The Addition of Hand-specific Skeletal Maturity Parameters Does Not Improve Skeletal Maturity Estimation Accuracy of the Modified Fels Wrist System.

BACKGROUND: The Modified Fels Wrist system is potentially the most accurate clinically accessible skeletal maturity system utilizing hand or wrist radiographs. During development, parameters distal to the metacarpals were excluded. We attempted to further optimize the Modified Fels wrist system through the inclusion of hand parameters distal to the metacarpals. METHODS: Forty-three new anteroposterior (AP) hand radiographic parameters were identified from the Fels and Greulich and Pyle (GP) skeletal maturity systems. Twelve parameters were eliminated from further evaluation for poor correlation with skeletal maturity, poor reliability, and lack of relevance in the peripubertal years. In addition to the 8 previously described Modified Fels Wrist parameters, 31 hand radiographic parameters were evaluated on serial peripubertal AP hand radiographs to identify the ones most important for accurately estimating skeletal age. This process produced a "Modified Fels hand-wrist" model; its performance was compared with (1) GP only; (2) Sanders Hand (SH) only; (3) age, sex, and GP; (4) age, sex, and SH; and (5) Modified Fels Wrist system. RESULTS: Three hundred seventy-two radiographs from 42 girls and 38 boys were included. Of the 39 radiographic parameters that underwent full evaluation, 9 remained in the combined Modified Fels Hand-Wrist system in addition to chronological age and sex. Four parameters are wrist specific, and the remaining 5 are hand specific. The Hand-Wrist system outperformed both GP and SH in estimating skeletal maturity ( P <0.001). When compared with the Modified Fels Wrist system, the Modified Fels Hand-Wrist system performed similarly regarding skeletal maturity estimation (0.36±0.32 vs. 0.34±0.26, P =0.59) but had an increased (worse) rate of outlier predictions >1 year discrepant from true skeletal maturity (4.9% vs. 1.9%, P =0.01). CONCLUSIONS: The addition of hand parameters to the existing Modified Fels Wrist system did not improve skeletal maturity estimation accuracy and worsened the rate of outlier estimations. When an AP hand-wrist radiograph is available, the existing Modified Fels wrist system is best for skeletal maturity estimation. LEVEL OF EVIDENCE: Level III.

Prospective Multicenter Preliminary Validation of Limb Deformity-modified Scoliosis Instruments in Pediatric Patients With Limb Deformity.

INTRODUCTION: There are few disease-specific patient-reported outcome measures (PROMs) for use in pediatric limb deformity (LD), with authors instead relying on generic PROMs such as the Pediatric Outcomes Data Collection Instrument (PODCI) to assess treatment outcomes from the patient's perspective. The purpose of this study was to perform preliminary validation of 2 disease-specific PROMs in pediatric patients with LD. METHODS: LD modifications were created by substituting the word "limb" for "back" in the Early Onset Scoliosis Questionnaire (EOSQ, ages 10 and younger) and the Scoliosis Research Society (SRS, ages 11 to 18) survey, creating the LD-EOSQ and LD-SRS instruments. Children were preoperatively administered the age-appropriate LD-PROMs (n=34 LD-EOSQ; n=30 LD-SRS) and PODCI questionnaires. LD-PROMs were assessed for construct (convergent and discriminant) validity, floor and ceiling effects, content validity, and minimal clinically important difference. RESULTS: Both LD-EOSQ and LD-SRS demonstrated excellent preliminary convergent validity with similar PODCI domains and discriminant validity with demographic information, deformity data, and LLRS-AIM scores. There were minimal floor or ceiling effects. Content validity was achieved in 100% of LD-EOSQ surveys and more than 80% of LD-SRS surveys. Minimal clinically important difference was 0.4 for LD-EOSQ and 0.3 for LD-SRS. CONCLUSIONS: The LD-EOSQ for patients aged 10 and under and LD-SRS for patients aged 11 to 18 demonstrated preliminary validity and reliability in the pediatric LD population. These measures provide more information specifically related to familial impact in younger children and self-image and mental health in adolescents compared to the PODCI and should be further evaluated for use in these patients. LEVEL OF EVIDENCE: Level II-diagnostic. Prospective cross-sectional cohort design.

Developmental Anatomy of the Radial Bow in Pediatric Patients Using 3D Imaging.

BACKGROUND: While radial bow shape is well characterized in adults, its development in children is not well understood. Previous studies on the radial bow use radiographs, thus, rotational positioning of the forearm could alter bowing measurements. This study used 3D imaging to better assess the pediatric radial bow. METHODS: Computed tomography scans from the New Mexico Decedent Image Database were obtained for ages 2 to 16 (females) and 18 (males) (n=152). 3D models were generated using Slicer and Rhino software. Length of the entire radial bow (bicipital tuberosity to sigmoid notch), maximum radial bow, location of the maximum radial bow (bicipital tuberosity to the point of maximum bowing), and distal, middle, and proximal third radial bows were measured. RESULTS: The length of the entire bow increased with age, with a strong correlation with age ( r =0.90, P <0.01). The maximum bow increased with age, with a strong correlation with age ( r =0.78, P <0.01). The maximum bow normalized to the length of the entire bow increased mildly with age, mean 0.059 ± 0.012 ( r =0.24, P =0.0024), but seems to plateau around age 8. The location of the maximum bow increased with age ( r =0.85, P <0.01). The normalized location of the maximum bow remained constant between ages, with a mean of 0.41 ± 0.10 ( r =0.12, P =0.14). The normalized distal third bow mildly increased with age ( r =0.34, P <0.01), the normalized middle third bow mildly increased with age ( r =0.25, P <0.01), and the normalized proximal third bow remained constant between ages ( r =0.096, P =0.24). CONCLUSIONS: Normalized values for maximum, distal third, and middle third radial bow increase with age, while normalized values for location and proximal third radial bow remain relatively constant, suggesting the proportional shape of the radius changes during development, although qualitatively plateaus after age 8. LEVEL OF EVIDENCE: Retrospective comparative study, Level-III.

Correlations Between Eight Comprehensive Skeletal Maturity Systems in a Modern Peripubertal Pediatric Population.

BACKGROUND: Several skeletal maturity systems allow for accurate skeletal age assessment from a wide variety of joints. However, discrepancies in estimates have been noted when applying systems concurrently. The aims of our study were to (1) compare the agreement among 8 different skeletal maturity systems in modern pediatric patients and (2) compare these discrepancy trends qbetween modern and historic children. METHODS: We performed a retrospective (January 2000 to May 2022) query of our picture archiving and communication systems and included peripubertal patients who had at least two radiographs of different anatomic regions obtained ≤3 months apart for 8 systems: (1) proximal humerus ossification system (PHOS), (2) olecranon apophysis ossification staging system (OAOSS), (3) lateral elbow system, (4) modified Fels wrist system, (5) Sanders Hand Classification, (6) optimized oxford hip system, (7) modified Fels knee system, and (8) calcaneal apophysis ossification staging system (CAOSS). Any abnormal (ie, evidence of fracture or congenital deformity) or low-quality radiographs were excluded. These were compared with a cohort from a historic longitudinal study. SEM skeletal age, representing the variance of skeletal age estimates, was calculated for each system and used to compare system precision. RESULTS: A total of 700 radiographs from 350 modern patients and 954 radiographs from 66 historic patients were evaluated. In the modern cohort, the greatest variance was seen in PHOS (SEM: 0.28 y), Sanders Hand (0.26 y), and CAOSS (0.25 y). The modified Fels knee system demonstrated the smallest variance (0.20 y). For historic children, the PHOS, OAOSS, and CAOSS were the least precise (0.20 y for all). All other systems performed similarly in historic children with lower SEMs (range: 0.18 to 0.19 y). The lateral elbow system was more precise than the OAOSS in both cohorts. CONCLUSIONS: The precision of skeletal maturity systems varies across anatomic regions. Staged, single-parameter systems (eg, PHOS, Sanders Hand, OAOSS, and CAOSS) may correlate less with other systems than those with more parameters. LEVEL OF EVIDENCE: Level III-retrospective study.

The Reliability of the Modified Fels Knee Skeletal Maturity System.

BACKGROUND: The recently described Modified Fels knee skeletal maturity system (mFels) has proven utility in prediction of ultimate lower extremity length in modern pediatric patients. mFels users evaluate chronological age, sex, and 7 anteroposterior knee radiographic parameters to produce a skeletal age estimate. We developed a free mobile application to minimize the learning curve of mFels radiographic parameter evaluation. We sought to identify the reliability of mFels for new users. METHODS: Five pediatric orthopaedic surgeons, 5 orthopaedic surgery residents, 3 pediatric orthopaedic nurse practitioners, and 5 medical students completely naïve to mFels each evaluated a set of 20 pediatric anteroposterior knee radiographs with the assistance of the (What's the Skeletal Maturity?) mobile application. They were not provided any guidance beyond the instructions and examples embedded in the app. The results of their radiographic evaluations and skeletal age estimates were compared with those of the mFels app developers. RESULTS: Averaging across participant groups, inter-rater reliability for each mFels parameter ranged from 0.73 to 0.91. Inter-rater reliability of skeletal age estimates was 0.98. Regardless of group, steady proficiency was reached by the seventh radiograph measured. CONCLUSIONS: mFels is a reliable means of skeletal maturity evaluation. No special instruction is necessary for first time users at any level to utilize the (What's the Skeletal Maturity?) mobile application, and proficiency in skeletal age estimation is obtained by the seventh radiograph. LEVEL OF EVIDENCE: Level II.

Which Application Factors Are Associated With Outstanding Performance in Orthopaedic Surgery Residency?

BACKGROUND: Identifying ideal candidates for orthopaedic surgery residency is difficult. Data available for applicant selection are evolving; preclinical grades and the Alpha Omega Alpha (AOA) honors society are being phased out at some medical schools. Similarly, three-digit United States Medical Licensing Examination (USMLE) Step 1 scores have been eliminated. There is renewed interest in improving resident selection to provide a diverse, comprehensive educational opportunity that produces orthopaedic surgeons who are prepared for practice. QUESTIONS/PURPOSES: We sought to identify whether (1) academic achievements, (2) letters of recommendation, (3) research activity, and (4) miscellaneous factors available on Electronic Residency Application Service (ERAS) applications were associated with outstanding residency performance. METHODS: Ten faculty members (22% of all full-time faculty) with extensive educational involvement for at least 7 years, whose expertise covered all subspecialty departments at an urban, academic orthopaedic surgery residency program, were given an anonymous survey on the performance of the four most recent classes of residency graduates (24 residents). This survey was developed due to the lack of a validated residency outcomes tool or objective metrics for residency performance. The evaluated criteria were decided upon after discussion by a relatively large group of academic orthopaedic surgeons considering the factors most important for graduating orthopaedic residents. The faculty were selected based on their long-term knowledge of the residency, along with their diversity of specialty and backgrounds; there were no nonresponders. Faculty graded each resident on a scale from 1 to 10 (higher is better) on six criteria: surgical technical skills, research productivity, clinical knowledge, professionalism, personality, and fellowship match. The mean of the faculty ratings made by all faculty for all six criteria was calculated, producing the overall residency performance score. Factors available on each resident's ERAS application were then correlated with their overall residency performance score. Categorical ERAS factors, including AOA status, five or more honors in core clerkships, at least three exceptional letters of recommendation, collegiate athletics participation, expertise with a musical instrument, and research (6-year) track residents, were correlated with overall residency performance score via point biserial analysis. Continuous ERAS factors including USMLE Step 1 and Step 2 scores, number of publications before residency, number of research years before residency, medical school ranking, and number of volunteer experiences were correlated with overall residency performance score via Pearson correlation. USMLE Step 1 three-digit scores were evaluated despite their recent elimination because of their historic importance as a screening tool for residency interviews and for comparison to USMLE Step 2, which retains a three-digit score. Application factors with a p < 0.2 on univariate analysis (five or more honors in core clerkships, at least three exceptional letters of recommendation, research track residents) were included in a stepwise linear regression model with "overall residency performance score" as the outcome variable. All p values < 0.05 were considered significant. RESULTS: The mean overall residency performance score was 7.9 ± 1.2. Applicants with at least five honors grades in core clerkships had overall residency performance scores 1.2 points greater than those of their peers (95% confidence interval (CI) 0.3 to 2.0; p = 0.01, Cohen ƒ 2 = 0.2, representing a small effect size). ERAS applications including at least three exceptional letters of recommendation were associated with a 0.9-point increase in residency performance (95% CI 0.02 to 1.7; p = 0.046, Cohen ƒ 2 = 0.1, representing a small effect size). Participation in the residency research (6-year) track was associated with a 1-point improvement in residency performance (95% CI 0.1 to 1.9; p = 0.03, Cohen ƒ 2 = 0.2, again, representing a small effect size). Together, these three factors accounted for 53% of the variance in overall residency performance score observed in this study. CONCLUSION: Past clinical excellence, measured by core clerkship grades and exceptional letters of recommendation, is associated with slightly improved overall orthopaedic residency performance scores. Applicants meeting both criteria who also complete a research track residency may perform substantially better in residency than their counterparts, as these three factors accounted for half of all the variance observed in the current study. Although minimum requirements are necessary, traditionally used screening factors (such as USMLE scores, AOA status, medical school rank, and number of publications) may be of less utility in identifying successful future residents than previously thought. LEVEL OF EVIDENCE: Level III, therapeutic study.

Applicability of Shoulder, Olecranon, and Wrist-based Skeletal Maturity Estimation Systems to the Modern Pediatric Population.

BACKGROUND: The proximal humerus ossification system (PHOS), olecranon apophyseal ossification system (OAOS), and modified Fels wrist skeletal maturity system (mFWS) were recently developed or updated using a historical, mostly White, pediatric population. These upper extremity skeletal maturity systems have demonstrated skeletal age estimation performance superior or equivalent to Greulich and Pyle in historical patients. Their applicability to modern pediatric populations has not yet been evaluated. METHODS: We reviewed anteroposterior shoulder, lateral elbow, and anteroposterior hand and wrist x-rays of 4 pediatric cohorts: White males, Black males, White females, and Black females. Peripubertal x-rays were evaluated: males 9 to17 years and females 7 to 15 years. Five nonpathologic radiographs for each age and joint were randomly selected from each group. Skeletal age estimates made by each of the 3 skeletal maturity systems were plotted against the chronological age associated with each radiograph and compared between cohorts, and with the historical patients. RESULTS: Five hundred forty modern radiographs were evaluated (180 shoulders, 180 elbows, and 180 wrists). All radiographic parameters had inter- and intra-rater reliability coefficients at or above 0.79, indicating very good reliability. For PHOS, White males had delayed skeletal age compared with Black males (Δ-0.12 y, P =0.02) and historical males (Δ-0.17 y, P <0.001). Black females were skeletally advanced compared with historical females (Δ0.11 y, P =0.01). For OAOS, White males (Δ-0.31 y, P <0.001) and Black males (Δ-0.24 y, P <0.001) had delayed skeletal age compared with historical males. For mFWS, White males (Δ0.29 y, P =0.024), Black males (Δ0.58 y, P <0.001), and Black females (Δ0.44 y, P <0.001) had advanced skeletal age compared with historical counterparts of the same sex. All other comparisons were not significant ( P >0.05). CONCLUSIONS: The PHOS, OAOS, and mFWS have mild discrepancies in skeletal age estimates when applied to modern pediatric populations depending on the race and sex of the patient. LEVEL OF EVIDENCE: Level III - retrospective chart review.

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.

Assessment and Validation of Anterior Humeral Line for Diagnosing Supracondylar Humerus Fractures in the Pediatric Population.

INTRODUCTION: Pediatric supracondylar humerus fractures are commonly evaluated using the anterior humeral line (AHL) on a lateral radiograph. Rotational variations in radiographic projection are common due to child discomfort and could lead to changes in management based on where the AHL intersects the capitellum. The purpose of this study was to establish whether rotational variations in elbow rotation leads to significant changes in AHL position and whether drawing the AHL based on the distal humerus versus shaft is more tolerant to rotation. METHODS: Fifty children with nonoperative supracondylar humerus fractures were identified with sub optimally positioned injury and well positioned follow-up lateral radiographs. The proportion of the bone anterior to the intersection of the AHL and the capitellum was measured using the humeral shaft versus distal humerus to guide position of the AHL. This process was repeated on ten pediatric humerus dry cadaveric specimens which were imaged in 5-degree rotational increments along the axis of the humeral shaft from -20 to +20 degrees. RESULTS: AHL position correlated poorly when measured on rotated lateral radiographs of clinical patients versus non-rotated lateral radiographs when using the distal humerus as a guide (intraclass correlation coefficient 0.14), compared with when using the humeral shaft as a guide (intraclass correlation coefficient 0.81). When assessing the pediatric humerus dry cadavers between the 2 techniques, there was greater statistically significant variation in rotated positions compared with the neutral position in the distal humerus AHL measurement approach compared with the humeral shaft AHL measurement approach, with the mean AHL within the central third of the capitellum for more rotational positions when using the shaft compared with the distal humerus. CONCLUSIONS: With rotated lateral elbow radiographs in supracondylar humerus fractures, utilizing the humeral shaft provides more consistent AHL measurements than utilizing the distal humerus, and thus drawing the line starting at the shaft of the humerus is recommended for surgical decision making.

Disparities in Pediatric Orthopedic Surgery Care During the COVID-19 Pandemic Pre-vaccine and Post-Vaccine Availability.

BACKGROUND: The COVID-19 pandemic has led to significant disruptions in medical care, resulting in an estimated 40% of US adults avoiding care. However, the return to baseline health care utilization following COVID-19 restrictions within the pediatric orthopedic population remains unexplored. We sought to analyze the visit volume and demographics of pediatric orthopedic patients at 3 timepoints: prepandemic (2019), pandemic (2020), and pandemic post-vaccine availability (2021), to determine the impact of COVID-19 restrictions on our single-center, multisite institution. METHODS: We performed a retrospective cohort study of 6318 patients seeking treatment at our institution from May through August in 2019, 2020, and 2021. Patient age, sex, address, encounter date, and ICD-10 codes were obtained. Diagnoses were classified into fractures and dislocations, non-fracture-related trauma, sports, elective, and other categories. Geospatial analysis comparing incidence and geospatial distribution of diagnoses across the time periods was performed and compared with the Centers for Disease Control (CDC) social vulnerability index (SVI). RESULTS: The total number of pediatric orthopedic visits decreased by 22.2% during the pandemic ( P <0.001) and remained 11.6% lower post-vaccine availability compared with prepandemic numbers ( P <0.001). There was no significant difference in age ( P =0.097) or sex ( P =0.248) of the patients across all 3 timepoints; however, patients seen during the pandemic were more often White race (67.7% vs. 59.3%, P <0.001). Post-vaccine availability, trauma visits increased by 18.2% ( P <0.001) and total fractures remained 13.4% lower than prepandemic volume ( P <0.001). Sports volume decreased during the pandemic but returned to prepandemic volume in the post-vaccine availability period ( P =0.298). Elective visits did not recover to prepandemic volume and remained 13.0% lower compared with baseline ( P <0.001). Geospatial analysis of patient distribution illustrated neighborhood trends in access to care during the COVID-19 pandemic, with fewer patients from high SVI and low socioeconomic status neighborhoods seeking fracture care during the pandemic than prepandemic. Post-vaccine availability, fracture population distribution resembled prepandemic levels, suggesting a return to baseline health care utilization. CONCLUSION: Pediatric orthopedic surgery visit volume broadly decreased during the COVID-19 pandemic and did not return to prepandemic levels. All categories increased in the post-vaccine availability time point except elective visits. Geospatial analysis revealed that neighborhoods with a high social vulnerability index (SVI) were associated with decreased fracture visits during the pandemic, whereas low SVI neighborhoods did not experience as much of a decline. Future research is needed to study these neighborhood trends and more completely characterize factors preventing equitable access to care in the pediatric orthopedic population. LEVEL OF EVIDENCE: Retrospective Study, Level III.

Comparison of pelvic incidence measurement using lateral x-ray, standard ct versus ct with 3d reconstruction.

PURPOSE: Pelvic incidence (PI) is a position independent parameter used to quantify spinopelvic sagittal balance. PI is generally measured on lateral radiographs, but more recent studies have suggested better accuracy with standard CT scans versus three-dimensional (3D) CT scans. This study compares PI obtained from lateral XR, standard CT scan and CT scan with 3D reconstruction. METHODS: A total of 77 subjects with lateral XRs of the pelvis or lumbosacral spine and CT scans of the pelvis were randomly selected. Pelvic incidence on lateral XRs, standard CT scans and CT scans utilizing multiplanar reconstruction were measured and compared using intraclass correlation coefficients (ICC). PI was also measured on serial images in 28 individuals using the same imaging modality within 3 years and evaluated using ICC. RESULTS: Mean ± SD of PI measurements on XR, standard CT and CT with 3D reconstruction were 56° ± 13°, 53° ± 12° and 53° ± 12°, respectively, demonstrating a small but significant elevation of PI measurement on XR (P < 0.001). ICC values demonstrated a higher correlation between standard CT and 3D CT (ICC 0.986), compared to XR and standard CT (ICC 0.934) and XR and 3D CT (ICC 0.937). PI measurements on repeated imaging of the same individual also demonstrated that both CT methods produced more consistent measurements (ICC 0.986 for standard CT, 0.981 for 3D CT, 0.935 for XR). CONCLUSION: Although standard XR does provide a high level of reliability, it appears to slightly overestimate PI. CT scans do provide increased reliability, with no additional benefit of 3D reconstructions over standard CT.

Lower Limb Deformity Correction: Analysis and Preoperative Planning.

Lower limb deformities have a wide range of presentations and require significant preparation and planning from the surgeon to correct. It is important to provide a clear and systematic approach to preoperative planning for these cases and to detail three well-established correction techniques: external fixation, plate fixation, and intramedullary nail fixation. In using a simple mnemonic that lays out the systematic analysis of various axis lines and joint angles from proximal to distal in the lower extremity, deformities can be readily identified, and correction strategies can be effectively used to produce a successful deformity correction that restores colinear alignment to the lower limb. Additional pearls and pitfalls for these techniques are also provided to assist with some of the nuances that exist in the field.

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.

Estimating Skeletal Maturity by Segmented Linear Modeling of Key AP Knee Radiographic Parameters.

BACKGROUND: The recently described Modified Fels knee system allows for accurate skeletal maturity estimation using a single anteroposterior knee radiograph but requires evaluation of 7 parameters. A faster method may have clinical utility in the outpatient setting. METHODS: Seven anteroposterior knee radiographic parameters associated with 90% of the final height (an enhanced skeletal maturity standard compared with peak height velocity) were analyzed in 78 children. Segmented linear regression and generalized estimating equation analyses were used to identify the subsets of parameters most important for accurate skeletal maturity estimation for different patient demographics and parameter scores. This process produced abbreviated skeletal maturity systems, which include fewer parameters and are quicker to use. The accuracy of the resulting abbreviated skeletal maturity systems was evaluated and compared with the full 7-parameter Modified Fels knee system and with the Greulich and Pyle (GP) left-hand bone age. RESULTS: A total of 326 left knee radiographs from 41 girls (range, 7 to 15 y) and 37 boys (range, 9 to 17 y) were included. Models generated by segmented regression and generalized estimating equation analysis required fewer parameters (range, 1 to 5 parameters) than the full Modified Fels knee system (7 parameters). Skeletal age estimates produced by segmented regression models were more accurate than GP (P<0.05) and not significantly different from the full Modified Fels system (P>0.05). The percentage of outlier estimations (estimations >1 y off from actual skeletal age) made by segmented regression models was not significantly different from GP (P>0.05) or the Modified Fels knee system (P>0.05). CONCLUSION: An abbreviated version of the Modified Fels knee system estimates skeletal maturity more accurately than the GP system with just 2 to 3 radiographic knee parameters. CLINICAL RELEVANCE: The abbreviated Modified Fels knee system may allow for rapid skeletal age estimation (~30 s) appropriate for routine outpatient practice.

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.

An Anatomic Study of the Proximal Tibial Epiphysis With Relevance to Percutaneous Epiphysiodesis Using Transphyseal Screws (PETS).

BACKGROUND: Percutaneous epiphysiodesis using transphyseal screws (PETS) is a common procedure to correct lower extremity limb-length discrepancies in the pediatric population. A potential complication of this procedure is development of tibial valgus deformity, which may occur secondary to decreased screw purchase in the thinner medial proximal tibial epiphysis. The thickness of the proximal tibial epiphysis has not yet been well quantified, which was the aim of this study. METHODS: Three-dimensional surface scans of 32 cadaveric proximal tibial epiphyses in specimens aged 3 to 17 years old were obtained and computer modeling software was utilized to measure the thickness of the proximal tibial epiphysis at 20 standardized potential screw insertion points according to a generated 5×4 map. RESULTS: When normalized to the total width of the proximal tibial epiphysis, the lateral side is thicker compared with the medial side. The positions with the greatest thickness are located at the midline in the sagittal plane and 33% of the total physeal width away from the medial and lateral edges in the coronal plane (0.265 and 0.261 normalized thickness, respectively). The proximal tibial epiphysis is particularly thin 25% from the medial edge (normalized thickness range: 0.196 to 0.221). Multiple regression analysis revealed a significant relationship between increasing age and female sex with thinner normalized medial and lateral heights. CONCLUSIONS: During PETS, areas for greater screw purchase are located centrally in the sagittal plane and 33% of the total width away from the medial and lateral edges of the proximal tibial epiphysis in the coronal plane. Caution should be taken when inserting screws in the medial 25% of the proximal tibial epiphysis as it is thinner relative to the lateral edge, particularly in females. CLINICAL RELEVANCE: This study provides quantitative, anatomic data on the thickness of the proximal tibial epiphysis, which can direct screw placement during PETS for correcting limb-length discrepancies. These data may help lessen the risk of developing tibial valgus deformity although future clinical studies are necessary to fully evaluate this possibility.

The Optimized Oxford Hip Skeletal Maturity System Proves Resilient to Rotational Variation.

BACKGROUND: The recently described optimized Oxford skeletal maturity system utilizes anteroposterior (AP) hip radiographs to accurately, rapidly, and reliably estimate skeletal maturity. However, in the real-world setting, significant positional variation in AP hip radiographs may influence the accuracy of optimized Oxford skeletal age estimates. We sought to evaluate the consistency of skeletal age estimations using the optimized Oxford system between differently rotated radiographs. METHODS: Thirty normal computerized tomography scans of males (15 children, 9 to 15 y) and females (15 children, 8 to 14 y) were obtained retrospectively, converted into 3D reconstructions, and then used to produce simulated hip radiographs in five different rotational positions. The optimized Oxford system was applied to the 150 simulated AP hip radiographs (5 differently rotated views of 30 hips) to produce a skeletal age estimate for each. RESULTS: Rotational position did not have a statistically significant effect on the skeletal age (P=0.84) using 1-way repeated measures analysis of variance. Of the 5 radiographic parameters in the optimized Oxford system, only greater trochanter height showed significant rotational variation after Greenhouse-Geisser correction (F2.58, 74.68=5.98, P<0.001). However, post hoc analyses showed that the greater trochanter height obtained at the most centered position was not different from the other 4 rotational positions (P>0.05 for all). CONCLUSION: The optimized Oxford skeletal maturity system is resilient to rotational variation. Mildly to moderately rotated radiographs obtained in the modern clinical setting can be used for skeletal age estimation by this method, broadening the clinical usage of this system. LEVEL OF EVIDENCE: Level III-diagnostic study.

The Utility of the Modified Fels Knee Skeletal Maturity System in Limb Length Prediction.

BACKGROUND: Predicting ultimate lower extremity length is important in the treatment of lower limb length discrepancy (LLD), congenital limb deficiency, and other etiologies. Utilizing skeletal age over chronological age improves the prediction of ultimate lower extremity length. The recently described modified Fels knee skeletal maturity system allows for skeletal age estimation via imaging always available in LLD patients. We sought to compare the accuracy of the modified Fels knee skeletal maturity system versus chronological age in ultimate limb length prediction of a modern adolescent clinical population. METHODS: The medical records of all patients treated at our institution over a 20-year period with unilateral lower extremity pathology and available lower extremity imaging before and after reaching skeletal maturity were reviewed. Skeletal maturity was defined radiographically by closed distal femoral, proximal tibial, and proximal fibular physes. The femoral, tibial, and lower extremity length was measured in all radiographs. The modified Fels knee skeletal maturity system was applied to all radiographs obtained before maturity to estimate skeletal age. The accuracy of 3 widely utilized lower extremity length prediction systems was compared when utilizing estimated Fels skeletal age versus chronological age inputs. RESULTS: A total of 245 radiographs (109 before maturity) from 43 patients were eligible for inclusion. On cross-sectional analysis, linear modeling using Fels skeletal ages was uniformly associated with higher (improved) R2 values than chronological age-based models. On longitudinal analysis, skeletal age mixed-effects models had significantly lower (improved) Akaike information criterion and Bayesian information criterion values than chronological age models in all cases. Cohen d values were also significantly different (P<0.05) for the skeletal age models compared with chronological age models in all cases. CONCLUSIONS: In the treatment of LLD, the modified Fels knee skeletal maturity system can be readily applied to available imaging to improve the prediction of ultimate femoral, tibial, and lower extremity length. This skeletal maturity system may have significant utility in the estimation of ultimate LLD and determination of appropriate timing of epiphysiodesis. LEVEL OF EVIDENCE: Level III.

The Influence of Retrograde Femoral Nail Removal With and Without Interpositional Fat Grafting on Distal Femoral Physeal Behavior: A Sheep Study.

BACKGROUND: Previous investigations have demonstrated that up to 7% of the distal femoral physis can be violated using a rigid, retrograde nail without growth inhibition or arrest. The purpose of this investigation was to evaluate the behavior of the distal femoral physis after retrograde femoral nail removal in a sheep model, with and without placement of an interpositional fat graft. METHODS: Retrograde femoral nails were placed in 8 skeletally immature sheep. Implants were removed at 8 weeks, with the residual defects left open (n=4) or filled with autologous fat graft (n=4). Differences in femoral length between surgical versus contralateral control femurs were measured after an additional 3 (n=4) or 5 months (n=4) before sacrifice, and the physis was evaluated histologically. RESULTS: When compared with control limbs, femoral length was significantly shorter in limbs sacrificed at 3 months (mean: 3.9±1.3 mm; range: 2.7 to 5.7 mm) compared with limbs at 5 months (mean: 1.0±0.4 mm; range: 0.4 to 1.2 mm) ( P =0.005). No significant difference in mean shortening was appreciated in limbs without (2.4±1.6 mm) versus with fat grafting (2.5±2.3 mm) ( P =0.94). Histologic analysis revealed no osteoid formation across the physis in sheep sacrificed at 3 months, whereas there was evidence of early osteoid formation across the physis in sheep at 5 months. All specimens demonstrated evidence of an active physes. CONCLUSIONS: Femurs undergoing retrograde implant placement were significantly shorter when compared with control limbs in sheep sacrificed at 3 months, whereas differences were nominal in sheep sacrificed at 5 months after retrograde implant removal, suggesting growth inhibition with nail removal improved with time. Fat grafting across the distal femoral physis did not result in a significant difference in femoral lengths. Histologic evidence at 5 months revealed early development of a bone bridge, emphasizing the importance of follow-up to skeletal maturity in patients treated with retrograde nailing across an open physis. LEVEL OF EVIDENCE: Level IV.

An anatomical study defining the safe range of angles in percutaneous iliosacral and transsacral screw fixation.

Percutaneous iliosacral screw fixation and transsacral fixation are challenging procedures requiring extensive knowledge of sacral anatomy to avoid damaging nearby neurovascular structures. Greater knowledge of anatomical screw trajectory and size allowances would be helpful to guide surgical placement. An anatomical study of 40 cadaveric sacra in specimens ages 18-65 was performed. Three-dimensional surface scans were obtained, and computer modeling software was used to simulate a 7.3 mm diameter screw with 1 mm buffer inserted orthogonal to the sacroiliac joint in the pelvic inlet and outlet views. Transsacral screws were also inserted into S1 and S2 vertebrae. For screws orthogonal to the sacroiliac joint, the overall mean screw insertion angle was 4.1° ± 7.5° (range, -18.3° to 22.0°) in the inlet view in the posterior to anterior direction, and 21.7° ± 5.1° (range, 8.2°-36.3°) in the outlet view in the caudal to cranial direction. Before breaching the sacrum, the range of sacral tunnel lengths was between 31.1 and 70.1 mm with a range of diameters between 9.3 and 13.3 mm. Transsacral screws inserted into either the S1 or S2 vertebrae did not breach the sacrum in 40% (16/40) at each level. 30% (12/40) of sacra could not safely accommodate both S1 and S2 transsacral screws. There is an initial screw insertion angle range of -4° to 12° in the inlet view and 16°-27° in the outlet view. There was always adequate size to accept a 7.3 mm or larger screw.