Predicting Success of Deformity Correction With Tension Band Plating in Early-Onset Tibia Vara.

BACKGROUND: Angular deformity correction with tension band plating has not been as successful in early-onset tibia vara (EOTV) as it has been in other conditions. Our hypothesis is that perioperative factors can predict the success of lateral tibial tension band plating (LTTBP) in patients with EOTV. METHODS: A retrospective review was performed at 7 centers evaluating radiographic outcomes of LTTBP in patients with EOTV (onset <7 y of age). Single-event tibial LTTBP outcome was assessed through medial proximal tibial angle (MPTA). The final limb alignment following comprehensive limb growth modulation (CLGM), which could include multiple procedures, was assessed by mechanical axis zone (MAZone), mechanical tibio-femoral angle (mTFA), and mechanical axis deviation (MAD). Preoperative age, weight, deformity severity, medial physeal slope, and Langenskiöld classification +/- modification were investigated as predictors of outcome. Success was defined as the correction or overcorrection to normal age-adjusted alignment. The minimum follow-up was 2 years except when deformity correction, skeletal maturity, or additional surgery occurred. RESULTS: Fifty-two patients with 80 limbs underwent 115 tibial LTTBP procedures at a mean age of 5.3 y, including 78 primary, 21 implant revisions, and 15 reimplantations for recurrence. Tibial LTTBP resulted in a mean change of +8.6 o in MPTA and corrected 53% of tibias. CLGM resulted in MAD correction for 54% of limbs.Univariate analysis showed that success was best predicted by preoperative age, weight, MPTA, and MAD. Multivariate analysis identified that preoperative-MPTA/MAD and preoperative-weight<70 kg were predictive of MPTA and MAD correction, respectively. The probability of success tables are presented for reference. CONCLUSION: Successful correction of MPTA to age-adjusted norms following a single-event LTTBP occurred in 53% of tibias and was best predicted by preoperative-MPTA and preoperative body weight <70 kg. Comprehensive growth modulation corrected limbs in 54%. The probability of correction to age-adjusted MAD is best estimated by preoperative-MAZone 1 or 2 (MAD ≤40 mm). Limbs with preoperative-MAD>80 mm improved, but ultimately all failed to correct completely with CLGM. Osteotomy may need to be considered with these severe deformities. While modified Langenskiöld classification and medial physeal slope have been shown to predict the outcome of osteotomy, they were not predictive for LTTBP. Change in MPTA was common after physeal untethering. LEVEL OF EVIDENCE: Level-III.

Predicting Deformity Correction of Growth Modulation in Late-onset Tibia Vara.

BACKGROUND: Growth modulation in late-onset tibia vara (LOTV) has been reported to yield variable results. We hypothesized that parameters of deformity severity, skeletal maturity, and body weight could predict the odds of a successful outcome. METHODS: A retrospective review of tension band growth modulation for LOTV (onset ≥8 y) was performed at 7 centers. Tibial/overall limb deformity and hip/knee physeal maturity were assessed on preoperative anteroposterior standing lower-extremity digital radiographs. Tibial deformity change with first-time lateral tibial tension band plating (first LTTBP) was assessed by medial proximal tibia angle (MPTA). Effects of a growth modulation series (GMS) on overall limb alignment were assessed by mechanical tibiofemoral angle (mTFA) and included changes from implant removal, revision, reimplantation, subsequent growth, and femoral procedures during the study period. The successful outcome was defined as radiographic resolution of varus deformity or valgus overcorrection. Patient demographics, characteristics, maturity, deformity, and implant selections were assessed as outcome predictors using multiple logistic regression. RESULTS: Fifty-four patients (76 limbs) had 84 LTTBP procedures and 29 femoral tension band procedures. For each 1-degree decrease in preoperative MPTA or 1-degree increase in preoperative mTFA the odds of their successful correction decreased by 26% in the first LTTBP and 6% by GMS, respectively, controlling for maturity. The change in odds of success for GMS assessed by mTFA was similar when controlling for weight. Closure of a proximal femoral physis decreased the odds of success for postoperative-MPTA by 91% with first LTTBP and for final-mTFA by 90% with GMS, controlling for preoperative deformity. Preoperative weight ≥100 kg decreased the odds of success for final-mTFA with GMS by 82%, controlling for preoperative mTFA. Age, sex, race/ethnicity, type of implant, and knee center peak value adjusted age (a method for bone age) were not predictive of outcome. CONCLUSIONS: Resolution of varus alignment in LOTV using first LTTBP and GMS, as quantified by MPTA and mTFA, respectively, is negatively impacted by deformity magnitude, hip physeal closure, and/or body weight ≥100 kg. The presented table, utilizing these variables, is helpful in the prediction of the outcome of the first LTTBP and GMS. Even if complete correction is not predicted, growth modulation may still be appropriate to reduce deformity in high-risk patients. LEVEL OF EVIDENCE: Level III.

Femoral Deformity in Tibia Vara and Its Response to Growth Modulation.

BACKGROUND: While tibia vara is a disorder of the proximal tibial physis, femoral deformity frequently contributes to the overall limb malalignment. Our purpose was to determine how femoral varus deformity in tibia vara responds to growth modulation, with/without lateral tension band plating (LTBP) to the femur. METHODS: One-hundred twenty-seven limbs undergoing LTBP for tibia vara were reviewed. All had tibial LTBP and 35 limbs also had femoral LTBP for varus. Radiographs were measured for correction of the mechanical lateral distal femoral angle (mLDFA) and mechanical axis deviation (MAD). Preoperative-femoral varus was defined with an age-adjusted guide: mLDFA >95 degrees for 2 to below 4 years and mLDFA >90 degrees for 4 to 18 years. The 35 limbs having femoral LTBP were compared with 50 limbs with femoral varus and no femoral LTBP. In addition, 42 limbs that did not have preoperative-femoral varus were followed. Patients with early-onset (below 7 y) tibia vara were compared with those with late-onset (≥8 y). Outcome success was based on published age-adjusted mLDFA and MAD norms. RESULTS: Following femoral LTBP, the mean mLDFA decreased from 98.0 to 87.1 degrees. All femurs had some improvement, with 28/35 femurs (80%) achieving complete correction. One limb, with late follow-up, overcorrected, requiring reverse (medial) femoral tension band plating.For the 50 limbs with femoral varus and only tibial LTBP, 16/22 limbs (73%) with early-onset and 11/28 limbs (39%) with late-onset completely corrected their femoral deformities. If the limb had preoperative-femoral varus, femoral LTBP statistically correlated with successful mLDFA correction and improvement of MAD, only in the late-onset group.Forty-two limbs, without preoperative-femoral varus, had no change in their mean mLDFA of 87 degrees. However, 4 femurs (10%) ended with posttreatment varus. CONCLUSIONS: Femoral LTBP is effective in correcting femoral varus deformity in the tibia vara. For femoral varus associated with late-onset tibia vara, femoral LTBP should be considered. Those that had femoral LTBP had statistically more successful femoral and overall limb varus correction. However, in early-onset tibia vara, with associated femoral varus, observation is warranted because 73% of femurs are corrected without femoral intervention. This study was underpowered to show additional improvement with femoral LTBP in the early-onset group. Even limbs with normal femoral alignment, should be observed closely for the development of femoral varus, during tibial LTBP treatment for tibia vara. LEVEL OF EVIDENCE: Level III.

A bifactor approach to subscore assessment.

Bifactor confirmatory factor analysis models and statistical indices computed from them have previously been used to provide evidence for the appropriateness of utilizing a unidimensional interpretation of multidimensional data. However, the ability of bifactor indices to aid in the assessment of subscore strength has not been investigated. A simulation study was conducted to relate bifactor indices to the strength of subscores corresponding to specific factors. The bifactor indices OmegaHS and ECVSS were found to be strongly predictive of subscore strength conditional upon OmegaS. The number of factors was also found to play a minor role in this relationship. Cutoffs for assessing the appropriateness of interpreting subscores were constructed based on OmegaHS or ECVSS conditional upon OmegaS and the number of factors. For low subscore reliability (OmegaS = .60), OmegaHS = .25 or ECVSS = .45 is sufficient that the subscore has a good chance of having added value (VAR > 1.1) above and beyond the total score. For moderate reliability (OmegaS = .80), OmegaHS = .20 or ECVSS = .30 is sufficient, and the role of OmegaHS or ECVSS diminishes as OmegaS increases further. A subscore having added value does not necessitate its interpretation. Instead, when subscores are desired to be interpreted, high OmegaHS or ECVSS can be considered as evidence that such an interpretation is statistically appropriate. Finally, we illustrate the use of these cutoffs with an empirical data set. When combined with prior bifactor research, this work extends a framework of using confirmatory bifactor models for dimensionality assessment. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Guided Growth Procedures: Broken Tension Band Implants in Patients With Blount Disease.

BACKGROUND: Tension band plate and screw implants (TBI) are frequently used for temporary hemiepiphyseodeses to manage angular deformity in growing children. The reported implant breakage rate, when TBI is used for deformities in patients with Blount disease, is much higher than when used in other diagnoses. Our hypothesis is that perioperative factors can identify risks for TBI breakage. METHODS: A retrospective case-control study was performed of 246 TBI procedures in 113 patients with Blount disease at 8 tertiary pediatric orthopaedic centers from 2008 to 2018. Patient demographics, age at diagnosis, weight, body mass index (BMI), radiographic deformity severity measures, location, and types of implants were studied. The outcome of implant breakage was compared with these perioperative factors using univariate logistic regression with Bonferroni correction for multiplicity to significance tests. RESULTS: There were 30 broken implants (12%), failing at mean 1.6 years following implantation. Most failures involved the metaphyseal screws. Increased BMI was associated with increased implant breakage. Increased varus deformity was directly associated with greater implant breakage and may be a more important factor in failure for those below 7 years compared with those 8 years or above at diagnosis. There was a 50% breakage rate for TBI with solid 3.5 mm screws in Blount disease with onset 8 years or above of age. No demographic or implant factors were found to be significant. CONCLUSIONS: Breakage of TBI was associated with increased BMI and varus deformity in patients with Blount disease. Larger studies are required to determine the relative contribution and limits of each parameter. Solid 3.5 mm screws should be used with caution in TBI for late-onset Blount disease. LEVEL OF EVIDENCE: Level III.

Examining the Structure and Validity of Self-Report Measures of DSM-5 Alternative Model for Personality Disorders Criterion A.

The Level of Personality Functioning Scale (LPFS) operationalizes Criterion A of the DSM-5 Alternative Model for Personality Disorders. Despite progress in LPFS measurement development and validation, there is a lack of research, and some disagreement, concerning structural, convergent, and incremental validity of LPFS self-report measures. The present study aimed to compare the LPFS Self-Report, LPFS Self-Report of Criterion A, and LPFS Brief Form. Internal structure was assessed through principal component analyses, factor analyses, and bifactor analyses of unidimensionality. Associations with both pathological and basic personality characteristics among the LPFS measures were explored. Incremental validity of LPFS severity in predicting pathological personality outcomes controlling for basic personality traits, and the reverse, were examined. Results suggest a unidimensional structure robustly associated with other pathological personality assessments. LPFS severity and basic personality traits mutually offered unique explanatory power. We discuss the implications of assessing personality pathology using LPFS self-report measures.

To Reverse Item Orientation or Not to Reverse Item Orientation, That Is the Question.

To investigate the effect of using negatively oriented items, we wrote semantic reversals of the items in the Rosenberg Self Esteem Scale, UCLA Loneliness Scale, and the General Belongingness Scale and used them to create four experimental conditions. Participants (N = 2,019) were recruited through Amazon's Mechanical Turk. Data were assessed for dimensionality, item functioning, instrument properties, and associations with other variables. Regarding dimensionality, although a two-factor model (positively vs. negatively oriented factors) exhibits better fit than a unidimensional model across all conditions, bifactor indices were used to argue that a unidimensional interpretation of the data can be employed. With respect to item functioning, factor loadings were found to be nearly invariant across conditions, but thresholds were not. Concerning instrument properties, inclusion of negatively oriented items results in lower mean scores and higher score variances. Instruments with both positively and negatively oriented items demonstrated lower reliability estimates than those with only one orientation. For associations with other variables, path coefficients in a model where loneliness mediates the effects of belongingness on life satisfaction and self-esteem were found to vary across conditions. Findings suggest that negatively oriented items have minor impact on instrument quality, but influence measurement model and path coefficients.

Psychometric properties of the Intolerance of Uncertainty Scale-12 in generalized anxiety disorder: Assessment of factor structure, measurement properties and clinical utility.

Intolerance of uncertainty is a psychological vulnerability implicated in the development and maintenance of generalized anxiety disorder (GAD). The Intolerance of Uncertainty Scale-12 (IUS-12) is a widely used measure, however no studies have thoroughly tested the psychometric properties in a clinically diagnosed GAD sample. This study aimed to evaluate the factor structure, measurement properties and clinical utility of the IUS-12 in clinical and non-clinical samples. Participants were screened using the Anxiety Disorders Interview Schedule for DSM-IV to ascertain clinical (n = 136: principal diagnosis of GAD) or non-clinical status (n = 76). Confirmatory factor analysis determined that the bifactor type (two-factor testlet) model demonstrated significantly better fit in comparison to the unidimensional model for the clinical sample. The IUS-12 exhibited limited multidimensionality indicating that only the total score provides meaningful interpretation. The IUS-12 demonstrated good construct validity (with DASS-21, MCQ-30, and PSWQ), good internal consistency, as well as good test-retest reliability over 12-weeks. The IUS-12 demonstrated responsivity to treatment following cognitive behavioral therapy and mindfulness based psychological interventions. Receiver operating characteristic curve analysis indicated an optimal cut-off score of 28 for distinguishing individuals with GAD from non-clinical cases. Overall, the IUS-12 is a valid, reliable and clinically useful instrument for individuals with GAD.

Comparison of Single-Response Format and Forced-Choice Format Instruments Using Thurstonian Item Response Theory.

One of the most cited methodological issues is with the response format, which is traditionally a single-response Likert response format. Therefore, our study aims to elucidate and illustrate an alternative response format and analytic technique, Thurstonian item response theory (IRT), for analyzing data from surveys using an alternate response format, the forced-choice format. Specifically, we strove to give a thorough introduction of Thurstonian IRT at a more elementary level than previous publications in order to widen the possible audience. This article presents analyses and comparison of two versions of a self-report scale, one version using a single-response format and the other using a forced-choice format. Drawing from lessons learned from our study and literature, we present a number of recommendations for conducting research using the forced-choice format and Thurstonian IRT, as well as suggested avenues for future research.