The relationship of calcaneal apophyseal ossification and Sanders hand scores to the timing of peak height velocity in adolescents

The Creation and Validation of an Ankle Bone Age Atlas and Data Predicting Remaining Ankle Growth

BACKGROUND

The purpose of the current study was 2-fold: (1) to create and validate an ankle bone age atlas spanning the pediatric and adolescent years and (2) to utilize this atlas in conjunction with distal tibia/fibular growth data as measured on serial radiographs to develop a predictive growth model for the lower extremity.

METHODS

Radiographs were surveyed to identify distinguishable, reproducible, radiographic features. Radiographic features of the tibia, fibula, hindfoot, and midfoot from 270 patients were identified and a "standard" for each age/sex was selected to create an atlas. A separate cohort of 90 ankle radiographs was selected to validate the atlas. A subcohort of 41 patients with left-hand radiographs within 3 months of ankle imaging was used to compare the 2 bone age approaches. Harris growth lines were evaluated in 304 serial images of the distal tibia to determine the remaining growth.

RESULTS

The distal tib/fib ossification centers provided the best age assessment for early childhood (male age: 1 to 8 y; female age: 1 to 4 y). The ossification/fusion of the calcaneal apophysis provided the best age assessment in the preadolescent stage (male age: 6 to 14 y; female age: 5 to 12 y). The closure of the distal tib/fib physes best determined skeletal maturity (male age: 14 to 16 y; female age: 12 to 14 y). The ankle atlas had excellent interobserver and intraobserver reliability (intraclass correlation coefficient=0.993, P <0.001 and 0.998, P <0.001), respectively. We found an excellent correlation between the patient's chronologic age and ankle bone age ( r =0.984; P <0.001). Ankle bone age assessment and Greulich and Pyle were correlated ( rs =0.822, P <0.001). We found that males with a bone age of ≥15 years and females with a bone age of ≥13 years had ≤2 mm of residual growth of the distal tibia/fibula physes.

CONCLUSIONS

bone age can be determined using ankle films ordered to assess/treat ankle injuries. This tool, along with our growth remaining table, may have important clinical implications when managing patients with ankle trauma with premature physeal closure.

LEVEL OF EVIDENCE

IV.

Substantial mismatch of skeletal maturity assessment between Risser sign and Simplified Skeletal Maturity Scale/Thumb Ossification Composite Index in patients with adolescent idiopathic scoliosis

BACKGROUND

Recently, hand skeletal maturity systems such as the Simplified Skeletal Maturity Scale (SSMS) or Thumb Ossification Composite Index (TOCI) have been introduced to attempt to prospectively predict the occurrence of peak height velocity (PHV) in adolescents. This study aims to compare the frequency of the mismatch in estimation of HV between Risser sign (RS) and SSMS/TOCI stages in adolescent idiopathic scoliosis (AIS) patients.

METHODS

One hundred thirty-three female patients with AIS were included. The mean age of the patients was 13.1 years. A whole spine and hand X-rays were obtained to establish skeletal maturity stage according to RS, SSMS, and TOCI systems. A mismatch resulting in overestimation (MOE) with RS compared to SSMS/TOCI was defined as the combination of RS 3-4/SSMS 3-5 or RS 3-4/TOCI 4-6, whereas a mismatch resulting in underestimation (MUE) with RS and SSMS/TOCI was defined as RS 0-1/SSMS 6-8 or RS 0-1/TOCI 7-8. Height velocity (HV) was compared between MOE/non-MOE and MUE/non-MUE groups.

RESULTS

Between RS and SSMS, the rates of the MOE and MUE groups were 4.3% and 1.7%, respectively. Between RS and TOCI, rates were 2.8% and 1.7%, respectively. With the combination of RS and SSMS stages, an estimate of HV of 5.6 cm/year in the MOE group was significantly larger than that of 2.7 cm/year in the non-MOE group, and 3.7 cm/year in the MUE group was significantly smaller than 6.9 cm/year in the non-MUE group. Likewise, with the combination of RS and TOCI stages, an estimate of HV of 5.8 cm/year in the MOE group was significantly greater that of 2.7 cm/year in the non-MOE group, and 3.7 cm/year in the MUE group was significantly smaller than 6.9 cm/year in the non-MUE group.

CONCLUSIONS

These findings support the use of SSMS/TOCI as the standard for assessing HV and skeletal maturity in patients with AIS.

Pediatric anterior cruciate ligament tears and associated lesions: Epidemiology, diagnostic process, and imaging

The incidence of anterior cruciate ligament injuries in skeletally immature patients has increased in recent years. The gold standard treatment of this type of trauma in children is not yet established. Conservative management may underestimate the risk of new meniscal and chondral tears; on the other hand, a more interventional approach may expose the patient to iatrogenic damage to the growth plate. A correct approach to the skeletally immature patient with knee trauma is therefore essential to guide the decision-making process. This review article aims to present an update on the epidemiology and diagnostic process of pediatric patients with anterior cruciate ligament tears and possible associated injuries. Level of Evidence: V.

Using Skeletal Maturity in Pediatric Orthopaedics: A Primer

This article provides researchers with the background and guidance necessary to practically incorporate skeletal maturity estimation into any study of adolescents with imaging of the shoulder, elbow, hand, hip, knee, or foot. It also provides clinicians with a comprehensive, concise synopsis of systems that can be used to estimate skeletal maturity in clinical practice. In the article, we provide a relatively brief overview of each currently available skeletal maturity system that has been validated on a longitudinal dataset. The supplementary files include 2 PowerPoint files for each skeletal maturity system. The first PowerPoint file offers examples and instructions for using each radiographic system. The second PowerPoint file includes 20 graded radiographs that can be used for reliability analyses in the research setting. We have also developed a free mobile application available on the iOS and Android platforms named "What's the Skeletal Maturity?" that allows clinicians to rapidly estimate skeletal maturity on any patient using any commonly obtained orthopaedic radiograph.

Measuring Proximal Tibial Metaphyseal Width and Lateral Epiphyseal Height Improves Determination of Remaining Growth in Children

BACKGROUND

Accurate assessments of skeletal maturity is of critical importance to guide type and timing of orthopaedic surgical interventions. Several quantitative markers of the proximal tibia were recently developed using historical knee radiographs. The purpose of the present study was to determine which marker would be most effective in assessment of full-length radiographs in a modern pediatric patient population.

METHODS

All full-length radiographs at our institutions between 2013 and 2018 were reviewed. Inclusion criteria for our study required that the child reached final height as defined by 2 consecutive unchanged heights, at least 6 months apart, after age 16 for boys and 14 for girls. Patients with metabolic bone disease, prior surgery such as epiphysiodesis, or previous infections around the knee were excluded. Summary statistics for each of the 3 proximal tibial ratios were calculated and multiple linear regression was performed with percent of growth remaining as a dependent variable. A recommended regression model is presented and evaluated.

RESULTS

A total of 692 full-length radiographs met inclusion criteria. Proximal tibial ratios were calculated and averaged values for each percent of growth remaining was presented. Multiple linear regression demonstrated that using all 3 variables led to overfitting of the model so tibial metaphyseal width/lateral tibial epiphyseal height was selected as the optimal ratio for use by clinicians. The optimal model for determining growth was found to have R2=0.723 in the developmental set and R2=0.762 in an excluded validation set.

CONCLUSIONS

This study demonstrates that the proximal tibial metaphyseal width/lateral tibial epiphyseal height is the ideal measurement for clinicians seeking to determine growth remaining in children. It presents average values between 0% and 25% of growth remaining. This study also develops and validates a multivariable regression model for determining percentage of growth remaining in children that will allow for quantitative determination of growth using full-length radiographs.

LEVEL OF EVIDENCE

Level III.

Modification and application of the proximal humerus ossification system to adolescent idiopathic scoliosis patients

PURPOSE

We have previously demonstrated that proximal humeral ossification patterns are reliable for assessing peak height velocity in growing patients. Here, we sought to modify the system by including medial physeal closure and evaluate whether this system combined with the Cobb angle correlates with progression to surgery in patients with adolescent idiopathic scoliosis.

METHODS

We reviewed 616 radiographs from 79 children in a historical collection to integrate closure of the medial physis into novel stages 3A and 3B. We then analyzed radiographs from the initial presentation of 202 patients with adolescent idiopathic scoliosis who had either undergone surgery or completed monitoring at skeletal maturity. Summary statistics for the percentage of patients who progressed to the surgical range were calculated for each category of humerus and Cobb angle.

RESULTS

The intra-observer and inter-observer ICC for assessment of the medial physis was 0.6 and 0.8, respectively. Only 3.4% of radiographs were unable to be assessed for medial humerus closure. The medial humerus physis begins to close about 1 year prior to the lateral physis and patients with a closing medial physis, but an open lateral physis were found to be the closest to PHV (0.7 years). Stratifying patients by Cobb angle and modified humerus stage yield categories with low and high risks of progression to the surgical range.

CONCLUSION

The medial humerus can be accurately evaluated and integrated into a new modified proximal humerus ossification system. Patients with humerus stage 3A or below have a higher rate of progression to the surgical range than those with humerus stage 3B or above.

The More the Merrier: Integrating Multiple Models of Skeletal Maturity Improves the Accuracy of Growth Prediction

BACKGROUND

Multiple systems using radiographic skeletal markers to measure development have been described, including the Greulich and Pyle Atlas (GP), the Fels Method (Fels), and the Sanders Hand Classification (Sanders). The purpose of this study was to quantitatively assess whether the integration of skeletal maturity assessment methods and demographic variables improves the accuracy of pediatric growth predictions over the use of skeletal markers or chronologic age alone.

METHODS

The Brush Inquiry contains prospectively collected longitudinal data on children who lived in Cleveland, Ohio between 1926 and 1942. A total of 16 boys and 29 girls were selected for study. All had age, height, and an anteroposterior radiograph of the hand at each of 3 visits. Those visits occurred at 85%, 90%, and 95% of final height. We determined the growth completed at each visit by dividing the height observed by the final height at skeletal maturity. Boys and girls were analyzed separately using chronologic age, height, GP, Fels, and Sanders. The residual difference between the height predicted and actual height, as well as the SD of the prediction error of the cohort at each time point was calculated. To account for multiple visits from each subject, all linear models were produced using the generalized estimating equations (GEEs) procedure.

RESULTS

For boys, age, GP, and Fels performed similarly in predicting growth remaining at all 3 time points. For girls, age, GP, and Fels performed similarly in predicting growth remaining at the 85% and 95% time points; however, the Fels Method demonstrated improved performance at the 90% time point compared with chronologic age (P = 0.0076) and GP alone (P = 0.0155). For both boys and girls, the most accurate multivariate GEE model with the lowest SD of prediction error integrated Fels, age, GP, Sanders, and height.

CONCLUSIONS

The most accurate multivariate GEE model of growth prediction for both boys and girls integrated Fels, age, GP, Sanders, and height. When calculating the amount of growth remaining, it is prudent to integrate multiple systems for greater predictive accuracy.

LEVEL OF EVIDENCE

Level III.

An insight of how multiple skeletal maturity indices can be used for growth assessment: relationship between the simplified olecranon, simplified digital, and distal radius and ulna classifications

This cross-sectional study aims to investigate the relationship between the simplified olecranon, simplified digital, and distal radius and ulna (DRU) classifications, and whether they can aid in more comprehensive maturity assessment together. Left hand and wrist and lateral elbow radiographs from pediatric patients were assessed using the three skeletal maturity indices. The association between maturity indices was investigated using Goodman and Kruskal's gamma, and by mapping of individual grades based on chronological age. Specific maturity grades, at which peak height velocity (PHV) occurs as previously identified, were based upon to explore how the three systems interact. A total of 114 patients (63.2% girls) were studied. Correlations and associations between the three maturity parameters were significant (all at P < 0.001). Mapping revealed uneven spans and coverage of different periods by each index. Olecranon stage 1 coincided with R3 (for girls), R4 (for boys), U3, and SS1. Olecranon stage 5 occurred as early as R7, U6, and SS4. Upon elbow fusion, the simplified digital (SS5-SS8) and DRU (R8-R11 and U7-U9) classifications can be used for assessment until maturity. The inter-relationship of the simplified hand, wrist, and olecranon methods indicates their combined use. DRU grades can be used in growth periods which are less well covered. Prepubertal and growth acceleration phase of pubertal growth spurt can best be assessed by both the simplified olecranon (stages 1-3) and DRU classifications (R1-R5 and U1-U4). All three indices are required during PHV. For post-PHV, DRU (R8-R11 and U7-U9) and simplified digital method (SS5-SS8) complement each other for assessment until skeletal maturity.

Combining Lower Extremity Radiographic Markers Begets More Accurate Predictions of Remaining Skeletal Growth

BACKGROUND

Radiographic markers of skeletal maturity are vital to the prediction and interpretation of skeletal growth patterns. Accurate predictions of skeletal maturity factor into the management of common musculoskeletal disorders. Bone age is conventionally measured using hand and wrist radiographs. The primary study objective was to optimize skeletal maturity estimates based on the morphology of markers at the hip, knee, and foot rather than conventional upper extremity radiographs.

METHODS

This was a retrospective analysis of children from the Bolton-Brush collection with anteroposterior radiographs of the hip and anteroposterior and lateral radiographs of the knee and foot, and heights recorded at the time of each radiograph. The percent growth achieved (%GA) was calculated as a function of final patient height. Poor quality radiographs were excluded, leaving 50 patients-32 females and 18 males-and 1068 radiographs for analysis. Skeletal maturity was evaluated using the Oxford bone, O'Connor knee, and calcaneal apophyseal scores. Interrater and intrarater reliability analyses were performed for hip and knee scores. Multiple linear regressions were conducted on these scores and chronologic age as predictors of %GA. Mean differences were calculated between actual and estimated %GAs. All analyses were performed in Prism 8.0.

RESULTS

Each lower extremity skeletal maturity score served as statistically significant, independent predictors of %GA, the accuracy and strength of which increased with the addition of chronologic age. The integration of all 3 systems and chronologic age yielded the most predictive, accurate model predictive of %GA, which can be used to determine percent growth remaining. However, this fully integrated system was not statistically superior to the combination of knee and foot scores and knee score and chronologic age, which yield similarly accurate %GA predictions. The hip and knee systems demonstrated good to excellent interrater and intrarater reliability.

CONCLUSIONS

Integration of bone age scores across different regions of the lower extremity has the potential to facilitate orthopaedic decision-making using radiographs already obtained in the treatment of pediatric musculoskeletal conditions.

LEVEL OF EVIDENCE

Level IV.

A Simplified Skeletal Maturity Scale and Thumb Ossification Composite Index to Assess Skeletal Maturity and Predict Height Velocity in Japanese Females with Adolescent Idiopathic Scoliosis

INTRODUCTION

Since Little et al. first reported that peak height velocity (PHV) could be described as a reliable clinical marker for the prediction of remaining growth and curve progression of adolescent idiopathic scoliosis (AIS) in clinical practice, much attention has been paid to PHV as a possible predictor of curve progression in patients with AIS. However, PHV itself is only identified retrospectively, so its value is not available at the first outpatient clinic visit. Using the simplified skeletal maturity scale (SSMS) and the thumb ossification composite index (TOCI) staging systems, this study aims to assess skeletal maturity and predict height velocity (HV) in Japanese female patients with AIS.

METHODS

This study involved 95 female patients with AIS, ranging from 9 to 17 years old. A standing AP radiograph of the entire spine and a hand radiograph were retrospectively obtained to establish the skeletal maturity stage in accordance with the SSMS and TOCI systems. Height measurements were recorded at each visit; HV was calculated as the height change (cm) divided by the time interval (years).

RESULTS

The TOCI stage rating increased identically to the SSMS stage rating increase. The chi-square test showed that there was a significant correlation between the two scoring systems (χ2=720.4). The Cramer V correlation also demonstrated a very strong correlation (Cramer V=0.62). Regarding the relationship between HV and each SSMS and TOCI stage, HV decreased as SSMS and TOCI stages increased. η 2 equaled to 0.67 in both groups and displayed a strong correlation between HV and SSMS and TOCI stages.

CONCLUSIONS

These findings suggest that evaluation of the rate of HV using these radiological assessments is of supreme importance for determining the status of pubertal maturity and predicting the remaining amount of adolescent growth at the outpatient clinic visit.

Predicting Growth Quantitatively Through Proximal Tibia Radiograph Markers

BACKGROUND

The creation of accurate markers for skeletal maturity has been of significant interest to orthopaedic surgeons. They guide the management of diverse disorders such as adolescent idiopathic scoliosis, leg length discrepancy, cruciate ligament injuries, and slipped capital femoral epiphysis. Multiple systems have been described to predict growth using radiographic skeletal markers; however, no such system has yet been developed for the proximal tibia. The purpose of this study was to establish quantitative radiographic parameters within the proximal tibia that can be used to assess degree of skeletal maturity.

METHODS

From the Bolton Brush collection, 94 children, consisting of 49 girls and 4 boys between the ages of 3 and 18 years old, were followed annually throughout growth with serial radiographs and physical examinations. Final height at maturity was used to calculate the growth remaining at each visit. Multiple measurements for each knee radiograph were performed and correlated with the percentage of growth remaining. Tibial epiphysis width, tibial metaphysis width, and height of the lateral tibial epiphysis were measured on each film and the composite ratios between each of these sets of variables along with their respective accuracy and reliability were calculated. Single and multiple linear regression models were constructed to determine accuracy of prediction. Interobserver and intraobserver studies were performed with 4 investigators ranging from medical student to senior attending and calculated using the intraclass correlation coefficient. All 4 examiners measured all of the subjects and the ratios created were averaged.

RESULTS

Tibial epiphysis width, tibial metaphysis width, and height of the lateral tibial epiphysis were all found to be strongly correlated with growth remaining with R values ranging from 0.57 to 0.84. In addition, all 3 ratios were found to be reliable with intraobserver and interobserver intraclass correlation coefficients ranging from 0.92 to 0.94 and 0.80 to 0.94, respectively. A multiple linear regression model demonstrated that combining these 3 ratios allows for a predictive R value of 0.917, showing that these ratios when combined were highly predictive of growth remaining. All findings were independent of sex (P=0.996).

CONCLUSIONS

We describe 3 measurements that can easily be obtained on an anteroposterior radiograph of the knee. We demonstrate that ratios of these variables can be measured reliably and correlate closely with remaining growth, independent of sex. Together, we believe that these factors will improve the accuracy of determining growth from lower extremity radiographs that include the proximal tibia.

CLINICAL RELEVANCE

This study provides a new quantitative technique to evaluate growth in the lower extremity, which can inform a range of conditions including adolescent idiopathic scoliosis, leg length discrepancy, cruciate ligament injury, and slipped capital femoral epiphyses.

Relationship Between Sever Disease and Skeletal Maturity

BACKGROUND

Sever disease is a common condition in active, growing children. This condition presents as pain in the heel and is thought to be an overuse condition of the calcaneal apophysis. There are currently no defined radiographic diagnostic criteria for evaluation of Sever disease, with radiographs generally showing normal appearance of the calcaneal apophysis. A better understanding of the relationship of Sever disease and skeletal maturity may allow for improved interpretation of radiographs when trying to diagnose this condition.

METHODS

ICD-9 code 732.5 was used to search for patients diagnosed with Sever disease from 2007 to 2015 at a single hospital. For every patient with Sever disease with available calcaneal imaging within 40 days of diagnosis, heel x-rays were staged for calcaneal maturity score using a previously described calcaneal skeletal maturity assessment system. Controls matched by age, race, and sex were evaluated for calcaneal stage to compare with the Sever patients.

RESULTS

The chart review yielded 78 patients diagnosed with Sever disease by the orthopaedic attending, 39 of which have x-rays around the time of diagnosis. Calcaneal scores averaged 2.2±0.8 for all patients, 2.1±0.9 for male individuals, and 2.3±0.8 for female individuals. The average age for male individuals was 10.4±1.9 years and for female individuals, 9.2±2.2 years. The ages of diagnosis were similar for patients with and without x-rays. Twenty-two of 39 patients with Sever disease were calcaneal stage 2, and 37 of 39 were stages 1, 2, or 3. We calculated the absolute difference from stage 2 for the Sever and control groups. Mean difference from stage 2 was 0.51±0.68 for the Sever patients and 0.95±0.79 for control patients (P=0.01).

CONCLUSION

Sever disease occurs in a very narrow range of skeletal maturity, as measured by the calcaneal skeletal maturity assessment system and our observations with chronological age. When compared with age-matched and race-matched controls, stage 2 was seen more frequently in the Sever patients. If a child is not within calcaneal stages 1, 2, or 3, then a different diagnosis should be considered.

LEVEL OF EVIDENCE

Level III-retrospective case-control study.

Bracing in Adolescent Idiopathic Scoliosis Trial (BrAIST): Development and Validation of a Prognostic Model in Untreated Adolescent Idiopathic Scoliosis Using the Simplified Skeletal Maturity System

STUDY DESIGN

Prognostic study and validation using prospective clinical trial data.

OBJECTIVE

To derive and validate a model predicting curve progression to ≥45° before skeletal maturity in untreated patients with adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Studies have linked the natural history of AIS with characteristics such as sex, skeletal maturity, curve magnitude, and pattern. The Simplified Skeletal Maturity Scoring System may be of particular prognostic utility for the study of curve progression. The reliability of the system has been addressed; however, its value as a prognostic marker for the outcomes of AIS has not. The BrAIST trial followed a sample of untreated AIS patients from enrollment to skeletal maturity, providing a rare source of prospective data for prognostic modeling.

METHODS

The development sample included 115 untreated BrAIST participants. Logistic regression was used to predict curve progression to ≥45° (or surgery) before skeletal maturity. Predictors included the Cobb angle, age, sex, curve type, triradiate cartilage, and skeletal maturity stage (SMS). Internal and external validity was evaluated using jackknifed samples of the BrAIST data set and an independent cohort (n = 152). Indices of discrimination and calibration were estimated. A risk classification was created and the accuracy evaluated via the positive (PPV) and negative predictive values (NPV).

RESULTS

The final model included the SMS, Cobb angle, and curve type. The model demonstrated strong discrimination (c-statistics 0.89-0.91) and calibration in all data sets. The classification system resulted in PPVs of 0.71-0.72 and NPVs of 0.85-0.93.

CONCLUSIONS

This study provides the first rigorously validated model predicting a short-term outcome of untreated AIS. The resultant estimates can serve two important functions: 1) setting benchmarks for comparative effectiveness studies and 2) most importantly, providing clinicians and families with individual risk estimates to guide treatment decisions.

LEVEL OF EVIDENCE

Level 1, prognostic.

The Proximal Humeral Ossification System Improves Assessment of Maturity in Patients with Scoliosis

BACKGROUND

We recently developed a classification system to assess skeletal maturity by scoring proximal humeral ossification in a similar way to the canonical Risser sign. The purpose of the present study was to determine whether our system can be used to reliably assess radiographs of the spine for modern patients with idiopathic scoliosis, whether it can be used in combination with the Sanders hand system, and whether the consideration of patient factors such as age, sex, and standing height improves the accuracy of predictions.

METHODS

We retrospectively reviewed 414 randomized radiographs from 216 modern patients with scoliosis and measured reliability with use of the intraclass correlation coefficient (ICC). We then analyzed 606 proximal humeral radiographs for 70 children from a historical collection to determine the value of integrating multiple classification systems. The age of peak height velocity (PHV) was predicted with use of linear regression models, and performance was evaluated with use of tenfold cross-validation.

RESULTS

The proximal humeral ossification system demonstrated excellent reliability in modern patients with scoliosis, with an ICC of 0.97 and 0.92 for intraobserver and interobserver comparisons, respectively. The use of our system in combination with the Sanders hand system yielded 7 categories prior to PHV and demonstrated better results compared with either system alone. Linear regression algorithms showed that integration of the proximal part of the humerus, patient factors, and other classification systems outperformed models based on canonical Risser and triradiate-closure methods.

CONCLUSIONS

Humeral head ossification can be reliably assessed in modern patients with scoliosis. Furthermore, the system described here can be used in combination with other parameters such as the Sanders hand system, age, sex, and height to predict PHV and percent growth remaining with high accuracy.

CLINICAL RELEVANCE

The proximal humeral ossification system can improve the prediction of PHV in patients with scoliosis on the basis of a standard spine radiograph without a hand radiograph for the determination of bone age. This increased accuracy for predicting maturity will allow physicians to better assess patient maturity relative to PHV and therefore can help to guide treatment decision-making without increasing radiation exposure, time, or cost. The present study demonstrates that assessment of the proximal humeral physis is a viable and valuable aid in the determination of skeletal maturity as obtained from radiographs of the spine that happen to include the shoulder in adolescent patients with idiopathic scoliosis.

Incidence and Fusion of Os Trigonum in a Healthy Pediatric Population

BACKGROUND

Accessory ossicles off the talus (os trigonum) are a common radiographic finding seen within the foot with variable symptomatology in adult and pediatric patients. Although most studies have examined the incidence of these anatomic variants in a retrospective manner, few have longitudinally followed the behavior of os trigonum over time. The aim of this study was to investigate the incidence, mean age of appearance and fusion, and fusion rate of os trigonum in a large cohort of asymptomatic pediatric patients.

METHODS

A total of 2620 serial digitized unilateral foot and ankle radiographs from 261 healthy white children (age range, 0.25 to 7 y at enrollment) were retrospectively reviewed. Radiographs were examined to determine the incidence of os trigonum, noting age of appearance and if present, the age of fusion. Skeletal maturity was graded based on ossification pattern of the calcaneal apophysis.

RESULTS

Radiographic evidence of os trigonum was present in 18% of patients (n=16 females, n=15 males) with radiographs extending 1 SD beyond the average age of os trigonum appearance. There was no difference in incidence between females and males (P=0.27), and os trigonum was found to appear at a significantly younger age in females (9.1±1.8 y) than males (10.4±2.0 y, P=0.04). Overall, 70% (n=26) of subjects with os trigonum achieved fusion by age 17 (mean, 9.5±1.6 y in females, 11.2±1.6 in males) with no significant difference between sexes (P=0.61). Grading of skeletal maturity at the time of fusion showed that both male and female subjects underwent fusion on average between calcaneal stages 2 and 3 (P=0.5).

CONCLUSIONS

This study confirms a relatively large prevalence of os trigonum in a random pediatric population, and clarifies both the average age of onset and high rate of fusion at a relatively narrow range of skeletal maturity.

LEVEL OF EVIDENCE

Prognostic level II-retrospective study.

Humeral Head Ossification Predicts Peak Height Velocity Timing and Percentage of Growth Remaining in Children

BACKGROUND

Understanding skeletal maturity is important in the management of idiopathic scoliosis. Iliac apophysis, triradiate cartilage, hand, and calcaneal ossification patterns have previously been described to assess both peak height velocity (PHV) and percent growth remaining; however, these markers may not be present on standard spine radiographs. The purpose of this study was to describe a novel maturity assessment method based on proximal humeral epiphyseal ossification patterns.

METHODS

Ninety-four children were followed at least annually throughout growth with serial radiographs and physical examinations. The PHV of each child was determined by measuring the change in height observed at each visit and adjusting for the interval between visits. Percent growth remaining was determined by comparing current to final standing height. The humeral head periphyseal ossification was grouped into stages by 8 investigators ranging from medical student to attending surgeon.

RESULTS

The morphologic changes involving the proximal humeral physis were categorized into 5 stages based on development of the humeral head epiphysis and fusion of the lateral margin of the physis. Our novel classification scheme was well distributed around the PHV and reliably correlated with age of peak growth and percent growth remaining with >70% nonoverlapping interquartile ranges. Furthermore, the scheme was extremely reliable with intraclass correlation coefficients of 0.96 and 0.95 for intraobserver and interobserver comparisons, respectively.

CONCLUSIONS

The humeral head classification system described here was strongly correlated with age of PHV as well as percentage growth remaining. Furthermore, the staging system was extremely reliable in both interobserver and intraobserver correlations suggesting that it can be easily generalized.

CLINICAL RELEVANCE

As a view of the humeral head is almost always present on standard scoliosis spine x-ray at our institution, our classification can be easily adapted by surgeons to gain additional insight into skeletal maturity of patients with scoliosis. We believe that our method will significantly improve the evaluation of the child with scoliosis without increasing radiation exposure, time, or cost.

Binary and analogue markers of skeletal maturity: clinical utility of the thenar and plantar sesamoids

PURPOSE

We investigate the thenar and plantar sesamoids as markers of skeletal maturity, and grade appearance using two scales, a binary system (absent or present), and an analogue system that relies upon judging regular changes in morphological appearance.

METHODS

We studied 94 healthy children (49 female and 45 male patients) between ages three and 18 years who had approximately 700 serially acquired sets of radiographs and physical examinations. The children had at least annual radiographs taken of the left hand and left foot. Velocity of growth was calculated and curves were fit to a cubic spline model to determine age of maximum height velocity, or peak height velocity (PHV). Appearance of the plantar and thenar sesamoids was recorded using a binary system classifying the sesamoids as absent or present and an analogue system classifying the sesamoid as absent, present as a small ossification centre or larger than a small ossification centre.

RESULTS

The plantar sesamoids appear 1.67 years before PHV and reach mature size 1.02 years after PHV. The thenar sesamoids appear 0.32 years before PHV and reach mature size 2.25 years after PHV. The plantar sesamoids are present and thenar sesamoids are absent at a mean 1.5 years prior to PHV. No patients had the thenar sesamoids present while the plantar sesamoids were absent.

CONCLUSION

As binary markers, when the plantar and thenar sesamoids are considered together it is possible to localize maturity. As analogue markers, they offer more information. The sesamoids also allow clarification of the calcaneal and Sanders stages.

LEVEL OF EVIDENCE

Not Applicable.

What is the most accurate and reliable methodological approach for predicting peak height velocity in adolescents? A systematic review

OBJECTIVES

To identify the most accurate method of predicting peak height velocity in adolescents.

DESIGN

Systematic review.

METHODS

A comprehensive literature search of six electronic databases and reference lists was conducted. Studies that met selection criteria of (1) observational longitudinal cohort study (2) reproducible method/s of predicting peak height velocity (3) minimum six-month follow-up (4) healthy male and/or female adolescent subjects, with the exception of participants with adolescent idiopathic scoliosis, were considered for review. Studies were screened using a modified quality assessment checklist, with only those scoring >50% included. The type of surrogate measure of peak height velocity, its reliability and ability to predict peak height velocity were extracted from the year or stage immediately preceding peak height velocity. We defined "predict" as when both the estimates of effect and 95% confidence intervals of the surrogate occurred prior to the actual age of PHV.

RESULTS

The nine included studies examined three anthropometric, three equation and four radiographic-based surrogates for PHV. Of these, the radiographic measures were reported to exhibit moderate to high intra- and inter-rater reliability. Three of the four radiographic surrogates predicted PHV. Two anthropometric measures also predicted PHV but reliability of the measures is unknown. All equation-based methods predicted the timing of PHV to occur later than it actually happened when applied in the year prior to expected PHV.

CONCLUSIONS

In the year/stage immediately preceding peak height velocity, radiograph-based methods appear to be accurate and reliable surrogates.