Pediatric Foot: Development, Variants, and Related Pathology.

Pediatric foot development throughout childhood and adolescence can present a diagnostic dilemma for radiologists because imaging appearances may be confused with pathology. Understanding pediatric foot development and anatomical variants, such as accessory ossification centers, is essential to interpret musculoskeletal imaging in children correctly, particularly because many of these variants are incidental but others can be symptomatic. We first briefly review foot embryology. After describing common accessory ossification centers of the foot, we explain the different patterns of foot maturation with attention to irregular ossification and bone marrow development. Common pediatric foot variants and pathology are described, such as tarsal coalitions and fifth metatarsal base fractures. We also discuss pediatric foot alignment and various childhood foot alignment deformities.

[Long-term clinical and radiological results of metatarsophalangeal resection arthroplasty in patients with large forefoot deformities]. / Resultados clínicos y radiológicos a largo plazo de la artroplastía de resección metatarsofalángica en pacientes con grandes deformidades del antepié.

INTRODUCTION: metatarsophalangeal resection arthroplasty is considered a salvage surgical procedure able to improve the quality of life of patients with major forefoot deformities. MATERIAL AND METHODS: a retrospective observational study of 31 patients (36 feet) with major forefoot deformities operated at our institution was performed. Thirty two feet required additional surgery involving the first ray, most of them (72.2%) through MTP joint fusion. The mean follow-up period was 10.3 ± 4.6 years. Most patients were women (87.1%), the mean age was 74.2 ± 11.5 years. RESULTS: at the final follow-up, mean AOFAS score was 77.9 ± 10.2 points and mean MOxFQ score was 18.3 ± 8.3 points. Visual analog scale (VAS) for pain improved significantly from 7.5 ± 1.2 points to 3.4 ± 2.1 points on average. Good clinical results were also reported on ability to put on shoes comfortably. The mean resection arthroplasty spaces at the end of the study were 1.3, 1.8, 2.5 and 4.4 mm, for second to fifth rays, respectively. The mean sizes of remodeling osteophytes at the end of the study were 1.6, 1.4, 1.1 and 0.7 mm, respectively. Significant improvement was also achieved in the hallux valgus angle (HVA) and intermetatarsal angle (IMA) at the end of the study. CONCLUSION: in our experience, metatarsophalangeal resection arthroplasty continues to be a valid choice in patients with major forefoot deformities, with satisfactory long-term clinical and radiographic results.

INTRODUCCIÓN: la artroplastía de resección metatarsofalángica se considera un procedimiento quirúrgico de salvamento capaz de mejorar la calidad de vida de pacientes con deformidades importantes en el antepié. MATERIAL Y MÉTODOS: se realizó un estudio observacional retrospectivo de 31 pacientes (36 pies) con deformidades importantes en el antepié operados en nuestra institución. Treinta y dos pies requirieron cirugía adicional que involucró el primer metatarsiano, la mayoría de ellos (72.2%) a través de la fusión de la articulación metatarsofalángica. El período de seguimiento promedio fue 10.3 ± 4.6 años. La mayoría de los pacientes fueron mujeres (87.1%), con una edad promedio de 74.2 ± 11.5 años. RESULTADOS: en la última visita de seguimiento, la puntuación AOFAS promedio fue de 77.9 ± 10.2 puntos y la puntuación MOxFQ promedio fue de 18.3 ± 8.3 puntos. La escala visual analógica (EVA) para el dolor mejoró significativamente, pasando de 7.5 ± 1.2 puntos a 3.4 ± 2.1 puntos de media. También se constataron buenos resultados clínicos en cuanto a la capacidad de calzarse con comodidad. Los espacios de resección promedio al final del estudio fueron 1.3, 1.8, 2.5 y 4.4 mm para el segundo al quinto radio, respectivamente. Los tamaños promedio de los osteofitos por remodelación al final del estudio fueron de 1.6, 1.4, 1.1 y 0.7 mm, respectivamente. También se logró una mejora significativa en el ángulo de hallux valgus (AHV) y en el ángulo intermetatarsiano (IMA) al final del estudio. CONCLUSIÓN: en nuestra experiencia, la artroplastía de resección metatarsofalángica sigue siendo una opción válida en pacientes con deformidades graves del antepié, con resultados clínicos y radiográficos satisfactorios a largo plazo.

Risk Factors for Midfoot Arthritis Associated With Medical History by Weight Bearing Computed Tomography.

Tarso-metatarsal joints and naviculocuneiform joints comprising midfoot is the second most commonly involved joints following the first metatarsophalangeal joint in the foot. However, related factors of midfoot arthritis (MA) have been rarely reported. The bony structure and alignment can be more precisely assessed using Weight-Bearing Computed Tomography (WBCT) than conventional radiographs. Therefore, the aim of this study was to investigate risk factors for MA related to medical history and comorbid foot deformities using WBCT. WBCT data from September 2014 to April 2022 were extracted from a single referral hospital. All cases were divided into two groups by the presence of MA. Twenty-five potential related factors including demographics, etiology, and common co-occurring foot deformities were collected for comparison. Six hundred six cases (247 males and 359 females) among consecutive 1316 cases between September 2014 to April 2022 were selected. One hundred thirty-nine male cases (56.3%) and 210 female cases (58.5%) showed MA. In stepwise multiple logistic regression analysis, 5 factors remained statistically significant. The multivariate-adjusted odds ratios for age, laterality, body mass index (BMI), Progressive Collapsing Foot Deformity (PCFD), and lesser toe deformities (LTD) were 1.08, 1.54, 1.05, 6.62, and 3.03 respectively. Risk factors for MA associated with medical history and foot deformities included age, laterality, BMI, PCFD, and LDT.

Forefoot Morphotypes in Cavovarus Feet: A Novel Assessment of Deformity.

BACKGROUND: The cavovarus foot is a complex 3-dimensional deformity. Although a multitude of techniques are described for its surgical management, few of these are evidence based or guided by classification systems. Surgical management involves realignment of the hindfoot and soft tissue balancing, followed by forefoot balancing. Our aim was to analyze the pattern of residual forefoot deformities once the hindfoot is corrected, to guide forefoot correction. METHODS: We included 20 cavovarus feet from 16 adult patients with Charcot-Marie-Tooth who underwent weightbearing CT (mean age 43.4 years, range: 22-78 years, 14 males). Patients included had flexible deformities, with no previous surgery. Using specialized software (Bonelogic 2.1, Disior) a 3-dimensional, virtual model was created. Using morphologic data captured from normal feet in patients without pathology as a guide, the talonavicular joint of the cavovarus foot was digitally reduced to a "normal" position to simulate the correction that would be achieved during surgical correction. Models of the corrected position were exported and geometrically analyzed using Blender 3.64 to identify anatomical trends. RESULTS: We identified 4 types of cavovarus forefoot morphotypes. Type 0 was defined as a balanced forefoot (2 cases, 10%). Type 1 was defined as a forefoot where the first metatarsal was relatively plantarflexed to the rest of the foot, with no significant residual adduction after talonavicular joint correction (12 cases, 60%). Type 2 was defined as a forefoot where the second and first metatarsals were progressively plantarflexed, with no significant adduction (4 cases, 20%). Type 3 was defined as a forefoot where the metatarsals were adducted after talonavicular derotation (2 cases, 10%). CONCLUSION: In this relatively small cohort, we identified 4 forefoot morphotypes in cavovarus feet that might help surgeons to recognize and anticipate the residual forefoot deformities after hindfoot correction. Different treatment strategies may be required for different morphotypes to achieve balanced correction. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Radiological angle assessment of Haglund's deformity: validation on Magnetic Resonance Imaging.

PURPOSE: Haglund's deformity, an abnormality at the postero-superior corner of the calcaneus is a common cause of posterior heel pain. To date numerous measurements of radiological angles related to the calcaneus have been proposed to differentiate between symptomatic and asymptomatic patients with the deformity. Traditionally, these measurements have been assessed on plain radiographs. The aim of this study was to identify measurements which can be applied to Magnetic Resonance Imaging (MRI) studies of the ankle. METHODS: A retrospective cohort analysis of 30 MRI ankle studies from patients with symptomatic Haglund's deformity and 32 normal studies as controls was undertaken. The angle of BRINK, the Achilles angle, Calcaneal pitch, Achilles-plantar fascia angle and soleus calcaneal distance were measured on optimal T2 fat-saturated sagittal slices. RESULTS: There was a statistically significant difference (p < 0.0001) in the angle of BRINK between the Haglund's and control group. The Area-Under-the-Curve (AUC) was 0.7783 in keeping with good discrimination between the two groups. The angle of BRINK measurement is reproducible, with an intra-observer ICC of 0.837 and an inter-observer ICC of 0.824. There was no statistically significant difference between the two groups for the other measurements. In the Haglund's group the Achilles tendon was more likely to attach to the mid 1/3 of the posterior calcaneus as opposed to the superior 1/3 (p = 0.02), calcaneal oedema was more likely to be present (p < 0.001) and non-insertional tendinopathy was more likely to be present (p < 0.001). The presence of a retrocalcaneal bursa is non-specific (p = 0.602). CONCLUSION: The angle of BRINK demonstrates good discrimination between normal and Haglund's cases on MRI studies and may improve patient management by supporting surgical decision-making. Future work should correlate the angle of BRINK to long-term outcomes.

Radiographic Analysis of Valgus Ankle Deformity With or Without Medial Longitudinal Arch Collapse.

BACKGROUND: Establishing a surgical plan for ankle deformities necessitates a comprehensive understanding of the deforming forces involved, and the morphology of the ankle deformity plays an important role as well. Valgus tibiotalar tilt development has mostly been described in patients with a low medial longitudinal arch, as seen in progressive collapsing foot deformity (PCFD). However, some valgus ankles demonstrate no radiographic evidence of a collapsed medial arch. This study aims to investigate whether there are differences in the radiographic morphology of valgus ankle deformities between patients with and without a low medial longitudinal arch to explore if they have different etiologies. METHODS: We retrospectively reviewed patients who underwent surgical treatment for asymmetric valgus ankle deformity at our institution between 2017 and 2021. Patients with a valgus tibiotalar tilt (TT) greater than 4 degrees and Meary angle greater than 30 degrees (mean: 38.9) were included in the PCFD group (n = 29). The non-PCFD group (n = 24) with TT greater than 4 degrees and Meary angle less than 4 degrees (mean: 0.3) was also established. In the weightbearing ankle anteroposterior view, the TT and medial distal tibial angle were measured. Additionally, to assess the mediolateral position of the talus, the talar center migration (TCM) and lateral talar dome-plafond distance (LTD-P) ratio in the coronal plane were measured. In weightbearing computed tomography (WBCT), the degree of axial plane talocalcaneal subluxation and the prevalence of sinus tarsi bony impingement were assessed. Intergroup comparison was conducted. RESULTS: Both groups demonstrated a similar degree of TT, with a mean of 11.6 degrees in the PCFD group and 13.7 degrees in the non-PCFD group (P = .2330). However, the PCFD group showed a significantly greater TCM and LTD-P ratio compared with those of the non-PCFD group (P < .0001), indicating that PCFD patients have a more medially translated talus in ankle anteroposterior radiographs. WBCT showed that the PCFD group on average had 18 degrees greater axial plane talocalcaneal subluxation (P < .0001) and 52% higher prevalence of sinus tarsi bony impingement (P = .0002) compared with the non-PCFD group. CONCLUSION: This study suggests that valgus ankles may exhibit different radiographic morphologies depending on the status of the longitudinal arch. Valgus ankles in PCFD patients tend to have a more medially translated talus. This finding may suggest the presence of different deforming forces between the 2 groups and may indicate the need for different treatment strategies to address talar tilt. LEVEL OF EVIDENCE: Level III, case-control.

Does foot shape really matter? Correlation of patient reported outcomes with radiographic assessment in progressive collapsing foot deformity reconstruction: A systematic review.

BACKGROUND: In progressive collapsing foot deformity (PCFD), the goal of surgery is to obtain a well-balanced plantigrade foot. It remains unclear if restoration of the alignment and subsequent improvement in radiological parameters is associated with improved patient-reported outcome measures (PROMs). The aim of the current systematic review was to investigate whether there is a correlation between radiographic assessment and PROMs in patients treated surgically for flexible PCFD. MATERIALS AND METHODS: The study was conducted in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines. A comprehensive literature search was performed in Pubmed, EMBASE, Cochrane Central Register of Controlled Trails (CENTRAL), and KINAHL. We included all the studies reporting both PROMs and radiological outcomes in patients treated surgically for PCFD. The quality of the included studies was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal tool. RESULTS: Six retrospective studies were included. Radiological parameters related to forefoot plantarflexion were associated with statistically significant differences in postoperative PROMs. A neutral hindfoot and midfoot position was positively correlated with postoperative PROMs but a statistically significant difference could not be established in all studies. The medial arch height was positively correlated with PROMs, but in one study this was the case only in revision surgeries. CONCLUSION: The literature so far suggests restoration of the alignment may be associated with improved PROMs. Future prospective studies that investigate possible radiological and clinical correlations in PCFD surgery are needed. LEVEL OF EVIDENCE: III.

Association Between Weightbearing CT and MRI Findings in Progressive Collapsing Foot Deformity.

BACKGROUND: Weightbearing computed tomography (WBCT) scans allow for a better understanding of foot alignment in patients suffering from progressive collapsing foot deformity (PCFD). However, soft tissue integrity (eg, spring ligament complex or tibialis posterior tendon) cannot be easily assessed via WBCT. As performing both WBCT and magnetic resonance imaging (MRI) might not be cost effective, we aimed to assess whether there is an association between osseous and soft tissue findings in WBCT and MRI. METHODS: In this observational study, a consecutive cohort of 24 patients of various stages of PCFD (mean age 51 ± 18 years) underwent WBCT scans and MRI. Twenty-four healthy individuals of similar age, body mass index (BMI), and sex with WBCT scans were used as a control group. In addition to of osseous sinus tarsi impingement, 4 commonly used 3-dimensional (3D) measurements (talocalcaneal overlap [TCO], talonavicular coverage [TNC], Meary angle [MA], axial/lateral) were obtained using a dedicated postprocessing software (DISIOR 2.1, Finland) on the WBCT data sets. Sinus tarsi obliteration, spring ligament complex, tibiospring ligament integrity, as well as tibialis posterior tendon degeneration were evaluated with MRI. Statistical analysis was performed for significant (P < .05) correlation between findings. RESULTS: None of the assessed 3D measurements correlated with either spring ligament complex or tibiospring ligament tears. BMI and TCO were found to be associated with tibialis posterior tendon tears. Seventy-five percent of patients with osseous sinus tarsi impingement on WBCT also showed signs of sinus tarsi obliteration on MRI. CONCLUSION: Although WBCT reflects foot alignment and can reveal osseous sinus tarsi impingement in PCFD patients, the association between WBCT-based 3D measurements and ligament or tendon tears assessed via MRI is limited. WBCT appears complimentary to MRI regarding its diagnostic value. Both imaging options add important information and may impact decision making in the treatment of PCFD patients. LEVEL OF EVIDENCE: Level IV, observational study.

The Role of the Transverse Arch in Progressive Collapsing Foot Deformity.

BACKGROUND: The transverse arch (TA) has recently been shown to significantly increase the intrinsic stiffness of the midfoot when coupled with the medial longitudinal arch (MLA). Progressive collapsing foot deformity (PCFD) is a complex deformity that ultimately results in a loss of stiffness and collapse of the MLA. The role of the TA has not been investigated in patients diagnosed with this disorder using weightbearing CT (WBCT). Therefore, this study aims to answer the following questions: (1) Is the curvature of the TA decreased in PCFD? (2) Where within the midfoot does TA curvature flattening happen in PCFD? METHODS: A retrospective review of weightbearing CT images was conducted for 32 PCFD and 32 control feet. The TA curvature was assessed both indirectly using previously described methods and directly using a novel measurement termed the transverse arch plantar (TAP) angle that assesses the angle formed between the first, second, and fifth metatarsals in the coronal plane. Location of TA collapse was also assessed in the coronal plane. RESULTS: The TAP angle was significantly higher in PCFD (mean 115.2 degrees, SD 10.7) than in the control group (mean 100.8 degrees, SD 7.9) (P < .001). No difference was found using the calculated normalized TA curvature between PCFD (mean 17.1, SD 4.8) and controls (mean 18.3, SD 4.0) (P = .266). Location of collapse along the TA in PCFD was most significant at the second metatarsal and medial cuneiform. CONCLUSION: The TA is more collapsed in PCFD compared to controls. This collapse was most substantial between the plantar medial cuneiform and the plantar second metatarsal. This may represent a location of uncoupling of the TA and MLA. LEVEL OF EVIDENCE: Level III, retrospective case control.

The Reliability of Common Radiographic Measurements Used to Describe Foot Deformities.

Radiographic measurements are frequently used to classify deformity and determine treatment options. Correlation coefficients can be used to determine inter- and intrarater reliability. Reliability is a required feature of any measurement if the measurement is to provide valid information. We calculated correlation coefficients for standard radiographic measurements used to categorize foot deformities: this was done for 52 sets of radiographs assessed by 5 raters. We aimed for generalizability, and kept rater instructions to match what was originally published for each measurement of interest with schematic illustration. Overall, our results mostly showed a lack of inter-rater reliability (correlation coefficients <0.4), and strong intrarater reliability (correlation coefficients >0.6), for 12 forefoot and 12 rearfoot radiographic measurements that are commonly used. The results of this investigation bring into question the routine use of radiographic measurements to categorize deformity, select treatments, and measure surgical outcomes, between surgeons, because the validity of these measurements appears to be threatened by weak inter-rater reliability. In order for these measurements to be considered useful, it may be necessary for surgeons to more rigorously define and practice making standard radiographic measurements.

Medializing Calcaneal Osteotomy for progressive collapsing foot deformity alters the three-dimensional subtalar joint alignment.

BACKGROUND: A medializing calcaneal osteotomy (MCO) is considered as one of the key inframalleolar osteotomies to correct progressive collapsing foot deformity (PCFD). While many studies were able to determine the post-operative hind- and midfoot alignment, alternations of the subtalar joint alignment remained obscured by superposition on plain radiography. Therefore, we aimed to assess the hind-, midfoot- and subtalar joint alignment pre- compared to post-operatively using 3D weightbearing CT (WBCT) imaging. METHODS: Seventeen patients with a mean age of 42 ± 17 years were retrospectively analyzed. Inclusion criteria consisted of PCFD deformity corrected by a medializing calcaneal osteotomy (MCO) as main procedure and imaged by WBCT before and after surgery. Exclusion criteria were patients who had concomitant calcaneal lengthening osteotomies, mid-/hindfoot fusions, hindfoot coalitions, and supramalleolar procedures. Image data were used to generate 3D models and compute the hindfoot (HA), midfoot (MA) - and subtalar joint (STJ) alignment in the coronal, sagittal and axial plane, as well as distance maps. RESULTS: Pre-operative measurements of the HA and MA improved significantly relative to their post-operative equivalents p < 0.05). The post-operative STJ alignment showed significant inversion (2.8° ± 1.7), abduction (1.5° ± 1.8), and dorsiflexion (2.3° ± 1.7) of the talus relative to the calcaneus (p < 0.05) compared to the pre-operative alignment. The displacement between the talus and calcaneus relative to the sinus tarsi increased significantly (0.6 mm±0.5; p < 0.05). CONCLUSION: This study detected significant changes in the sagittal, coronal, and axial plane alignment of the subtalar joint, which corresponded to a decompression of the sinus tarsi. These findings contribute to our clinical practice by demonstrating the magnitude of alteration in the subtalar joint alignment that can be expected after PCFD correction with MCO as main procedure.

Supramalleolar Osteotomies in Cavovarus Foot Deformity: Why Patient-Specific Instruments Make a Difference.

Supramalleolar osteotomy enables correction of the ankle varus deformity and is associated with improvement of pain and function in the short term and long term. Despite these beneficial results, the amount of surgical correction is challenging to titrate and the procedure remains technically demanding. Most supramalleolar osteotomies are currently planned preoperatively on 2-dimensional weight-bearing radiographs and executed peroperatively using free-hand techniques. This article encompasses 3-dimensional planning and printing techniques based on weight-bearing computed tomography images and patient-specific instruments to correct ankle varus deformities.

Foot deformities in rheumatoid arthritis patients and their effects on foot functions.

OBJECTIVE: Foot problems are common clinical disorders in patients with Rheumatoid Arthritis (RA). The aim of this study was to investigate the frequency and impact of foot and ankle problems in patients with RA. PATIENTS AND METHODS: A total of 164 feet of 82 RA patients with a diagnosis of one year or more were evaluated. Deformities including HV, CT, SF, PC, PP, MPS, MPV, and HT were examined in all RA patients. The Foot Function Index was used to measure the impact of these deformities on pain, disability, and movement limitations. Radiological changes were measured using the modified Larsen score. RESULTS: The frequency of deformity in RA patients was found to be 95.1%, with HV deformity being the most common at 84.1%. There was a statistically significant relationship between SF, HV, PP, and PC deformities and disease duration. In our sample of 82 patients, 70 (85.3%) reported past or present foot pain complaints. The most common site of pain was the ankle joint, with 44 (53.7%) patients experiencing ankle pain. A statistically significant increase in the frequency of ankle pain was found as DAS28 scores, body mass index (BMI), and disease duration increased. There was also a correlation between an increase in DAS28 scores and the frequency of forefoot pain. A significant correlation was found between MPV, HV, PP, and PC deformities and high FFI scores. Larsen radiological scores were not correlated with foot-ankle pain or duration of pain. CONCLUSIONS: These findings suggest that foot deformities are common in RA, and it is important to address them early in the disease course to minimize functional disability and improve quality of life.

Assessment of foot deformities in individuals with cerebral palsy using weight-bearing CT.

OBJECTIVE: The aims of this study were to visualize and quantify relative bone positions in the feet of individuals with cerebral palsy (CP) with a foot deformity and compare bone positions with those of typically developed (TD) controls. MATERIALS AND METHODS: Weight-bearing CT images of 14 individuals with CP scheduled for tendon transfer and/or bony surgery and of 20 TD controls were acquired on a Planmed Verity WBCT scanner. Centroids of the navicular and calcaneus with respect to the talus were used to quantify foot deformities. All taluses were aligned and the size and dimensions of the individuals' talus were scaled to correct for differences in bone sizes. In order to visualize and quantify variations in relative bone positions, 95% CI ellipsoids and standard deviations in its principle X-, Y-, and Z-directions were determined. RESULTS: In individuals with CP (age 11-17), a large variation in centroid positions was observed compared to data of TD controls. Radiuses of the ellipsoids, representing the standard deviations of the 95% CI in the principle X-, Y-, and Z-directions, were larger in individuals with CP compared to TD controls for both the calcaneus (3.16 vs 1.86 mm, 4.26 vs 2.60 mm, 9.19 vs 3.60 mm) and navicular (4.63 vs 1.55 mm, 5.18 vs 2.10 mm, 16.07 vs 4.16 mm). CONCLUSION: By determining centroids of the calcaneus and navicular with respect to the talus on WBCT images, normal and abnormal relative bone positions can be visualized and quantified in individuals with CP with various foot deformities.

The spectrum of foot deformities in Loeys-Dietz syndrome.

Loeys-Dietz syndrome (LDS) is characterized by a wide spectrum of musculoskeletal manifestations, including foot deformities. The spectrum of foot deformities in LDS has not been previously characterized. Our objective was to describe the incidence and characteristics of foot deformities in LDS. We retrospectively reviewed the demographic, clinical and imaging data for patients diagnosed with LDS who were seen at our Orthopedic surgery department from 2008 to 2021. We performed descriptive analyses and compared distributions of deformities by LDS genetic mutations. Of the 120 patients studied, most presented for evaluation of foot deformities ( N = 56, 47%) and scoliosis ( N = 45; 38%). Ninety-seven patients (81%) had at least one foot deformity, and 87% of these patients had bilateral foot deformities. The most common deformities were pes planovalgus (53%) and talipes equinovarus (34%). Of patients with foot deformities, 58% presented for evaluation of the feet. Of patients with pes planovalgus, only 17% presented for evaluation of the feet. Among patients with pes planovalgus, 2% underwent surgery and 16% used orthotics compared with 76% and 42%, respectively, for patients with talipes equinovarus. We found no association between deformities and genetic mutations. Bilateral foot deformities are highly prevalent in patients with LDS and are the most common reason for presentation to orthopedic surgeons. Although pes planovalgus is the most common deformity, it rarely prompted surgical treatment. Orthopedic surgeons treating LDS patients should be aware of the unique characteristics of foot deformities in LDS.

Deformities Influencing Different Classes in Progressive Collapsing Foot.

Background: The current classification system of progressive collapsing foot deformity (PCFD) is comprised of 5 possible classes. PCFD is understood to be a complex, three-dimensional deformity occurring in many regions along the foot and ankle. The question remains whether a deformity in one area impacts other areas. The objective of this study is to assess how each one of the classes is influenced by other classes by evaluating each associated angular measurement. We hypothesized that positive and linear correlations would occur for each class with at least one other class and that this influence would be high. Methods: We retrospectively assessed weight bearing CT (WBCT) measurements of 32 feet with PCFD diagnosis. The classes and their associated radiographic measurements were defined as follows: class A (hindfoot valgus) measured by the hindfoot moment arm (HMA), class B (midfoot abduction) measured by the talonavicular coverage angle (TNCA), class C (medial column instability) measured by Meary's angle, class D (peritalar sub-luxation) measured by the medial facet uncoverage (MFU), and class E (ankle valgus) measured using the talar tilt angle (TTA). Multivariate analyses were completed comparing each class measurement to the other classes. A p-value <0.05 was considered significant. Results: Class A showed substantial positive correlation with class C (ρ=0.71; R2=0.576; p=0.001). Class B was substantially correlated with class D (ρ=0.74; R2=0.613; p=0.001). Class C showed a substantial positive correlation with class A (ρ=0.71; R2=0.576; p=0.001) and class D (ρ=0.75; R2=0.559; p=0.001). Class D showed substantial positive correlation with class B and class C (ρ=0.74; R2=0.613; p=0.001), (ρ=0.75; R2=0.559; p=0.001) respectively. Class E did not show correlation with class B, C or D (ρ=0.24; R2=0.074; p=0.059), (ρ=0.17; R2=0.071; p=0.179), and (ρ=0.22; R2=0.022; p=0.082) respectively. Conclusion: This study was able to find relations between components of PCFD deformity with exception of ankle valgus (Class E). Measurements associated with each class were influenced by others, and in some instances with pronounced strength. The presented data may support the notion that PCFD is a three-dimensional complex deformity and suggests a possible relation among its ostensibly independent features. Level of Evidence: III.

Radiographic Cutoff Values for Predicting Lateral Bony Impingement in Progressive Collapsing Foot Deformity.

BACKGROUND: Lateral bony impingement is a major cause of lateral foot pain in progressive collapsing foot deformity (PCFD). Weightbearing computed tomography (WBCT) provides better sensitivity than standard radiographs for detecting impingement. However, many orthopaedic centers have not yet acquired WBCT imaging. This study aimed to (1) investigate the correlation of common radiographic parameters measured on standard weightbearing radiographs with talocalcaneal and calcaneofibular distance assessed with WBCT and (2) establish radiographic cutoff values to detect bony impingement as identified on WBCT. METHODS: Ninety-one patients treated for PCFD with standard preoperative radiographs and WBCT were identified. Patients with asymmetric ankle arthritis (talar tilt >2 degrees) were excluded. The talocalcaneal distance at the sinus tarsi and calcaneofibular distance were measured in multiplanar reconstructed WBCT images. Impingement was defined as direct abutment between bones. The relationships between WBCT measurements and 4 common parameters (talonavicular coverage angle [TNC], talo-first metatarsal angle, calcaneal pitch, and hindfoot moment arm [HMA]) in standard radiographs were assessed with Pearson correlations. Receiver operating characteristic curve analysis evaluated the ability of radiographic cutoffs to detect sinus tarsi or calcaneofibular bony impingement, and the area under curve (AUC), sensitivity, specificity, negative and positive predictive value (PPV) were calculated. RESULTS: Talocalcaneal distance narrowing at the sinus tarsi strongly correlated with TNC (r = 0.64, P < .001), and the calcaneofibular distance narrowing correlated with the HMA moderately yet best among the parameters (r = 0.55, P < .001). TNC (AUC = 0.837, 95% CI 0.745-0.906) and HMA (AUC=0.959, 95% CI 0.895-0.989) provided the best predictive ability for sinus tarsi and calcaneofibular bony impingement, respectively. A TNC threshold of 41.2 degrees had a 100% PPV for predicting sinus tarsi impingement, whereas an HMA threshold of 38.1 mm had a 100% PPV for calcaneofibular impingement. CONCLUSION: This study provides evidence that TNC and HMA measurements made on standing radiographs could be used to indicate potential lateral bony impingement in PCFD. Narrowing of talocalcaneal distance best correlated with abduction deformity of the foot, and the narrowing of calcaneofibular distance was best correlated with valgus hindfoot deformity. LEVEL OF EVIDENCE: Level III, case control study.

Does tibialis posterior dysfunction correlate with a worse radiographic overall alignment in progressive collapsing foot deformity? A retrospective study.

BACKGROUND: Posterior Tibial Tendon (PTT) dysfunction is considered to have an important role in Progressive Collapsing Foot Deformity (PCFD). The objective of our study was to assess the relationship between PTT status and three-dimensional foot deformity in PCFD. METHODS: Records from 25 patients with PCFD were included for analysis. The PTT was considered deficient in patients with a positive single heel rise test or a deficit in inversion strength. Three-dimensional foot deformity was assessed using the Foot and Ankle Offset (FAO) from Weight-Bearing-CT imaging. Hindfoot valgus, midfoot abduction and medial longitudinal arch collapse were assessed on X-Rays using hindfoot moment arm, talonavicular coverage angle and Meary's angle respectively. Deland and Rosenberg MRI classifications were used to classify PTT degeneration. RESULTS: PCFD with PTT deficit (13/25) had a mean FAO of 7.75 + /- 3.8% whereas PCFD without PTT deficit had a mean FAO of 6.68 + /- 3.9% (p = 0.49). No significant difference was found between these groups on the hindfoot moment arm and the talonavicular coverage angle (respectively p = 0.54 and 0.32), whereas the Meary's angle was significantly higher in case of PCFD with PTT deficit (p = 0.037). No significant association was found between PTT degeneration on MRI and FAO. CONCLUSION: PCFD associated three-dimensional deformity, hindfoot valgus and midfoot abduction were not associated with PTT dysfunction. PTT dysfunction was only associated with a worse medial longitudinal arch collapse in our study. Considering our results, it does not appear that PTT is the main contributor to PCFD. LEVEL OF EVIDENCE: Level III, Retrospective Comparative Study.

Intra- and Interobserver Reliability of the New Classification System of Progressive Collapsing Foot Deformity.

BACKGROUND: Historical concept of flatfoot as posterior tibial tendon dysfunction (PTTD) has been questioned. Recently, the consensus group published a new classification system and recommended renaming PTTD to Progressive Collapsing Foot Deformity (PCFD). The new PCFD classification could be effective in providing comprehensive information on the deformity. To date, there has been no study reporting intra- and interobserver reliability and the frequency of each class in PCFD classification. METHODS: This was a single-center, retrospective study conducted from prospectively collected registry data. A consecutive cohort of PCFD patients evaluated from February 2015 to October 2020 was included, consisting of 92 feet in 84 patients. Classification of each patient was made using characteristic clinical and radiographic findings by 3 independent observers. Frequencies of each class and subclass were assessed. Intraobserver and inteobserver reliabilities were analyzed with Cohen kappa and Fleiss kappa, respectively. RESULTS: Mean sample age was 54.4, 38% was male and 62% were female. 1ABC (25.4%) was the most common subclass, followed by 1AC (8.7%) and 1ABCD (6.9%). Only a small percentage of patients had isolated deformity. Class A was the most frequent component (89.5%), followed by C in 86.2% of the cases. Moderate interobserver reliability (Fleiss kappa = 0.561, P < .001, 95% CI 0.528-0.594) was found for overall classification. Very good intraobserver reliability was found (Cohen kappa = 0.851, P < .001, 95% CI 0.777-0.926). CONCLUSION: Almost half (49.3%) of patients had a presentation dominantly involving the hindfoot (A) with various combinations of midfoot and/or forefoot deformity (B), (C) with or without subtalar joint involvement (D). The new system may cover all possible combinations of the PCFD, providing a comprehensive description and guiding treatment in a systematic and individualized manner, but this initial study suggests an opportunity to improve overall interobserver reliability. LEVEL OF EVIDENCE: Level III, retrospective diagnostic study.

Presencia de huesos accesorios del tarso: variantes anatómicas normales con potencialidad patológica / Presence of accessory bones of the tarsus: normal anatomical variants with pathological potential / Presença de ossos acessórios do tarso: variantes anatômicas normais com potencial patológico

El conjunto de patologías bajo el nombre de síndromes dolorosos de pie y tobillo engloban diferentes tendinopatías asociadas entre varios factores clínicos a la presencia de huesos accesorios tarsianos. La correcta identificación y diferenciación radiológica de estas variantes anatómicas en virtud de su capacidad de influir en la dinámica normal del tarso motivan el estudio de su incidencia. Nuestro objetivo es determinar la presencia de distintos huesos accesorios tarsianos en una muestra poblacional. Se expone el resultado de un estudio observacional retrospectivo en 240 pacientes entre 15 y 85 años de edad atendidos en un centro privado de la ciudad de Las Piedras, Canelones, con radiografías de pie y tobillo preexistentes en la base de datos institucional. Se determinó presencia de huesos accesorios tarsianos en 23 pacientes (9,58%), identificando hallazgos de Os Trigonum (1,66%), Proceso de Stieda (3.33%), Os Peroneum (2,93%) y Os Navicular (1,66%). Se presenta en tablas el análisis de frecuencia correspondiente y estudio de contingencia entre variantes encontradas, edad y sexo del paciente. El resultado de la investigación busca aportar al conocimiento de variantes anatómicas normales correlativas a procesos patológicos infradiagnosticados, desde el rol de la anatomía radiológica.

The group of pathologies under the name of foot and ankle pain syndromes encompass different tendinopathies associated among various clinical factors with the presence of accessory tarsal bones. The correct identification and radiological differentiation of these anatomical variants, by virtue of their ability to influence the normal dynamics of the tarsus, motivated the study of their incidence. Our objective is to determine the presence of different tarsal accessory bones in a population sample. Here we present the results of a retrospective observational study in 240 patients between 15 and 85 years of age, treated in a private health center in the city of Las Piedras, Canelones, with pre-existing ankle and foot x-rays in the institutional database. The presence of tarsal accessory bones was determined in 23 patients (9.58%), identifying findings of Os Trigonum (1.66%), Stieda Process (3.33%), Os Peroneum (2.93%) and Os Navicular (1, 66%). The corresponding frequency analysis and contingency study between the variants found, age and sex of the patient are exposed in tables. The result of the research seeks to contribute to the knowledge of normal anatomical variants correlative to under diagnosed pathological processes, from the role of radiological anatomy.

O grupo de patologias com a denominação de síndromes dolorosas no pé e tornozelo engloba diferentes tendinopatias associadas entre diversos fatores clínicos à presença de ossos acessórios do tarso. A correta identificação e diferenciação radiológica dessas variantes anatômicas em virtude de sua capacidade de influenciar a dinâmica normal do tarso motiva o estudo de sua incidência. Nosso objetivo é determinar a presença de diferentes ossos acessórios do tarso em uma amostra populacional. É apresentado o resultado de um estudo observacional retrospectivo em 240 pacientes entre 15 e 85 anos de idade atendidos em um centro privado na cidade de Las Piedras, Canelones, com radiografias de pé e tornozelo pré-existentes no banco de dados institucional. A presença de ossos acessórios do tarso foi determinada em 23 pacientes (9,58%), identificando achados de Os Trigonum (1,66%), Processo de Stieda (3,33%), Os Peroneum (2,93%) e Os Navicular (1,66%). A correspondente análise de frequência e estudo de contingência entre as variantes encontradas, idade e sexo do paciente são apresentados em tabelas. O resultado da pesquisa busca contribuir para o conhecimento das variantes anatômicas normais correlativas aos processos patológicos subdiagnosticados, a partir do papel da anatomia radiológica.