Height and Extremity-Length Prediction for Healthy Children Using Age-Based Versus Peak Height Velocity Timing-Based Multipliers

Subclassification of Sanders Maturation Stage 3 Demonstrates Differences in Spine and Total Height Velocity Between 3A and 3B in Patients With Idiopathic Scoliosis

STUDY DESIGN

A single-center retrospective case-control study.

OBJECTIVE

To compare the spine and total height velocity between Sanders maturation stage (SMS) 3A and 3B.

SUMMARY OF BACKGROUND DATA

Identifying SMS 3 is critical for treating growing children because it represents the early phase of rapid adolescent growth. However, there is limited literature available that clearly describes the growth differences between 3A and 3B.

MATERIALS AND METHODS

The current study included consecutive patients with idiopathic scoliosis staged SMS 3 from January 2012 to December 2021. T1-S1 spine height, total body height, and curve magnitude were measured at the initial and follow-up visits. In addition to the spine and total height velocity calculated per month, corrected height velocity was estimated for curve magnitude using a validated formula. Mann-Whitney U test was used to compare SMS 3A and 3B outcomes, followed by a multiple linear regression model to evaluate the association of the SMS subclassifications to growth velocity adjusted for confounding factors.

RESULTS

A total of 204 patients (66% girls, mean age: 12.3±1.3 y) met the inclusion criteria. Patients staged SMS 3A had higher spine height velocity (mm/month) in both girls (2.3 vs. 1.5, P <0.001) and boys (2.6 vs. 1.7, P <0.001), as well as total height velocity [mm/month; (5.8 vs. 4.3, P <0.001 for girls; 6.6 vs. 4.5, P <0.001 for boys]. Corrected velocity showed similar results with greater spine and total height velocity in SMS 3A. Multivariate analysis indicated a significant association of the SMS subclassification to the spine and total height velocity. The scoliosis curve progression was comparable between SMS 3A and 3B.

CONCLUSIONS

SMS 3A and 3B had differential growth velocity in the spine and total body height. These results indicate the importance of the SMS 3 subclassification for managing scoliosis treatment, including observation, bracing, and surgical interventions with fusion and growth modulation.

LEVEL OF EVIDENCE

Level III-case-control study.

Differences in spine growth potential for Sanders maturation stages 7A and 7B have implications for treatment of idiopathic scoliosis

PURPOSE

This study aimed to clarify the differences in spine and total body height growth and curve progression between Sanders maturation stage (SMS) 7A and 7B in patients with adolescent idiopathic scoliosis (AIS).

METHODS

This retrospective case-control study involving patients with AIS at SMS 7 evaluated the differential gains in the spine (T1-S1) and total body height and curve progression between SMS 7A and 7B. A validated formula was used to calculate the corrected height, accounting for height loss due to scoliosis. A multivariable non-linear and logistic regression model was applied to assess the distinct growth and curve progression patterns between the SMS 7 subtypes, adjusting for potential confounders.

RESULTS

A total of 231 AIS patients (83% girls, mean age 13.9 ± 1.2 years) were included, with follow-up averaging 3.0 years. Patients at SMS 7A exhibited larger gains in spine height (9.9 mm vs. 6.3 mm) and total body height (19.8 mm vs. 13.4 mm) compared with SMS 7B. These findings remained consistent even after adjustments for curve magnitude. Non-linear regression models showed continued spine and total body height increases plateauing after 2 years, significantly greater in SMS 7A. More SMS 7A patients had curve progression over 10°, with an adjusted odds ratio of 3.31.

CONCLUSION

This study revealed that patients staged SMS 7A exhibited more spine and total body growth and a greater incidence of substantial curve progression than those at 7B. These findings imply that delaying brace discontinuation until reaching 7B could be beneficial, particularly for those with larger curves.

LEVEL OF EVIDENCE

Level III (Case-control study).

Validation of central peak height method for final adult height predictions on long leg radiographs

Aims

Accurate skeletal age and final adult height prediction methods in paediatric orthopaedics are crucial for determining optimal timing of growth-guiding interventions and minimizing complications in treatments of various conditions. This study aimed to evaluate the accuracy of final adult height predictions using the central peak height (CPH) method with long leg X-rays and four different multiplier tables.

Methods

This study included 31 patients who underwent temporary hemiepiphysiodesis for varus or valgus deformity of the leg between 2014 and 2020. The skeletal age at surgical intervention was evaluated using the CPH method with long leg radiographs. The true final adult height (FHTRUE) was determined when the growth plates were closed. The final height prediction accuracy of four different multiplier tables (1. Bayley and Pinneau; 2. Paley et al; 3. Sanders - Greulich and Pyle (SGP); and 4. Sanders - peak height velocity (PHV)) was then compared using either skeletal age or chronological age.

Results

All final adult height predictions overestimated the FHTRUE, with the SGP multiplier table having the lowest overestimation and lowest absolute deviation when using both chronological age and skeletal age. There were no significant differences in final height prediction accuracy between using skeletal age and chronological age with PHV (p = 0.652) or SGP multiplier tables (p = 0.969). Adult height predictions with chronological age and SGP (r = 0.769; p ≤ 0.001), as well as chronological age and PHV (r = 0.822; p ≤ 0.001), showed higher correlations with FHTRUE than predictions with skeletal age and SGP (r = 0.657; p ≤ 0.001) or skeletal age and PHV (r = 0.707; p ≤ 0.001).

Conclusion

There was no significant improvement in adult height prediction accuracy when using the CPH method compared to chronological age alone. The study concludes that there is no advantage in routinely using the CPH method for skeletal age determination over the simple use of chronological age. The findings highlight the need for more accurate methods to predict final adult height in contemporary patient populations.

Congenital Posteromedial Bowing of Tibia: Comparison of Early and Late Lengthening

BACKGROUND

Congenital posteromedial bowing of tibia (CPMBT), a rare anomaly, is characterized by a decreasing deformity and a gradually increasing limb shortening. Lengthening in CPMBT has not been studied extensively. Our series compares the duration and complications of lengthening in younger versus older children to determine early lengthening safety and benefits.

METHODS

We studied 28 tibial lengthenings performed by a single surgeon in 23 patients, divided into 2 equal groups of 14 segments: group A 5 years or younger (preschool) and group B above 5 years. All were lengthened with circular external fixators, of which 3 were lengthened over a nail. We measured preoperative (bo) and postoperative (po) sagittal, coronal, and oblique plane deformities, initial limb length discrepancy (LLD), percentage LLD (% LLD), amount of lengthening (AmtL), percentage lengthening (%L), external fixator duration (EFD), and external fixator index (EFI). We graded complications by Lascombes' criteria, results by Association for the Study and Application of the Methods of Ilizarov bone score.

RESULTS

The mean age was 8.8±7.1 years; the mean follow-up was 7.9 years. Group A had significantly greater bo-sagittal, coronal, and oblique plane deformities. Mean LLD (3.4 cm in group A vs. 4.1 cm in group B) was similar in both. Expected LLD at maturity (LLDM) using the multiplier method was greater than previously reported (mean, range in group A: 7.2 cm, 4.4 to 9.5 cm; group B: 5 cm, 2.5 to 9.7 cm). Though AmtL (3.5 and 4.1 cm) was similar in both, %L was 24% in group A and 15.7% in group B (P=0.002). EFD (116.6 days) and EFI (33.7 days/cm) were lesser in group A compared with group B (200.3 days, P=0.001; 50.2 days/cm, P=0.01). Lascombes' triple contract was fulfilled in 11/14 lengthenings in group A versus 3/14 in group B. Association for the Study and Application of the Methods of Ilizarov bone score was good and excellent in both groups (P=0.44).

CONCLUSIONS

In a large series of lengthenings in CPMBT, we found younger children presenting with large deformities and large projected length discrepancies could be safely lengthened with significantly lesser EFD and complications than in older children.

LEVEL OF EVIDENCE

Level IV-therapeutic study.

Ossification and Fusion of the Vertebral Ring Apophysis as an Important Part of Spinal Maturation

In scoliosis, most of the deformity is in the disc and occurs during the period of rapid growth. The ring apophyses form the insertion of the disc into the vertebral body, they then ossify and fuse to the vertebrae during that same crucial period. Although this must have important implications for the mechanical properties of the spine, relatively little is known of how this process takes place. This study describes the maturation pattern of the ring apophyses in the thoracic and lumbar spine during normal growth. High-resolution CT scans of the spine for indications not related to this study were included. Ossification and fusion of each ring apophysis from T1 to the sacrum was classified on midsagittal and midcoronal images (4 points per ring) by two observers. The ring apophysis maturation (RAM) was compared between different ages, sexes, and spinal levels. The RAM strongly correlated with age (R = 0.892, p < 0.001). Maturation differed in different regions of the spine and between sexes. High thoracic and low lumbar levels fused earlier in both groups, but, around the peak of the growth spurt, in girls the mid-thoracic levels were less mature than in boys, which may have implications for the development of scoliosis.