Changes in femoral anteversion after intramedullary nailing for pediatric femoral shaft fracture: a multicenter study.

BACKGROUND: The rotational change after using a flexible intramedullary (IM) nail for femoral shaft fractures has been a concern for many surgeons. Recently, a statistical shape model (SSM) was developed for the three-dimensional reconstruction of the femur from two-dimensional plain radiographs. In this study, we measured postoperative femoral anteversion (FAV) in patients diagnosed with femoral shaft fractures who were treated with flexible IM nails and investigated age-related changes in FAV using the SSM. METHODS: This study used radiographic data collected from six regional tertiary centers specializing in pediatric trauma in South Korea. Patients diagnosed with femoral shaft fractures between September 2002 and June 2020 and patients aged < 18 years with at least two anteroposterior (AP) and lateral (LAT) femur plain radiographs obtained at least three months apart were included. A linear mixed model (LMM) was used for statistical analysis. RESULTS: Overall, 72 patients were included in the study. The average patient age was 7.6 years and the average follow-up duration was 6.8 years. The average FAV of immediate postoperative images was 27.5 ± 11.5°. Out of 72 patients, 52 patients (72.2%) showed immediate postoperative FAV greater than 20°. The average FAV in patients with initial FAV > 20° was 32.74°, and the LMM showed that FAV decreased by 2.5° (p = 0.0001) with each 1-year increase from the time of initial trauma. CONCLUSIONS: This study explored changes in FAV after femoral shaft fracture using a newly developed technology that allows 3D reconstruction from uncalibrated 2D images. There was a pattern of change on the rotation of the femur after initial fixation, with a 2.5° decrease of FAV per year.

Anatomic consideration of the radial nerve in relation to humeral length for unilateral external fixation: a retrospective study using magnetic resonance imaging findings in korean.

BACKGROUND: This study aimed to present a safe zone for distal pin insertion for external fixation using magnetic resonance imaging (MRI) images. METHODS: All patients who took at least one upper arm MRI from June 2003 to July 2021 were searched via a clinical data warehouse. For measuring the humerus length, proximal and distal landmarks were set as the highest protruding point of the humeral head and lowermost margin of ossified bone of the lateral condyle, respectively. For children or adolescents with incomplete ossification, the uppermost and lowermost ossified margin of the ossification centers were set as proximal and distal landmarks respectively. The anterior exit point (AEP) was defined as the location of the radial nerve exiting the lateral intermuscular septum to the anterior humerus and distance between the distal margin of the humerus and AEP was measured. The proportions between the AEP and full humeral length were calculated. RESULTS: A total of 132 patients were enrolled for final analysis. The mean humerus length was 29.4 cm (range 12.9-34.6 cm). The mean distance between the ossified lateral condyle and AEP was 6.6 cm (range 3.0-10.6 cm). The mean ratio of the anterior exit point and humeral length was 22.5% (range 15.1-30.8%). The minimum ratio was 15.1%. CONCLUSION: A percutaneous distal pin insertion for humeral lengthening with an external fixator may be safely done within 15% length of the distal humerus. If pin insertion is required more proximal than distal 15% of the humeral shaft, an open procedure or preoperative radiographic assessment is advised to prevent iatrogenic radial nerve injury.

Rebound phenomenon and its risk factors after hemiepiphysiodesis using tension band plate in children with coronal angular deformity.

BACKGROUND: This study was performed to evaluate the rebound phenomenon after the correction of coronal angular deformity by hemiepiphysiodesis using tension band plate in children and to identify its risk factors. METHODS: We reviewed 50 children (mean age, 11.0 ± 2.5 years) with 94 physes who had undergone hemiepiphysiodesis using tension band plate due to coronal angular deformity of the lower limb. Patients' demographic data including sex, age at initial surgery and plate removal, affected bone (distal femur or proximal tibia), affected side, and body mass index were collected. The mechanical lateral distal femoral angle (mLDFA) and the mechanical medial proximal tibial angle (mMPTA) were measured from the teleradiogram, Physes were divided into rebound and non-rebound group, and rebound group was defined as the physes which had ≥ 5° of mLDFA or mMPTA returning to its original deformity. Generalized estimating equation based multivariable analysis was used to identify the risk factors for the rebound phenomenon after the deformity correction. RESULTS: A total of 41 physes classified into rebound group and 53 physes into non-rebound group. There were significant differences in the age at initial surgery (p = 0.004), the age at implant removal (p = 0.002), the amount of correction (p = 0.001), and the rate of correction (p < 0.001) between two groups. The rate of correction was significantly associated with the rebound phenomenon (p = 0.044). The risk of rebound phenomenon was 1.2-fold higher as the rate of correction increased by 1° per year. The cutoff values of the correction rate between the two groups were 6.9°/year (p < 0.001). CONCLUSIONS: This study showed that the rebound group had younger age and faster correction rate than those in the non-rebound group. In addition, the correction rate for deformity was a significant risk factor for the rebound phenomenon after hemiepiphysiodesis using the tension band plate. Close monitoring after implant removal is required for children who have a rapid correction rate over 7°/year.

Radiographic Follow-up After Normal Ultrasound Screening of the Hip in Breech Infants.

BACKGROUND: Breech presentation is one of the most important risk factors for developmental dysplasia of the hip, and all breech infants should be screened. The necessity of further follow-up of developmental dysplasia of the hip after normal clinical and sonographic screening is a controversial subject. The purpose of this study to identify the incidence of delayed dysplasia in breech infants after normal ultrasound screening and the necessity of further clinical and radiologic follow-up in these patients. METHODS: We included the 292 breech babies (128 boys and 164 girls) who showed normal hip ultrasound screening results. To determine the incidence of delayed radiographic dysplasia, anteroposterior hip radiographs were taken between 12 and 24 months of age to measure the acetabular index (AI). RESULTS: The mean AI values were 22.8±3.4 in boys and 24.9±3.1 in girls. Applying the Tönnis criteria, 29 patients (9.9%) were considered to have delayed radiographic dysplasia (16 boys and 13 girls). No significant difference was found in any demographic variables between babies with and without delayed radiographic dysplasia. None of these 29 infants underwent any treatment for radiographic dysplasia. Applying Kuong's criteria to 292 infants, only 2 patients (0.7%) demonstrated radiographic dysplasia on the hip anteroposterior radiographs taken at 14 months. CONCLUSIONS: The incidence of radiographic dysplasia significantly varied depending on which criteria were applied. In order to find out more accurate incidence rates of delayed radiographic dysplasia, large-scale studies of the normative AI data for Korean infants are required. LEVEL OF EVIDENCE: Prognostic Level III.

Breech Presentation in Twins as a Risk Factor for Developmental Dysplasia of the Hip.

INTRODUCTION: Identifying risk factors associated with developmental dysplasia of the hip (DDH) is essential for early diagnosis and treatment. Breech presentation is a major DDH risk factor, possibly because of crowding of the fetus within the uterus. In multifetal pregnancy, fetuses are generally smaller than singletons, which may obscure the effect of breech presentation on fetal hips. Only a few studies have investigated the occurrence of DDH in multifetal pregnancies. In this study, we aimed to evaluate whether the breech presentation is a major risk factor of DDH in twin pregnancies. METHODS: This retrospective study included 491 consecutive live births (after 23+0 weeks gestation) delivered through cesarean section with at least 1 baby with noncephalic presentation in single or twin pregnancies from April 2013 to October 2018. We analyzed the incidence of DDH and its associated factors, including sex, breech, and multifetal pregnancy, with a generalized linear mixed model. RESULTS: The incidence of DDH was 12.5% in singleton with breech presentation, 9.8% in twin-breech presentation, and 0.7% in twin-cephalic presentation. Multivariate analysis showed that singleton-breech presentation (P=0.003), twin-breech presentation (P=0.003), and female sex (P=0.008) were independent risk factors for DDH. CONCLUSION: Breech presentation is an independent risk factor for DDH in twin pregnancies, although twin pregnancy itself is not an independent risk factor for DDH.

Intrasubject Radiographic Progression of Hallux Valgus Deformity in Patients With and Without Metatarsus Adductus: Bilateral Asymmetric Hallux Valgus Deformity.

This study was to analyze intrasubject radiographic progression of the hallux valgus deformity by comparing the mildly and severely affected sides in patients with bilateral asymmetric hallux valgus in the whole group as well as the metatarsus adductus and the nonmetatarsus adductus subgroups. A total of 186 patients with bilateral asymmetrical hallux valgus deformity with a difference of 5° or greater in the hallux valgus angle were included, and 11 radiographic measurements were analyzed. The radiographic differences between the mildly and severely affected sides were compared. Correlation between the changes in the hallux valgus angle and those in other measurements was analyzed, and multiple regression analyses were performed. The anteroposterior talo-second metatarsal angle showed no significant difference between the mildly and severely affected sides. Changes in the intermetatarsal angle and sesamoid rotation angle were significantly associated with the progression of hallux valgus angle in the whole group as well as the nonmetatarsus adductus subgroup. Change in the intermetatarsal angle (p = .006) was the significant factor associated with the progression of hallux valgus angle in the metatarsus adductus subgroup. The anteroposterior talo-second metatarsal angle might be useful in evaluating the overall foot shape in the hallux valgus deformity. Progression of the hallux valgus deformity might be pathophysiologically different between those with and without metatarsus adductus.

Cycling kinematics in healthy adults for musculoskeletal rehabilitation guidance.

BACKGROUND: Stationary cycling is commonly used for postoperative rehabilitation of physical disabilities; however, few studies have focused on the three-dimensional (3D) kinematics of rehabilitation. This study aimed to elucidate the three-dimensional lower limb kinematics of people with healthy musculoskeletal function and the effect of sex and age on kinematics using a controlled bicycle configuration. METHODS: Thirty-one healthy adults participated in the study. The position of the stationary cycle was standardized using the LeMond method by setting the saddle height to 85.5% of the participant's inseam. The participants maintained a pedaling rate of 10-12 km/h, and the average value of three successive cycles of the right leg was used for analysis. The pelvis, hip, knee, and ankle joint motions during cycling were evaluated in the sagittal, coronal, and transverse planes. Kinematic data were normalized to 0-100% of the cycling cycle. The Kolmogorov-Smirnov test, Mann-Whitney U test, Kruskal-Wallis test, and k-fold cross-validation were used to analyze the data. RESULTS: In the sagittal plane, the cycling ranges of motion (ROMs) were 1.6° (pelvis), 43.9° (hip), 75.2° (knee), and 26.9° (ankle). The coronal plane movement was observed in all joints, and the specific ROMs were 6.6° (knee) and 5.8° (ankle). There was significant internal and external rotation of the hip (ROM: 11.6°), knee (ROM: 6.6°), and ankle (ROM: 10.3°) during cycling. There was no difference in kinematic data of the pelvis, hip, knee, and ankle between the sexes (p = 0.12 to 0.95) and between different age groups (p = 0.11 to 0.96) in all anatomical planes. CONCLUSIONS: The kinematic results support the view that cycling is highly beneficial for comprehensive musculoskeletal rehabilitation. These results might help clinicians set a target of recovery ROM based on healthy and non-elite individuals and issue suitable guidelines to patients.

Evaluation of factors affecting external tibial torsion in patients with cerebral palsy.

BACKGROUND: Gait deviation and associated torsional problems are common in patients with cerebral palsy (CP). Although femoral anteversion in CP has been extensively reviewed in previous studies, only a few studies have focused on tibial torsion. Therefore, this study aimed to evaluate tibial torsion in patients with CP and investigate the affecting factors. METHODS: Consecutive patients with cerebral palsy who underwent 3-dimensional computed tomography for the assessment of rotational profiles were reviewed. Femoral anteversion and tibial torsion were measured, and the demographic characteristics of the patients were recorded. A linear mixed model was implemented to overcome the retrospective nature of the study. RESULTS: After the implementation of inclusion and exclusion criteria, 472 patients were enrolled for this study. With age, external tibial torsion increased, while femoral anteversion decreased. The factors affecting external tibial torsion were increased femoral anteversion (p = 0.0057), increased age (p < 0.0001), higher Gross Motor Function Classification System (GMFCS) level (p < 0.0001), and involved/uninvolved limbs of hemiplegia (p = 0.0471/p = 0.0047). CONCLUSIONS: Older age, GMFCS level IV/V, hemiplegia, and increased femoral anteversion were the independent risk factors of increased external tibial torsion; therefore, performing an imaging study is recommended for assessing the extent of tibial torsion in patients with such characteristics.

Effect of Screw Configuration on the Rate of Correction for Guided Growth Using the Tension-band Plate.

BACKGROUND: This study investigated the effect of screw configuration on the rate of correction of coronal angular deformity of the knee joint in children who underwent guided growth using the tension-band plate. METHODS: Consecutive patients (76 patients with 154 physes; mean age: 11.8±2.2 y) who underwent guided growth using the tension-band plate for coronal angular deformity (genu varum or genu valgum) were included. The mechanical lateral distal femoral angle, mechanical medial proximal tibial angle, and screw angle were measured from the teleroentgenograms of preoperative and postoperative periodic follow-up visits. RESULTS: The mean initial screw angle and the mean rate of correction were 16.7±10.5 degrees and 6.5±5.3 degrees per year, respectively. The rate of correction was significantly affected by age at surgery, sex, physis treated, severity of deformity, and rate of change in screw angle (all P<0.001). However, the initial screw angle and type of deformity did not affect the rate of correction. The rate of correction per year was 3.6 degrees higher in boys than in girls and 2.8 degrees higher in the distal femur than in the proximal tibia. A 1 degree increase in the rate of change in screw angle was associated with a 0.5 degree increase in the correction rate. Screw angle significantly increased with follow-up duration (P<0.001) and the change in screw angle was significantly affected by age, sex, and physis treated (all P<0.001). CONCLUSIONS: This study demonstrated that screw configuration did not affect the correction rate of coronal angular deformity for guided growth using the tension-band plate. Therefore, surgeons only need to insert the screws according to anatomic restriction, not considering the screw configuration when using the tension-band plate for guided growth in children. LEVEL OF EVIDENCE: Prognostic level III.

Leg length discrepancy, overgrowth, and associated risk factors after a pediatric tibial shaft fracture.

BACKGROUND: This study was performed to investigate leg length discrepancy (LLD), overgrowth, and associated risk factors after pediatric tibial shaft fractures. MATERIALS AND METHODS: This study included 103 patients younger than 14 years of age (mean age 7.1 years; 75 boys, 28 girls) with unilateral tibial shaft fracture and a minimum follow-up of 24 months. LLD was calculated as the difference between the lengths of the injured and uninjured limbs. Overgrowth was calculated by adding the fracture site shortening from the LLD. Risk factors were assessed in patients with LLD < 1 cm and ≥ 1 cm and overgrowth < 1 cm and ≥ 1 cm. RESULTS: Casting and titanium elastic nailing (TEN) were performed on 64 and 39 patients, respectively. The mean LLD and overgrowth were 5.6 and 6.4 mm, respectively. There were significant differences in sex (p = 0.018), age (p = 0.041), fibular involvement (p = 0.005), injury mechanism (p = 0.006), and treatment methods (p < 0.001) between patients with LLDs < 1 cm and ≥ 1 cm. There were significant differences in sex (p = 0.029), fibular involvement (p = 0.002), injury mechanism (p = 0.008), and treatment methods (p < 0.001) between patients with overgrowth < 1 cm and ≥ 1 cm. Sex and treatment methods were risk factors associated with LLD ≥ 1 cm and overgrowth ≥ 1 cm following pediatric tibial shaft fracture. The boys had a 7.4-fold higher risk of LLD ≥ 1 cm and 5.4-fold higher risk of overgrowth ≥ 1 cm than the girls. Patients who underwent TEN had a 4.3-fold higher risk of LLD ≥ 1 cm and 4.8-fold higher risk of overgrowth ≥ 1 cm than those treated by casting. CONCLUSIONS: Patients undergoing TEN showed greater LLD and overgrowth than those undergoing casting, with boys showing greater LLD and overgrowth than girls. Surgeons should consider the possibility of LLD and overgrowth after pediatric tibial shaft fractures, especially when performing TEN for boys. LEVEL OF EVIDENCE: Level III.

Transcultural adaptation and validation of a Korean version of the Oxford Ankle Foot Questionnaire for children.

BACKGROUND: The purpose of this study was to translate and transculturally adapt the original English version of the Oxford Ankle Foot Questionnaire (OAFQ) into a Korean version, and to evaluate its psychometric properties. METHODS: A Korean OAFQ for children was developed according to established guidelines. To test validity, 169 consecutive patients with foot and ankle problems and their caregivers each completed the OAFQ. The children also completed a Korean version of the KIDSCREEN-52 health related quality of life questionnaire (KIDSCREEN-52 HRQOL). To validate the Korean version of the OAFQ, reliability (child-parent agreement and internal consistency), feasibility (floor and ceiling effects), and construct validity were evaluated, and factor analysis was performed. RESULTS: In terms of reliability, Cronbach's α values were > 0.7 in all subscales of the OAFQ (0.765 to 0.901). Child-parent agreement was confirmed by high intraclass correlation coefficients for all subscales (0.791 to 0.863). In terms of construct validity, there were moderate correlations between the subscales of the OAFQ and the subscales of the KIDSCREEN-52 HRQOL. Factor analysis revealed a three-component solution for both the child/adolescent and parent-proxy version, by combining the school and play, and footwear items into one subscale. In terms of feasibility, no floor effects were found for all subscales. However, ceiling effects were observed for the school and play, and emotional subscales for child/adolescent and parent-proxy versions. CONCLUSIONS: The OAFQ was successfully translated and transculturally adapted into the Korean language; the Korean version of the OAFQ represents a reliable and valid instrument for evaluating children's foot or ankle problems. However, factor analysis suggested the use of a three-subscale questionnaire.

Differences in responses to English and Korean versions of the Caregiver Priorities & Child Health Index of Life with Disabilities (CPCHILD).

BACKGROUND: The purpose of this study was to identify differences in caregiver responses to Korean-language and English-language versions of the Caregiver Priorities & Child Health Index of Life with Disabilities (CPCHILD) questionnaire. METHODS: Patient data were acquired from the Cerebral Palsy Hip Outcomes Project database, which was established to run a large international multicenter prospective cohort study of the outcomes of hip interventions in cerebral palsy. Thirty-three children whose caregivers had completed the Korean version of CPCHILD were matched by propensity scoring with 33 children whose parents completed the English version. Matching was performed on the basis of 12 covariates: age, gender, gross motor function classification system level, migration percentage of right and hip, seizure status, feeding method, tracheostomy status, pelvic obliquity, spinal deformity, parental report of hip pain and contracture interfering with care. RESULTS: There were no significant differences in CPCHILD scores for section 4 (Communication and Social Interaction), and section 5 (Health) between two groups. Korean-language CPCHILD scores were significantly lower than English-language CPCHILD scores for section 1 (Personal Care/Activities of Daily Living), section 2 (Positioning, Transferring and Mobility), section 3 (Comfort and Emotions) and section 6 (Overall Quality of Life) as well as in terms of total score. CONCLUSIONS: Cultural influences, and the community or social environment may impact the caregivers' perception of the health-related quality of life of their children. Therefore, physicians should consider these differences when interpreting the study outcomes across different countries.

Progression of planovalgus deformity in patients with cerebral palsy.

BACKGROUND: Analyzing radiographic changes of pes planovalgus(PV) deformity of cerebral palsy(CP) patients according to age and influencing factors. METHODS: CP patients with PV deformity younger than 18 years old who had undergone more than a year of follow-up with at least two standing foot radiographs were included. Anteroposterior and lateral talo-first metatarsal(talo-1stMT), talo-second metatarsal(talo-2ndMT), and hallux valgus(HV) angles were measured on the radiographs. The rate of progression was adjusted by multiple factors using the linear mixed model, with the Gross Motor Function Classification System(GMFCS) level as the fixed effect and age and each subject as random effects. RESULTS: Overall, 194 patients were enrolled in this study, and 1272 standing foot radiographs were evaluated. The AP talo-2ndMT angle progressed by 0.59° (p < 0.0001) and 0.64° (p = 0.0007) in GMFCS level II and III patients, respectively; however, there was no significant change in GMFCS level I patients (p = 0.3269). HV was significantly affected by age in all three GMFCS groups; it increased by 0.48° (p < 0.0001), 0.66° (p < 0.0001), and 1.19° (p < 0.0001) for levels I, II, and III, respectively. The lateral talo-1stMT angle showed improvements in GMFCS level I and II patients (0.43°, p < 0.0001, and 0.61°, p < 0.0001, respectively). In GMFCS level III patients, there was no significant improvement in the lateral talo-1stMT angle (p = 0.0535). CONCLUSIONS: The GMFCS level was the single most important factor influencing the progression of radiographic indices in PV deformity in CP. The AP talo-1stMT and talo-2ndMT angles progressed in patients with GMFCS levels II and III. Physicians should take this result into consideration when planning the timing of the surgery. LEVEL OF EVIDENCE: Prognostic Level IV.

Discrepancy between true ankle dorsiflexion and gait kinematics and its association with severity of planovalgus foot deformity.

BACKGROUND: In planovalgus deformity with triceps contracture, a midfoot break happens, and ankle dorsiflexion (ADF) occurs at the mid-tarsal joint during gait. Results of standard 3D gait analysis may misinterpret the true ankle dorsiflexion because it recognizes the entire foot as a single rigid segment. We performed this study to investigate whether the severity of planovalgus deformity is associated with the discrepancy between the value of ADF evaluated by physical examination and 3-dimensional (3D) gait analysis. In addition, we aimed to identify the radiographic parameters associated with this discrepancy and their relationships. METHODS: Consecutive 40 patients with 65 limbs (mean age, 11.7 ± 5.5 years) with planovalgus foot deformity and triceps surae contracture were included. All patients underwent 3D gait analysis, and weightbearing anteroposterior (AP) and lateral (LAT) foot radiographs. ADF with knee extension was measured using a goniometer with the patient's foot in an inverted position. RESULTS: Twenty-one limbs underwent operation for planovalgus foot deformity, and 56 limbs underwent operation for equinus deformity. The difference between ADF on physical examination and ADF at initial contact on gait analysis was 17.5 ± 8.4°. Differences between ADF on physical examination and ADF at initial contact on gait analysis were significantly associated with the LAT talus-first metatarsal angle (p = 0.008) and calcaneal pitch angle (p = 0.006), but not associated with the AP talus-first metatarsal angle (p = 0.113), talonavicular coverage angle (p = 0.190), talocalcaneal angle (p = 0.946), and naviculocuboid overlap (p = 0.136). CONCLUSION: The discrepancy between ADF on physical examination and 3D gait analysis was associated with the severity of planovalgus deformity, which was evaluated on weightbearing LAT foot radiographs. Therefore, physicians should be cautious about interpreting results from 3D gait analysis and perform a careful physical examination to assess the degree of equinus deformity in patients with planovalgus foot deformity.

Aggravation of Ankle Varus Incongruency Following Total Knee Replacement Correcting ≥10° of Genu Varum Deformity: A Radiographic Assessment.

BACKGROUND: This study aimed to investigate the change in ankle varus incongruencies following total knee replacement (TKR) in patients with preoperative genu varum deformity of ≥10°. METHODS: The study cohort was composed of patients who underwent TKR in a single institution for knee osteoarthritis with preoperative genu varum deformity of ≥10° and concomitant varus ankle incongruencies. Eight radiographic measurements were evaluated preoperatively and postoperatively: mechanical tibiofemoral angle, mechanical lateral distal femoral angle, medial proximal tibial angle, lateral distal tibial angle, tibial plafond inclination, talar inclination, tibiotalar tilt angle (TTTA), and tibia-mechanical axis angle. Of these, TTTA represented the quantitative degree of ankle joint incongruency. RESULTS: A total of 110 patients (male = 2; female = 108) were included in the analysis. The mean patient age was 68.9 (standard deviation [SD] 7.2) years at the time of TKR. All radiographic measurements showed significant changes postoperatively, representing the appropriate correction of genu varum deformity and restoration of the mechanical axis. Nineteen patients (17.3%) showed postoperative decrease in TTTA, 2 (1.8%) remained the same, and 89 (80.9%) showed increase. Overall, mean preoperative and postoperative TTTA were 3.3° (SD 2.2°) and 4.7° (SD 2.9°), respectively (P < .001), representing the aggravation of varus ankle incongruencies. CONCLUSION: Varus ankle incongruencies showed aggravation following TKR despite correction of genu varum deformity and restoration of the mechanical axis. This could be an important cause of postoperative increase or development of ankle pain following TKR. Therefore, patients with preoperative varus ankle incongruencies need to be warned of possible aggravation of ankle symptoms and be evaluated before TKR. LEVEL OF EVIDENCE: Prognostic level III.

Development and Validation of a Mobile Application for Measuring Femoral Anteversion in Patients With Cerebral Palsy.

BACKGROUND: Computed tomography (CT) provides benefits for 3-dimensional (3D) visualization of femur deformities. However, the potential adverse effects of radiation exposure have become a concern. Consequently, a biplanar imaging system EOS has been proposed to enable reconstruction of the 3D model of the femur. However, this system requires a calibrated apparatus, the cost of which is high, and the area occupied by it is substantial. The purpose of this study was to develop a mobile application that included a new method of 3D reconstruction of the femur from conventional radiographic images and to evaluate the validity and reliability of mobile the application when measuring femoral anteversion. METHODS: The statistical shape model, graph-cut algorithm, and iterative Perspective-n-Point algorithm were utilized to develop the application. The anteroposterior and lateral images of a femur can be input using the embedded camera or by file transfer, and the touch interface aids accurate contouring of the femur. Regarding validation, the CT scans and conventional radiographic images of 36 patients with cerebral palsy were used. To evaluate concurrent validity, the femoral anteversion measurements on the images reconstructed from the mobile application were compared with those from the 3D CT images. Three clinicians assessed interobserver reliability. RESULTS: The mobile application, which reconstructs the 3D image from conventional radiographs, was successfully developed. Regarding concurrent validity, the correlation coefficient between femoral anteversion measured using 3D CT and the mobile application was 0.968 (P<0.001). In terms of interobserver reliability, the intraclass correlation coefficient among the 3 clinicians was 0.953. CONCLUSIONS: The measurement of femoral anteversion with the mobile application showed excellent concurrent validity and reliability in patients with cerebral palsy. The proposed mobile application can be used with conventional radiographs and does not require additional apparatus. It can be used as a convenient technique in hospitals that cannot afford a CT machine or an EOS system. LEVEL OF EVIDENCE: Level III-diagnostic.

Overgrowth of the lower limb after treatment of developmental dysplasia of the hip: incidence and risk factors in 101 children with a mean follow-up of 15 years.

Background and purpose - There are few studies on overgrowth of the affected limb after treatment of developmental dysplasia of the hip (DDH). We investigated the incidence of overgrowth and its risk factors in DDH patients.Patients and methods - 101 patients were included in this study. Overgrowth was defined by 2 criteria: when the height of the femoral head of the affected side was higher than that of the contralateral side by more than 10 mm, or by more than 15 mm. The potential risk factors of distinct overgrowth were retrospectively examined using multivariable analysis.Results - When overgrowth was defined as femoral head height difference (FHHD) > 10 mm, its incidence was 44%, and only femoral osteotomy was identified as a significant risk factor with a relative risk (RR) of 1.6 (95% confidence interval [CI] 1.0-2.5). When overgrowth was defined as FHHD > 15 mm, its incidence was 23%, and femoral osteotomy was identified as the only significant risk factor with an RR of 2.3 (CI 1.2-4.5). Overgrowth developed more frequently in patients who underwent femoral osteotomy at the age of 2 to 4 years (87%) than in the others (46%) (p = 0.04).Interpretation - Overgrowth of the affected limb is common in DDH patients. Patients who underwent femoral osteotomy, especially at the age of 2 to 4 years, may require careful follow-up because of the substantial risk for overgrowth.

Radiographic changes of the mid-tarsal joint after calcaneal lengthening for planovalgus foot deformity.

BACKGROUND: This study evaluate the radiographic changes in the mid-tarsal joint, including the calcaneocuboid and talonavicular (TN) joints after calcaneal lengthening for planovalgus deformity in children. METHODS: This study included 38 patients (68 feet) who underwent calcaneal lengthening for planovalgus deformity. Radiographic osteoarthritic changes at the CC or TN joint were defined as modified Kellgren-Lawrence grade of ≥1. RESULTS: Among the 68 feet, 31 feet (45.6%) showed radiographic osteoarthritic changes at the CC joint and 20 (29.4%) showed changes at the TN joint. Risk of radiographic osteoarthritic changes at the CC joint was associated with increased age at surgery (OR = 1.2, p = 0.038). Risk of radiographic osteoarthritic changes at the TN joint was associated with increased age at surgery (OR = 2.2; p = 0.002), preoperative AP talus-1st metatarsal angle (OR = 1.1; p = 0.044), and degree of CC subluxation (OR = 2.1; p = 0.007). CONCLUSIONS: Surgeons should consider the risk factors in the surgical correction of planovalgus deformity to prevent mid-tarsal arthritis.

Effects of soft tissue surgery on transverse kinematics in patients with cerebral palsy.

BACKGROUND: Gait disturbances, including flexed knee gait, stiff knee gait, and tip-toeing gait, are common in patients with cerebral palsy (CP). There has been no reports regarding kinematic changes in the transverse plane after soft tissue surgeries, such as distal hamstring lengthening (DHL), rectus femoris transfer (RFT), and tendo-Achilles lengthening (TAL). This study aimed to evaluate changes in the transverse plane after soft tissue surgery in patients with CP by assessing the effects of the DHL, RFT, and TAL. METHODS: The study enrolled 156 consecutive patients (mean age, 8.4 years; range, 4.4 to 20.9), representing 213 operated limbs, who underwent soft tissue surgery including DHL with semitendinosus transfer, RFT, and TAL. All patients were assessed by preoperative and 1-year postoperative three-dimensional gait analysis. Changes in transverse plane kinematics after soft tissue surgery and affecting factors were analyzed. RESULTS: Sagittal kinematics including knee flexion at initial contact, ankle dorsiflexion at initial contact, and mean ankle dorsiflexion in the stance phase were significantly improved after single event multilevel surgery (all p < 0.001). Transverse kinematics, including mean tibial rotation and foot progression angle, were significantly improved to a more external angle after soft tissue surgeries (- 2.9°, p = 0.004 and - 9.5°, p < 0.001). The mean hip rotation was significantly improved to a more external angle by RFT (- 4.7°, p = 0.010) and the foot progression angle was significantly improved to a more external angle by TAL (- 3.9°, p = 0.028). CONCLUSIONS: This study found that the transverse kinematics were improved to a more external angle after soft tissue surgery in patients with CP. Therefore, clinicians should consider that soft tissue surgery can affect the transverse plane kinematics in patients with CP. To confirm our findings, further research regarding the natural history of femoral and tibial torsion in children with CP is needed.

Physeal and Subphyseal Distraction Osteogenesis in Atrophic-type Congenital Pseudarthrosis of the Tibia: Efficacy and Safety.

PURPOSE: To examine the efficacy, safety, and clinical outcomes of distraction osteogenesis through the physis (PDO) or through subphyseal osteotomy (SPDO) in patients with atrophic-type congenital pseudarthrosis of tibia with proximal tibial dysplasia. METHODS: To validate the efficacy and safety of PDO and SPDO, radiographic and clinical parameters were compared between 5 patients who underwent proximal tibial metaphyseal or metadiaphyseal lengthening as a control (group 1) and 7 patients who underwent PDO or SPDO (group 2). Postoperative complication was also compared between the groups. RESULTS: A significant difference in terms of healing index (group 1, 83.3±24.7 d/cm; group 2, 35.0±11.1 d/cm; P=0.001) and percentage increase (11.0%±3.7% vs. 23.1%±10.5%, P=0.034) was observed between the 2 groups. According to the Paley classification, group 1 included 1 "problems" case and 3 "obstacles" cases, whereas group 2 included 2 "problems" cases and 1 "obstacles" case. According to the Lascombes classification, group 1 included 2 grade IIIb cases and 3 grade IV cases, whereas group 2 included 6 grade I cases and 1 grade IIa case. Severe complications were significantly higher in group 1 compared with the group 2 (P=0.007). CONCLUSIONS: This study demonstrated that PDO or SPDO can be effectively and safely performed for tibial lengthening in atrophic-type congenital pseudarthrosis of tibia patients with proximal tibial dysplasia. LEVEL OF EVIDENCE: Level III.