Thumb Ossification Composite Index (TOCI) for Predicting Peripubertal Skeletal Maturity and Peak Height Velocity in Idiopathic Scoliosis: A Validation Study of Premenarchal Girls with Adolescent Idiopathic Scoliosis Followed Longitudinally Until Skeletal Maturity

Distinguishing risk of curve progression in adolescent idiopathic scoliosis with bone microarchitecture phenotyping: a 6-year longitudinal study

Low bone mineral density and impaired bone quality have been shown to be important prognostic factors for curve progression in adolescent idiopathic scoliosis (AIS). There is no evidence-based integrative interpretation method to analyze high-resolution peripheral quantitative computed tomography (HR-pQCT) data in AIS. This study aimed to (1) utilize unsupervised machine learning to cluster bone microarchitecture phenotypes on HR-pQCT parameters in girls with AIS, (2) assess the phenotypes' risk of curve progression and progression to surgical threshold at skeletal maturity (primary cohort), and (3) investigate risk of curve progression in a separate cohort of girls with mild AIS whose curve severity did not reach bracing threshold at recruitment (secondary cohort). Patients were followed up prospectively for 6.22 ± 0.33 years in the primary cohort (n = 101). Three bone microarchitecture phenotypes were clustered by fuzzy C-means at time of peripubertal peak height velocity (PHV). Phenotype 1 had normal bone characteristics. Phenotype 2 was characterized by low bone volume and high cortical bone density, and phenotype 3 had low cortical and trabecular bone density and impaired trabecular microarchitecture. The difference in bone quality among the phenotypes was significant at peripubertal PHV and continued to skeletal maturity. Phenotype 3 had significantly increased risk of curve progression to surgical threshold at skeletal maturity (odd ratio [OR] = 4.88; 95% CI, 1.03-28.63). In the secondary cohort (n = 106), both phenotype 2 (adjusted OR = 5.39; 95% CI, 1.47-22.76) and phenotype 3 (adjusted OR = 3.67; 95% CI, 1.05-14.29) had increased risk of curve progression ≥6° with mean follow-up of 3.03 ± 0.16 years. In conclusion, 3 distinct bone microarchitecture phenotypes could be clustered by unsupervised machine learning on HR-pQCT-generated bone parameters at peripubertal PHV in AIS. The bone quality reflected by these phenotypes was found to have significant differentiating risk of curve progression and progression to surgical threshold at skeletal maturity in AIS.

Ultrasound supports clinical decision-making in determining the Sanders' skeletal maturity score of the hand

PURPOSE

The Sanders Scoring System has revolutionized the way we assess the remaining growth potential of the skeleton. However, because it involves radiation exposure, it must be used with caution in children. The purpose of the study was to evaluate whether the Sanders skeletal maturity score (SMS) could be accurately determined using ultrasound (U).

METHODS

We took radiographs (R) of the hand and performed U of the thumb and index finger in 115 patients between six and 19 years of age who were undergoing treatment for scoliosis or limb deformities. Paediatric orthopaedic surgeons, a paediatrician, and a paediatric radiologist were evaluated the blinded images. Those classified images are based on the SMS and the Thumb Ossification Composite Index (TOCI).

RESULTS

Intrarater reliability was high for SMS and slightly weaker for TOCI, but still significant. Interrater reliability was clear for R and weaker for U in both staging systems. Ultimately, SMS 3 and 7 achieved the highest percentage of concordance (P) of 71.7% and 66.0%, respectively, when U was performed. Combining the clinically relevant groups of SMS 3&4 and SMS 7&8 also significantly increased peak scores (SMS 3 and 4 P = 76.7%; SMS 7 and 8 P = 79.7%). The probabilities of peak scores were significantly weaker when the TOCI score was examined.

CONCLUSION

Our study shows that U can be used effectively especially to measure stages 3 and 4 and stages 7 and 8 of SMS. The U method is easy to use and therefore may offer advantages in clinical practice without the need for radiation exposure.

Is there a skeletal age index that can predict accurate curve progression in adolescent idiopathic scoliosis? A systematic review

BACKGROUND

The diagnosis of adolescent idiopathic scoliosis requires clinical and radiographic evaluation; the management options vary depending on the severity of the curve and potential for progression. Identifying predictors of scoliosis progression is crucial to avoid incorrect management; clinical and radiographic factors have been studied as potential predictors. The present study aims to review the literature on radiological indexes for the peak height velocity or curve acceleration phase to help clinicians manage treatment of patients with adolescent idiopathic scoliosis.

METHODS

This systematic review was carried out in accordance with Preferential Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The search was carried out including only peer-reviewed articles written in English that described the radiological indexes assessing skeletal maturity in patients with adolescent idiopathic scoliosis and evaluated their correlation with curve progression, expressed as peak height velocity and/or curve acceleartion phase.

RESULTS

Thirteen studies were included and showed promising results in terms of reliable radiological indexes. Risser staging gives a general measure of skeletal maturity, but it cannot be used as a primary index for driving the treatment of patients with adolescent idiopathic scoliosis since more reliable indexes are available.

CONCLUSION

Skeletal maturity quantification for adolescent idiopathic scoliosis has the potential to significantly modify disease management. However, idiopathic scoliosis is a complex and multifactorial disease: therefore, it is unlikely that a single index will ever be sufficient to predict its evolution. Therefore, as more adolescent idiopathic scoliosis progression-associated indexes are identified, a collective scientific effort should be made to develop a therapeutic strategy based on reliable and reproducible algorithms.

Handgrip strength assessment at baseline in addition to bone parameters could potentially predict the risk of curve progression in adolescent idiopathic scoliosis

Introduction

Adolescent idiopathic scoliosis (AIS) is characterized by deranged bone and muscle qualities, which are important prognostic factors for curve progression. This retrospective case-control study aims to investigate whether the baseline muscle parameters, in addition to the bone parameters, could predict curve progression in AIS.

Methods

The study included a cohort of 126 female patients diagnosed with AIS who were between the ages of 12 and 14 years old at their initial clinical visit. These patients were longitudinally followed up every 6 months (average 4.08 years) until they reached skeletal maturity. The records of these patients were thoroughly reviewed as part of the study. The participants were categorized into two sub-groups: the progressive AIS group (increase in Cobb angle of ≥6°) and the stable AIS group (increase in Cobb angle <6°). Clinical and radiological assessments were conducted on each group.

Results

Cobb angle increase of ≥6° was observed in 44 AIS patients (34.9%) prior to skeletal maturity. A progressive AIS was associated with decreased skeletal maturity and weight, lower trunk lean mass (5.7%, p = 0.027) and arm lean mass (8.9%, p < 0.050), weaker dominant handgrip strength (8.8%, p = 0.027), deranged cortical compartment [lower volumetric bone mineral density (vBMD) by 6.5%, p = 0.002], and lower bone mechanical properties [stiffness and estimated failure load lowered by 13.2% (p = 0.005) and 12.5% (p = 0.004)]. The best cut-off threshold of maximum dominant handgrip strength is 19.75 kg for distinguishing progressive AIS from stable AIS (75% sensitivity and 52.4% specificity, p = 0.011).

Discussion

Patients with progressive AIS had poorer muscle and bone parameters than patients with stable AIS. The implementation of a cut-off threshold in the baseline dominant handgrip strength could potentially be used as an additional predictor, in addition to bone parameters, for identifying individuals with AIS who are at higher risk of experiencing curve progression.

Applicability of the Modified Fels and Optimized Oxford Skeletal Maturity Estimation Systems to the Modern Pediatric Population

BACKGROUND

The recently developed modified Fels knee and optimized Oxford hip skeletal maturity systems (SMS) have demonstrated impressive performance compared with the Greulich and Pyle skeletal age atlas when applied to the same historical, mostly white, pediatric population. We sought to determine whether these 2 systems require modification before being used in modern children.

METHODS

We collected knee and hip radiographs between January 2015 and September 2020 from our electronic medical record from 4 groups of children: (1) white males, (2) black males, (3) white females, and (4) black females. Males between 9 and 17 years and females between 7 and 15 years were included. After reliability analyses, 5 nonpathologic radiographs for each age and joint were randomly selected from each group and evaluated with the appropriate SMS. The mean discrepancy between each group's chronological age at the time of radiograph and estimated skeletal age was compared between our modern cohort and the historical Bolton-Brush children. After normality testing, paired t tests or Wilcoxon signed-rank tests were performed, as appropriate. A Bonferroni correction was applied to address multiple testing.

RESULTS

Three hundred sixty modern radiographs were evaluated (180 knees and 180 hips). All 7 modified Fels knee parameters and all 5 optimized Oxford hip parameters had inter and intrarater reliability coefficients ≥0.7, indicating good to very good reliability. For the modified Fels knee SMS, white males (Δ0.74 y, P <0.001), black males (Δ0.69 y, P <0.001), and black females (Δ0.4 y, P =0.04) had advanced skeletal age compared with their historical counterparts of the same sex. No differences were found between historical and modern patients for the optimized Oxford hip SMS. No differences were found for either SMS comparing modern patients along racial lines ( P >0.05 for all).

CONCLUSIONS

Discrepancies in skeletal age estimates made by the modified Fels knee SMS exist between modern pediatric white males, black males, and black females and their historic counterparts. No differences were found when using optimized Oxford hip SMS. Future studies should evaluate how these translate to clinical decision-making.

LEVEL OF EVIDENCE

Level III; retrospective chart review.

Patients with Adolescent Idiopathic Scoliosis Have Higher Metabolic Cost during High-Intensity Interval Training

BACKGROUND

Patients with adolescent idiopathic scoliosis (AIS) are found to have a lower level of physical activity, and may have reduced exercise capacity due to spinal deformity. Previous study showed the benefits of high-intensity interval training (HIIT), named E-Fit, which is specifically designed for patients with AIS to improve musculoskeletal health and psychological well-being. To optimize the beneficial effects of training, the current study aimed to investigate the appropriate exercise intensity and metabolic demand in patients with AIS when performing E-Fit.

METHODS

In all, 22 female subjects, 10 diagnosed with AIS and 12 gender-matched healthy controls, aged between 10 and 16 years, were recruited. Subjects were instructed to perform two trials of a seven min E-Fit. Breath-by-breath gas exchange parameters including oxygen consumption (VO₂), heart rate (HR) and the rate of perceived exertion (PRE) were measured during exercise. Demographic data and clinical features of AIS and body composition were obtained. Metabolic demand between AIS and control groups was compared using MANOVA with covariates adjustment.

RESULTS

Patients with AIS had an earlier onset of menarche (p = 0.01), higher visceral adipose tissue (p = 0.04) and percentage body fat (p = 0.03) as compared to controls. Patients with AIS showed a significantly higher adjusted means of VO₂ average in both the first (p = 0.014) and second trials (p = 0.011) of E-Fit. The adjusted mean of the highest measured VO₂ was higher than healthy controls and reached statistical significance in the second trial (p = 0.004). Both the AIS and control group exercised at a similar percentage of VO₂ peak (64.26% vs. 64.60%).

CONCLUSION

Patients with AIS showed higher oxygen consumption during E-Fit than heathy controls, which might indicate a higher metabolic cost. Patients with AIS could carry out exercise at a moderate exercise intensity similar to that of healthy controls, but special considerations in designing an exercise program, such as frequent rest intervals, would be useful to avoid fatigue among patients with AIS.

The Interrater and Intrarater Reliability of the Humeral Head Ossification System and the Proximal Femur Maturity Index Assessments for Patients with Adolescent Idiopathic Scoliosis

Background

Skeletal maturity can evaluate the growth and development potential of children and provide a guide for the management of adolescent idiopathic scoliosis (AIS). Recent studies have demonstrated the advantages of the Humeral Head Ossification System (HHOS) and the Proximal Femur Maturity Index (PFMI), based on standard scoliosis films, in the management of AIS patients. We further assessed the HHOS and the PFMI method's reliability in the interrater and intrarater.

Methods

The data from 38 patients, including the humeral head and proximal femur on standard scoliosis films, were distributed to the eight raters in the form of a PowerPoint presentation. On 38 independent standard spine radiographs, raters utilized the HHOS and PFMI to assign grades. The PPT sequence was randomly changed and then reevaluated 2 weeks later. For every system, the 95% confidence interval (95% CI) and intraclass correlation coefficient (ICC) were calculated to evaluate the interrater and intrarater reliability.

Results

The HHOS was extremely reliable, with an intraobserver ICC of 0.802. In the first round, the interobserver ICC reliability for the HHOS was 0.955 (0.929-0.974), while in the second round, it was 0.939 (0.905-0.964). The PFMI was extremely reliable, with an intraobserver ICC of 0.888. In the first round, the interobserver ICC reliability for the PFMI was 0.967 (0.948-0.981), while in the second round, it was 0.973 (0.957-0.984).

Conclusions

The HHOS and PFMI classifications had excellent reliability. These two methods are beneficial to reduce additional exposure to radiation and expense for AIS. There are advantages and disadvantages to each classification. Clinicians should choose a personalized and reasonable method to assess skeletal maturity, which will assist in the management of adolescent scoliosis patients.

The thumb ossification composite index is the optimal intersection between Sanders and low-dose scoliosis sterioradiography

PURPOSE

Skeletal maturity assessment may be performed using low-dose scoliosis radiographs (LDSS) with simultaneous imaging of the hand or proximal humerus. We sought to compare the practicality, reliability and validity of the Sanders skeletal maturity staging (SMSS), proximal humerus ossification system (PHOS) and the thumb ossification composite index (TOCI) as skeletal maturity assessment tools using LDSS.

METHODS

A survey including 85 LDSS and 42 hand radiographs was administered to four orthopedic clinicians. Each rater assessed the TOCI, SMSS and PHOS stage for each image. Standing LDSS with hands at the patient's side were used for TOCI, SMSS, and PHOS measurements. SMSS and TOCI measurements on dedicated hand radiographs were assessed as a comparison. Interobserver reliability was calculated for each scale using Fleiss' kappa. For SMSS and TOCI, intraobserver correlation between measurements on LDSS and measurements on hand radiographs were also assessed.

RESULTS

472 TOCI measurements, 288 SMSS measurements, and 340 measurements were collected. Kappa interobserver reliability for TOCI was 0.79 (strong) using hand radiographs and 0.74 (strong) using LDSS. Kappa for SMSS was 0.66 (strong) using hand radiographs and 0.45 (moderate) using LDSS. Kappa for PHOS was 0.51 (moderate) using LDSS. Intraobserver agreement between LDSS and hand imaging averaged 0.78 (strong) for TOCI and 0.34 (weak) for SMSS.

CONCLUSION

Skeletal maturity assessment with TOCI using LDSS demonstrates strong interobserver reliability when hands are placed at the patient's side and correlates well with assessment on hand radiographs. TOCI achieved better inter- and intraobserver reliability compared to SMSS and PHOS, likely because the thumb readily assumes a good position in standing scoliosis sterioradiographs.

LEVEL OF EVIDENCE

Diagnostic-Level III.

Predictive value of single-nucleotide polymorphisms in curve progression of adolescent idiopathic scoliosis

PURPOSE

Genetic diagnosis is a promising approach because several single-nucleotide polymorphisms (SNPs) associated with adolescent idiopathic scoliosis (AIS) progression have been reported. We review the predictive value of SNPs in curve progression of adolescent idiopathic scoliosis.

METHODS

We reviewed DNA-based prognostic testing to predict curve progression. Then, the multiple polymorphisms in loci related to AIS progression were also reviewed, and we elucidated the predictive value of SNPs from four functional perspectives, including endocrine metabolism, neuromuscular system, cartilage and extracellular matrix, enzymes, and cytokines.

RESULTS

The ScoliScores were less successful predictors than expected, and the weak power of predictive SNPs might account for its failure. Susceptibility loci in ESR1, ESR2, GPER, and IGF1, which related to endocrine metabolism, have been reported to predict AIS progression. Neuromuscular imbalance might be a potential mechanism of scoliosis, and SNPs in LBX1, NTF3, and SOCS3 have been reported to predict the curve progression of AIS. Susceptibility loci in SOX9, MATN1, AJAP1, MMP9, and TIMP2, which are related to cartilage and extracellular matrix, are also potentially related to AIS progression. Enzymes and cytokines play essential roles in regulating bone metabolism and embryonic development. SNPs in BNC2, SLC39A8, TGFB1, IL-6, IL-17RC, and CHD7 were suggested as predictive loci for AIS curve progression.

CONCLUSIONS

Many promising SNPs have been identified to predict the curve progression of AIS. However, conflicting results from replication studies and different ethnic groups hamper their reliability. Convincing SNPs from multiethnic populations and functional verification are needed.

Decreased cortical bone density and mechanical strength with associated elevated bone turnover markers at peri-pubertal peak height velocity: a cross-sectional and longitudinal cohort study of 396 girls with adolescent idiopathic scoliosis

Decreased cortical bone density and bone strength at peak height velocity (PHV) were noted in girls with adolescent idiopathic scoliosis (AIS). These findings could provide the link to the previously reported observation that low bone mineral density (BMD) could contribute as one of the prognostic factors for curve progression that mostly occurs during PHV in AIS.

INTRODUCTION

As part of the studies related to aetiopathogenesis of AIS, we assessed bone qualities, bone mechanical strength and bone turnover markers (BTMs) focusing at the peri-pubertal period and PHV in AIS girls.

METHODS

396 AIS girls in two separate cohorts were studied. Skeletal maturity was assessed using the validated thumb ossification composite index (TOCI). Bone qualities and strength were evaluated with high-resolution peripheral quantitative computed tomography (HR-pQCT) and finite element analysis (FEA).

RESULTS

Cohort-A included 179 girls (11.95 ± 0.95 years old). Girls at TOCI-4 had numerically the highest height velocity (0.71 ± 0.24 cm/month) corresponding to the PHV. Subjects at TOCI-4 had lower cortical volumetric BMD (672.36 ± 39.07 mg/mm³), cortical thickness (0.68 ± 0.08 mm) and apparent modulus (1601.54 ± 243.75 N/mm²) than: (a) those at TOCI-1-3 (724.99 ± 32.09 mg/mm³ (p < 0.001), 0.79 ± 0.11 mm (p < 0.001) and 1910.88 ± 374.75 N/mm² (p < 0.001), respectively) and (b) those at TOCI-8 (732.28 ± 53.75 mg/mm³ (p < 0.001), 0.84 ± 0.14 mm (p < 0.001), 1889.11 ± 419.37 N/mm² (p < 0.001), respectively). Cohort-B included 217 girls (12.22 ± 0.89 years old). Subjects at TOCI-4 had higher levels of C-terminal telopeptide of type 1 collagen (1524.70 ± 271.10 pg/L) and procollagen type 1 N-terminal propeptide (941.12 ± 161.39 µg/L) than those at TOCI-8 (845.71 ± 478.55 pg/L (p < 0.001) and 370.08 ± 197.04 µg/L (p < 0.001), respectively).

CONCLUSION

AIS girls had decreased cortical bone density and bone mechanical strength with elevated BTMs at PHV. Coupling of PHV with decreased cortical and FEA parameters could provide the link to the previously reported observation that low BMD could contribute as one of the prognostic factors for curve progression that mostly occurs during PHV in AIS.

Association of higher bone turnover with risk of curve progression in adolescent idiopathic scoliosis

OBJECTIVE

Emerging evidence suggest abnormal bone metabolism and defective bone qualities are associated to etipathogenesis of Adolescent Idiopathic Scoliosis (AIS). Systemic low bone mass is important prognosticator to predict risk of curve progression in AIS. The underlying mechanism is still unclear. We hypothesize that aberrant bone turnover correlates with bone qualities in AIS and associates to risk of curve progression.

SUBJECTS AND METHODS

Two cohorts were included in this study. The case-control study recruited 161 AIS girls and 161 ethnic/age-matched healthy girls. The longitudinal cohort recruited 128 AIS girls with two-year follow-up. Areal bone mineral density (BMD) at femoral necks were measured with dual-energy x-ray absorptiometry (DXA), and bone qualities of distal radius by high-resolution peripheral quantitative computed tomography (HR-pQCT). Time-lapse analysis of registered HR-pQCT images estimated local bone remodeling quantitatively. Serum levels of CTX and P1NP were measured with ELISA kits.

RESULTS

AIS presented significantly higher serum level of P1NP. In both AIS and control, the negative correlations were consistently observed between serum CTX/P1NP levels and most cortical bone quality parameters after adjustment to age. Significant correlation between serum bone turnover markers and trabecular bone parameters have been observed only in control. Progressive AIS has significant increase of serum P1NP level at first clinic visit. Time lapse register analysis showed high bone resorption and low net bone gain was associated with risk of progression in AIS.

CONCLUSIONS

Our study characterized AIS with higher serum bone turnover markers, which may contribute to defective bone qualities in AIS. For the first time, we showed that progressive AIS had higher systemic bone turnover markers level and local bone remodeling. This fresh evidence indicated association between disrupted bone turnover and risk of progression of AIS, which set the foundation of new prognostic method and of novel treatment target to curve progression. This study demonstrated the importance of bone metabolism in developing disease management of AIS to achieve goal of early prediction and non-surgical modulation.

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.

Relationship between hand and wrist bone age assessment methods

Assessment of skeletal maturity is crucial for managing growth related problems. Tanner and Whitehouse (TW) hand and wrist bone age assessment is an accurate method; however, it is complex and labor-intensive. Several simplified methods derived from the TW method were proposed, and each had its own character. The purpose of this study is to explore the relationship between these methods for accurate usage.Between 2018 and 2019, a cross-sectional study was performed with consecutive left hand and wrist x-rays obtained from a pediatric orthopedic clinic. Bone age assessments included the distal radius and ulna (DRU) classification, Sanders staging (S), thumb ossification composite index (T), and TW method. Somers delta correlation was conducted to determine the interchangeability of these stages. The mean bone age and standard deviation (SD) of each subgrade were compared and analyzed.Totally 103 films (92 girls) were analyzed with mean age of 12.1 years (range: 8.0-17.9 years). The radius (R) stages had good correlation with S, T, and U stages with a very high Somers delta correlation (P < .05). R5 had relatively large SD (1.5) and referred to T2 and T3; R6 and R7 had the smallest SD (0.3) with reference to T4 or S2; R8 referred to T5 or S3, S4, S5; R9 referred to S6 and S7.The internal relationship between the DRU and digital stages system was well proven. We also provided a simple and accurate way to assess the bone age by combination of some subgrades with smaller SD: 10y-proximal thumb covered without sesamoid (T2); 10.5y-sesamoid just appearing (T3); 11y-distal radial physis just covered (medial double joint line, R6); 11.5y-medial capping of distal radial physis (R7); 12y-bilateral capping of distal radial physis (R8) / phalangeal capping without fusion (S3); 12.5y-distal phalangeal physes start to fuse (S4); 13y-distal phalangeal physes fused (S5); 13.5y-proximal phalangeal physes start to fuse (S6); 14.5y-proximal phalangeal physes fused (S7); 15y-distal radial physis almost fused (R10).Level of Evidence: Diagnostic study, level III.

How do we follow-up patients with adolescent idiopathic scoliosis? Recommendations based on a multicenter study on the distal radius and ulna classification

PURPOSE

To determine the capability of the distal radius and ulna (DRU) classification for predicting the scoliosis progression risk within 1 year in patients with adolescent idiopathic scoliosis (AIS) and to develop simple recommendations for follow-up durations.

METHODS

Medical records of patients with AIS at two tertiary scoliosis referral centers were retrospectively reviewed for their DRU classification and major curve Cobb angles. Baseline DRU grades and Cobb angles with subsequent 1-year follow-up curve magnitudes were studied for scoliosis progression, which was defined as exacerbation of the Cobb angle by ≥ 6°. The relationship between DRU classification and scoliosis progression risk within 1 year was investigated. Patients were divided into three groups according to the Cobb angle (10°-19°, 20°-29°, ≥ 30°).

RESULTS

Of the 205 patients with 283 follow-up visits, scoliosis progression occurred in 86 patients (90 follow-up visits). Radius and ulna grades were significantly related to scoliosis progression (p < 0.001). R6, R7, and U5 grades were significantly related to scoliosis progression risk. The curve progression probability increased as the Cobb angle increased. Cobb angles ≥ 30°, with these grades, led to progression in > 80% of patients within 1 year. Curve progression was less likely for grades R9 and U7. Most patients with more mature DRU grades did not experience progression, even with Cobb angles ≥ 30°.

CONCLUSION

With R6, R7, and U5, scoliosis may progress within a short period; therefore, careful follow-up with short intervals within 6 months is necessary. R9 and U7 may allow longer 1-year follow-up intervals due to the lower progression risk.

Utilization of distal radius and ulna classification scheme in predicting growth peak and curve progression in idiopathic scoliosis girls undergoing bracing treatment

PURPOSE

Distal radius and ulna (DRU) classification scheme has been proposed for predicting skeletal maturity in patients with idiopathic scoliosis (IS). However, the utilization of DRU classification scheme in the assessment of growth peak and curve progression in IS was still inconclusive. This study aimed to correlate the distal radius and ulna stages with several indicators for growth potential and to evaluate the predictive value of DRU system for curve progression in braced female IS patients.

METHODS

This was a consecutive longitudinal study including physically immature IS girls receiving standardized bracing treatment and regularly followed up every 3-6 months until brace weaning. The following data of each visit were collected: chronologic age, standing height, Cobb angle, spinal length, Risser sign, digital skeletal age (DSA) scores and DRU scores. The height velocity (HV), spinal growth velocity (SGV) and angle velocity (AV) of each visit were calculated. The correlation among radius stage, ulna stage, Risser sign, height, spinal length, HV, SGV and AV was studied.

RESULTS

Forty braced IS girls with 349 longitudinal whole spine X-rays were reviewed. The average DRU scores at initial visit were R6.5 ± 1.1 and U4.5 ± 1.2 for radius and ulna, respectively. Both the radius stages between R5 and R8 and ulna stages between U3 and U6 indicated high SGV and high HV. The DSA scores were 402.1 ± 48.8 and 430.8 ± 44.4 at R7 and R8, respectively. The AV values were - 5.9 ± 12.4°/y and - 0.4 ± 1.5°/y at R5 and R6, which increased to 5.9 ± 17.3°/y, 3.1 ± 15.7°/y and 4.2 ± 12.2°/y at R7, R8 and R9, respectively. The DSA scores were 387.3 ± 65.7 for U5 and 432.9 ± 48.5 for U6, respectively. The AV values were - 3.1 ± 0.3°/y at U3, - 1.7 ± 9.3°/y at U4, 2.3 ± 16.1°/y at U5, 5.4 ± 15.5°/y at U6 and 4.4 ± 12.9°/y at U7.

CONCLUSIONS

Both distal radius and ulna scores correlate with the longitudinal growth potential, and thus, the DRU scoring scheme is an alternative predictor for growth potential and curve progression in girls with IS. These slides can be retrieved under Electronic Supplementary Material.

Cervical vertebral maturation (CVM) stage as a supplementary indicator for the assessment of peak height velocity (PHV) in adolescent idiopathic scoliosis (AIS)

BACKGROUND

Radiographic methods in evaluating the skeletal maturity include Risser sign and Tanner-Whitehouse score. They are either inappropriate or too complex for a busy clinic setting. The cervical vertebral maturation (CVM) stage is commonly used in orthodontics but has been less acknowledged in studies of spinal growth. The purpose of this study was to evaluate whether the CVM stage could be used as an alternative to Risser sign in determining peak height velocity (PHV).

METHODS

This was a two-stage study. Inclusion criteria for stage I study were adolescent female idiopathic scoliosis (AIS) patients, aged between 9-16 years old, who had undergone full spine imaging with clear visibility of the cervical spine. Patients in the stage II study had follow-up through CVM stage 2-4. The correlation between CVM and Risser was analyzed. The spinal growth parameters were measured at each follow-up, and the growth velocity of parameters (PaGVs) was calculated. The PaGVs at CVM stage 2-4 were further compared.

RESULTS

A total of 170 AIS patients were included for stage I study (mean age 12.7 years). The CVM stages were found to correlate strongly with the Risser sign (r=0.85, P<0.01). For those patients with Risser stage 0 with closed TC, 71% were CVM stage 3. Fifty-one patients were included for stage II study. The stature growth velocity averaged 5.4 cm/year in CVM stage 2 patients and 6.3 cm/year in CVM stage 3 patients, which was significantly greater growth than that in CVM stage 4 patients (3.3 cm/year, both P<0.01); similarly, the growth velocity of arm span, trunk height, and spinal lengths were also significantly higher in CVM stage 3 patients compared to CVM stage 2 and 4 patients.

CONCLUSIONS

The CVM stage could provide an alternative option for the assessment of skeletal maturity of subjects with idiopathic scoliosis. CVM stage 3 may be a new sign of PHV.

Evaluation of the reliability of a practical digital dental X-ray method for the first metacarpophalangeal joint to assist the skeletal age in peripubertal orthodontic period

OBJECTIVE

This study aimed to evaluate the validity of using of digital dental X-ray for the thumb region in assessment of skeletal maturation stage around functional orthodontic treatment time.

MATERIALS AND METHODS

The sample consisted of 200 patients (100 males and 100 females) aged between (9.5-18) years. Each patient underwent a hand-wrist radiograph and a digital radiograph for the thumb region taken by a dental X-ray machine. Skeletal changes were studied in the sesamoid bone and first Metacarpophalangeal joint region, and compared to Björk method.

RESULTS

Good correlation was noted between our thumb method stages (Th index) and hand-wrist maturation stages, so Th index has a good validity and reliability in assessment of maturation stages, in addition to its simplicity, accuracy and advantages in saving time, cost and decreasing radiographic exposure compared with hand-wrist maturation stages.

Sequential spine-hand radiography for assessing skeletal maturity with low radiation EOS imaging system for bracing treatment recommendation in adolescent idiopathic scoliosis: a feasibility and validity study

PURPOSE

The EOS-imaging system is increasingly adopted for clinical follow-up in scoliosis with the advantages of simultaneous biplanar imaging of the spine in an erect position. Skeletal maturity assessment using a hand radiograph is an essential adjunct to spinal radiography in scoliosis follow-up. This study aims at testing the feasibility and validity of a newly proposed EOS workflow with sequential spine-hand radiography for skeletal maturity assessment and bracing recommendation.

METHODS

EOS spine-hand radiographs from patients with diagnosis of idiopathic scoliosis, including both sexes and an age range of ten to 14 years, were scored using the Thumb Ossification Composite Index (TOCI), Sanders and Risser methods. Intraclass correlation coefficients (ICCs) were calculated for inter/intraobserver agreement and were tested with Cronbach's alpha values.

RESULTS

In all, 60 EOS-spine hand radiographs selected from subjects with diagnosis of adolescent idiopathic scoliosis (AIS), including 32 male patients (mean age 11.53 years; 10 to 14) and 28 female patients (mean age 11.50 years; 10 to 13) who underwent sequential spine-hand low dose EOS imaging were generated for analysis. The overall interobserver (ICC = 0.997) and intraobserver agreement (α > 0.9) demonstrated excellent agreement for TOCI staging; ICC > 0.994 for both TOCI and Sanders staging comparing traditional digital versus EOS hand radiography; ICC ≥ 0.841 for agreement on bracing recommendation among TOCI versus the Risser and Sanders system.

CONCLUSION

With the proposed new EOS workflow it was feasible to produce high image quality for skeletal maturity assessment with excellent reliability and validity to inform consistent bracing recommendation in AIS. The workflow is applicable for busy daily clinic settings in tertiary scoliosis centres with reduced time cost, improved efficiency and throughput of the radiology department.

LEVEL OF EVIDENCE

III.

Bone measurements at multiple skeletal sites in adolescent idiopathic scoliosis-an in vivo correlation study using DXA, HR-pQCT and QCT

Significant correlations for bone mineral density and bone microstructure between spinal and non-spinal skeletal sites (distal radius and proximal femur) in adolescent idiopathic scoliosis (AIS) patients were observed, indicating that proximal femoral DXA and distal radial HR-pQCT could provide valid clinical assessments in patients with AIS.

PURPOSE

Low bone mass is an important feature of adolescent idiopathic scoliosis (AIS), which is a complex 3D spinal deformity that affects girls during puberty. However, no clinical imaging modality is suitable for regular monitoring on their spinal bone qualities in rapid growth period. Therefore, we investigated whether bone mineral density (BMD) and bone microstructure at non-spinal sites correlated with BMD and mechanical property in the spine in AIS patients.

METHODS

Thirty-two AIS girls (16.7 ± 3.5 years old with mean Cobb angle of 67 ± 11°) who underwent pre-operative spine CT examination for navigation surgery were recruited. Volumetric BMD (vBMD) of lumbar spine (LS) was measured by quantitative computed tomography (QCT), vBMD and bone microstructure of distal radius (DR) by high-resolution peripheral QCT (HR-pQCT) and areal BMDs of total hip (TH) and femoral necks (FN) by dual-energy X-ray absorptiometry (DXA). Biomechanical properties of the DR and LS were estimated by finite element analysis (FEA). Pearson correlation was performed to study the correlation between bone parameters at these three sites.

RESULTS

LS vBMD correlated significantly with both FN and TH aBMD (R = 0.663-0.725, both p < 0.01) and with DR microstructural parameters (R = 0.380-0.576, all p < 0.05). Mechanical properties of LS and DR were also correlated (R = 0.398, p = 0.039).

CONCLUSIONS

Bone measurement at proximal femur and distal radius could provide an additional predictive power in estimating the bone changes at spine, which is the primary site of deformity in AIS patients. Our result indicated that DXA and HR-pQCT could provide a valid surrogate for spine bone measurements in AIS patients.

Brace Treatment in Adolescent Idiopathic Scoliosis Patients with Curve Between 40° and 45°: Effectiveness and Related Factors

OBJECTIVE

To investigate effectiveness of brace treatment in patients with adolescent idiopathic scoliosis with curve between 40° and 45° and to determine predictive factors associated with bracing outcome.

METHODS

Bracing was used to treat 90 patients with curve >40 degrees. Factors including Risser sign, age, sex, curve pattern, curve magnitude, and initial curve correction were compared between patients with curve improvement and patients with curve progression. Logistic regression analysis was used to determine the independent predictors of curve progression.

RESULTS

Curve was improved in 34 (37.8%) patients and stabilized in 12 (13.3%) patients. Remarkable curve progression >50 degrees was observed in 44 (48.9%) patients. Intergroup comparison showed significant differences between the 2 groups in terms of age (12.3 ± 1.4 years vs. 13.2 ± 1.6 years, P = 0.01), initial curve correction (2.2% ± 5.4% vs. 19.7% ± 12.2%, P < 0.001), and curve pattern (P = 0.03). Logistic regression analysis showed that initial curve correction of <10% (odds ratio = 12.82, P < 0.001) and Risser grade of 0 (odds ratio = 1.46, P = 0.04) were significant indicators of curve progression.

CONCLUSIONS

Bracing may produce a favorable outcome in certain patients with curve between 40° and 45°. It should be cautiously used in this situation, as there was a higher probability of bracing failure. It is important to differentiate patients at high risk of curve progression at an early stage to avoid overtreatment.

Validation Study of the Thumb Ossification Composite Index (TOCI) in Idiopathic Scoliosis: A Stage-to-Stage Correlation with Classic Tanner-Whitehouse and Sanders Simplified Skeletal Maturity Systems

BACKGROUND

The new simplified thumb ossification composite index (TOCI) based on ossification of the thumb epiphyses and adductor sesamoid has demonstrated simplicity, excellent reliability, and high accuracy for predicting skeletal maturity, comparable with the Sanders simplified skeletal maturity system (SSMS). It was our belief that, because the terminology of the SSMS system has been commonly used for skeletal maturity prediction in idiopathic scoliosis in publications over the past decade, the clinical applicability of the TOCI system would increase if the stages in the 2 systems were found to be interchangeable and highly correlated.

METHODS

Hand radiographs of 125 premenarchal girls with newly diagnosed adolescent idiopathic scoliosis who had been followed longitudinally until skeletal maturity were all scored with use of the Tanner-Whitehouse III (TW3) system (stages E through I), the TOCI, and the SSMS. The scores for the epiphyses of the ulnar 4 digits were compared with those for the thumb and correlated with the timing of peak height velocity. Correlations were analyzed with the chi-square test and Cramer V and Somers delta correlations.

RESULTS

Six hundred and forty-five hand radiographs (an average of 5 for each girl with idiopathic scoliosis) and 11,517 epiphyses were scored. The rate of concordance between TW3 stages F, G, and I for the thumb proximal phalangeal epiphysis and those for all of the epiphyses of the ulnar 4 digits were 72.5%, 72.5%, and 89.9%, respectively. The overall concordance rate (including all epiphyses) was 71.3%, with a very high Cramer V correlation and significance (p < 0.01). High interchangeability was demonstrated for the TOCI and SSMS stages, supported by a high Somers delta correlation (>0.8) with significance (p < 0.05).

CONCLUSIONS

The TOCI is highly practical for clinical use, and its stages are highly interchangeable with those of the SSMS.

CLINICAL RELEVANCE

The TOCI could serve as a simplified "marker" of skeletal maturity on hand radiographs and minimize the learning-curve problems associated with the SSMS in a busy clinical practice.