated to investigate the relationship between the alignment categories and SPECT/CT activation in the 8 areas.

RESULTS

Forty-nine patients (mean age 58.8 [SD 10.0] years) with 52 ankles with moderate to severe asymmetric OA were included. A significantly (Spearman rho -0.379 [P = .006] and Spearman rho -0.279 [P = .045]) higher proportion of ankles with radioisotope uptake in the anteromedial ankle joint areas (zones 1 and 5) was seen in the medial shift category. A significantly (Spearman rho .312 (P = .025)) higher proportion of ankles with radioisotope uptake in the anterolateral ankle joint area (zone 8) was seen in the lateral shift category.

CONCLUSION

We found in this patient group that the area of SPECT/CT uptake in asymmetric ankle OA was associated to MAJAP measured on hip-to-calcaneus weightbearing views, although the strength of the correlation is weak to moderate. Consequently, nonweightbearing metabolic SPECT/CT radiotracer uptake has the potential to help determine the area to unload in ankle joint-preserving alignment surgery.

Cone-Beam Weight-Bearing Computed Tomography of Ankle Arthritis and Total Ankle Arthroplasty

Weight-bearing computed tomography has multiple advantages in evaluating the hindfoot and ankle. It can assess hindfoot and ankle alignment, pathology in ankle arthritis, and complications related to total ankle replacements. It is an essential tool in ankle osteoarthritis diagnostic, preoperative planning, and total ankle replacement outcomes. It allows for better accuracy and reproducibility of alignment and implant size. In addition, it has the potential to more assertively detect complications related to weight bearing.

Coxa pedis: can calcaneal pronation angle be considered a predictive sign of medial plantar arch overload?

PURPOSE

To assess whether a correlation between the calcaneal pronation angle and the presence of internal plantar arch overload signs (such as upper-medial spring ligament lesion, posterior tibial tendon tenosynovitis, etc.) could lead to a better understanding of coxa pedis pathology.

MATERIAL AND METHODS

One hundred ankle MRIs of consecutive patients were retrospectively reviewed measuring the calcaneal pronation angle and either the presence or absence of internal plantar arch overload signs. Next, the association of overload signs with increasing pronation angle was evaluated to establish a cut-off point beyond which coxa pedis pathology could be defined.

RESULTS

The tibial-calcaneal angle values in patients with and without effusion proved to be significantly different (p < 0.0001). The tibial-calcaneal angle values in patients with and without oedema also demonstrated a significant difference (p < 0.0056). Regarding posterior tibial tendon, a significant difference was found between the two groups (p < 0.0001). For plantar fascia enthesopathy, the result was borderline significant (p < 0.054). A linear correlation was found between the value of pronation angle and the extent of spring ligament injury (p < 0.0001). In contrast, no correlation with age was found.

CONCLUSION

In conclusion, the literature associates medial longitudinal plantar arch overload with posterior tibial tendinopathy and spring ligament complex injuries. Our data show that both injuries are highly correlated with increased calcaneal pronation angle, which could be considered a predictive sign of internal plantar arch overload, prior to the development of the associated signs.

Assessment of Changes in Hindfoot Alignment of Total Ankle Arthroplasty for Ankle Osteoarthritis on Weightbearing Subtalar X-ray View

Background

Recovering normal hindfoot alignment and correcting deformity of the ankle joint following total ankle arthroplasty (TAA) in osteoarthritis (OA) is essential for improving clinical outcomes and increasing long-term survival. We aim to evaluate hindfoot alignment following standard TAA compared to TAA with a total talar prosthesis ("combined TAA") in varus-type OA patients.

Methods

This retrospective study was conducted between 2010 and 2022. We included 27 patients (30 feet) who underwent standard TAA and 19 patients (22 feet) who underwent combined TAA. Hindfoot alignment at the subtalar joint was measured by weightbearing subtalar radiographic view before and after surgery.

Results

In the standard TAA, the angle between the tibial shaft axis and the articular surface of the talar dome joint (TTS) changed from 75 to 87 degrees (P < .01), the angle between the tibial axis and the surface on the middle facet (TMC) from 89 to 94 degrees (P < .01), and the angle between the tibial axis and the surface on the posterior facet (TPC) from 80 to 84 degrees (P < .01). The angle between the articular surface of the talar dome and the posterior facet of the calcaneus (SIA) decreased from 4.7 to -2.5 degrees (P < .01). In the combined TAA, TTS angle changed from 77 to 88 degrees (P < .01), TMC angle from 93 to 101 degrees (P < .01), TPC angle from 84 to 90 degrees (P < .05), and SIA from 6.6 to 2.1 degrees (P < .01). Varus deviation to the subtalar joint (TMC, TPC) significantly improved postoperatively in both groups. However, TPC was smaller than TTS and SIA was negative in standard TAA, and TPC was larger than TTS and SIA was positive in combined TAA.

Conclusion

The amount of correction of the subtalar joint differed depending on the ligament dissection of the subtalar joint and shape of the talar component.

Level of Evidence

Level III, retrospective cohort study.

Cone-Beam Weight-Bearing Computed Tomography of Ankle Arthritis and Total Ankle Arthroplasty

Weight-bearing computed tomography has multiple advantages in evaluating the hindfoot and ankle. It can assess hindfoot and ankle alignment, pathology in ankle arthritis, and complications related to total ankle replacements. It is an essential tool in ankle osteoarthritis diagnostic, preoperative planning, and total ankle replacement outcomes. It allows for better accuracy and reproducibility of alignment and implant size. In addition, it has the potential to more assertively detect complications related to weight bearing.

Modified hindfoot alignment radiological evaluation and application in the assessment of flatfoot

BACKGROUND

Alignment is indispensable for the foot and ankle function, especially in the hindfoot alignment. In the preoperative planning of patients with varus or valgus deformity, the precise measurement of the hindfoot alignment is important. A new method of photographing and measuring hindfoot alignment based on X-ray was proposed in this study, and it was applied in the assessment of flatfoot.

METHODS

This study included 28 patients (40 feet) with flatfeet and 20 volunteers (40 feet) from January to December 2018. The hindfoot alignment shooting stand independently designed by our department was used to take hindfoot alignment X-rays at 10 degree, 15 degree, 20 degree, 25 degree, and 30 degree. We measured the modified tibio-hindfoot angle (THA) at the standard hindfoot aligment position (shooting at 20 degree) and evaluated consistency with the van Dijk method and the modified van Dijk method. In addition, we observed the visibility of the tibiotalar joint space from all imaging data at five projection angles and evaluated the consistency of the modified THA method at different projection angles. The angle of hindfoot valgus of flatfoot patients was measured using the modified THA method.

RESULTS

The mean THA in the standard hindfoot aligment view in normal people was significantly different among the three evaluation methods (P < .001). The results from the modified THA method were significantly larger than those from the Van Dijk method (P < .001) and modified Van Dijk method (P < .001). There was no significant difference between the results of the modified THA method and the weightbearing CT (P = .605), and the intra- and intergroup consistency were the highest in the modified THA group. The tibiotalar space in the normal group was visible in all cases at 10 degree, 15 degree, and 20 degree; visible in some cases at 25 degree; and not visible in all cases at 30 degree. In the flatfoot group, the tibiotalar space was visible in all cases at 10 degree, visible in some cases at 15 degree and 20 degree, and not visible in all cases at 25 degree and 30 degree. In the normal group, the modified THA was 4.84 ± 1.81 degree at 10 degree, 4.96 ± 1.77 degree at 15 degree, and 4.94 ± 2.04 degree at 20 degree. No significant differences were found among the three groups (P = .616). In the flatfoot group, the modified THA of 18 feet, which was visible at 10 degree, 15 degree and 20 degree, was 13.58 ± 3.57 degree at 10 degree, 13.62 ± 3.83 degree at 15 degree and 13.38 ± 4.06 degree at 20 degree. There were no significant differences among the three groups (P = .425).

CONCLUSIONS

The modified THA evaluation method is simple to use and has high inter- and intragroup consistency. It can be used to evaluate hindfoot alignment. For patients with flatfeet, the 10 degree position view and modified THA measurement can be used to evaluate hindfoot valgus.

Republication of "How Accurate Is Clinical Evaluation in Hindfoot Coronal Alignment?"

Background

Hindfoot coronal alignment is an important factor in the assessment of patients with many different foot and ankle complaints. A number of clinical and radiographic techniques have been described to measure hindfoot coronal alignment, but none of them are widely accepted. The purpose of the present study was to assess the correlation between clinical and radiographic hindfoot alignment measures and to evaluate the reproducibility of each.

Methods

We evaluated 85 patients with foot and/or ankle symptoms. Hindfoot clinical alignment was measured from photographs. Each patient was placed at a distance of 1 m from the observer, with both feet placed parallel. Four photographs were taken, at a height of 40 cm: a posterior view of both lower limbs including knees, a posterior view focalized on the studied hindfoot, an anterior view of the foot, and the last view of the medial aspect of the foot. Radiographic alignment was quantified on long axial view radiographs. Patients were lying over the film cassette with a focus distance of 1 m and the beam pointed to the ankle joint. The inclination angle of the beam was 45 degrees to the floor. Measurements were independently made by 2 observers, who were asked to classify pictures into 3 categories: varus, neutral, and valgus. Radiographic measurements were made using the angle measurement tool on the radiograph viewer. The intraclass correlation coefficients (ICCs) and the 95% confidence interval (CI) of the ICC were used to quantify the inter- and intraobserver reliability for clinical assessment. Radiographic parameters were correlated by calculating the Pearson correlation coefficient (r).

Results

The intraobserver ICC for clinical analysis was good for both observers, while the interobserver ICC was moderate for both measurements. Regarding radiographic assessment, there was significant intra- and interobserver reliability. The correlation between both methods was weak for both observers.

Conclusions

We found only weak intra- and interobserver correlations between the clinical and radiographic assessment of hindfoot coronal alignment. It is therefore necessary to complement the clinical evaluation of hindfoot alignment with an objective measurement method such as a long axial view radiograph. Further studies comparing different measurement methods need to be performed to establish the most objective evaluation.

Level of Evidence

Level III, diagnostic study.

Instabilität des oberen Sprunggelenks

Die symptomatische Bandinstabilität des oberen Sprunggelenks (OSG) ist eine häufige Pathologie und bedarf bei gescheiterter konservativer Therapie oft einer operativen Stabilisierung. Neben Anamnese und subjektiver Wahrnehmung des Patienten liefern klinische Untersuchung, funktionelle Diagnostik, Bildgebung und je nach Bedarf die Arthroskopie des Sprunggelenks wichtige Informationen. Meistens benötigt es eine Kombination mehrerer Untersuchungsmethoden, um die Diagnose einer behandlungsbedürftigen OSG-Instabilität zu stellen. Neben der Beurteilung der Stabilität ist ebenfalls die Feststellung von Zusatzpathologien wichtig. Dies beinhaltet auch das Erkennen einer pathologischen Rückfußachse, was essenziell für die weitere Behandlung sein kann. Die operative Therapie kann mittels Arthroskopie oder offener Operation mit weitgehend erfreulichen klinischen Resultaten durchgeführt werden.

Is there an optimal degree of correction for ankle varus deformity after supramalleolar osteotomy? A systematic review

BACKGROUND

There is no consensus on the angle targeted for in varus ankle deformity after supramalleolar osteotomy (SMOT). The aim of this study was to investigate which obtained correction has the best clinical outcome after valgus SMOT.

METHODS

A systematic review according PRISMA guidelines was conducted with studies being eligible for inclusion when published in English, German or Dutch, patients older than 18 years at study entrance, primary or posttraumatic varus ankle osteoarthritis, using any valgus SMOT technique, describing radiological alignment and clinical outcome at baseline and after at least 12 months follow-up. Risk of bias was assessed using the McMaster University Occupational Therapy Evidence-Based Practice Research Group quality assessment tool. The electronical databases PubMed, EMBASE and Cinahl were used as data sources. Included cohorts were categorized according to the mean obtained medial distal tibia angle (MDTA; ranged between 87° and 100°). A linear mixed effect model was used for individual patient data to assess the association between the MDTA and the (difference in) clinical outcome.

RESULTS

Thirty studies including 33 patient cohorts with 922 ankles were identified. At a mean follow-up of 4 years no differences in clinical outcome between correction categories were found. Individual data of 34 ankles showed no relationship between obtained MDTA and clinical outcome either.

CONCLUSION

This review could not demonstrate an optimal degree of correction after valgus SMOT. Results were hampered by biased low quality studies and the widespread use of unreliable 2D alignment measures such as the MDTA.

Measuring standing hindfoot alignment: reliability of different approaches in conventional x-ray and cone-beam CT

INTRODUCTION

Currently there is no consensus how hindfoot alignment (HA) should be assessed in CBCT scans. The aim of this study is to investigate how the reliability is affected by the anatomical structures chosen for the measurement.

MATERIALS AND METHODS

Datasets consisting of a Saltzman View (SV) and a CBCT of the same foot were acquired prospectively and independently assessed by five raters regarding HA. In SVs the HA was estimated as follows: transversal shift between tibial shaft axis and heel contact point (1); angle between tibial shaft axis and a tangent at the medial (2) or lateral (3) calcaneal wall. In CBCT the HA was estimated as follows: transversal shift between the centre of the talus and the heel contact point (4); angle between a perpendicular line and a tangent at the medial (5) or lateral (6) calcaneal wall; angle between the distal tibial surface and a tangent at the medial calcaneal wall (7). Intraclass correlation coefficients (ICC) were calculated to assess inter-rater reliability. A linear regression was performed to compare the different measurement regarding their correlation.

RESULTS

32 patients were included in the study. The ICCs for the measurements 1-7 were as follows: (1) 0.924 [95% CI 0.876-0.959] (2) 0.533 [95% CI 0.377-0.692], (3) 0.553 [95% CI 0.399-0.708], (4) 0.930 [95% CI 0.866-0.962], (5) 0.00 [95% CI - 0.111 to 0.096], (6) 0.00 [95% CI - 0.103 to 0.111], (7) 0.152 [95% CI 0.027-0.330]. A linear regression between measurement 1 and 4 showed a correlation of 0.272 (p = 0.036).

CONCLUSIONS

It could be shown that reliability of measuring HA depends on the investigated anatomical structure. Placing a tangent along the calcaneus (2, 3, 5, 6, 7) was shown to be unreliable, whereas determining the weight-bearing heel point (1, 4) appeared to be a reliable approach. The correlation of the measurement workflows is significant (p = 0.036), but too weak (0.272) to be used clinically.

An update on imaging of tarsal tunnel syndrome

Tarsal tunnel syndrome (TTS) is an entrapment neuropathy of the tibial nerve (TN) within the tarsal tunnel (TT) at the level of the tibio-talar and/or talo-calcaneal joints. Making a diagnosis of TTS can be challenging, especially when symptoms overlap with other conditions and electrophysiological studies lack specificity. Imaging, in particular MRI, can help identify causative factors in individuals with suspected TTS and help aid surgical management. In this article, we review the anatomy of the TT, the diagnosis of TTS, aetiological factors implicated in TTS and imaging findings, with an emphasis on MRI.

3D measurement techniques for the hindfoot alignment angle from weight-bearing CT in a clinical population

Cone-beam CT (CBCT) scans now enable accurate measurements on foot skeletal structures with the advantage of observing these in 3D and in weight-bearing. Among the most common skeletal deformities, the varus/valgus of the hindfoot is the most complex to be represented, and a number of measure proposals have been published. This study aims to analyze and to compare these measurements from CBCT scans in a real clinical population with large such deformity. Ten patients with severe acquired adult flatfoot and indication for surgery underwent CBCT scans (Carestream, USA) while standing on that leg, before and after surgical correction. Corresponding 3D shape of each bone of the distal shank and hindfoot were defined (Materialise, Belgium). Six different techniques from the literature were used to calculate the varus/valgus deformity, i.e. the inclination of the hindfoot in the frontal plane of the shank. Standard clinical measurements by goniometers were taken for comparison. According to these techniques, and starting from a careful 3D reconstruction of the relevant foot skeletal structures, a large spectrum of measurements was found to represent the same hindfoot alignment angle. Most of them were very different from the traditional clinical measures. The assessment of the pre-operative valgus deformity and of the corresponding post-operative correction varied considerably. CBCT finally allows 3D assessment of foot deformities in weight-bearing. Measurements from the different available techniques do not compare well, as they are based on very different approaches. It is recommended to be aware of the anatomical and functional concepts behind these techniques before clinical and surgical conclusions.

Evaluation of hindfoot and knee alignment by the hip-to-calcaneus view in patients with knee osteoarthritis and healthy individuals

BACKGROUND

Hip-to-calcaneus (HC) view is a whole-leg standing view that can visualize the hindfoot in detail. The aim of this study was to investigate the reliability and validity of tibiocalcaneal angle in HC view (H-TCA) by comparing it with that in long axial view (L-TCA). We also verified whether periarticular knee alignment parameters, measured conventionally in whole-leg standing radiography, could be measured in HC view.

METHOD

Sixty healthy volunteers and 61 patients with medial knee osteoarthritis were included. H-TCA was measured by two examiners in the healthy group, and intra-class correlation coefficients (ICCs) were evaluated. H-TCA and L-TCA were then measured in the healthy and osteoarthritis groups and correlated. Finally, we measured hip-knee-ankle angle, mechanical axis deviation ratio, mechanical lateral distal femoral angle, medial proximal tibial angle, and joint-line convergence angle in HC view and conventional whole-leg standing radiography to evaluate statistical differences and correlations.

RESULTS

The intra-observer and inter-observer ICCs were 0.86 and 0.76, respectively. Correlation coefficients (r) between H-TCA and L-TCA were r = 0.87 in healthy group and r = 0.81 in osteoarthritis group, indicating a strong positive correlation in both groups. There was no significant difference in periarticular knee alignment parameters between HC view and conventional whole-leg radiography.

CONCLUSIONS

Hindfoot evaluation in HC view showed high intra-observer and inter-observer reliabilities and strong positive correlation with TCA in long axial view. By using HC view before knee surgery, such as total knee arthroplasty, other necessary alignments can be evaluated simultaneously.

Coronal plane Calcaneal-Talar Orientation in Varus Ankle Osteoarthritis

BACKGROUND

We do not yet fully understand how the subtalar joint position is related to the varus osteoarthritic ankle joint. The purposes of this study were (1) to investigate the coronal orientation of the calcaneus relative to the talus according to the ankle osteoarthritis stage, talar tilt (TT), and (2) to determine if there is TT threshold at which apparent subtalar compensation begins to fade.

METHODS

We retrospectively reviewed 132 ankles that underwent weightbearing computed tomography (WBCT) for varus ankle osteoarthritis. The TT, subtalar inclination angle (SIA), and calcaneal inclination angle (CIA) were measured using WBCT. Ankles were divided into 5 groups according to Takakura stage and 2 groups according to the apparent compensation status of the subtalar joint and compared the index of the inclination of the subtalar joint relative to the ankle (SIA) or the index of the inclination of the calcaneus relative to the ankle (CIA). Additionally, we explored the relationship between SIA or CIA and the TT.

RESULTS

Apparent subtalar compensation (SIA and CIA) was significantly lower in Takakura stages 3b and 4. The SIA and CIA significantly differed according to the apparent compensation status (P < .001 and P = .030, respectively). The CIA of the noncompensated group varied widely, whereas the SIA was relatively constant. Furthermore, TT was greater than 9.5, which indicated a high probability of a noncompensated heel (sensitivity, 92.6%; specificity, 89.7%).

CONCLUSION

The position of the calcaneus appears compensatory with coronal plane orientation in varus ankle osteoarthritis when the TT is ≤9.5 degrees.

LEVEL OF EVIDENCE

Level IV, case series.

Imaging of progressive collapsing foot deformity with emphasis on the role of weightbearing cone beam CT

The term progressive collapsing foot deformity (PCFD) is currently recommended as the replacement to adult-acquired flatfoot deformity and posterior tibial tendon dysfunction to better reflect its pathology, which consists of a complex three-dimensional deformity involving the foot and ankle. The new consensus has also provided a new classification that requires clinical and radiographic findings for patient stratification into each class. However, conventional radiographs are susceptible to errors resulting from the inadequate positioning of patients, incorrect angulation of the X-ray tube, and overlapping of bone structures. Weightbearing cone beam computed tomography (WBCBCT), which has greater diagnostic accuracy than conventional radiograph, is useful for evaluating progressive collapsing foot deformity to determine medial arch collapse, hindfoot alignment, peritalar subluxation, posterior subtalar joint valgus, intrinsic talus valgus, and lateral extra-articular bone impingement. The present review aimed to discuss the new recommendations for nomenclature, classification, and imaging evaluation of PCFD, with an illustrative and quantitative focus on the measurements used in conventional radiography and WBCBCT. The measurements presented here are important criteria for decision-making.

Joint-Preserving Surgery in Varus Ankle Osteoarthritis

Ankle deformity is a disabling condition especially if concomitant with osteoarthritis (OA). Varus ankle OA is one of the most common ankle OA deformities. This deformity usually leads to unequal load distribution in the ankle joint and decreases joint contact surface area, leading to a progressive degenerative arthritic situation. Varus ankle OA might have multiple causative factors, which might present as a single isolated factor or encompassed together in a single patient. The etiologies can be classified as post-traumatic (e.g., after fractures and lateral ligament instability), degenerative, systemic, neuromuscular, congenital, and others. Treatment options are determined by the degree of the deformity and analyzing the pathology, which range from the conservative treatments up to surgical interventions. Surgical treatment of the varus ankle OA can be classified into two categories, joint-preserving surgery (JPS) and joint-sacrificing surgery (JSS) as total ankle arthroplasty and ankle arthrodesis. JPS is a valuable treatment option in varus ankle OA, which should not be neglected since it has showed a promising result, optimizing biomechanics and improving the survivorship of the ankle joint.

Treatment of Early to Intermediate Stage Ankle Osteoarthritis With Nonosteotomy Approaches: Intermediate-Term Efficacy

This study aimed to investigate the intermediate-term efficacy of nonosteotomy approaches in the treatment of early to intermediate stage ankle osteoarthritis (OA). Forty-two patients received treatment for early to intermediate stage ankle osteoarthritis with nonosteotomy approaches were reviewed. The surgical satisfaction was evaluated at 1 year after surgery and the last follow-up period; the American Orthopaedic Foot and Ankle Society (AOFAS) scale and Visual Analog Scale (VAS) were employed for the evaluation of function and pain, respectively, and the stage of ankle osteoarthritis was determined. At 1 year surgery and the last follow-up period, the surgical satisfaction was 37 (88.1%) and 35 (83.3%), respectively, and the favorable function was noted in 34 (80.9%) and 32 (76.2%), respectively. The AOFAS score significantly increased from 50.62 ± 10.81 (range 30-60) before surgery to 81.43 ± 12.00 (range 75-95) at 1 year after surgery (p < .0001) and 79.67 ± 10.34 (range 70-96) at the last follow-up period (p < .0001 vs before surgery; p = .107 vs 1 year). The VAS score reduced from 5.07 ± 1.57 (range 4-7) before surgery to 1.97 ± 1.41 (range 0-3) at 1 year (p < .0001) and 1.80 ± 1.15 (range 0-3) at the last follow-up period (p < .0001 vs before surgery; p = .265 vs 1 year). Moreover, the AOFAS score and VAS score in patients with ankle osteoarthritis at different stages were improved significantly after surgery (p < .0001). Intermediate-term follow-up period shows that nonosteotomy approaches are able to relieve pain and improve postoperative function in the treatment of early to intermediate stage ankle osteoarthritis; the improvement determined according to imaging examination is not completely consistent with that determined based on clinical function.

Joint Preserving Surgery for Valgus Ankle Osteoarthritis

Valgus ankle OA is a complex problem with multiple etiologies that can either be isolated or superimposed on top of other medical or musculoskeletal disorders. Proper medical history, physical, and preoperative radiological examinations are crucial in deciding on surgery and planning the surgical approach. JPS, especially the varisating medial closing-wedge SMOT with solid plate fixation, has been consistently associated with good outcomes for patients with valgus ankle OA. To further improve JPS for valgus ankle OA, further clinical and biomechanical studies are required to address the long-term clinical and functional outcomes and complications.

Assessment of Progressive Collapsing Foot Deformity Using Semiautomated 3D Measurements Derived From Weightbearing CT Scans

BACKGROUND

In progressive collapsing foot deformity (PCFD), hind- and midfoot deformities can be hard to characterize based on weightbearing plain radiography. Semiautomated 3-dimensional (3D) measurements derived from weightbearing computed tomography (WBCT) scans may provide a more accurate deformity assessment. In the present study, automated 3D measurements based on WBCT were used to compare hindfoot alignment of healthy individuals to patients with PCFD.

METHODS

The WBCT scans of 20 patients treated at our institution with either a flexible (N = 10) or rigid (N = 10) PCFD were compared with the WBCT scans of a control group of 30 healthy individuals. Using semiautomated image analysis software, from each set of 3D voxel images, we measured the talar tilt (TT), hindfoot moment arm (HMA), talocalcaneal angle (TCA; axial/lateral), talonavicular coverage (TNC), and talocalcaneal overlap (TCO). The presence of medial facet subluxation as well as sinus tarsi/subfibular impingement was additionally assessed.

RESULTS

With the exception of the TCA (axial/lateral), the analyzed measurements differed between healthy individuals and patients with PCFD. The TCA axial correlated with the TNC in patients with PCFD. An increased TCO combined with sinus tarsi impingement raised the probability of predicting a deformity as rigid.

CONCLUSION

Using 3D measurements, in this relatively small cohort of patients, we identified relevant variables associated with a clinical presentation of flexible or rigid PCFD. An increased TCO combined with sinus tarsi impingement raised the probability of predicting a deformity as rigid. Such WBCT-based markers possibly can help the surgeon in decision-making regarding the appropriate surgical strategy (eg, osteotomies vs realignment arthrodesis). However, prospective studies are necessary to confirm the utility of the proposed parameters in the treatment of PCFD.

LEVEL OF EVIDENCE

Level III, case-control study.

Clinico-radiological factors predicting the failure risk of conservative management in moderate to severe pediatric idiopathic flexible flatfoot

This study aimed to investigate the clinico-radiological factors of related future surgical treatment in patients with pediatric flexible flatfoot (FFF) who first visited the orthopedic clinic before the age of 10 years. Sixty-five patients diagnosed with moderate/severe idiopathic FFF deformity between the ages of 2-10 years were included. We developed prognostic models for the risk of the surgery during the follow-up period. Twenty (30.8%) patients required surgical treatment, and all of them underwent calcaneal lengthening osteotomy. Among them, 7 (10.8%) patients required concomitant Achilles-lengthening surgery. Unilateral involvement, older age, smaller calcaneal pitch angle, and higher talo-first metatarsal malalignment were considered high-risk factors for pediatric FFF surgery. Prognostic models identified three prognostic risk groups based on those factors, and survival curves revealed significant differences among the groups. Our prognostic models help predict the failure risk of conservative management of pediatric idiopathic FFF. Level of Evidence: Level III, prognostic study.

Short Term Clinico-Radiological Outcome of Extra Osseous Talo-Tarsal Stabilization (EOTTS) in Flat Foot: An Indian Perspective

INTRODUCTION

Flexible flat foot is one of the most common foot conditions found amongst any age group across the world. One very important reason for this condition is the incongruency or partial dislocation of one or more joints within the talo-tarsal mechanism. This flexible talo-tarsal malalignment is termed as recurrent talo-tarsal joint dislocation (RTTJD).

MATERIALS AND METHODS

Between 2016 and 2018, 32 patients were advised Extra osseous talo-tarsal stabilization (EOTTS) as a standalone procedure for RTTJD following detailed clinical examination including foot posture index (FPI) scoring and weight-bearing radiographic evaluation. Subjective assessment was done through Maryland Foot Score (MFS) questionnaire. Radiological parameters like talar declination angle, talar second metatarsal angle and tibio-calcaneal valgus angle were assessed for preoperative and postoperative comparison. 15 patients (20 feet) underwent surgery and rest 17 patients (25 feet) became our control group. A retrospective record analysis of longitudinal data was done over a period of 4 years. The purpose of this study is to depict the short-term results of EOTTS procedure in terms of functional and radiological improvement and compare it with the non-surgical group.

RESULT

Significant improvement was seen in MFS from 67.31 ± 16.04 to 95.47 ± 4.36 over a mean follow-up period of 30.66 ± 7.09 months. Total FPI improved by 96.83 ± 4.80% at final follow-up of EOTTS group. Radiologically, maximum correction achieved was in coronal plane (93.07 ± 30.05%).

CONCLUSION

EOTTS, as a standalone procedure improved the foot radiological angles and restored the normal foot biomechanics significantly in presence of competent spring ligament and posterior tibial tendon. This procedure resulted in excellent patient satisfaction score as assessed by MFS questionnaire.

LEVEL OF EVIDENCE

III.

Imaging and Treatment of Posttraumatic Ankle and Hindfoot Osteoarthritis

Posttraumatic osteoarthritis of the ankle and hindfoot is a common and frequently debilitating disorder. 70% to 90% of ankle osteoarthritis is related to prior trauma that encompasses a spectrum of disorders including fractures and ligamentous injuries that either disrupt the articular surface or result in instability of the joint. In addition to clinical evaluation, imaging plays a substantial role in the treatment planning of posttraumatic ankle and hindfoot osteoarthritis. Imaging evaluation must be tailored to specific clinical scenarios and includes weight bearing radiography that utilizes standard and specialty views, computed tomography which can be performed with a standard or a weight bearing technique, magnetic resonance imaging, and ultrasound evaluation. This review article aims to familiarize the reader with treatment rationale, to provide a brief review of surgical techniques and to illustrate expected imaging appearances of common operative procedures performed in the setting of posttraumatic ankle and hindfoot osteoarthritis, such as joint-preserving procedures, ankle fusion, subtalar fusion, tibiotalarcalcaneal fusion and ankle arthroplasty. Preoperative findings will be discussed along with the expected postoperative appearance of various procedures in order to improve detection of their complications on imaging and to provide optimal patient care.

Assessment of Hindfoot Alignment Comparing Weightbearing Radiography to Weightbearing Computed Tomography

BACKGROUND

Hindfoot alignment view (HAV) radiographs are widely utilized for 2-dimensional (2D) radiographic assessment of hindfoot alignment; however, the development of weightbearing computed tomography (WBCT) may provide more accurate methods of quantifying 3-dimensional (3D) hindfoot alignment. The aim of this study was to compare the 2D calcaneal moment arm measurements on HAV radiographs with WBCT.

METHODS

This retrospective cohort study included 375 consecutive patients with both HAV radiographs and WBCT imaging. Measurement of the 2D hindfoot alignment moment arm was compared between both imaging modalities. The potential confounding influence of valgus/varus/neutral alignment, presence of hardware, and motion artifact were further analyzed.

RESULTS

The intraclass correlation coefficients (ICCs) of interobserver and intraobserver reliability for measurements with both imaging modalities were excellent. Both modalities were highly correlated (Spearman coefficient, 0.930; P < .001). HAV radiographs exhibited a mean calcaneal moment arm difference of 3.9 mm in the varus direction compared with WBCT (95% CI, -4.9 to 12.8). The difference of hindfoot alignment between both modalities was comparable in subgroups with neutral/valgus/varus alignment, presence of hardware, and motion artifact.

CONCLUSION

Both HAV radiographs and WBCT are highly reliable and highly correlated imaging methods for assessing hindfoot alignment. Measurements were not influenced by severe malalignment, the presence of hardware, or motion artifact on WBCT. On average, HAV radiographs overestimated 3.9 mm of varus alignment as compared with WBCT.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Radiographic analysis of Müller-Weiss disease

BACKGROUND

The only classification of Müller-Weiss disease (MWD) is based primarily on Méary's talo-first metatarsal angle. It describes increasing sag of the medial longitudinal arch with greater degrees of compression and fragmentation of the navicular. Purportedly, the talar head pushes the subtalar joint into varus and drives the medial pole of the navicular medially, as it protrudes inferiorly and laterally. Its authors stipulated heel varus as a pre-requisite, coining the term 'paradoxical pes planus varus' to define heel varus and flatfoot as hallmark deformities of the condition.

METHODS

We measured Méary's and Kite's talocalcaneal angles, heel offset, anteroposterior thickness of the navicular at each naviculocuneiform (NC) joint, medial extrusion of the navicular and calculated percentage compression at each NC joint in 68 consecutive feet presenting with MWD. Morphology and activity at the various peri-navicular joints were studied using SPECT-CT in 45 feet.

RESULTS

Inverse relationships between Méary's angle and degree of navicular compression reach statistical significance at NC2 but not at NC3. Strong correlation exists between medial extrusion and percentage compression at NC2 and NC3. Medial extrusion is significantly greater on the affected side in unilateral cases and on the more compressed side in bilateral cases. Significant inverse relationships exist between Kite's angle and percentage compression at both NC2 and NC3 and degree of medial extrusion of the navicular. No correlation was detected between Kite's angle and either heel offset or Méary's angle. Varus heel offset was present in only 33% of cases. The combination of heel varus and negative Méary's angle was present in just 26% of cases, the commonest combination being heel valgus with sagging at 56%.

CONCLUSION

Our findings confirm part of Maceira's hypothesized pathomechanism of MWD. Reductions in Kite's talocalcaneal angle confirm that lateral and inferior protrusion of the talar head causes increasing compression and medial extrusion of the navicular. However, such shift of the talar head does not always lead to heel varus. As such, we caution against universal advocacy of lateral displacement calcaneal osteotomy, as the heel is not always in varus in MWD.

Effect of Lower-Extremity Angular Imbalance on Foot and Ankle Pain in Patients With Genu Varus Deformity

When there is a varus knee deformity, the ankle and foot compensate. However, the association between pain and angular change in the compensatory mechanism is not well understood. Therefore, we investigated the relationship between pain and angular change of the lower extremity in genu varus patients. Standing whole-lower-leg plain radiographs of 127 legs (77 patients) with >4° of genu varum were evaluated. Pain was assessed separately at the ankle, forefoot, and hindfoot. Knee, ankle, and subtalar joint angles were measured. Patients were divided into 3 groups according to the degree of lower leg angular imbalance (group 1, mild; group 2, moderate; group 3, severe). The presence of multiple pain locations differed significantly between groups and was significantly higher in group 3 than group 1 (p = .0061). Likewise, the subtalar angle was significantly more varus in group 3 than group 1 (p = .012). In conclusion, an unbalanced lower extremity with genu varum was associated with multiple foot and ankle pain, and the subtalar joint played a primary role in compensation for genu varum deformity.

Radiographic measurements on hindfoot alignment view in 1128 asymptomatic subjects

BACKGROUND

The primary aim of this study was to determine the mean values for three of the most common parameters measured to assess hindfoot alignment in asymptomatic subjects: hindfoot alignment angle (HAA), hindfoot alignment ratio (HAR), and hindfoot moment arm (HMA). The secondary aim was to evaluate the mean value of each parameter according to age and sex.

METHODS

We assessed 1128 asymptomatic subjects from January 2014 to June 2019. HAA, HAR and HMA were measured to evaluate the degree of hindfoot varus or valgus deviation on the hindfoot alignment view, described by Saltzman and el-Khoury. All subjects were divided into subgroups according to sex and age (<45 years versus ≥45 years).

RESULTS

The overall mean HAA, HAR, and HMA were -4.07 ± 3.48°, 0.21 ± 0.15, and -6.12 ± 5.22 mm, respectively. Female subjects ≥45 years old had the largest valgus deviation (HAA, -7.08 ± 6.34°; HAR 0.09 ± 0.25; HMA, -10.58 ± 11.46 mm).

CONCLUSIONS

HAA, HAR, and HMA evaluation revealed that asymptomatic subjects had a hindfoot alignment with valgus deviation. Furthermore, the degree of valgus deviation was the largest in female subjects aged ≥45 years. We hope that the results of our study will be helpful to inform other researchers about the usefulness of these parameters as references.

The Failed Deltoid Ligament in the Valgus Misaligned Ankle-How to Treat?

This article deals with the treatment of a chronically failed deltoid ligament complex in the valgus misaligned ankle. This is a challenging task in every orthopedic foot and ankle surgery. Before embarking on any surgery that relates to the deltoid ligament complex, it is mandatory to analyze any underlying cause that could promote the impairment. Once this is done, it might be of value in considering anatomic reconstructions. The article provides an anatomic reconstruction technique, which should help address the problem.

Lateral open wedge calcaneus osteotomy with bony allograft augmentation in adult acquired flatfoot deformity. Clinical and radiological results

Abstract

The aim of this study is to evaluate the results of patients underwent lateral open wedge calcaneus osteotomy with bony allograft augmentation combined with tibialis posterior and tibialis anterior tenodesis. Twenty-two patients underwent adult-acquired flatfoot deformity were retrospectively evaluated with a minimum 2-year follow-up. Radiographic preoperative and final comparison of tibio-calcaneal angle, talo–first metatarsal and calcaneal pitch angles have been performed. The Visual Analog Scale, American Orthopedic Foot and Ankle Score, the Foot and Ankle Disability Index and the Foot and Ankle Ability Measure were used for subjective and functional assessment. The instrumental range of motion has been also assessed at latest follow-up evaluation and compared with preoperative value. There was a significant improvement of final mean values of clinical scores (p < 0.001). Nineteen out of 22 (86.4%) patients resulted very satisfied or satisfied for the clinical result. There was a significant improvement of the radiographic parameters (p < 0.001). There were no differences between preoperative and final values of range of motion. One failure occurred 7 years after surgery. Adult-acquired flatfoot deformity correction demonstrated good mid-term results and low recurrence and complications rate.

Level of evidence

Level 4, retrospective case series.

[Adult Acquired Flatfoot Deformity: Diagnosis and Surgical Treatment]

The adult acquired flatfoot is a deformity with slow progression, which may leads to pain and restrictions of activities of daily living if untreated. Various treatment strategies, depending on the clinical and radiological presentation, exist. Therefore, an individual therapy approach is necessary for optimal treatment. This article covers etiopathologic aspects, conservative and operative treatments as well as postoperative mobilization and rehabilitation.

Techniques for 3D foot bone orientation angles in weight-bearing from cone-beam computed tomography

BACKGROUND

For the diagnosis and treatment of foot and ankle disorders, objective quantification of the absolute and relative orientation angles is necessary. The present work aims at assessing novel techniques for 3D measures of foot bone angles from current Cone-Beam technology.

METHODS

A normal foot was scanned via weight-bearing CT and 3D-model of each bone was obtained. Principal Component Analysis, landmark-based and mid-diaphyseal axes were exploited to obtain bone anatomical references. Absolute and relative angles between calcaneus and first metatarsal bone were calculated both in 3D and in a simulated sagittal projections. The effects of malpositioning were also investigated via rotations of the entire foot model.

RESULTS

Large angle variations were found between the different definitions. For the 3D relative orientation, variations larger than 10 degrees were found. Foot malposition in axial rotation or in varus/valgus can result in errors larger than 5 and 3 degrees, respectively.

CONCLUSIONS

New measures of foot bone orientation are possible in 3D and in weight-bearing, removing operator variability and the effects of foot positioning.

3D Assessment in Posttraumatic Ankle Osteoarthritis

BACKGROUND

Auto-generated 3-dimensional (3D) measurements based on weightbearing cone-beam computed tomography (CT) scan technology may allow for a more accurate hind- and midfoot assessment. The current study evaluated the reliability and clinical relevance of such measurements in patients with posttraumatic end-stage ankle osteoarthritis.

METHODS

Seventy-two patients treated at our institution for posttraumatic end-stage ankle osteoarthritis, with available weightbearing conventional radiographs and a cone-beam CT scan, were analyzed. Twenty healthy individuals aged between 40 and 70 years served as controls. Seven variables were measured on weightbearing conventional radiographs (2D) and compared to 3D measurements that were based on reconstructions from weightbearing cone-beam CT scans. The reliability of each measurement was calculated and subgroups formed according to commonly observed deformities.

RESULTS

Inter- and intraobserver reliability was superior for 3D compared to 2D measurements. The accuracy of 3D measurements performed on osteoarthritic ankles was similar to 3D measurements performed on healthy individuals. Thirty-three of the 72 included patients (46%) evidenced an inframalleolar compensation of a supramalleolar/intra-articular ankle deformity (78% = varus compensation; 22% = valgus compensation), whereas 24 of those 72 patients (33%) showed no compensation or a further increase of a supramalleolar/intra-articular ankle deformity (67% = varus deformity; 33% = valgus deformity).

CONCLUSION

Auto-generated 3D measurements of the hind- and midfoot were found to be reliable in both healthy individuals and patients with posttraumatic end-stage ankle osteoarthritis. Such measurements may be crucial for a detailed understanding of the location and extent of hindfoot deformities, possibly impacting decision making in the treatment of end-stage ankle osteoarthritis.

LEVEL OF EVIDENCE

Level III, comparative study.

Radiographic angular measurements of the foot and ankle in weight-bearing: A literature review

BACKGROUND

For the diagnosis and treatment of the foot and ankle, bone alignments have long been evaluated using planar radiographs in weight-bearing conditions and a large number of measurements have been reported. The present survey reviews the major radiographic angles that are currently present in the literature for a possible better comprehension and classification of them.

METHODS

PubMed and Google Scholar were used to retrieve technical and clinical papers related to these angles, and were classified based on five typologies and the three projection planes. These angles were grouped into one definition if they described similar concepts, regardless of their anatomical references and names. A corresponding original definition and diagrammatic representation are offered.

RESULTS

Thirty-one conceptual radiographic angles were identified across all descriptions from the literature: 18 in the sagittal plane, 9 in the transverse, and 4 in the coronal. Most angular measures represent relative bone orientations; absolute orientations, bone morphology and joint lines are less frequently used or reported.

CONCLUSIONS

The present survey reveals a confused scenario of angular measures, particularly in terms of anatomical references and names. It is therefore recommended to establish common relevant techniques and terminology.

Impact of Coleman Block Test on Adult Hindfoot Alignment Assessed by Clinical Examination, Radiography, and Weight-Bearing Computed Tomography

Background:

Cavovarus foot constitutes a complex 3-dimensional deformity. The Coleman block test has traditionally been used to distinguish between forefoot- and hindfoot-driven deformity. However, there has been no objective evaluation of the Coleman block test using radiographs or weightbearing computed tomography (WBCT). The purpose of this study was to compare hindfoot alignment in adult cavovarus feet with and without the Coleman block using clinical examination, radiography, and WBCT.

Methods:

Six feet in 6 patients with a clinical diagnosis of cavovarus foot deformity were prospectively enrolled. All feet underwent clinical photography with the camera positioned at 0 degrees to the heel, hindfoot alignment view radiography with the beam positioned 20 degrees off the ground, and WBCT, both with and without the Coleman block in place. Clinical photos were characterized using the standing talocalcaneal angle (STCA), radiographs were characterized using the hindfoot alignment angle (HAA), and WBCTs were characterized using manual and automated hindfoot alignment angle (HAA) and foot and ankle offset (FAO). Using paired analyses, measurements taken with the Coleman block in place were compared to those taken without the Coleman block. Finally, the different methods of measuring hindfoot alignment were tested for correlation with each other. Mean age was 56 years (range 38-69).

Results:

On clinical photography, the STCA decreased by 3.8 degrees with addition of the block (from 10.0±6.6 degrees varus without block to 6.2±7.1 degrees varus with block; P = .001). On radiograph, HAA decreased by 9.0 degrees with addition of the block (from 16.8±8.4 degrees varus without block to 7.5±6.3 degrees varus with block; P = .07). On WBCT, hindfoot alignment angle changed an average of 3.2 degrees (33.4 degrees varus without block, 30.2 degrees varus with block; P = .008). On WBCT, FAO decreased by 1.4% (from 11.3% varus without block to 10.1% varus with block; P = .003). Clinical examination and automated WBCT measurements were strongly correlated with each other.

Conclusion:

Clinical examination, radiograph, and WBCT demonstrated improvements in hindfoot varus using the Coleman block test in adults, but no patient demonstrated complete resolution of deformity regardless of the measurement modality. Clinical examination correlated strongly with automated WBCT measurements.

Level of Evidence:

Level IV, retrospective case review.

The horizontal calcaneofibular ligament: a sign of hindfoot valgus on ankle MRI

OBJECTIVE

Hindfoot valgus malalignment has been assessed on coronal MRI by the measurement of the tibio-calcaneal (TC) angle and apparent moment arm (AMA). This study aimed to determine if the calcaneofibular ligament (CFL) angle could be used as a further marker of hindfoot valgus malalignment on routine non-weight-bearing ankle MRI.

MATERIAL AND METHODS

One hundred ninety-five consecutive 3-T ankle MRI studies were identified from the hospital PACS system. The TC and CFL angles could be measured in 155 cases (78%), and the AMA on 153 cases.

RESULTS

The study group comprised 56 males and 72 females with a mean age of 46 years (range 4-89 years). In 27 patients, both ankles had been imaged. The Pearson correlation between the TC and CFL angles was -0.43, with a corresponding p value of 0.001 indicating a strong negative correlation between the TC and CFL angles. The CFL angle was significantly lower in those with hindfoot valgus (113 ± 14) compared with those without (123° ± 15°) (p = 0.001). The optimal cut-off point of the CFL angle for hindfoot valgus was ≤119°, with a sensitivity and specificity of 66% and 63% respectively. The Pearson correlation between the CFL angle and AMA was -0.10, with a corresponding p value of 0.21 indicating a weak negative correlation that did not reach statistical significance.

CONCLUSION

Hindfoot valgus as estimated by the increased TC angle on coronal non-weight-bearing ankle MRI is associated with a reduced CFL angle on sagittal MR images, but is not associated with AMA. Therefore, a horizontal orientation of the CFL on sagittal MR images may be a further useful sign of hindfoot valgus.

Hindfoot alignment of adult acquired flatfoot deformity: A comparison of clinical assessment and weightbearing cone beam CT examinations

BACKGROUND

Clinical assessment of hindfoot alignment (HA) in adult acquired flatfoot deformity (AAFD) can be challenging and weightbearing (WB) cone beam CT (CBCT) may potentially better demonstrate this three-dimensional (3D) deformity. Therefore, we compared clinical and WB CBCT assessment of HA in patients with AAFD.

METHODS

In this prospective study, we included 12 men and 8 women (mean age: 52.2, range: 20-88) with flexible AAFD. All subjects also underwent WB CBCT and clinical assessment of hindfoot alignment. Three fellowship-trained foot and ankle surgeons performed six hindfoot alignment measurements on the CT images. Intra- and Inter-observer reliabilities were calculated using intra-class correlation (ICC). Measurements were compared by paired T-tests, and p-values of less than 0.05 were considered significant.

RESULTS

The mean of clinically measured hindfoot valgus was 15.2 (95% confidence interval [CI]: 11.5-18.8) degrees. It was significantly different from the mean values of all WB CBCT measurements: Clinical Hindfoot Alignment Angle, 9.9 (CI: 8.9-11.1) degrees; Achilles tendon/Calcaneal Tuberosity Angle, 3.2 (CI: 1.3-5.0) degrees; Tibial axis/Calcaneal Tuberosity Angle, 6.1 (CI: 4.3-7.8) degrees; Tibial axis/Subtalar Joint Angle 7.0 (CI: 5.3-8.8) degrees, and Hindfoot Alignment Angle 22.8 (CI: 20.4-25.3) degrees. We found overall substantial to almost perfect intra- (ICC range: 0.87-0.97) and inter-observer agreements (ICC range: 0.51-0.88) for all WB CBCT measurements.

CONCLUSIONS

Using 3D WB CBCT can help characterize the valgus hindfoot alignment in patients with AAFD. We found the different CT measurements to be reliable and repeatable, and to significantly differ from the clinical evaluation of hindfoot valgus alignment.

LEVEL OF EVIDENCE

Level II-prospective comparative study.

3D Biometrics for Hindfoot Alignment Using Weightbearing Computed Tomography

BACKGROUND

Weightbearing computed tomography (WBCT) is a useful tool for the assessment of hindfoot alignment (HA). Foot ankle offset (FAO) is a recently introduced parameter, determined from WBCT images using semiautomatic software. The aim of this study was to determine the clinical relevance and reproducibility of FAO for the evaluation of HA.

METHODS

A prospective comparative study was performed on consecutive patients requiring bilateral WBCT between September 2017 and April 2018. Based on the clinical assessment of HA, patients were divided into 3 groups: (1) normal alignment group (G1), (2) valgus (G2), and (3) varus (G3). FAO and long axial view (HACT) were measured on WBCT images, and the groups were compared. The reproducibility of FAO and HACT was determined through intraclass correlation coefficients (ICCs). Regression analysis was performed to investigate the correlation between the 2 methods. Overall, 249 feet (126 patients) were included (G1 = 115, G2 = 78, and G3 = 56 feet).

RESULTS

The mean values for FAO and HACT were 1.2% ± 2.8% and 3.9 ± 3.1, respectively, in G1; 8.1% ± 3.7% and 9.7 ± 4.9 in G2; and -6.6% ± 4.8% and -8.2 ± 6.6 in G3. Intra- and interobserver reliability was 0.987 and 0.988 for FAO and 0.949 and 0.949 for HACT, respectively. There was a good linear correlation between HACT and FAO ( R² = 0.744), with a regression slope of 1.064.

CONCLUSIONS

WBCT was a useful method for the characterization of HA. FAO was reproducible and correlated well with physical examination.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

3D hindfoot alignment measurements based on low-dose biplanar radiographs: a clinical feasibility study

OBJECTIVE

To test a 3D-hindfoot alignment (HA) measurement technique based on low-dose biplanar radiographs (BPRs) in a clinical setting and compare the results with 2D-HA measurements on long axial view radiographs (LARs).

MATERIALS AND METHODS

This prospective study was approved by the local institutional review board. HA measurements on 3D-BPR and 2D-LAR of 50 patients (29 female; mean age 47 ± 16.6 years) were compared (positive values = valgus; negative values = varus). Two independent musculoskeletal radiologists (readers 1 and 2) performed 3D-HA measurements on BPR using a custom-made MATLAB code and measured HA on LAR during two separate readout sessions. Descriptive statistics and intraclass correlation coefficients (ICC) were calculated, and Bland-Altman plots were used for intermethod comparison.

RESULTS

Using BPRs, HA was 0.8° ± 9.°1 (range, -20.2 to 20.0) for reader 1, and 0.7° ± 9.5° (range, -21.2 to 18.3) for reader 2. HA on LARs was -2.0 ° ± 7.0° (range, -27.0° to 11.1°) for reader 1 and - 1.7° ± 7.0° (range, -24.1° to 14.3°) for reader 2. Interreader agreement for measurements was excellent, both for BPRs (ICC = 0.992; 95% CI:0.986-0.995) and LAR measurements (ICC = 0.962; 95% CI:0.932-0.978). Mean difference between the two methods was -2.43° (range, -29.4° to 25.6°) for reader 1 and -2.6° (range,-28.7° to 30.2°) for reader 2. On Bland-Altman plots, three measurements of reader 1 and six measurements of reader 2 were outside of the ±1.96 SD interval.

CONCLUSION

Hindfoot alignment measurements on 3D-BPR have an excellent interreader agreement in a clinical setting. Large measurement errors can occur in individual patients using 2D-LAR alone. Therefore, we suggest using 3D-BPR measurements in daily routine for the assessment of HA, which are independent of rotational foot malpositioning.

Compensatory Function of the Subtalar Joint for Lower Extremity Malalignment

It is important to evaluate the subtalar joint and hip-knee-ankle alignment to understand lower extremity alignment. In this review, we focused on the compensatory changes in the subtalar joint alignment for the deformity of the knee and ankle joint, reviewing previous research. The subtalar joint alignment was compensatory valgus in patients with varus knee and ankle deformity, whereas it was uncertain whether the subtalar joint alignment was compensatory varus in patients with valgus knee and ankle deformity. The subtalar joint valgus alignment improved after total knee arthroplasty or high tibial osteotomy for varus knee deformity, even if the deformity was severe. In contrast, whether the subtalar joint alignment changed after the surgery for ankle or valgus knee deformity has not been considered. Further research on the compensatory function of the subtalar joint is needed.

[Short-term effectiveness of talonavicular joint arthrodesis and calcaneus osteotomy for Müller-Weiss disease]

Objective

To investigate the short-term effectiveness of talonavicular joint arthrodesis and calcaneus osteotomy in the treatment of Müller-Weiss disease.

Methods

Between June 2015 and February 2017, 14 patients diagnosed Müller-Weiss disease, who were ineffective on conservative treatment, were treated with talonavicular joint arthrodesis and calcaneus osteotomy. There are 3 males and 11 females, with an average age of 46.2 years (range, 35-56 years). According to the Maceira grading criteria, 5 patients were rated as stage Ⅲ and 9 patients as stage Ⅳ. The disease duration ranged from 4 to 12 years (mean, 7 years). Preoperative X-ray films showed that all patients were not accompanied with adjacent joint arthritis. The hindfoot axis on Saltzman view was (9.8±2.8)°, calcaneal pitch angle (CPA) on lateral position was (14.7±5.1)°, Meary angle on lateral position was (4.8±2.8)°, and talar 1 meta-tarsal angle (T1MA) on anteroposterior position was (25.0±7.3)°. Preoperative visual analogue scale (VAS) score was 5.9±1.5, American Orthopedic Foot Ankle Society (AOFAS) ankle-hindfoot score was 58.8±17.6.

Results

All patients were followed up 14-27 months (mean, 22.3 months). Medial numbness and incision infection occurred in 2, 2 cases, respectively. The other patients had no obvious discomfort. At last follow-up, VAS score was 1.6±1.3 and AOFAS score was 90.6±2.7, showing significant differences when compared with preoperative ones ( t=8.18, P=0.00; t=-6.95, P=0.00). X-ray films showed that the talonavicular joint and calcaneus osteotomy achieved bony healing. The hindfoot axis on Saltzman view was (-2.5±2.7)°, CPA on lateral position was (25.0±5.2) °, Meary angle on lateral position was (2.6±2.1)°, T1MA on anteroposterior position was (8.1±3.8)°. There was no significant difference in Meary Angle between pre- and post-operation ( t=1.53, P=0.15). And there were significant differences in the hindfoot axis, CPA, and T1MA between pre- and post-operation ( t=11.93, P=0.00; t=-8.89, P=0.00; t=8.05, P=0.00).

Conclusion

For Müller-Weiss disease patients without adjacent joint arthritis, who are ineffective on conservative treatment, the satisfied short-term effectiveness can be obtained when treated by talonavicular joint arthrodesis and calcaneus osteotomy.

Sonographic and radiographic findings of posterior tibial tendon dysfunction: a practical step forward

The purpose of this article is to describe the sonographic and radiographic findings in the diagnosis and treatment of posterior tibial tendon dysfunction. Ultrasound and radiographs play a crucial role in the diagnosis of posterior tibial tendon dysfunction and in imaging the postoperative changes related to posterior tibial tendon dysfunction. Early detection and diagnosis of posterior tibial tendon dysfunction is important in helping to prevent further progression of disease, obviating the need for more invasive and complex procedures.

Open Technique for In Situ Subtalar Fusion

The subtalar joint plays an important role for the hindfoot when accommodating during gait. Joint degeneration may be caused by posttraumatic, inflammatory, and pathologic biomechanical changes. Once conservative treatment has failed, subtalar fusion should be considered. The indication for surgery is based on thorough clinical and radiographic evaluation. Several techniques for subtalar fusion are published in literature. This article aims to describe a technique for in situ arthrodesis of the subtalar joint, paying special attention to biomechanical aspects as well as preoperative clinical and radiological work-up.

Correlation of Clinical Evaluation and Radiographic Hindfoot Alignment in Stage II Adult-Acquired Flatfoot Deformity

BACKGROUND

Previous work has demonstrated that the amount of radiographic hindfoot correction required at the time of adult-acquired flatfoot deformity (AAFD) operative treatment can be predicted by the amount of radiographic deformity present before surgery. Successful outcomes after reconstruction are closely correlated with hindfoot valgus correction. However, it is not clear if differences exist between clinical and radiographic assessment of hindfoot valgus. The purpose of this study was to evaluate the correlation between radiographic and clinical evaluation of hindfoot alignment in patients with stage II AAFD.

METHODS

Twenty-nine patients (30 feet) with stage II AAFD, 17 men and 12 women, mean age of 51 (range, 20-71) years, were prospectively recruited. In a controlled and standardized fashion, bilateral weightbearing radiographic hindfoot alignment views were taken. Radiographic parameters were measured by 2 blinded and independent readers: hindfoot alignment angle (HAA) and hindfoot moment arm (HMA). Clinical photographs of hindfoot alignment were taken in 3 different vertical camera angulations (0, 20, and 40 degrees). Pictures were assessed by the same readers for standing tibiocalcaneal angle (STCA) and resting calcaneal stance position (RCSP). Intra- and interobserver reliability were assessed by Pearson/Spearman's and intraclass correlation coefficient (ICC), respectively. Relationship between clinical and radiographic hindfoot alignment was evaluated by a linear regression model. Comparison between the different angles (RCSP, STCA, and HAA) was performed using the Wilcoxon rank-sum test. P values of less than .05 were considered significant.

RESULTS

We found overall almost perfect intraobserver (range, 0.91-0.99) and interobserver reliability (range, 0.74-0.98) for all measures. Mean value and confidence interval (CI) for RCSP and STCA were 10.8 degrees (CI, 10.1-11.5) and 12.6 degrees (CI, 11.7-13.4), respectively. The position of the camera did not influence readings of clinical alignment ( P > .05). The mean HMA was 18.7 mm (CI, 16.3-21.1 mm), and the mean HAA was 23.5 degrees (CI, 21.1-26.0). Clinical and radiographic hindfoot alignment were found to significantly correlate ( P < .05). However, the radiographic HAA demonstrated increased valgus compared to both clinical alignment measurements, with a mean difference of 12.8 degrees from the RCSP (CI, 11.0-14.5, P < .0001) and 11.0 degrees from the STCA (CI, 9.2-12.8, P < .0001).

CONCLUSION

We found significant correlation between radiographic and clinical hindfoot alignment in patients with stage II AAFD. However, radiographic measurements of HAA demonstrated significantly more pronounced valgus alignment than the clinical evaluation. The results of our study suggest that clinical evaluation of hindfoot alignment in patients with AAFD potentially underestimates the bony valgus deformity. One should consider these findings when using clinical evaluation in the treatment algorithm of flatfoot patients.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Lateral collapse of the tarsal navicular in patients with rheumatoid arthritis: Implications for pes planovarus deformity

OBJECTIVES

In patients with rheumatoid arthritis (RA), the talonavicular joint is commonly involved and midfoot collapse can lead to progressive flattening of the arch. Despite a general awareness of the important structural role of the talonavicular joint in rheumatoid foot disease, details of its destructive pattern have not been elucidated.

METHODS

We cross-sectionally investigated 176 RA patients (342 feet) and classified their feet into the following five groups according to radiographic findings: arthritis (RA changes with normal navicular shape), Müller-Weiss Disease (MWD) (collapse of the lateral aspect of the tarsal navicular), flat (flattened navicular), ankylosis (ankylosis of the talonavicular joint), and normal. We compared medical histories and radiographic measurements among all five groups.

RESULTS

The arthritis group comprised 91 feet, 36 in the MWD group, nine in the flat group, 12 in the ankylosis group, and 194 classified as normal. The MWD group demonstrated a trend towards pes planovarus deformity in contrast to pes planovalgus deformity in the arthritis group. Corticosteroid use and the mean daily dosage were the highest in the MWD group.

CONCLUSIONS

This report revealed a high prevalence of MWD-like changes to the navicular in RA patients and its association with pes planovarus deformity and corticosteroid usage.

Radiologic analysis of hindfoot alignment: Comparison of Méary, long axial, and hindfoot alignment views

BACKGROUND

Among radiographic views available for assessing hindfoot alignment, the antero-posterior weight-bearing view with metal cerclage of the hindfoot (Méary view) is the most widely used in France. Internationally, the long axial view (LAV) and hindfoot alignment view (HAV) are used also. The objective of this study was to compare the reliability of these three views.

HYPOTHESIS

The Méary view with cerclage of the hindfoot is as reliable as the LAV and HAV for assessing hindfoot alignment.

MATERIAL AND METHODS

All three views were obtained in each of 22 prospectively included patients. Intra-observer and inter-observer reliabilities were assessed by having two observers collect the radiographic measurements then computing the intra-class correlation coefficients (ICCs).

RESULTS

The intra-observer and inter-observer ICCs were 0.956 and 0.988 with the Méary view, 0.990 and 0.765 with the HAV, and 0.997 and 0.991 with the LAV, respectively. Correlations were far stronger between the LAV and HAV than between each of these and the Méary view. Compared to the LAV and HAV, the Méary view indicated a greater degree of hindfoot valgus.

DISCUSSION

Intra-observer reliability was excellent with both the LAV and HAV, whereas inter-observer reliability was better with the LAV. Excellent reliability was also obtained with the Méary view. Combining the Méary view to obtain a radiographic image of the clinical deformity with the LAV to measure the angular deviation of the hindfoot axis may be useful when assessing hindfoot malalignment. A comparison of the three views in a larger population is needed before clinical recommendations can be made.

LEVEL OF EVIDENCE

II, prospective study.

Changes in hindfoot alignment after total knee arthroplasty in knee osteoarthritic patients with varus deformity

PURPOSE

Hindfoot alignment can affect the weight-bearing kinematics of the knee joint in patients undergoing total knee arthroplasty (TKA). This study evaluated the change in hindfoot alignment after TKA by prospectively analysing the correlation between the knee joint and the hindfoot deformity, the post-operative improvement in the hindfoot deformity, and the long-term post-operative changes in hindfoot alignment.

METHODS

This study included 195 knees from 117 patients with osteoarthritis who underwent TKA between 2012 and 2013. The mechanical alignment angle of the knee joint and the hindfoot alignment angle were measured preoperatively and 6 weeks, 1, and 2 years post-operatively. The patients were divided into two groups according to the severity of the preoperative knee joint deformity: <10° varus (group 1, N = 81) and ≥10° varus (group 2, N = 114). The preoperative and post-operative radiologic parameters of the axis of the knee joint and hindfoot were evaluated, and the results were compared. A Spearman correlation analysis was used to assess the differences in both the mechanical alignment and the hindfoot alignment pre- and post-operatively.

RESULTS

After TKA, the hindfoot valgus deformity improved from 5.2° (±3.8) valgus to 2.1° (±3.9) valgus. At 6 weeks post-operatively, the hindfoot alignment angle was 1.4° (±3.5) valgus and 2.5° (±4.1) valgus in group 1 and group 2, respectively; the difference between the two groups was not statistically significant. Hindfoot alignment showed greater valgus with increasing varus of the mechanical alignment of the knee joint preoperatively (-0.484, p < 0.001) and post-operatively (-0.147, p = 0.040). The post-operative 1- and 2-year hindfoot alignment angles were 2.2° (±4.2) valgus and 2.2° (±4.1) valgus, respectively. None of the differences between the post-operative hindfoot alignment angles were statistically significant.

CONCLUSIONS

The stable improvement in the hindfoot deformity after TKA demonstrates that a valgus deformity of the hindfoot in a patient with a varus knee joint deformity does not require preoperative correction. In patients with a residual hindfoot deformity and pain 6 weeks after TKA, active treatment should be considered because no further improvement can be expected.

LEVEL OF EVIDENCE

Prospective cohort study, Level II.

How Accurate Is Clinical Evaluation in Hindfoot Coronal Alignment?

Background:

Hindfoot coronal alignment is an important factor in the assessment of patients with many different foot and ankle complaints. A number of clinical and radiographic techniques have been described to measure hindfoot coronal alignment, but none of them are widely accepted. The purpose of the present study was to assess the correlation between clinical and radiographic hindfoot alignment measures and to evaluate the reproducibility of each.

Methods:

We evaluated 85 patients with foot and/or ankle symptoms. Hindfoot clinical alignment was measured from photographs. Each patient was placed at a distance of 1 m from the observer, with both feet placed parallel. Four photographs were taken, at a height of 40 cm: a posterior view of both lower limbs including knees, a posterior view focalized on the studied hindfoot, an anterior view of the foot, and the last view of the medial aspect of the foot. Radiographic alignment was quantified on long axial view radiographs. Patients were lying over the film cassette with a focus distance of 1 m and the beam pointed to the ankle joint. The inclination angle of the beam was 45 degrees to the floor. Measurements were independently made by 2 observers, who were asked to classify pictures into 3 categories: varus, neutral, and valgus. Radiographic measurements were made using the angle measurement tool on the radiograph viewer. The intraclass correlation coefficients (ICCs) and the 95% confidence interval (CI) of the ICC were used to quantify the inter- and intraobserver reliability for clinical assessment. Radiographic parameters were correlated by calculating the Pearson correlation coefficient (r).

Results:

The intraobserver ICC for clinical analysis was good for both observers, while the interobserver ICC was moderate for both measurements. Regarding radiographic assessment, there was significant intra- and interobserver reliability. The correlation between both methods was weak for both observers.

Conclusions:

We found only weak intra- and interobserver correlations between the clinical and radiographic assessment of hindfoot coronal alignment. It is therefore necessary to complement the clinical evaluation of hindfoot alignment with an objective measurement method such as a long axial view radiograph. Further studies comparing different measurement methods need to be performed to establish the most objective evaluation.

Level of Evidence:

Level III, diagnostic study.