Is the Greulich and Pyle atlas applicable to all ethnicities? A systematic review and meta-analysis

Methods of Assessing Skeletal Maturity When Planning Surgeries About the Knee

Increased participation in youth sports has led to more knee injuries necessitating surgical intervention. Among the youngest athletes, such procedures typically involve physeal-respecting techniques for anterior cruciate ligament reconstruction, medial patellofemoral ligament reconstruction for patellar instability, osteochondritis dissecans fixation, and implant-mediated guided growth procedures. In each case, the choice of appropriate intervention is critically dependent on a patient's skeletal maturity. Compared with chronologic age, skeletal age accounts for individual maturation and is the benchmark for determination of development in orthopaedics. This is historically assessed using the Greulich and Pyle method, in which bone age is determined through comparison of a patient's hand radiograph with the closest standard radiograph from an atlas of American children from the early 1900s. In the setting of knee pathology, obtaining additional imaging requires further radiation and time. Several bone age determination methods exist incorporating radiographic characteristics of the distal femur, proximal tibia, and/or proximal fibula. This study therefore sought to review available methods for determination of skeletal age when planning surgeries about the knee using readily available, routine knee imaging. The review focuses on both radiograph and MRI-based skeletal maturity staging systems that surgeons may use to guide appropriate treatment while describing the strengths and weaknesses of each method.

Influence of Biological Maturation on the Career Trajectory of Football Players: Does It Predict Elite Success?

Background: Early-maturing players tend to have physical advantages during formative stages, but it remains unclear whether these advantages translate into long-term professional success. This study examines how biological maturation influences participation and career trajectories in youth football. Methods: Anthropometric and competitive data were collected from 47 players (13.53 ± 1.08 years) in a top-tier academy during the 2010-2011 season. The maturation status was assessed using the Tanner-Whitehouse II RUS method, and the career outcomes were tracked in 2024-2025. Results: Early-maturing players showed higher anthropometric values and greater participation. However, late maturers were more likely to reach professional football (p = 0.003), with all players competing in the top five European leagues belonging to the late-maturing group. Conclusions: Early maturation does not guarantee professional success. Strategies such as bio-banding and personalized training can reduce biases and support talent development, highlighting the need for a more holistic approach to player evaluation.

Children's bone age development is delayed with increasing altitude: a multicentre study

OBJECTIVES

To investigate the bone age (BA) characteristics of children living in high-altitude regions and determine the impact of altitude on the development of BA.

METHODS

From June 2014 to July 2022, 1318 children with left-hand-wrist radiographs were retrospectively enrolled from 3 different geographical altitudes (Beijing 43.5 m above sea level [asl], Lhasa 3650 m asl, and Nagqu 4500 m asl). The predicted age difference (PAD), defined as the difference between BA and chronologic age (CA), was considered the indicator for delayed or advanced growth. The PAD of children from the 3 regions in total and according to different age groups, genders, and ethnicities were compared. The linear regression model was used to assess the effect of altitude on PAD.

RESULTS

A total of 1284 children (CA: 12.00 [6.45-15.72] years; male: 837/1284, 65.2%) were included in the study with 407 from Beijing, 491 from Lhasa, and 386 from Nagqu. The PAD for Beijing, Lhasa, and Nagqu were 0.1 [-0.30 to 0.65], -0.40 [-1.20 to 0.27], and -1.42 [-2.32 to -0.51] years, respectively. A linear regression analysis showed that altitude significantly contributed to PAD (compared to Beijing, Lhasa coefficient = -0.57, P < .001; Nagqu coefficient = -1.55, P < .001).

CONCLUSIONS

High altitude might be an independent contributor to the delayed BA development of children.

ADVANCES IN KNOWLEDGE

The impact of altitude on BA development was revealed for the first time, highlighting the necessity of considering the altitude of the area when evaluating BA development for children residing in high-altitude regions.ke.

Juxtaposition of bone age and sexual maturity rating of the Taiwanese population

Background

Bone age (BA) and sexual maturity rating (SMR) are crucial measures in assessing adolescent growth and development. However, studies specifically focusing on the association between BA and SMR in the Taiwanese adolescent population are limited. This study aims to utilize AI-assessed BA results to establish a relationship between BA and SMR in the Taiwanese adolescent population, particularly regarding the initiation of puberty.

Materials and methods

The electronic medical records of bone age assessments conducted between January 1, 2019, and December 31, 2019, were reviewed retrospectively. For individuals with multiple records, only the latest entry within this period was retained. Records lacking a valid SMR or presenting significant medical conditions were excluded from the analysis. Males aged 7-17 years and females aged 6-16 years were included in the study.

Results

The onset of puberty was observed to occur at a median bone age of 11.50 years (95% CI: 11.42-11.83) for males and 9.33 years (95% CI: 9.25-9.50) for females.

Conclusion

The consistency between BA and SMR could serve as an alternative approach for assessing pubertal status in peripubertal children, providing a less intrusive evaluation regardless of chronological age (CA).

A machine learning approach for age prediction based on trigeminal landmarks

OBJECTIVE

The aim of this study was to estimate the chronological age (CA) of a growing individual using a new machine learning approach on Cone Beam Computed Tomography (CBCT).

MATERIALS AND METHODS

The dataset included 48 CBCT and hand-wrist radiographs of growing individuals. 12 landmarks related to trigeminal trajectories were plotted on each CBCT and principal component analysis was applied for dimensionality reduction. The estimated CA was obtained using a decision tree. Finally, a genetic algorithm was implemented to select the best set of landmarks that would optimize the estimation. The age was also assessed following Greulich and Pyle's (GP) method on hand-wrist radiographs. The results (GP and Machine Learning) were then compared to the true CA.

RESULTS

Among the 12 landmarks, the genetic algorithm selected 7 optimal features, and 12 principal components out of 36. The best results for age prediction were obtained by a combination of genetic algorithm, principal component analysis, and regression tree where the Mean Squared Error (MSE) and Mean Absolute Error (MAE) were respectively 1.29 and 0.92. These outcomes showed improved accuracy compared to those of the hand-wrist method (MSE = 2.038 and MAE = 1.775).

CONCLUSIONS

A numerical application on a dataset of CBCT showed that the proposed machine learning method achieved an improved accuracy compared to conventional methods and had satisfying performance in assessing age for forensic purposes. Validation of the presented method on a larger and more diverse sample would pave the way for future applications in forensic science as a tool for age prediction.

Functional and radiologic outcomes of non-displaced scaphoid waist fractures in adolescents approaching skeletal maturity: Comparison between conservative treatment and percutaneous screw fixation

BACKGROUND

Treatment of scaphoid waist fractures is generally conservative in children but surgical in adults, given the relatively high risk of non-union in adults. In adolescents, the required therapeutic strategy is less well defined. The objective of this study was to compare the radiographic and clinical parameters, and the rate of complications, between non-surgical orthopedic treatment (OT) and surgical treatment (ST) by percutaneous screw fixation of these fractures in adolescents approaching skeletal maturity.

HYPOTHESIS

ST of non-displaced scaphoid waist fractures in adolescents allows radiographic union, a functional result and a complication rate comparable to that of ST.

METHODS

This single-center retrospective study included patients who presented with a non-displaced scaphoid waist fracture, with a chronological age (CA) and a bone age (BA) between 14 and 18 years. Clinical and radiographic parameters and complications were analyzed during the trauma and at one year, including functional scores, between two groups of patients; OT and ST.

RESULTS

Thirty-seven patients had OT (63.8%) and 21 had ST (36.2%). The median CA was 16 years [14.25-16]. The median BA was 16 years [15;17] according to the Greulich and Pyle method and corresponded to R9 [R7-R10] and U7 [U7;U8] according to the Distal Radius and Ulnar (DRU) classification system. All non-unions were found in the OT group (23.4% vs. 0%, p=0.019). The duration of immobilization (8 weeks) and the number of consultations were higher after OT than ST. Functional scores were lower in patients with non-union after OT (p≤0.002) CONCLUSION: OT of scaphoid waist fractures in adolescents results in a higher rate of non-union than ST, similar to the rate found in adults. Findings from this study recommend a surgical approach by percutaneous screw fixation.

LEVEL OF EVIDENCE

III; comparative retrospective study.

Percent Final Height Is a Novel Method That Identifies Differences Between the Rate of Development in American Children of Different Races

INTRODUCTION

The Greulich & Pyle (G&P) Radiographic Atlas of Skeletal Development uses hand x-rays obtained between 1926 and 1942 on children of Caucasian ancestry. Our study uses modern Caucasian, Black, Hispanic, and Asian children to investigate patterns of development as a function of percent final height (PFH).

METHODS

A retrospective review, at a single institution, was conducted using children who received a hand x-ray, a height measurement taken within 60 days of that x-ray, and a final height. BA and CA were compared between races. PFH was calculated by dividing height at the time of the x-ray by their final height. To further evaluate differences between races in CA or BA, PFH was then modeled as a function of CA or BA using a fifth-degree polynomial regression, and mean ages at the 85th PFH were compared. Patients were then divided into Sanders stages 1, 2-4, and 5-8 and the mean PFH, CA, and BA of the Asian, Black, and Hispanic children were compared with the White children using Student t test. P values less than 0.05 were considered significant.

RESULTS

We studied 498 patients, including 53 Asian, 83 Black, 190 Hispanic, and 172 White patients. Mean BA was significantly greater than CA in Black males (1.27 y) and females (1.36 y), Hispanic males (1.12 y) and females (1.29 y), and White females (0.74 y). Hispanic and Black patients were significantly more advanced in BA than White patients ( P <0.001). At the 85th PFH, White and Hispanic males were older than Black males by at least 7 months ( P <0.001), and White females were significantly older than Hispanic females by 6.4 months ( P <0.001). At 85th PFH for males, Hispanic and Black males had greater BA than White males by at least 5 months ( P <0.001), and Asian females had a greater BA than Black females by at least 5 months ( P <0.001). Compared with White children, Hispanic children were significantly younger at Sanders 2-4 than White children, and Black children were skeletally older at Sanders 5-8.

CONCLUSIONS

BA was greater than CA by ≥1 year in Black and Hispanic children, and that these children had a significantly greater BA than their White counterparts. Black males and Hispanic females reached their 85th PFH at younger ages, and Hispanic males and Asian females were the most skeletally mature at their 85th PFH. Our results suggest that BA and CA may vary as a function of race, and further studies evaluating growth via the 85th PFH may be necessary.

LEVEL OF EVIDENCE

Therapeutic Study - Level IV.

The Validation of the Greulich and Pyle Atlas for Radiological Bone Age Assessments in a Pediatric Population from the Canary Islands

Bone age assessments measure the growth and development of children and adolescents by evaluating their skeletal maturity, which is influenced by various factors like heredity, ethnicity, culture, and nutrition. The clinical standards for this assessment should be up to date and appropriate for the specific population being studied. This study validates the GP-Canary Atlas for accurately predicting bone age by analyzing posteroanterior left hand and wrist radiographs of healthy children (80 females and 134 males) from the Canary Islands across various developmental stages and genders. We found strong intra-rater reliability among all three raters, with Raters 1 and 2 indicating very high consistency (intra-class coefficients = 0.990 to 0.996) and Rater 3 displaying slightly lower but still strong reliability (intra-class coefficients = 0.921 to 0.976). The inter-rater agreement was excellent between Raters 1 and 2 but significantly lower between Rater 3 and the other two raters, with intra-class coefficients of 0.408 and 0.463 for Rater 1 and 0.327 and 0.509 for Rater 2. The accuracy analysis revealed a substantial underestimation of bone age compared to chronological age for preschool- (mean difference = 17.036 months; p < 0.001) and school-age males (mean difference = 13.298 months; p < 0.001). However, this was not observed in females, where the mean difference was minimal (3.949 months; p < 0.239). In contrast, the Atlas showed greater accuracy for teenagers, showing only a slight overestimation (mean difference = 3.159 months; p = 0.823). In conclusion, the GP-Canary Atlas demonstrates overall precision but requires caution as it underestimates the BA in preschool children and overestimates it in school-age girls and adolescents.

Acceleration of skeletal maturation in Central Europe over the last two decades: insights from two cohorts of healthy children

BACKGROUND

Deviations between the determination of bone age (BA) according to Greulich and Pyle (G&P) and chronological age (CA) are common in Caucasians. Assessing these discrepancies in a population over time requires analysis of large samples and low intra-observer variability in BA estimation, both can be achieved with artificial intelligence-based software. The latest software-based reference curve contrasting the BA determined by G&P to the CA of Central European children dates back over two decades.

OBJECTIVE

To examine whether the reference curve from a historical cohort from the Netherlands (Rotterdam cohort) between BA determined by G&P and CA still applies to a current Central European cohort and derive a current reference curve.

MATERIALS AND METHODS

This retrospective single-center study included 1,653 children and adolescents (aged 3-17 years) who had received a radiograph of the hand following trauma. The G&P BA estimated using artificial intelligence-based software was contrasted with the CA, and the deviations were compared with the Rotterdam cohort.

RESULTS

Among the participants, the mean absolute error between BA and CA was 0.92 years for girls and 0.97 years for boys. For the ages of 8 years (boys) and 11 years (girls) and upward, the mean deviation was significantly greater in the current cohort than in the Rotterdam cohort. The reference curves of both cohorts also differed significantly from each other (P < 0.001 for both boys and girls).

CONCLUSION

The BA of the current Central European population and that of the curve from the Rotterdam cohort from over two decades ago differ. Whether this effect can be attributed to accelerated bone maturation needs further evaluation.

Congenital and Traumatic Conditions of the Pediatric Hand: Overview for the Radiologist

Alignment, longitudinal growth, and function of the musculoskeletal unit of the pediatric hand is complex due to the combination of open growth plates, ossification variations, and their relationship with finger tendinous and ligamentous attachments. This review presents the basics of normal development, acquired and congenital variations, and traumatic conditions of the pediatric hand from the perspective of the pediatric musculoskeletal radiologist and hand surgeon. This multimodality imaging article focuses on non-oncologic and non-rheumatologic conditions of the pediatric hand, inclusive of fingers, thumb, and metacarpal bones.

The impact of HIV infection on skeletal maturity in peripubertal children in Zimbabwe: a cross-sectional study

INTRODUCTION

HIV infection and its treatment compromises skeletal development (growth and maturation). Skeletal maturity is assessed as bone age (BA) on hand and wrist radiographs. BA younger than chronological age (CA) indicates delayed development. We conducted a cross-sectional study to determine differences between BA and CA (i.e., skeletal maturity deviation [SMD]), and risk factors associated with SMD in peripubertal children with and without HIV established on antiretroviral therapy (ART) including use of tenofovir disoproxil fumarate (TDF).

METHODS

Children with HIV taking ART for at least two years and a comparison group of HIV-negative children, aged 8-16 years and frequency-matched by age and sex, were recruited from HIV clinics and local schools in the same catchment area, in Harare, Zimbabwe. BA was assessed from non-dominant hand-wrist radiographs using the Tanner Whitehouse 3 method. Negative SMD values correspond to delayed development, i.e., BA younger than CA. Multivariable linear regression models determined factors associated with SMD overall, and in children with HIV.

RESULTS

In total, 534 participants (54% males) were included; by design CA was similar in males and females, whether living with or without HIV. Mean (SD) SMD was more negative in CWH than in HIV-negative children in both males [-1.4(1.4) vs. -0.4(1.1) years] and females [-1.1(1.3) vs. -0.0(1.2) years]. HIV infection and weight-for-age Z-score<-2 were associated with more negative SMD in both males and females after adjusting for socio-economic status, orphanhood, pubertal stage, and calcium intake. Age at ART initiation was associated with SMD in both males and females with those starting ART later more delayed: starting ART aged 4-8 years 1.14 (-1.84, -0.43), or over 8 years 1.47 (-2.30, -0.65) (p-value for trend < 0.001). Similar non-significant trends were seen in males. TDF exposure TDF exposure whether < 4years or ≥ 4 years was not associated with delayed development.

CONCLUSION

Perinatally-acquired HIV infection and being underweight were independently associated with delayed skeletal maturation in both males and females. Starting ART later was independently associated with skeletal maturation delay in CWH. Given the known effects of delayed development on later health, it is important to find interventions to ensure healthy weight gain through early years and in CWH to initiate ART as early as possible.

Applicability and robustness of an artificial intelligence-based assessment for Greulich and Pyle bone age in a German cohort

PURPOSE

The determination of bone age (BA) based on the hand and wrist, using the 70-year-old Greulich and Pyle (G&P) atlas, remains a widely employed practice in various institutions today. However, a more recent approach utilizing artificial intelligence (AI) enables automated BA estimation based on the G&P atlas. Nevertheless, AI-based methods encounter limitations when dealing with images that deviate from the standard hand and wrist projections. Generally, the extent to which BA, as determined by the G&P atlas, corresponds to the chronological age (CA) of a contemporary German population remains a subject of continued discourse. This study aims to address two main objectives. Firstly, it seeks to investigate whether the G&P atlas, as applied by the AI software, is still relevant for healthy children in Germany today. Secondly, the study aims to assess the performance of the AI software in handling non-strict posterior-anterior (p. a.) projections of the hand and wrist.

MATERIALS AND METHODS

The AI software retrospectively estimated the BA in children who had undergone radiographs of a single hand using posterior-anterior and oblique planes. The primary purpose was to rule out any osseous injuries. The prediction error of BA in relation to CA was calculated for each plane and between the two planes.

RESULTS

A total of 1253 patients (aged 3 to 16 years, median age 10.8 years, 55.7 % male) were included in the study. The average error of BA in posterior-anterior projections compared to CA was 3.0 (± 13.7) months for boys and 1.7 (± 13.7) months for girls. Interestingly, the deviation from CA tended to be even slightly lower in oblique projections than in posterior-anterior projections. The mean error in the posterior-anterior projection plane was 2.5 (± 13.7) months, while in the oblique plane it was 1.8 (± 13.9) months (p = 0.01).

CONCLUSION

The AI software for BA generally corresponds to the age of the contemporary German population under study, although there is a noticeable prediction error, particularly in younger children. Notably, the software demonstrates robust performance in oblique projections.

KEY POINTS

· Bone age, as determined by artificial intelligence, aligns with the chronological age of the contemporary German cohort under study.. · As determined by artificial intelligence, bone age is remarkably robust, even when utilizing oblique X-ray projections..

CITATION FORMAT

· Pape J, Hirsch F, Deffaa O et al. Applicability and robustness of an artificial intelligence-based assessment for Greulich and Pyle bone age in a German cohort. Fortschr Röntgenstr 2024; 196: 600 - 606.

Development of a simplified new method of bone age estimation using three bones of the hand and wrist

Though the Greulich and Pyle (GP) method is easy, inter-observer variability, differential maturation of hand bones influences ratings. The Tanner-Whitehouse (TW) method is more accurate, but cumbersome. A simpler method combining the above, such that it utilizes fewer bones without affecting accuracy, would be widely used and more applicable in clinical practice.

OBJECTIVES

1. Devising a simplified method utilizing three bones of the hand and wrist for bone age (BA) assessment. 2. Testing whether the 3 bone method gives comparable results to standard methods (GP,TW2,TW3) in Indian children.

METHODS

Developmental stages and corresponding BA for radius, hamate, terminal phalanx (left middle finger) epiphyses combining stages from GP,TW3 atlases were described; BA were rated by two blinded observers. 3 bone method ratings were compared with the same dataset analyzed earlier using GP,TW2,TW3 (4 raters).

RESULTS

Radiographs analysed:493 (Girls=226). Mean chronological age:9.4 ± 4.6 yrs, mean BA 3 bone:9.8 ± 4.8 yrs, GP:9.6 ± 4.8 yrs, TW3:9.3 ± 4.5 yrs, TW2:9.9 ± 5.0 yrs. The 3 bone method demonstrated no significant inter-observer variability (p = 0.3, mean difference = 0.02 ± 0.6 yrs); a strong positive correlation (p < 0.0001) with GP (r = 0.985), TW3 (r = 0.983) and TW2 (r = 0.982) was noted. Bland-Altman plots demonstrated good agreement; the root mean square errors between 3 bone and GP,TW3,TW2 ratings were 0.6,0.7,0.6 years; mean differences were 0.19,0.49,-0.14 years respectively. Greatest proportion of outliers (beyond ±1.96 SD of mean difference) was between 6 and 8 years age for difference in 3 bone and GP, and between 4-6 years for difference in 3 bone and TW3,TW2.

CONCLUSION

The 3 bone method has multiple advantages; it is easier, tackles differential maturation of wrist and hand bones, has good reproducibility, without compromising on accuracy rendering it suitable for office practice.

Standardization of Weightage Assigned to Different Segments of the Hand X-ray for Assessment of Bone Age by the Greulich-Pyle Method

Introduction

Bone age (BA) assessment is important in evaluating disorders of growth and puberty; the Greulich and Pyle atlas method (GP) is most used. We aimed to determine the weightage to be attributed by raters to various segments of the hand x-ray, namely, distal end of radius-ulna (RU), carpals, and short bones for rating bone age using the GP atlas method.

Methods

692 deidentified x-rays from a previous study (PUNE-dataset) and 400 from the Radiological Society of North America (RSNA-dataset) were included in the study. Mean of BA assessed by experienced raters was termed reference rating. Linear regression was used to model reference age as function of age ratings of the three segments. The root-mean-square-error (RMSE) of segmental arithmetic mean and weighted mean with respect to reference rating were computed for both datasets.

Results

Short bones were assigned the highest weightage. Carpals were assigned higher weightage in pre-pubertal PUNE participants as compared to RSNA, vice-versa in RU segment of post-pubertal participants. The RMSE of weighted mean ratings was significantly lower than for the arithmetic mean in the PUNE dataset.

Conclusion

We thus determined weightage to be attributed by raters to segments of the hand x-ray for assessment of bone age by the GP method.

Does ethnicity influence bone health index in children? A pilot study

BACKGROUND

Several pathological conditions can lead to variations in bone mineral content during growth. When assessing bone age, bone mineral content can be estimated without supplementary cost and irradiation. Manual assessment of bone quality using the Exton-Smith index (ESI) and automated assessment of the bone health index (BHI) provided by the BoneXpert® software are available but still not validated in different ethnic groups.

OBJECTIVE

Our aim is to provide normative values of the ESI and BHI for healthy European Caucasian and first-generation children of North Africans living in Europe.

MATERIALS AND METHODS

A sex- and aged-match population of 214 girls (107 European-Caucasian and 107 North African) and 220 boys (111 European-Caucasian and 109 North African) were retrospectively and consecutively included in the study. Normal radiographs of the left hand and wrist from healthy children were retrieved from those performed in a single institution from 2008 to 2017 to rule out a left-hand fracture. Radiographs were processed by BoneXpert® to obtain the BHI and BHI standard deviation score (SDS). One radiologist, blinded to BHI values, manually calculated ESI for each patient. The variability for both methods was assessed and compared using the standard deviation (SD) of the median (%) for each class of age and sex, and ESI and BHI trends were compared by sex and ethnic group.

RESULTS

The final population comprised 434 children ages 3 to 15 years (214 girls). Overall, BHI was lower in North African children (mean = 4.23 for girls and 4.17 in boys) than in European Caucasians (mean = 4.50 for girls and 4.68 in boys) (P < 0.001). Regardless of ethnicity, 29 girls (13.6%) and 34 boys (15.5%) had BHI more than 2 SD from the mean. While correlated to BHI, ESI has a higher variability than BHI and is more pronounced from 8-12 years for both sexes (mean ESI in European Caucasian girls and boys 17.47 and 20.87, respectively) (P < 0.001). ESI showed more than 15% variability in European girls from 8-12 years and a plateau in North African boys from 12 years to 16 years. However, the BHI has less than 15% variability regardless of age and ethnic group.

CONCLUSION

BHI may be a reliable tool to detect children with abnormal bone mineral content, with lower variability compared to ESI and with specific trends depending on sex and ethnicity.

The Modified Fels and Abbreviated Modified Fels Knee Skeletal-Maturity Systems in the Prediction of Leg-Length Discrepancy

BACKGROUND

The Modified Fels (mFels) and Abbreviated Modified Fels (abFels) knee systems have been recently developed as options for grading skeletal maturity without the need for a separate hand radiograph. We sought to determine the interobserver reliability of these systems and to compare their prediction accuracy with that of the Greulich and Pyle (G-P) atlas in a cohort managed with epiphysiodesis for leg-length discrepancy (LLD).

METHODS

Three reviewers scored 20 knee radiographs using the mFels system, which includes 5 qualitative and 2 quantitative measures as well as a quantitative output. Short leg length (SL), long leg length (LL), and LLD prediction errors at maturity using the White-Menelaus (W-M) method and G-P, mFels, or abFels skeletal age were compared in a cohort of 60 patients managed with epiphysiodesis for LLD.

RESULTS

Intraclass correlation coefficients for the 2 quantitative variables and the quantitative output of the mFels system using 20 knee radiographs ranged from 0.55 to 0.98, and kappa coefficients for the 5 qualitative variables ranged from 0.56 to 1, indicating a reliability range from moderate to excellent. In the epiphysiodesis cohort, G-P skeletal age was on average 0.25 year older than mFels and abFels skeletal ages, most notably in females. The majority of average prediction errors between G-P, mFels, and abFels were <0.5 cm, with the greatest error being for the SL prediction in females, which approached 1 cm. Skeletal-age estimates with the mFels and abFels systems were statistically comparable.

CONCLUSIONS

The mFels skeletal-age system is a reproducible method of determining skeletal age. Prediction errors in mFels and abFels skeletal ages were clinically comparable with those in G-P skeletal ages in this epiphysiodesis cohort. Further work is warranted to optimize and validate the accuracy of mFels and abFels skeletal ages to predict LLD and the impact of epiphysiodesis, particularly in females. Both the mFels and abFels systems are promising means of estimating skeletal age, avoiding additional radiation and health-care expenditure.

LEVEL OF EVIDENCE

Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Should we consider the sex when estimating bone age from hand bone biometrics?

BACKGROUND

Recently, it was proposed to estimate age from the biometric information of hand bones. We observed that these estimations became less precise as children get older, especially from the age of 13-15 years.

OBJECTIVE

This study aimed to evaluate the influence of considering sex for age estimation based on hand bones biometrics.

MATERIALS AND METHODS

The study sample consisted of metacarpals and proximal phalanges measurements collected on 1003 medical images performed at Nancy and Marseille Hospitals of individuals aged under 21 years. This sample was divided into two subgroups delineated by the age of 13, as it is a relevant legal threshold for most European countries. First, the influence of sex on the hand bones biometrics and on the estimated age was evaluated. Then, based on these results, new sex-specific age estimation formulas were constructed from linear models and their precision was assessed using residual analysis, in comparison with previous global formulas.

RESULTS

An influence of sex was only highlighted from the age of 13 and for the total study sample. Thus, new sex-specific age estimation formulas were built for the [1-21] global sample and the [13-21] subsample. Even though the differences with the previous formulas were minor, age was more accurately estimated when sex was considered.

CONCLUSION

Considering sex in age estimation is relevant when relying on hand bone biometrics. A new tool was proposed to select the most appropriate age estimation formula, based on the discriminant analysis result and the a priori knowledge of the sex.

Skeletal age estimation of living adolescents and young adults: A pilot study on conventional radiography versus magnetic resonance imaging and staging technique versus atlas method

OBJECTIVE

To compare conventional radiography (CR) and magnetic resonance imaging (MRI) of the left hand/wrist and both clavicles for forensic age estimation of adolescents and young adults.

MATERIALS AND METHODS

CR and MRI were prospectively conducted in 108 healthy Caucasian volunteers (52 males, 56 females) aged 16 to 21 years. Skeletal development was assessed by allocating stages (wrist, clavicles) and atlas standards (hand/wrist). Inter- and intra-observer agreements were quantified using linear weighted Cohen's kappa, and descriptive statistics regarding within-stage/standard age distributions were reported.

RESULTS

Inter- and intra-observer agreements for hand/wrist CR (staging technique: 0.840-0.871 and 0.877-0.897, respectively; atlas method: 0.636-0.947 and 0.853-0.987, respectively) and MRI (staging technique: 0.890-0.932 and 0.897-0.952, respectively; atlas method: 0.854-0.941 and 0.775-0.978, respectively) were rather similar. The CR atlas method was less reproducible than the staging technique. Inter- and intra-observer agreements for clavicle CR (0.590-0.643 and 0.656-0.770, respectively) were lower than those for MRI (0.844-0.852 and 0.866-0.931, respectively). Furthermore, although shifted, wrist CR and MRI within-stage age distribution spread were similar, as were those between staging techniques and atlas methods. The possibility to apply (profound) substages to clavicle MRI rendered a more gradual increase of age distributions with increasing stages, compared to CR.

CONCLUSIONS

For age estimation based on the left hand/wrist and both clavicles, reference data should be considered anatomical structure- and imaging modality-specific. Moreover, CR is adequate for hand/wrist evaluation and a wrist staging technique seems to be more useful than an atlas method. By contrast, MRI is of added value for clavicle evaluation.

Bone Age Assessment Using Artificial Intelligence in Korean Pediatric Population: A Comparison of Deep-Learning Models Trained With Healthy Chronological and Greulich-Pyle Ages as Labels

OBJECTIVE

To develop a deep-learning-based bone age prediction model optimized for Korean children and adolescents and evaluate its feasibility by comparing it with a Greulich-Pyle-based deep-learning model.

MATERIALS AND METHODS

A convolutional neural network was trained to predict age according to the bone development shown on a hand radiograph (bone age) using 21036 hand radiographs of Korean children and adolescents without known bone development-affecting diseases/conditions obtained between 1998 and 2019 (median age [interquartile range {IQR}], 9 [7-12] years; male:female, 11794:9242) and their chronological ages as labels (Korean model). We constructed 2 separate external datasets consisting of Korean children and adolescents with healthy bone development (Institution 1: n = 343; median age [IQR], 10 [4-15] years; male: female, 183:160; Institution 2: n = 321; median age [IQR], 9 [5-14] years; male: female, 164:157) to test the model performance. The mean absolute error (MAE), root mean square error (RMSE), and proportions of bone age predictions within 6, 12, 18, and 24 months of the reference age (chronological age) were compared between the Korean model and a commercial model (VUNO Med-BoneAge version 1.1; VUNO) trained with Greulich-Pyle-based age as the label (GP-based model).

RESULTS

Compared with the GP-based model, the Korean model showed a lower RMSE (11.2 vs. 13.8 months; P = 0.004) and MAE (8.2 vs. 10.5 months; P = 0.002), a higher proportion of bone age predictions within 18 months of chronological age (88.3% vs. 82.2%; P = 0.031) for Institution 1, and a lower MAE (9.5 vs. 11.0 months; P = 0.022) and higher proportion of bone age predictions within 6 months (44.5% vs. 36.4%; P = 0.044) for Institution 2.

CONCLUSION

The Korean model trained using the chronological ages of Korean children and adolescents without known bone development-affecting diseases/conditions as labels performed better in bone age assessment than the GP-based model in the Korean pediatric population. Further validation is required to confirm its accuracy.

Precision and Accuracy of Radiological Bone Age Assessment in Children among Different Ethnic Groups: A Systematic Review

AIM

The aim was to identify, evaluate, and summarize the findings of relevant individual studies on the precision and accuracy of radiological BA assessment procedures among children from different ethnic groups.

MATERIALS AND METHODS

A qualitative systematic review was carried out following the MOOSE statement and previously registered in PROSPERO (CRD42023449512). A search was performed in MEDLINE (PubMed) (n = 561), the Cochrane Library (n = 261), CINAHL (n = 103), Web of Science (WOS) (n = 181), and institutional repositories (n = 37) using MeSH and free terms combined with the Booleans "AND" and "OR". NOS and ROBINS-E were used to assess the methodological quality and the risk of bias of the included studies, respectively.

RESULTS

A total of 51 articles (n = 20,100) on radiological BA assessment procedures were precise in terms of intra-observer and inter-observer reliability for all ethnic groups. In Caucasian and Hispanic children, the Greulich-Pyle Atlas (GPA) was accurate at all ages, but in youths, Tanner-Whitehouse radius-ulna-short bones 3 (TW3-RUS) could be an alternative. In Asian and Arab subjects, GPA and Tanner-Whitehouse 3 (TW3) overestimated the BA in adolescents near adulthood. In African youths, GPA overestimated the BA while TW3 was more accurate.

CONCLUSION

GPA and TW3 radiological BA assessment procedures are both precise but their accuracy in estimating CA among children of different ethnic groups can be altered by racial bias.

Validation of a deep learning algorithm for bone age estimation among patients in the city of São Paulo, Brazil

Objective

To validate a deep learning (DL) model for bone age estimation in individuals in the city of São Paulo, comparing it with the Greulich and Pyle method.

Materials and Methods

This was a cross-sectional study of hand and wrist radiographs obtained for the determination of bone age. The manual analysis was performed by an experienced radiologist. The model used was based on a convolutional neural network that placed third in the 2017 Radiological Society of North America challenge. The mean absolute error (MAE) and the root-mean-square error (RMSE) were calculated for the model versus the radiologist, with comparisons by sex, race, and age.

Results

The sample comprised 714 examinations. There was a correlation between the two methods, with a coefficient of determination of 0.94. The MAE of the predictions was 7.68 months, and the RMSE was 10.27 months. There were no statistically significant differences between sexes or among races (p > 0.05). The algorithm overestimated bone age in younger individuals (p = 0.001).

Conclusion

Our DL algorithm demonstrated potential for estimating bone age in individuals in the city of São Paulo, regardless of sex and race. However, improvements are needed, particularly in relation to its use in younger patients.

Evaluation of two methods of bone age assessment in peripubertal children in Zimbabwe

OBJECTIVES

Bone age (BA) measurement in children is used to evaluate skeletal maturity and helps in the diagnosis of growth disorders in children. The two most used methods are Greulich and Pyle (GP), and Tanner and Whitehouse 3 (TW3), both based upon assessment of a hand-wrist radiograph. To our knowledge no study has compared and validated the two methods in sub-Saharan Africa (SSA), and only a few have determined BA despite it being a region where skeletal maturity is often impaired for example by HIV and malnutrition. This study aimed to compare BA as measured by two methods (GP and TW3) against chronological age (CA) and determine which method is most applicable in peripubertal children in Zimbabwe.

METHODS

We conducted a cross-sectional study of boys and girls who tested negative for HIV. Children and adolescents were recruited by stratified random sampling from six schools in Harare, Zimbabwe. Non-dominant hand-wrist radiographs were taken, and BA assessed manually using both GP and TW3. Paired sample Student t-tests were used to calculate the mean differences between BA and chronological age (CA) in boys and girls. Bland-Altman plots compared CA to BA as determined by both methods, and agreement between GP and TW3 BA. All radiographs were graded by a second radiographer and 20 % of participants of each sex were randomly selected and re-graded by the first observer. Intraclass correlation coefficient assessed intra- and inter-rater reliability and coefficient of variation assessed precision.

RESULTS

We recruited 252 children (111 [44 %] girls) aged 8.0-16.5 years. The boys and girls were of similar mean ± SD CA (12.2 ± 2.4 and 11.7 ± 1.9 years) and BA whether assessed by GP (11.5 ± 2.8 and 11.5 ± 2.1 years) or TW3 (11.8 ± 2.5 and 11.8 ± 2.1 years). In boys BA was lower than CA by 0.76 years (95 % CI: -0.95, -0.57) when using GP, and by 0.43 years (95 % CI: -0.61, -0.24) when using TW3. Among the girls there was no difference between BA and CA by either GP [-0.19 years (95 % CI: -0.40, 0.03)] or TW3 [0.07 years (95 % CI: -0.16, 0.29)]. In both boys and girls, there were no systematic differences between CA and TW3 BA across age groups whereas agreement improved between CA and GP BA as children got older. Inter-operator precision was 1.5 % for TW3 and 3.7 % for GP (n = 252) and intra-operator precision was 1.5 % for TW3 and 2.4 % for GP (n = 52).

CONCLUSION

The TW3 BA method had better precision than GP and did not systematically differ from CA, meaning that TW3 is the preferred method of assessment of skeletal maturity in Zimbabwean children and adolescents. TW3 and GP methods do not agree for estimates of BA and therefore cannot be used interchangeably. The systematic differences in GP BA assessments over age means it is not appropriate for use in all age groups or stages of maturity in this population.

A real-time automated bone age assessment system based on the RUS-CHN method

Background

Bone age is the age of skeletal development and is a direct indicator of physical growth and development in children. Most bone age assessment (BAA) systems use direct regression with the entire hand bone map or first segmenting the region of interest (ROI) using the clinical a priori method and then deriving the bone age based on the characteristics of the ROI, which takes more time and requires more computation.

Materials and methods

Key bone grades and locations were determined using three real-time target detection models and Key Bone Search (KBS) post-processing using the RUS-CHN approach, and then the age of the bones was predicted using a Lightgbm regression model. Intersection over Union (IOU) was used to evaluate the precision of the key bone locations, while the mean absolute error (MAE), the root mean square error (RMSE), and the root mean squared percentage error (RMSPE) were used to evaluate the discrepancy between predicted and true bone age. The model was finally transformed into an Open Neural Network Exchange (ONNX) model and tested for inference speed on the GPU (RTX 3060).

Results

The three real-time models achieved good results with an average (IOU) of no less than 0.9 in all key bones. The most accurate outcomes for the inference results utilizing KBS were a MAE of 0.35 years, a RMSE of 0.46 years, and a RMSPE of 0.11. Using the GPU RTX3060 for inference, the critical bone level and position inference time was 26 ms. The bone age inference time was 2 ms.

Conclusions

We developed an automated end-to-end BAA system that is based on real-time target detection, obtaining key bone developmental grade and location in a single pass with the aid of KBS, and using Lightgbm to obtain bone age, capable of outputting results in real-time with good accuracy and stability, and able to be used without hand-shaped segmentation. The BAA system automatically implements the entire process of the RUS-CHN method and outputs information on the location and developmental grade of the 13 key bones of the RUS-CHN method along with the bone age to assist the physician in making judgments, making full use of clinical a priori knowledge.

Orthopaedic Diagnoses in the Black Pediatric Population

The Black pediatric population is one that has been historically underserved and continues to have unmet needs. Factors including lack of diversity in orthopaedic studies and in historical standards, such as bone age, may inadvertently lead to inferior care. There are certain conditions in this population for which the practicing orthopaedic surgeon should have a higher degree of suspicion, including slipped capital femoral epiphysis, Blount disease, and postaxial polydactyly. Systemic diseases with higher rates in this population have orthopaedic manifestations, including sickle cell disease, vitamin D deficiency, and obesity. Racial discrepancies in access to prenatal care can have orthopaedic consequences for babies, especially cerebral palsy and myelodysplasia. Racial discrepancy exists in evaluation for nonaccidental trauma. Increased awareness of these issues better prepares practitioners to provide equitable care.

The Dimeglio Olecranon Method Is Reliable in Diverse, Contemporary Patients for Predicting Future Growth

BACKGROUND

Growth assessment, which relies on a combination of radiographic and clinical markers, is an integral part of clinical decision-making in pediatric orthopaedics. The aim of this study is to evaluate the accuracy and reliability of the Diméglio skeletal age system using a modern cohort of pediatric patients.

METHODS

A retrospective review was undertaken of all patients at a large tertiary pediatric hospital who had lateral forearm radiographs (before the age of 14 y for females and before 16 y for males). In addition, all of these patients had height measurements within 60 days of their forearm x-ray and a final height listed in their medical records. The x-rays were graded by 5 reviewers according to the Diméglio skeletal age system. Inter and intraobserver reliability was tested.

RESULTS

One hundred forty-seven patients with complete radiographs and height data were evaluated by 5 observers ranging in experience from medical students to senior pediatric orthopaedic surgeons. The Diméglio system demonstrated excellent reliability across levels of training with an intraobserver correlation coefficient of 0.995 (95% CI, 0.991-0.997) and an interobserver correlation coefficient of 0.906 (95% CI, 0.857-0.943). When the Diméglio stage was paired with age and sex in a multivariable linear regression model predicting the percent of final height, the adjusted R2 was 78.7% (model P value <0.001), suggesting a strong relationship between the Diméglio stage (plus age and sex) and percent of final height.

CONCLUSION

This unique approach to maturity assessment demonstrates that the Diméglio staging system can be used effectively in a modern, diverse patient population.

LEVEL OF EVIDENCE

Level II; retrospective cohort study.

Bone-specific median age of hand-wrist maturation from Sudan

BACKGROUND

Maturation of bones in the hand-wrist region varies among individuals of the same age and among world groups. Although some studies from Africa report differences to other ethnic groups, the lack of detailed bone-specific maturity data prevents meaningful comparisons.

AIM

The aim of this study was to describe bone-specific maturity for developing hand-wrist bones in individuals in Khartoum, Sudan.

SUBJECTS AND METHODS

The sample was selected from healthy patients attending a dental hospital in Khartoum with known age and ancestry (males = 280, females = 330; aged between 3 and 25 years). Bones were assessed from radiographs of the left hand and wrist after the Greulich and Pyle Atlas (1959). Median ages of attainment for bone stages were calculated using probit analysis for each stage in males and females separately.

RESULTS

Maturity data for stages of the phalanges, metacarpals, carpals and radius and ulna in males and females are presented. Median ages in females were earlier compared to males for all stages. These results are largely earlier than previously published findings or where these could be calculated.

CONCLUSION

These results of individual maturity stages of phalanges, metacarpals, carpals and the distal epiphyses of the radius and ulna are useful to assess maturity in growing individuals from Sudan.

Bone age assessment: Large-scale comparison of Greulich-Pyle method and Tanner-Whitehouse 3 method for Taiwanese children

BACKGROUND

The Greulich-Pyle (GP) and Tanner-Whitehouse 3 (TW3) methods are two common methods for assessing bone age (BA). The applicability of these methods for populations other than those in the United States and Europe has been questioned. Thus, this study tested the applicability of these methods for Taiwanese children.

METHODS

In total, 1476 radiographs (654 boys, 822 girls) were analyzed. A subset of 200 radiographs was evaluated to determine intrarater and interrater reliability and the time required to yield a BA assessment. BA was determined by two reviewers using the GP method and two of the TW3 methods (the Radial-Ulnar-Short bones [RUS] method and the carpals method [Carpal]). The GP and TW3 methods were directly compared using statistical techniques. A subgroup analysis by age was performed to compare BA and chronological age using a paired t test for each age group.

RESULTS

The average times required to yield an assessment using the GP and TW3-RUS methods were 0.79 ± 0.14 and 3.01 ± 0.84 min (p < 0.001), respectively. Both the intrarater and interrater correlation coefficients were higher for the GP method (0.993, 0.992) than the TW3-RUS (0.985, 0.984) and TW3-Carpal (0.981, 0.973) methods. The correlation coefficient for the GP and TW3-RUS methods was highest in the pubertal stage (0.898 for boys and 0.909 for girls). The mean absolute deviations for the GP and TW3-RUS methods in the pubertal stage were 0.468 years (boys) and 0.496 years (girls). Both the GP and TW3-Carpal methods underestimated BA for boys in the prepubertal stage. Both the GP and TW3-RUS methods overestimated BA for girls in the pubertal and postpubertal stages.

CONCLUSION

The GP and TW3-RUS methods exhibit strong agreement in the pubertal and postpubertal stages for both sexes. With appropriate adjustments based on Taiwanese data, both methods are applicable to our children.

Comparison of "Human" and Artificial Intelligence Hand-and-Wrist Skeletal Age Estimation in an Epiphysiodesis Cohort

BACKGROUND

We previously demonstrated that the White-Menelaus arithmetic formula combined with skeletal age as estimated with the Greulich and Pyle (GP) atlas was the most accurate method for predicting leg lengths and residual leg-length discrepancy (LLD) at maturity in a cohort of patients treated with epiphysiodesis. We sought to determine if an online artificial intelligence (AI)-based hand-and-wrist skeletal age system provided consistent readings and to evaluate how these readings influenced the prediction of the outcome of epiphysiodesis in this cohort.

METHODS

JPEG images of perioperative hand radiographs for 76 subjects were independently submitted by 2 authors to an AI skeletal age web site (http://physis.16bit.ai/). We compared the accuracy of the predicted long-leg length (after epiphysiodesis), short-leg length, and residual LLD with use of the White-Menelaus formula and either human-estimated GP or AI-estimated skeletal age.

RESULTS

The AI skeletal age readings had an intraclass correlation coefficient (ICC) of 0.99. AI-estimated skeletal age was generally greater than human-estimated GP skeletal age (average, 0.5 year greater in boys and 0.1 year greater in girls). Overall, the prediction accuracy was improved with AI readings; these differences reached significance for the short-leg and residual LLD prediction errors. Residual LLD was underestimated by ≥1.0 cm in 26 of 76 subjects when human-estimated GP skeletal age was used (range of underestimation, 1.0 to 3.2 cm), compared with only 10 of 76 subjects when AI skeletal age was used (range of underestimation, 1.1 cm to 2.2 cm) (p < 0.01). Residual LLD was overestimated by ≥1.0 cm in 3 of 76 subjects by both methods (range of overestimation, 1.0 to 1.3 cm for the human-estimated GP method and 1.0 to 1.6 cm for the AI method).

CONCLUSIONS

The AI method of determining hand-and-wrist skeletal age was highly reproducible in this cohort and improved the accuracy of prediction of leg length and residual discrepancy when compared with traditional human interpretation of the GP atlas. This improvement could be explained by more accurate estimation of skeletal age via a machine-learning AI system calibrated with a large database.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Current and emerging artificial intelligence applications for pediatric musculoskeletal radiology

Artificial intelligence (AI) is playing an ever-increasing role in radiology (more so in the adult world than in pediatrics), to the extent that there are unfounded fears it will completely take over the role of the radiologist. In relation to musculoskeletal applications of AI in pediatric radiology, we are far from the time when AI will replace radiologists; even for the commonest application (bone age assessment), AI is more often employed in an AI-assist mode rather than an AI-replace or AI-extend mode. AI for bone age assessment has been in clinical use for more than a decade and is the area in which most research has been conducted. Most other potential indications in children (such as appendicular and vertebral fracture detection) remain largely in the research domain. This article reviews the areas in which AI is most prominent in relation to the pediatric musculoskeletal system, briefly summarizing the current literature and highlighting areas for future research. Pediatric radiologists are encouraged to participate as members of the research teams conducting pediatric radiology artificial intelligence research.

A comparison of bone age assessments using automated and manual methods in children of Indian ethnicity

BACKGROUND

Bone age is useful for pediatric endocrinologists in evaluating various disorders related to growth and puberty. Traditional methods of bone age assessment, namely Greulich and Pyle (GP) and Tanner-Whitehouse (TW), have intra- and interobserver variations. Use of computer-automated methods like BoneXpert might overcome these subjective variations.

OBJECTIVE

The aim of our study was to assess the validity of BoneXpert in comparison to manual GP and TW methods for assessing bone age in children of Asian Indian ethnicity.

MATERIALS AND METHODS

We extracted from a previous study the deidentified left hand radiographs of 920 healthy children aged 2-19 years. We compared bone age as determined by four well-trained manual raters using GP and TW methods with the BoneXpert ratings. We computed accuracy using root mean square error (RMSE) to assess how close the bone age estimated by BoneXpert was to the reference rating.

RESULTS

The standard deviations (SDs) of rating among the four manual raters were 0.52 years, 0.52 years and 0.47 years for GP, TW2 and TW3 methods, respectively. The RMSEs between the automated bone age estimates and the true ratings were 0.39 years, 0.41 years and 0.36 years, respectively, for the same methods. The RMSE values were significantly lower in girls than in boys (0.53, 0.5 and 0.47 vs. 0.39, 0.47 and 0.4) by all the methods; however, no such difference was noted in classification by body mass index. The best agreement between BoneXpert and manual rating was obtained by using 50% weight on carpals (GP50). The carpal bone age was retarded in Indian children, more so in boys.

CONCLUSION

BoneXpert was accurate and performed well in estimating bone age by both GP and TW methods in healthy Asian Indian children; the error was larger in boys. The GP50 establishes "backward compatibility" with manual rating.

The Percentage of Mature Height as a Morphometric Index of Somatic Growth: A Formal Scrutiny of Conventional Simple Ratio Scaling Assumptions

PURPOSE

To assess conventional assumptions that underpin the percentage of mature height index as the simple ratio of screening height (numerator) divided by actual or predicted adult height (denominator).

METHODS

We examined cross-sectional data from 99 academy youth soccer players (chronological age range, 11.5 to 17.7 y) skeletally immature at the screening time and with adult height measurements available at follow-up.

RESULTS

The y-intercept value of -60 cm (95% confidence interval, -115 to -6 cm) from linear regression between screening height and adult height indicated the failure to meet the zero y-intercept assumption. The correlation coefficient between present height and adult height of .64 (95% confidence interval, .50 to .74) was not equal to the ratio of coefficient of variations between these variables (CVx/CVy = 0.46) suggesting Tanner's special circumstance was violated. The non-zero correlation between the ratio and the denominator of .21 (95% confidence interval, .01 to .39) indicated that the percentage of mature height was biased low for players with generally shorter adult height, and vice versa.

CONCLUSION

For the first time, we have demonstrated that the percentage of mature height is an inconsistent statistic for determining the extent of completed growth, leading to potentially biased inferences for research and applied purposes.

Estimating Skeletal Maturity Using Wrist Radiographs During Preadolescence: The Epiphyseal:Metaphyseal Ratio

BACKGROUND

Although skeletal maturity is most relevant during adolescence, it has utility in treatment of younger patients in some circumstances, such as scoliosis, limb length discrepancy, or endocrinopathies. Currently, a quick, accurate, and reproducible method of estimating skeletal maturity in preadolescents using wrist radiographs is lacking.

METHODS

Serial anteroposterior wrist radiographs taken at historical growth study visits leading up to the chronological age (CA) associated with 90% of the final height (an enhanced skeletal maturity standard as compared with peak height velocity) were analyzed in 102 children. Epiphyseal and metaphyseal widths of 5 physes were evaluated: distal radius, distal ulna, first metacarpal, third metacarpal, and fifth metacarpal. Ulnar styloid height and radial styloid height were also measured, for a total of 7 epiphyseal:metaphyseal radiographic parameters. Greulich and Pyle (GP) bone age was also measured. A combination of stepwise linear regression and generalized estimating equation analyses was used to produce a skeletal maturity estimation model incorporating demographics (CA and sex) and the epiphyseal:metaphyseal ratios significantly correlated with skeletal maturity.

RESULTS

A total of 273 left anteroposterior hand-wrist radiographs from 56 girls (163 radiographs, range 4 to 13 y) and 46 boys (112 radiographs, range 3.8 to 15 y) were included. The demographics+ratios model had better prediction accuracy than GP only and GP with demographics (0.44, 0.87, and 0.47 y mean discrepancy from actual skeletal age, P <0.05 for both comparisons). There was no significant difference in the rate of outlier skeletal age estimates, defined as an estimate >1 year off from the true skeletal age, between the demographics+ratios model and the demographics+GP model (5.9% vs. 8.4%, P =0.12).

CONCLUSIONS

When combined with CA and sex data, measurement of the epiphyseal:metaphyseal ratios of the left first and third metacarpals allows for improved skeletal maturity estimation compared with the GP technique.

CLINICAL RELEVANCE

Our modified wrist skeletal maturity system offers a relatively quick and reproducible method for estimating skeletal maturity extending into the juvenile age range. This study is a level III retrospective study of longitudinal human growth data obtained from the Bolton Brush Collection in Cleveland, Ohio.

Applicability of the Greulich and Pyle bone age standards to Taiwanese children: A Taipei experience

BACKGROUND

The Greulich and Pyle (GP) method is one of the most common radiographic techniques for bone age (BA) assessment. The applicability of this method to ethnic populations outside of the United States has been investigated in several recent studies worldwide. Currently, limited data are available on the accuracy of the GP method for the Taiwanese population. The purpose of this study was to determine whether the GP standards are applicable to contemporary Taipei children.

METHODS

Clinical data from October 1, 2010, to March 31, 2020, were retrospectively collected from a general hospital in Taipei. BA was determined by a senior pediatrician and was reviewed by a senior pediatric radiologist according to the GP standards. Comparison of BA and chronological age (CA) was performed in children with body weight and height in the 15th to the 85th percentiles of normal children. Ethnic variations in the maturation process in the ulnar bone were investigated. All data were statistically analyzed.

RESULTS

In total, 2465 medical records were collected. After excluding those with diseases and unqualified data, 654 records of boys and 809 of girls were analyzed. In boys, the mean BA was significantly delayed between 6 and 9 years of age compared with the CA. In girls, the mean BA was generally advanced between 7 and 15 years of age. Ulnar bone maturation tended to be delayed in young boys.

CONCLUSION

A significant discrepancy between CA and BA was observed in our population. Delayed ulnar bone maturation in young boys was confirmed. Children in Taipei exhibit a different maturation pattern than children on whom the GP standards were based.

Re-Assessment of Applicability of Greulich and Pyle-Based Bone Age to Korean Children Using Manual and Deep Learning-Based Automated Method

PURPOSE

To evaluate the applicability of Greulich-Pyle (GP) standards to bone age (BA) assessment in healthy Korean children using manual and deep learning-based methods.

MATERIALS AND METHODS

We collected 485 hand radiographs of healthy children aged 2-17 years (262 boys) between 2008 and 2017. Based on GP method, BA was assessed manually by two radiologists and automatically by two deep learning-based BA assessment (DLBAA), which estimated GP-assigned (original model) and optimal (modified model) BAs. Estimated BA was compared to chronological age (CA) using intraclass correlation (ICC), Bland-Altman analysis, linear regression, mean absolute error, and root mean square error. The proportion of children showing a difference >12 months between the estimated BA and CA was calculated.

RESULTS

CA and all estimated BA showed excellent agreement (ICC ≥0.978, p<0.001) and significant positive linear correlations (R²≥0.935, p<0.001). The estimated BA of all methods showed systematic bias and tended to be lower than CA in younger patients, and higher than CA in older patients (regression slopes ≤-0.11, p<0.001). The mean absolute error of radiologist 1, radiologist 2, original, and modified DLBAA models were 13.09, 13.12, 11.52, and 11.31 months, respectively. The difference between estimated BA and CA was >12 months in 44.3%, 44.5%, 39.2%, and 36.1% for radiologist 1, radiologist 2, original, and modified DLBAA models, respectively.

CONCLUSION

Contemporary healthy Korean children showed different rates of skeletal development than GP standard-BA, and systemic bias should be considered when determining children's skeletal maturation.

Validation of automated bone age analysis from hand radiographs in a North American pediatric population

BACKGROUND

Radiographic bone age assessment by automated software is precise and instantaneous.

OBJECTIVE

The aim of this study was to evaluate the accuracy of an automated tool for bone age assessment.

MATERIALS AND METHODS

We compared a total of 586 bone age radiographs from 451 patients, which had been assessed by three radiologists from 2013 to 2018, with bone age analysis by BoneXpert, using the Greulich and Pyle method. We made bone age comparisons in different patient groups based on gender, diagnosis and race, and in a subset with repeated bone age studies. We calculated Spearman correlation (r) and accuracy (root mean square error, or R²).

RESULTS

Bone age analyses by automated and manual assessments showed a strong correlation (r=0.98; R²=0.96; P<0.0001), with the mean bone age difference of 0.12±0.76 years. Bone age comparisons by the two methods remained strongly correlated (P<0.0001) when stratified by gender, common endocrine conditions including growth disorders and early/precocious puberty, and race. In the longitudinal analysis, we also found a strong correlation between the automated software and manual bone age over time (r=0.7852; R²=0.63; P<0.01).

CONCLUSION

Automated bone age assessment was found to be reliable and accurate in a large cohort of pediatric patients in a clinical practice setting in North America.

Classification of Distal Growth Plate Ossification States of the Radius Bone Using a Dedicated Ultrasound Device and Machine Learning Techniques for Bone Age Assessments

X-ray imaging, based on ionizing radiation, can be used to determine bone age by examining distal growth plate fusion in the ulna and radius bones. Legal age determination approaches based on ultrasound signals exist but are unsuitable to reliably determine bone age. We present a low-cost, mobile system that uses one-dimensional ultrasound radio frequency signals to obtain a robust binary classifier enabling the determination of bone age from data of girls and women aged 9 to 24 years. These data were acquired as part of a clinical study conducted with 148 subjects. Our system detects the presence or absence of the epiphyseal plate by moving ultrasound array transducers along the forearm, measuring reflection and transmission signals. Even though classical digital signal processing methods did not achieve a robust classifier, we achieved an F1 score of approximately 87% for binary classification of completed bone growth with machine learning approaches, such as the gradient boosting machine method CatBoost. We demonstrate that our ultrasound system can classify the fusion of the distal growth plate of the radius bone and the completion of bone growth with high accuracy. We propose a non-ionizing alternative to established X-ray imaging methods for this purpose.

The Application of Magnetic Resonance Imaging in Skeletal Age Assessment

METHOD

The study includes 80 patients identified from an endocrine clinic, two males and two females from each of 5 age groups (<5, 5 to 7, 8 to 10, 11 to 13, and 14 to 16 years). Skeletal age as determined from an open MRI scanner and radiographs performed on the same day was compared for each child. Two observers assess the skeletal age from radiographs and MRI images independently. After a period of at least three weeks, observers determined the skeletal age of all patients independently. All of the images were in different and random orders, on both of the assessment occasions. The agreement was assessed using the interclass correlation coefficient and Bland Altman plots. Problem Statement. The recurrent use of left-hand radiography in children with chronic conditions might result in the patient being exposed to the same image several times throughout the course of their lives. Use of radiation-free methods such as magnetic resonance imaging (MRI) may be able to assist in reducing the risks associated with radiation exposure, if done properly.

RESULTS

Patients' age ranged from 3 to 16 years, in which the mean of the chronological age was 9.3 years (±2.9) and 9.8 years (±2.7) in girls and boys, respectively. The interrater agreement for skeletal age determination was 0.984 for radiographs and 0.976 for MRI scans. Using the G&P technique, for Observer 1, intraobserver agreement for radiographs and DXA was 0.993 and 0.983, respectively, and 0.995 and 0.994, respectively, for Observer 2. Plotting the rater readings against the line of equality shows no significant differences between readings acquired from radiographs and MRI scans.

CONCLUSION

For the study contribution, it is possible to employ open compact MRI to determine the skeletal age of a person. Our results showed that left-hand MRI scans were of better quality than the radiographs.

Research trends in forensic anthropology: A bibliometric analysis

This paper aims to examine the worldwide research development and trends in forensic anthropology by using bibliometric analysis. Scopus database was used to identify published papers on forensic anthropology from 1948 to 2020. A total of 4,499 records were analyzed for yearly publication productivity, authorship and citation pattern, types of documents, most productive journals, organizations, authors, and countries, frequently cited papers, most used keywords, countries of collaboration, and three-field plot analysis in the domain of forensic anthropology. The results indicated that the highest grand total publications were between the years 2016 and 2019, while the highest multi-authored publications were in the year 2018. The most productive journal, author, organization, and country were the 'Journal of Forensic Sciences' with grand total publications of 934, 'Cattaneo, C.' with 97 publications, 'Centre National de la Recherche Scientifique' with 130 publications, and the United States with 1020 total cited papers, respectively. The document with the highest number of citations was 'Buckberry and Chamberlain, 2002, Am J Phys Anthropol' with a total of 387. Three-field plot analysis regarding the most outstanding keyword-source-country was "Forensic anthropology"- "Journal of Forensic Sciences" and "Forensic Science International"- "USA", "France", and "UK". The predomination of certain countries over others in the field of forensic anthropology limits its prosperity as ethnic variety is of important regard. Research collaborations were mainly observed between the United States and European countries, which highlights the need for strengthening collaborations between developed and developing nations.

Racial and gender differences of cervical vertebral maturation staging between African Americans versus Caucasian patients of various age groups: A retrospective study

BACKGROUND AND OBJECTIVE

The primary purpose of this study was to compare CVM staging between African American (AA) and Caucasian (CC) subjects, grouped based on gender. The secondary objectives were to conduct a CVM comparison of (1) male vs. female subjects, grouped based on their race, and (2) AA vs. CC subjects, categorized based on their age group.

MATERIALS AND METHODS

All patients between 8-18 years of age (University of XXX), meeting the criteria, were included between the period of the year 2007 to 2020. Three blinded independent evaluators analysed the lateral cephalograms for a 6-stage CVM system (CS1 to CS6) as described by McNamara and Franchi. Samples were divided based on race, gender, and age to conduct the statistical analysis for racial and gender comparisons.

RESULTS

Out of the initial 1,300 lateral cephalograms, 1,276 with the mean age: 12.7 years SD 2.5 years, and median CVM: 4 (IQR: 25% percentile- 2 and 75% percentile- 4) were included. Gender-specific racial age comparison showed no significant differences for male subjects for most of the CVM stages (P>0.05). Overall and race-specific gender comparison of age showed significant differences for almost all CVM stages (P<0.05). No significant difference of CVM was found on racial comparison for overall, females (P=0.6131) or males (P=0.0825) subjects. On age-specific racial comparison, AA girls (8-10 years) were skeletally more mature than CC girls (P=0.0143); over 14-year-old CC girls (P<0.0001) and over 16-year-old CC boys (P=0.0008), being skeletally more mature than AA boys of the same age.

CONCLUSIONS

There was no significant difference between AA and CC subjects on gender-specific comparisons for most of the CVM stages. A significant difference of age was observed for most of the CVM stage between male and female subjects on race-specific comparisons. Female patients were ahead in skeletal maturity as compared to males for each CVM stage. The CVM for 8-12-year-old AA females was significantly higher than that of the CC females, whereas the CVM for>14-year-old CC females was significantly higher than AA females.

Forensic age assessment by 3.0 T MRI of the wrist: adaption of the Vieth classification

OBJECTIVES

In order to find a reliable method to correctly assess majority in both sexes by MRI, a study was conducted to evaluate the applicability of the recently presented Vieth classification in wrist MRI, after it had originally been proposed for knee MRI.

METHODS

After receiving a positive vote by the ethics committee, the left-hand wrists of 347 male and 348 female volunteers of German nationality in the age bracket 12-24 years were scanned. Before conducting the prospective, cross-sectional examinations, an informed consent was obtained from each volunteer. A 3.0 T MRI scanner was used, acquiring a T1 turbo spin-echo sequence (TSE) and a T2 TSE sequence with fat suppression by spectral presaturation with inversion recovery (SPIR). The images were assessed by applying the Vieth classification. Minimum, maximum, mean ± standard deviation, and median with lower and upper quartiles were defined. Intra- and interobserver agreements were determined by calculating the kappa coefficients. Differences between the sexes were analyzed using the Mann-Whitney U test.

RESULTS

By applying the unmodified Vieth classification with corresponding schematics, it was possible to assess majority in both sexes via the epiphyseal-diaphyseal fusion of the distal radius and in males also via the epiphyseal-diaphyseal fusion of the distal ulna. The Mann-Whitney U test implied significant sex-related differences for all stages. For both epiphyses, the intra- and interobserver agreement levels were very good (κ > 0.8).

CONCLUSION

If confirmed by further studies, it would be possible to determine the completion of the 18th year of life in both sexes by 3.0 T MRI of the wrist and using the Vieth classification.

KEY POINTS

• The Vieth classification allows determining majority in males and females alike based on the distal radius' epiphysis by 3.0 T MRI of the wrist. • The Vieth classification also allows determining majority in males based on the distal ulna's epiphysis by 3.0 T MRI of the wrist, but not in females. • The presented data can be deemed referential within certain discussed boundaries.

Artificial Intelligence-Assisted Bone Age Assessment to Improve the Accuracy and Consistency of Physicians With Different Levels of Experience

BACKGROUND

The accuracy and consistency of bone age assessments (BAA) using standard methods can vary with physicians' level of experience.

METHODS

To assess the impact of information from an artificial intelligence (AI) deep learning convolutional neural network (CNN) model on BAA, specialists with different levels of experience (junior, mid-level, and senior) assessed radiographs from 316 children aged 4-18 years that had been randomly divided into two equal sets-group A and group B. Bone age (BA) was assessed independently by each specialist without additional information (group A) and with information from the model (group B). With the mean assessment of four experts as the reference standard, mean absolute error (MAE), and intraclass correlation coefficient (ICC) were calculated to evaluate accuracy and consistency. Individual assessments of 13 bones (radius, ulna, and short bones) were also compared between group A and group B with the rank-sum test.

RESULTS

The accuracies of senior, mid-level, and junior physicians were significantly better (all P < 0.001) with AI assistance (MAEs 0.325, 0.344, and 0.370, respectively) than without AI assistance (MAEs 0.403, 0.469, and 0.755, respectively). Moreover, for senior, mid-level, and junior physicians, consistency was significantly higher (all P < 0.001) with AI assistance (ICCs 0.996, 0.996, and 0.992, respectively) than without AI assistance (ICCs 0.987, 0.989, and 0.941, respectively). For all levels of experience, accuracy with AI assistance was significantly better than accuracy without AI assistance for assessments of the first and fifth proximal phalanges.

CONCLUSIONS

Information from an AI model improves both the accuracy and the consistency of bone age assessments for physicians of all levels of experience. The first and fifth proximal phalanges are difficult to assess, and they should be paid more attention.

Tanner-Whitehouse and Modified Bayley-Pinneau Adult Height Predictions in Elite Youth Soccer Players from the Middle East

PURPOSE

To provide the first scrutiny of adult height prediction protocols based on automated Greulich-Pyle and Tanner-Whitehouse (TW) skeletal ages applied to elite youth soccer players from the Middle East.

METHODS

We examined the application of modified Bayley-Pinneau (BoneXpert®), TW-II, and TW-III protocols using mixed-longitudinal data available for 103 subjects (chronological age range, 19.4 to 27.9 yr) previously enrolled as academy student-athletes (annual screening range, one to six visits). Random-effects generalized additive models quantified the presence of systematic mean differences between actual versus predicted adult height. Effects were deemed practically equivalent based on the location of the confidence interval (95% CI) against a realistic difference value of Δ = ± 1 cm. Each model pooled residual standard deviation described the actual precision of height predictions and was used to calculate a 95% prediction interval.

RESULTS

The BoneXpert® method overpredicted adult height systematically at chronological ages in the range of approximately 13.5 to 14.5 yr (95% CI range, -1.9 to -1 cm) and Greulich-Pyle skeletal ages between 13.5 and 15 yr (95% CI range, -3.1 to -1 cm). Effects based on TW-II were practically equivalent across the chronological and skeletal age measurement ranges, with this protocol yielding adult height predictions with a precision (standard deviation) of approximately ±2.6 cm. The mean TW-III effects indicated systematic adult height overpredictions until the attainment of 14.5 and 15 yr of chronological age (95% CI range, -3.8 to -1.1 cm) and TW-III skeletal age (95% CI range: -5.2 to -2.3 cm), respectively.

CONCLUSIONS

Tanner-Whitehouse-II adult height prediction method provided more consistent estimates and can be considered the method of choice for talent development purposes in youth soccer players from the Middle East.

A probability model for assessing age relative to the 18-year old threshold based on magnetic resonance imaging of the knee combined with radiography of third molars in the lower jaw

OBJECTIVE

This study aims to generate a statistical model based on magnetic resonance imaging of the knee and radiography of third molars in the lower jaw, for assessing age relative to the 18-year old threshold.

METHODS

In total, 58 studies correlating knee or tooth development to age were assessed, 5 studies for knee and 7 studies for tooth were included in the statistical model. The relation between the development of the anatomical site, based on a binary system, and age were estimated using logistic regression. Separate meta-populations for knee and tooth were generated from the individual based data for men and women. A weighted estimate of probabilities was made by combining the probability densities for knee and tooth. Margin of errors for males and females in different age groups and knee and tooth maturity were calculated within the larger framework of transition analysis using a logit model as a base. Evidentiary values for combinations of knee and tooth maturity were evaluated with likelihood ratios.

RESULTS

For males, the sensitivity for the method was calculated to 0.78 (probability of correctly classifying adults), the specificity 0.90 (probability of correctly classifying minors), the negative predictive value 0.80 (proportion identified minors are minors) and the positive predictive value 0.89 (proportion identified adults are adults) indicating a model better at identifying minors than adults. The point at which half the female population has reached closed knee lies before the 18-year threshold, adding the knee as an indicator lowers specificity and increases sensitivity. The sensitivity when using tooth as an indicator for females is 0.24 and specificity 0.97, signifying few minors misclassified as adults but also a low probability of identifying adults. The negative predictive value for women when using tooth as the sole indicator is 0.56 and positive predictive value 0.88. Probabilities were calculated for males and females assuming a uniform age distribution between 15 and 21years. The calculated margin of error of minors classified as adults in a population between 15 and 21 years with the model was 11% for males and 12% for females. Further, the evidentiary value as well as margin of error vary for different combinations of knee and tooth maturity.

CONCLUSION

The statistical model based on the combination of MRI knee and radiography of mandibular third molars is a valid method to assess age relative to the 18-year old threshold when applied on males and of limited value in females.

CYP11B1 variants influence skeletal maturation via alternative splicing

We performed genome-wide association study meta-analysis to identify genetic determinants of skeletal age (SA) deviating in multiple growth disorders. The joint meta-analysis (N = 4557) in two multiethnic cohorts of school-aged children identified one locus, CYP11B1 (expression confined to the adrenal gland), robustly associated with SA (rs6471570-A; β = 0.14; P = 6.2 × 10-12). rs6410 (a synonymous variant in the first exon of CYP11B1 in high LD with rs6471570), was prioritized for functional follow-up being second most significant and the one closest to the first intron-exon boundary. In 208 adrenal RNA-seq samples from GTEx, C-allele of rs6410 was associated with intron 3 retention (P = 8.11 × 10-40), exon 4 inclusion (P = 4.29 × 10-34), and decreased exon 3 and 5 splicing (P = 7.85 × 10-43), replicated using RT-PCR in 15 adrenal samples. As CYP11B1 encodes 11-β-hydroxylase, involved in adrenal glucocorticoid and mineralocorticoid biosynthesis, our findings highlight the role of adrenal steroidogenesis in SA in healthy children, suggesting alternative splicing as a likely underlying mechanism.

Traditional and New Methods of Bone Age Assessment-An Overview

Bone age is one of biological indicators of maturity used in clinical practice and it is a very important parameter of a child’s assessment, especially in paediatric endocrinology. The most widely used method of bone age assessment is by performing a hand and wrist radiograph and its analysis with Greulich-Pyle or Tanner-Whitehouse atlases, although it has been about 60 years since they were published. Due to the progress in the area of Computer-Aided Diagnosis and application of artificial intelligence in medicine, lately, numerous programs for automatic bone age assessment have been created. Most of them have been verified in clinical studies in comparison to traditional methods, showing good precision while eliminating inter- and intra-rater variability and significantly reducing the time of assessment. Additionally, there are available methods for assessment of bone age which avoid X-ray exposure, using modalities such as ultrasound or magnetic resonance imaging.

A Novel Shorthand Approach to Knee Bone Age Using MRI: A Validation and Reliability Study

Background:

Bone-age determination remains a difficult process. An atlas for bone age has been created from knee-ossification patterns on magnetic resonance imaging (MRI), thereby avoiding the need for radiographs and associated costs, radiation exposure, and clinical inefficiency. Shorthand methods for bone age can be less time-consuming and require less extensive training as compared with conventional methods.

Purpose:

To create and validate a novel shorthand algorithm for bone age based on knee MRIs that could correlate with conventional hand bone age and demonstrate reliability across medical trainees.

Study Design:

Cohort study (diagnosis); Level of evidence, 2.

Methods:

Included in this study were adolescent patients who underwent both knee MRI and hand bone age radiographs within 90 days between 2009 and 2018. A stepwise algorithm for predicting bone age using knee MRI was developed separately for male and female patients, and 7 raters at varying levels of training used the algorithm to determine the bone age for each MRI. The shorthand algorithm was validated using Spearman rho (r_S) to correlate each rater’s predicted MRI bone age with the recorded Greulich and Pyle (G&P) hand bone age. Interrater and intrarater reliability were also calculated using intraclass correlation coefficients (ICCs).

Results:

A total of 38 patients (44.7% female) underwent imaging at a mean age of 12.8 years (range, 9.3-15.7 years). Shorthand knee MRI bone age scores were strongly correlated with G&P hand bone age (r_S = 0.83; P < .001). The shorthand algorithm was a valid predictor of G&P hand bone age regardless of level of training, as medical students (r_S = 0.75), residents (r_S = 0.81), and attending physicians (r_S = 0.84) performed similarly. The interrater reliability of our shorthand algorithm was 0.81 (95% CI, 0.73-0.88), indicating good to excellent interobserver agreement. Respondents also demonstrated consistency, with 6 of 7 raters demonstrating excellent intrarater reliability (median ICC, 0.86 [range, 0.68-0.96]).

Conclusion:

This shorthand algorithm is a consistent, reliable, and valid way to determine skeletal maturity using knee MRI in patients aged 9 to 16 years and can be utilized across different levels of orthopaedic and radiographic expertise. This method is readily applicable in a clinical setting and may reduce the need for routine hand bone age radiographs.