Inter-prefectural and urban-rural regional disparities in lung cancer surgery: a Japanese nationwide population-based cohort study from 2017 to 2019.

PURPOSE: To investigate regional disparities in lung cancer surgery in Japan. METHODS: The annual incidence of lung cancer, lung cancer surgery, and the number of board-certified thoracic surgeons in Japan during 2014-2019 were investigated using a national open database. Lung cancer surgeries were categorized by procedure (wedge resection, segmentectomy, lobectomy, pneumonectomy) and approach (open, thoracoscopic). Disparities in 47 prefectures and urban-rural disparities during 2017-2019 were evaluated using the Gini coefficient and an unpaired t-test. Correlation was assessed using Pearson's correlation method. RESULTS: The national annual average incidences of lung cancer and lung cancer surgery were 121,106 and 50,959, respectively, in 2014-2019. The use of the thoracoscopic approach increased over time in all procedures, except pneumonectomies. The Gini coefficients of lung cancer, thoracoscopic surgery, and board-certified thoracic surgeons indicated low inequality across prefectures; however, those of open surgery indicated high inequality. Open surgery was more common in urban areas than in rural areas. The number of thoracoscopic surgeries and board-certified thoracic surgeons by prefecture were moderately correlated. CONCLUSION: The thoracoscopic approach is becoming more common in lung cancer surgery, with little inter-prefectural regional disparity in the incidence of lung cancer, thoracoscopic surgeries, or the number of board-certified thoracic surgeons.

Validation of Wistar-Kyoto rats kept in solitary housing as an animal model for depression using voxel-based morphometry.

Major depressive disorder is a common psychiatric condition often resistant to medication. The Wistar-Kyoto (WKY) rat has been suggested as an animal model of depression; however, it is still challenging to translate results from animal models into humans. Solitary housing is a mild stress paradigm that can simulate the environment of depressive patients with limited social activity due to symptoms. We used voxel-based morphometry to associate the solitary-housed WKY (sWKY) rat model with data from previous human studies and validated our results with behavioural studies. As a result, atrophy in sWKY rats was detected in the ventral hippocampus, caudate putamen, lateral septum, cerebellar vermis, and cerebellar nuclei (p < 0.05, corrected for family-wise error rate). Locomotor behaviour was negatively correlated with habenula volume and positively correlated with atrophy of the cerebellar vermis. In addition, sWKY rats showed depletion of sucrose consumption not after reward habituation but without reward habituation. Although the application of sWKY rats in a study of anhedonia might be limited, we observed some similarities between the regions of brain atrophy in sWKY rats and humans with depression, supporting the translation of sWKY rat studies to humans.

Relationship between arthritis of the second and third tarsometatarsal joints and incongruity of the first tarsometatarsal joint in patients with hallux valgus.

OBJECTIVES: Hallux valgus is associated with tarsometatarsal arthritis; its pathophysiology remains unknown. Therefore, we aimed to elucidate the relationship between arthritis of the second and third tarsometatarsal joints and incongruity of the first tarsometatarsal joint in the sagittal plane. METHODS: Forty-three patients (64 feet) with hallux valgus who underwent surgery at University Hospital Kyoto Prefectural University of Medicine were included and divided into two groups: control (without second and third tarsometatarsal joint degeneration) and osteoarthritis (with second and third tarsometatarsal joint degeneration). Intergroup comparisons of the incongruity of the first tarsometatarsal joint in the sagittal plane, age, body mass index, hallux valgus angle, first-second intermetatarsal angle, metatarsus adductus angle, Meary's angle, and calcaneal pitch angle were performed. RESULTS: The proportion of patients with incongruity of the first tarsometatarsal joint was significantly higher in the osteoarthritis group than in the control group. Logistic regression analysis identified incongruity of the first tarsometatarsal joint and metatarsus adductus angle as significant related factors for arthritis of the second and third tarsometatarsal joints. CONCLUSIONS: Incongruity of the first tarsometatarsal joint in the sagittal plane was involved in the development of arthritis of the second and third tarsometatarsal joints in patients with hallux valgus.

The inter-prefectural regional disparity of healthcare resources and representative surgical procedures in orthopaedics and general surgery: a nationwide study in Japan during 2015-2019.

BACKGROUND: Few reports have examined the localized regional disparity in representative surgical procedures in orthopaedics and general surgery globally. This study aimed to clarify the inter-prefectural regional disparity and relationships between healthcare resources and representative surgical procedures using a nationwide database in Japan. METHODS: The number of medical specialists in orthopaedics, general surgery, and anaesthesiology, as well as the number of hospitals, and the incidence of representative surgical procedures in orthopaedics and general surgery were evaluated annually per 100,000 inhabitants/people by prefecture in Japan during 2015-2019. Medium-sized regional disparities were evaluated using the Gini coefficient. Correlation coefficients were calculated for the defined variables and ageing rate. We also compared the urban and rural regional disparities in all study variables. RESULTS: The annual average number/incidence and Gini coefficients were 110.6 and 0.11 for femur fracture surgery, 106.3 and 0.09 for cholecystectomy, 14.2 and 0.11 for orthopaedic surgeon specialists, 17.6 and 0.09 for general surgeon specialists, 5.9 and 0.13 for anaesthesiology specialists, and 8.1 and 0.21 for hospitals, respectively. The correlation coefficients by the incidence of femur fracture surgery were 0.74 for orthopaedic surgeon specialists (p < 0.001), 0.63 for hospitals (p < 0.001), and 0.62 for the ageing rate (p < 0.001); those by the incidence of cholecystectomy were 0.60 for general surgeon specialists (p < 0.001) and 0.59 for hospitals (p < 0.001). The number/incidence of orthopaedic surgeon specialists, hospitals, femur fracture surgery, and cholecystectomy, as well as the ageing rate, were significantly higher in rural prefectures than in urban prefectures (p < 0.05). CONCLUSIONS: Inter-prefectural regional disparity was small, although certain items were unevenly distributed in the rural prefectures, which is contrary to our expectations. Higher prevalence was recognised in rural prefectures due to the higher ageing rate; however, supply and demand are balanced. This study provides basic data for healthcare policy development in a medium-sized community. LEVEL OF EVIDENCE: III.

Trends and age- and sex-stratified analysis of hallux valgus correction surgery from 2014 to 2019: A nationwide population-based cohort study in Japan.

BACKGROUND: Epidemiological studies on hallux valgus (HV) are challenging owing to differences in sampling and diagnostic criteria across studies. This study aimed to indirectly clarify HV epidemiology using a national database. METHODS: The age- and sex-stratified annual number rate of HV correction (RHVC) per 100,000 people in Japan during 2014-2019 were examined. RESULTS: The average annual RHVC was 3.0. RHVC had unimodal (peak, 65-79 years) and bimodal (peaks, 15-19 and 70-74 years) distributions among males and females, respectively, and increased over time in males aged 50-54 and 75-79 years and females aged 80-84 years. CONCLUSIONS: RHVC increases with increasing age and occurs commonly in female teens. The recent RHVC in Japan was lower than that reported in Europe and the United States, with an increasing trend among elderly people. LEVEL OF EVIDENCE: III.

Sweep imaging with Fourier transform as a tool with MRI for evaluating the effect of teriparatide on cortical bone formation in an ovariectomized rat model.

BACKGROUND: Teriparatide (TPTD) is a drug for osteoporosis that promotes bone formation and improves bone quality. However, the effects of TPTD on cortical bone are not well understood. Sweep imaging with Fourier transform (SWIFT) has been reported as a useful tool for evaluating bound water of cortical bone, but it has yet to be used to investigate the effects of TPTD on cortical bone. This study aimed to evaluate the consequences of the effect of TPTD on cortical bone formation using SWIFT. METHODS: Twelve-week-old female Sprague-Dawley rats (n = 36) were reared after ovariectomy to create a postmenopausal osteoporosis model. They were divided into two groups: the TPTD and non-TPTD groups. Rats were euthanized at 4, 12, and 24 weeks after initiating TPTD treatment. Tibial bones were evaluated using magnetic resonance imaging (MRI) and bone histomorphometry. In MRI, proton density-weighted imaging (PDWI) and SWIFT imaging were performed. The signal-to-noise ratio (SNR) was calculated for each method. The same area evaluated by MRI was then used to calculate the bone formation rate by bone histomorphometry. Measurements were compared using the Mann-Whitney U-test, and a P-value of < 0.05 was considered significant. RESULTS: PDWI-SNR was not significantly different between the two groups at any time point (P = 0.589, 0.394, and 0.394 at 4, 12, and 24 weeks, respectively). Contrarily, SWIFT-SNR was significantly higher in the TPTD group than in the non-TPTD group at 4 weeks after initiating treatment, but it was not significantly different at 12 and 24 weeks (P = 0.009, 0.937, and 0.818 at 4, 12, and 24 weeks, respectively). The bone formation rate assessed by histomorphometry was significantly higher in the TPTD group than in the non-TPTD group at all timepoints (P < 0.05, all weeks). In particular, at 4 weeks, the bone formation rate was markedly higher in the TPTD group than in the non-TPTD group (P = 0.028, 1.98 ± 0.33 vs. 0.09 ± 0.05 µm3/µm2/day). CONCLUSIONS: SWIFT could detect increased signals of bound water, reflecting the effect of TPTD on the cortical bone. The signal detected by SWIFT reflects a marked increase in the cortical bone formation rate.

Early stage and small medial osteochondral lesions of the talus in the presence of chronic lateral ankle instability: A retrospective study.

BACKGROUND: In chronic lateral ankle instability (CLAI), the instability of the ankle joint results in repeated microtrauma to the articular cartilage. How the lesion condition or stage is affected by the presence of lateral instability in medial osteochondral lesions of the talus (OLT) is unclear. We aimed to examine whether CLAI is associated with the size and staging of medial OLT on radiographs, magnetic resonance (MR) images, and arthroscopy. METHODS: Forty-five patients with medial OLTs in 45 ankles were reviewed. Radiographs were assessed for damage and lesion classification. The tibio-talar tilting angle (TTA) was measured. The patients were divided into two groups: the CLAI group and the stable group. The lesion classification on radiographs, MR images, and arthroscopy, and size on MR images were statistically compared. RESULTS: The CLAI group had a mean TTA of 8.15 ± 3.41°, whereas the stable group had a mean TTA of 2.24 ± 1.64°. The CLAI group had a lower clinical score than the stable group at the initial visit to our clinic. The CLAI group presented with lesions of significantly shorter longitudinal and transverse diameters. Stages of medial OLT on radiographs, MR images, and arthroscopic evaluation were earlier in the CLAI group than those in the stable group. CONCLUSIONS: Patients with CLAI presented in the early stages of OLT and had significantly smaller lesions than those without CLAI. The patients without CLAI may be selected for surgery at an early phase.

The influence of hallux valgus and flatfoot deformity on metatarsus primus elevatus: A radiographic study.

BACKGROUND: Metatarsus primus elevatus (MPE), a dorsal elevation of the first metatarsal in relation to the lesser metatarsals on lateral-view radiographs, is an indicator of hallux rigidus. The angle between the articular surfaces of the base of the first metatarsal and the anterior part of the medial cuneiform (M1C1A) reflects the sagittal instability of the first tarsometatarsal (TMT) joint. MPE may also indicate instability of the first metatarsal. The purpose of this study was to identify the influence of hallux valgus (HV) and flatfoot (FF) deformities on measurements obtained from first metatarsal-related radiographic images. METHODS: Standing radiographic images of 134 feet were investigated. In dorsoplantar-view radiographs, HV and intermetatarsal angles were evaluated. The position of the medial sesamoid was classified with a grading system (Hardy score). In lateral-view radiographs, MPE, M1C1A, and Meary's angle were measured. The subjects were divided into 4 groups: the normal group (G1), HV(-)FF(-); the HV group (G2), HV(+)FF(-); the FF group (G3), HV(-)FF(+); and the dual group (G4), HV(+)FF(+). The radiographic parameters were compared among the groups. RESULTS: MPE in the HV patients (G2 and G4) was less than that in the non-HV participants (G1 and G3). MPE in G4 was less than that in G3. The odds ratios of the Hardy score were higher in G2, G3 and G4 than in G1. The ratios were higher in the FF patients (G3 and G4) than in the non-FF participants (G1 and G2) and were higher in G4 than in G2. CONCLUSIONS: FF affects sesamoid dislocation, and the combination of HV and FF further increases sesamoid dislocation. Combined with M1C1A and the Hardy score, MPE may be a useful indicator of three-dimensional instability of the first TMT joint. First TMT joint-related operations may be considered for severe HV treatment in G4 patients.

Reproducibility of radiographic methods for assessing longitudinal tarsal axes Part 2: Severe cavus or flatfoot study.

INTRODUCTION: Calcaneal pitch angle and Meary's angle are commonly used to assess longitudinal foot arches on lateral-view radiographs. The aim of this study was to examine and evaluate the radiographic longitudinal foot arch measurement methods with the best intraobserver and interobserver reliabilities for patients with (1) severe cavus deformity and (2) severe flatfoot deformity. METHODS: Standing radiographic images of 22feet with severe cavus foot deformity and 49feet with severe flatfoot deformity were obtained to measure the longitudinal axes of the talus, first metatarsal, calcaneus and plantar surface, which were defined using six, five, four and three different methods, respectively, selected from previous reports. Intraobserver and interobserver correlation coefficients were calculated. RESULTS: The results are generally consistent with those of Part 1. The best intraobserver and interobserver correlation coefficients for the tarsal axes were obtained using methods involving a line bisecting the angle formed by the lines tangential to the superior and inferior margins of the talus, a line connecting the centre of the first metatarsal head and the midpoint of the visualized base of the first metatarsal, and a line drawn tangential to the inferior surface of the calcaneus. For the plantar axis, a method that used the horizontal plane (as a reference axis) was regarded as the best approach. CONCLUSIONS: The aforementioned methods were considered to be optimal for the radiographic assessment of longitudinal foot arches in patients with severe cavus or flatfoot deformity. This study may contribute to the more accurate assessment of any foot deformity.

Reproducibility of radiographic methods for assessing longitudinal tarsal axes: Part 1: Consecutive case study.

INTRODUCTION: Calcaneal pitch angle and Meary's angle are commonly used to assess longitudinal foot arches on lateral-view radiographs. However, the methods used to obtain the talar, first metatarsal, calcaneal, and plantar axes differ across multiple reports, and no study has evaluated the reproducibility of these approaches. The aim of this study was to determine the most reproducible methods for radiographically evaluating longitudinal axes. METHODS: Standing radiographic images of 40 feet from 21 consecutive outpatients were obtained to measure longitudinal axes of the talus, first metatarsal, calcaneus and plantar surface, which were defined using six, five, four and three different methods, respectively, selected from previous reports. Intraobserver and interobserver correlation coefficients were calculated. RESULTS: The best intraobserver and interobserver correlation coefficients for the talar, first metatarsal, and calcaneal axes were obtained using methods involving a line bisecting the angle formed by the lines tangential to the superior and inferior margins of the talus, a line connecting the centre of the first metatarsal head and the midpoint of the visualized base of the first metatarsal, and a line drawn tangential to the inferior surface of the calcaneus, respectively. For the plantar axis, a method that used the horizontal plane (as a reference axis) was regarded as the best approach, although intraobserver and interobserver correlation coefficients could not be calculated because all values were zero. CONCLUSIONS: The aforementioned methods were considered to be optimal for the radiographic assessment of longitudinal foot arches. This study could contribute to more accurate assessments of foot deformities.

A kinematic and kinetic analysis of the hip and knee joints in patients with posterior tibialis tendon dysfunction; comparison with healthy age-matched controls.

BACKGROUND: The biomechanical abnormalities in patients with posterior tibial tendon dysfunction (PTTD) have been described, but few studies have investigated biomechanical chains of adjacent joints. Therefore, we examined the gait pattern of the lower extremity in subjects with PTTD, focusing on the hip and knee joints. METHODS: We compared 19 PTTD patients (average age: 67.1) with 30 age-matched control subjects (average age: 65.1). Gait analysis was performed with a nine-camera motion-capture system and four force plates, using the Vicon Plug-In-Gait and Vicon Nexus software. Temporal-spatial parameters were compared between PTTD and control subjects, and motion and ground reaction force data were compared between the affected limb, the contralateral limb, and the right limb in control subjects. RESULTS: Subjects with PTTD had increased stance phase ratio and decreased stride length, cadence, and gait speed. The limbs of subjects with PTTD showed increased knee internal rotation at lording response, which was biased to abduction in the knee joint during the gait cycle, and irregular hip flexion and knee extension moment in the terminal stance, even under control of gait speed. SIGNIFICANCE: We believe that the subjects with PTTD have an increased risk of knee osteoarthritis in both the affected and contralateral limbs.

Early detection of osteoarthritis in rabbits using MRI with a double-contrast agent.

BACKGROUND: Articular cartilage degeneration has been evaluated by magnetic resonance imaging (MRI). However, this method has several problems, including its time-consuming nature and the requirement of a high magnetic field or specialized hardware. The purpose of this study was to sequentially assess early degenerative changes in rabbit knee articular cartilage using MRI with a new double-contrast agent. METHODS: We induced osteoarthritis (OA) in the right knee of rabbits by anterior cruciate ligament transection and partial medial meniscectomy. Proton density-weighted images and T2-calculated images were obtained before and after contrast agent injection into the knee. The signal intensity ratio (SIR) values on the proton density-weighted images were calculated by dividing the signal intensity of the articular cartilage by that of joint fluid. Six rabbits were examined using MRI at 2 (designated 2-w OA) and 4 weeks (4-w OA) after the operation. Histological examination was performed 4 weeks after the operation. One rabbit was histologically examined 2 weeks after the operation. The control consisted of six rabbits that were not subjected to the operation. The SIR values, T2 values and the thicknesses of the cartilage of the 2-w OA, 4-w OA and the control before and after contrast agent injection were analyzed. The Mankin score and OARSI (Osteoarthritis Research Society International) score were used for the histological evaluation. RESULTS: Significant differences in the SIR and T2 values of the medial and lateral condyles of the femur were found between the control and the 4-w OA only after contrast agent injection. No significant differences were found in the SIR and T2 values before contrast agent injection between the control, the 2-w OA and 4-w OA. The thickness of the articular cartilage revealed no significant differences. In the histological assessment, the Mankin score and OARSI score sequentially increased from the control to the 4-w OA. CONCLUSION: We evaluated the SIR and T2 values of the knees in a rabbit OA model and a control model using a new double-contrast agent. MRI with this agent enabled OA detection earlier than using conventional MRI.

Towards patient-specific medializing calcaneal osteotomy for adult flatfoot: a finite element study.

Clinically in medializing calcaneal osteotomy (MCO), foot and ankle surgeons are facing difficulties in choosing appropriate surgical parameters due to the individual differences in deformities among flatfoot patients. Traditional cadaveric studies have provided important information regarding the biomechanical effects of tendons, ligaments, and plantar fascia, but limitations have been reached when dealing with individual differences and tailoring patient-specific surgeries. Therefore, this study aimed at implementing the finite element (FE) method to investigate the effect of different MCO parameters to help foot and ankle surgeons performing patient-specific surgeries. This study constructed FE models of a flatfoot and a healthy foot based on computed tomography (CT) images. After validating the FE models with experimental measurements, differences in plantar stress were compared between two models and a criterion was established for evaluating the performance of surgical simulations. Four MCO parameters were then studied through FE simulations. Results suggested that the transverse angle, ß, and translation distance, d, affected surgical performance. Therefore, special attentions may be recommended when choosing these two parameters clinically. However, the sagittal angle, α, and osteotomy position, p, were found to have less effect on the MCO performance.

Magnetic resonance imaging findings of chronic plantar fasciitis before and after extracorporeal shock wave therapy.

INTRODUCTION: The objective of this study is to examine the relationships between treatment outcome and changes in magnetic resonance (MR) imaging findings after extracorporeal shock wave therapy (ESWT) for chronic plantar fasciitis. METHODS: The subjects were 23 feet of 23 patients of refractory plantar fasciitis. The mean age was 53.7 years. The thickness of the plantar fascia (PF) and findings of a high-signal intensity area (HSIA) inside the PF, edema around the PF, and bone marrow edema (BME) of the calcaneus were investigated on MR images. The Japanese Society for Surgery of the Foot (JSSF) ankle-hindfoot scale and a visual analogue scale (VAS) were used. Correlations between an improvement in symptoms and one in the MRI findings were analyzed. RESULTS: The mean thickness of the PF was 4.4±1.6mm before ESWT and 4.6±1.8mm six months after ESWT. After ESWT, there was a decrease in the numbers of feet showing HSIA inside the PF from 15 to 6, in edema around the PF from 16 to 2, and in BME of the calcaneus from 11 to 4. Clinical outcomes improved with ESWT from 70.3±5.5 to 88.6±9.1 points (JSSF), 74.1±25.3 to 28.5±24.4 points (VAS), respectively. Improvements in symptoms according to the JSSF and VAS scores and improvement in edema around the PF on MR images showed a significant correlation. CONCLUSIONS: Edema around the PF improved significantly in association with an improvement in symptoms after ESWT.

Relationship Between Grading With Magnetic Resonance Imaging and Radiographic Parameters in Posterior Tibial Tendon Dysfunction.

The objective of the present study was to elucidate the relationship between the state of the posterior tibial tendon (PTT) on magnetic resonance images and foot deformity. The cases included 34 feet in 27 patients with PTT deformity and the controls included 18 feet in 12 patients who had undergone magnetic resonance imaging for other foot diseases. The PTT was closely examined on the magnetic resonance images and classified using the Conti classification. The control feet with no injury to the PTT were classified as grade 0. The talonavicular coverage angle, lateral talo-first metatarsal angle, medial cuneiform to fifth metatarsal height, calcaneal pitch angle, and varus-valgus angle were measured as radiographic parameters for flatfoot deformation, and the relation between the Conti classification and each parameter was examined statistically. A significant difference was observed in the talonavicular coverage angle between grade 0 and the other grades; the lateral talo-first metatarsal angle between grade 0 and the other grades and between grades 1 and 3; the medial cuneiform to fifth metatarsal height among grades 0, 2, and 3 and grades 1, 2, and 3; the calcaneal pitch angle between grades 1 and 3; and the varus-valgus angle among grades 0, 2, and 3 and between grades 1 and 3. Eversion of the forefoot was observed, along with an advanced collapse in the medial longitudinal arch, from an early stage of PTT injury.

Examination of the Correlation Between Foot Morphology Measurements Using Pedography and Radiographic Measurements.

Pedography provides excellent visualization of the footprint. However, the correlation between the footprint images and radiographic measures has not been thoroughly evaluated. Therefore, the objectives of our study were to examine the correlation between the pedography-based measures of foot morphology and radiographic measurements and to propose reference values for the diagnosis of flatfoot using footprint imaging. The plantar footprints of 100 right feet were photographed using a pedography standing platform. The sole and arch areas were measured to calculate the footprint index (FPI). The lateral talar-first metatarsal angle (LTM) and calcaneal pitch angle (CP) were measured on standing lateral radiographs, and the talonavicular coverage angle was measured on frontal radiographs. The Pearson moment correlation between the FPI and radiography-based measures was calculated. The area under the receiver operating characteristic curve was calculated using an LTM of <-4° as the identifying criterion of flatfoot. The sensitivity and specificity of FPI were calculated for LTM values <-4°. The FPI correlated with the LTM (y = -17.964 ± 52.644x, R = 0.588) and CP (y = 9.2304 ± 27.739x, R = 0.659) but not with the talonavicular coverage angle (y = 26.01 ± 15.78x, R = 0.207). The area under the receiver operating characteristic curve was 0.753, with a cutoff FPI of 0.208, yielding a sensitivity of 0.462 and specificity of 0.934 for flatfoot identification. Pedography could provide an easy screening tool for flatfoot, with an FPI cutoff of 0.208, yielding a specificity of 93.4%.

Investigation of the Longitudinal Relaxation Time of Rat Tibial Cortical Bone Using SWIFT.

Sweep imaging with Fourier transform (SWIFT) method has been developed to image tissues with very short T2 values, such as cortical bone. The purpose of this study was to measure the T1 value of the rat cortical bone. It was approximately 120 ms on 7.04T. This result could thus be useful for studying bony tissue according to the SWIFT method in the future.

Diagnostic Characteristics of Standard Radiographs and Magnetic Resonance Imaging of Ruptures of the Tibialis Posterior Tendon.

The present study aimed to diagnose complete rupture (CR) and longitudinal rupture (LR) of the posterior tibial tendon (PTT) from the magnetic resonance imaging findings in patients with PTT dysfunction and to analyze and compare the radiographs from each group to identify radiographic indicators related to the progression of PTT injury that would allow the radiographic diagnosis of CR. We evaluated 32 feet in 27 patients with PTT dysfunction (mean age 66.5, range 49 to 82, years). Radiographs were used to acquire weightbearing anteroposterior images of the foot, which were used to measure the talonavicular coverage angle. Lateral images of the foot were also acquired with the patients in the standing position. These were used to measure the lateral talometatarsal angle, calcaneal pitch angle, and medial cuneiform-fifth metatarsal height. From the axial MRI findings, the patients were divided into a CR group and an LR group, and the radiographic attributes of the CR group were analyzed. Of the 32 feet in 27 patients, 12 feet (37.5%) in 11 patients displayed CR and 20 feet (62.5%) in 18 patients displayed LR. The talonavicular coverage angle was 48.3° ± 17.3° in the CR group and 33.6° ± 13.6° in the LR group (p = .012), and the talometatarsal angle was -28.8° ± 22.5° in the CR group and -25.4° ± 14.4° in the LR group (p = .596). The calcaneal pitch angle was 10.4° ± 6.7° in the CR group and 10.2° ± 8.0° in the LR group (p = .935). Finally, the medial cuneiform-fifth metatarsal height was -4.2 ± 7.1 mm in the CR group and 2.1 ± 4.7 mm in the LR group (p = .005). When a medial cuneiform-fifth metatarsal height of ≤0 mm or talonavicular coverage angle of ≥50° was used as the diagnostic criterion for CR on weightbearing radiographs, the sensitivity was 71.4%, specificity 88.9%, and diagnostic accuracy 81.3%; hence, we believe these to be satisfactory diagnostic criteria for CR.