Comparison of surgical outcomes between bioabsorbable and metal screw fixation for distal tibial physeal fracture in children and adolescent.

PURPOSE: This study aimed to compare the surgical outcomes between bioabsorbable and metal screw fixation for distal tibial physeal fracture in children and adolescents, radiographically and clinically. METHODS: This study included consecutive 67 children and adolescents who underwent open reduction and internal fixation using metal or bioabsorbable screws for the distal tibia physeal fracture. All patients underwent preoperative radiographs, three-dimensional computed tomography scans, and postoperative follow-up teleradiogram. Patients were divided into metal (N = 40) and bioabsorbable groups (N = 27). We compared the surgical outcomes between the two groups in terms of clinical and radiographic outcomes, length of hospital stays, and medical cost. RESULTS: Follow-up duration were significantly longer in the metal group than that in the bioabsorbable group. There was no significant difference in the incidence of growth arrest after surgery and the scores of the Oxford Ankle and Foot Questionnaire between the two groups. However, the total hospital stay was significantly longer in the metal group (5.2 ± 4.8 days) compared to the bioabsorbable group (2.6 ± 0.5 days). Medical costs were significantly higher in the bioabsorbable group than in the metal group with a difference of 397 US dollars. CONCLUSIONS: The use of bioabsorbable screws exhibited therapeutic effects equivalent to that of metal screws for pediatric distal tibia physeal fractures regarding clinical and radiological outcomes. Moreover, it had the advantage of avoiding the need for repeated general anesthesia and secondary operation for implant removal. Therefore, the use of bioabsorbable screws may be a favourable surgical option for treating pediatric fractures.

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.

Lower extremity deformity and its risk factors in patients with solitary osteochondromas.

BACKGROUND: This study aimed to demonstrate the occurrence of lower extremity deformities and their risk factors in patients with solitary osteochondromas. METHODS: We retrospectively reviewed consecutive patients with solitary osteochondromas around the knee. The laterality (left or right), involved bone (femur or tibia), tumor type (pedunculated or sessile), and direction (medial or lateral) were examined. The whole limb length (WLL), mechanical lateral distal femoral angle (mLDFA), and medial proximal tibial angle (MPTA) were measured using teleroentgenogram. Lower limb deformity was defined as a difference of more than 5° in mLDFA or MPTA in both lower extremities or a difference in WLL of more than 1 cm. Patients were divided into two groups, with deformity and without deformity. RESULTS: Lower extremity deformities were observed in 8 of 83 patients. Significant difference in the type of osteochondroma (p = 0.004) between the groups was observed. Differences in sex, age, laterality, involved bone, direction, and distance from the physis to the osteochondroma between groups were not statistically significant. The sessile type of osteochondroma was a risk factor for lower limb deformity with an odds ratio of 24.0 according to Firth's logistic regression analysis. CONCLUSION: In our cohort with solitary osteochondroma, lower limb deformities were observed in 8 (9.6%) out of the 83 patients and these were significantly associated with sessile-type tumors. Therefore, patients with sessile-type solitary osteochondroma around the knee require careful surveillance of lower limb alignment with whole leg teleroentgenogram.

Transcultural adaptation and validation of a Korea version of Pedi-IKDC questionnaire.

BACKGROUND: This study aimed to translate and transculturally adapt the English version of the Pedi-IKDC questionnaire into Korean and evaluate the psychometric properties of the Korean Pedi-IKDC questionnaire in terms of internal consistency, feasibility (floor and ceiling effect), construct validity, test-retest reliability, and factor analysis. METHODS: The original English version of the Pedi-IKDC questionnaire was translated and transculturally adapted into Korean according to established guidelines. A total of 239 patients aged 7-18 years who visited the hospital because of knee pain or discomfort were considered eligible for the study. These patients completed the Korean version of the Pedi-IKDC and Pediatric Quality of Life questionnaires (PedsQL). The correlation between the PedsQL and Pedi-IKDC questionnaires was assessed to confirm the validity of the questionnaire. To verify the validity of the Korean Pedi-IKDC questionnaire, internal consistency, feasibility, test-retest reliability, and construct validity were evaluated, and a factor analysis was performed. RESULTS: Internal consistency was found to be satisfactory in all subscales (Cronbach's alpha ≥ 0.7). The test-retest reliability was satisfactorily high for all subscales (Intraclass correlation coefficient: 0.81-0.84). A high correlation was observed between the total Pedi-IKDC score and the score on the physical-health subscale of child version of the PedsQL (Correlation coefficients: 0.720). There were no floor effects in all subscales, but ceiling effects were observed in four questions. Additionally, factor analysis suggested that the questionnaire could be divided into two subscales. CONCLUSION: The Korean version of the Pedi-IKDC questionnaire was successfully translated and transculturally adapted according to the established guidelines. The Korean Pedi-IKDC questionnaire has been proven reliable and valid.

Validity of measurement of femoral anteversion angle using FEMORA® software based on two-dimensional radiographic imaging examination femur in children with cerebral palsy in Indonesia.

Introduction: Children with spastic cerebral palsy (CP) often show an increase in femoral anteversion angle (FAA). Computed tomography (CT) scan is the main modality for evaluating FAA in these patients, however, due to significant radiation exposure, it carries a high carcinogenic risk. FEMORA® software is expected to be able to accurately assess FAA even with conventional X-ray images that only require low radiation exposure. However, its validity has not been tested in various populations or CT devices. This study aimed to validate the FEMORA® software by comparing it to CT scans done on an Indonesian population. Material and methods: All spastic CP patients of the outpatient clinic at Dr. Soetomo Hospital between March and November 2022, were included. The FEMORA® Software evaluation was performed by three examiners. The calculation results were averaged and compared with those of the CT scan. Intraclass correlation coefficient (ICC), reliability, and correlation were be assessed. Results: There were 36 patients included in this study. Most were female (n = 22; 61,1 %) and the average age was 7,28 years old. Interobserver preoperative analysis using ICC showed good outcomes (p = 0.918; 95 % CI, 0.858-0.955). FAA measurement results using FEMORA® and CT scans were 41,71 ± 12,90 and 32,68 ± 11,85, respectively. Correlation coefficient between the two values is 0.634 (p < 0.001). Conclusion: FEMORA® software demonstrates a good and significant correlation with FAA measurement using CT scan.

Comparison of Functional and Cosmetic Outcomes According to Fracture Level in Gartland Type III Pediatric Supracondylar Humerus Fractures.

Background: Supracondylar humerus (SCH) fractures in children have been traditionally categorized according to the Wilkins-modified Gartland classification scheme, which is solely based on the degree of displacement. As this classification does not consider fracture patterns in the coronal or sagittal plane, the relationship between the fracture pattern and prognosis in SCH fractures remains unclear. Therefore, the purpose of this study was to evaluate the relationship between the fracture level and prognosis of pediatric SCH fractures. Methods: Medical records and radiographs of 786 patients with SCH fractures who underwent surgical treatment between March 2004 and December 2017 were reviewed. A total of 192 patients were included in this study. Anteroposterior elbow radiographs taken at the time of injury were evaluated to obtain the level of fracture. Functional outcomes were evaluated based on modified Flynn grading at the last follow-up. Results: Of 192 patients included in this study, 24 (12.1%), 148 (74.8%), and 20 (10.1%) had fractures in zone 1 (metaphyseal-diaphyseal area), zone 2 (between zones 1 and 3), and zone 3 (metaphyseal-epiphyseal area), respectively. There were significant differences in age at the time of injury (p = 0.011), direction of fracture displacement (p = 0.014), and loss of carrying angle (p < 0.001) between fractures in zone 3 and those in zone 1 or zone 2. Zone 3 fractures and classic zone 2 fractures also showed significant difference in outcomes, with zone 3 fractures having more unsatisfactory outcome than classic zone 2 fractures (p = 0.049). Conclusions: For SCH fractures, varus deformity of the elbow was more common in zone 3 (metaphyseal-epiphyseal area) than in the other zones. Thus, pediatric orthopedic surgeons should be mindful of the possibility of cubitus varus deformity when treating SCH fractures in zone 3. A thorough postoperative follow-up is required.

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.

Normative Values of Tibial Tubercle-Trochlear Groove Distance and Tibial Tubercle-Posterior Cruciate Ligament Distance in Children.

BACKGROUND: Patellar instability is a common knee pathology in skeletally immature patients. In skeletally mature populations, a tibial tubercle-trochlear groove (TT-TG) distance of ≥20 mm is generally considered a pathological value. However, as pediatric patients grow and as the TT-TG distance varies with age, applying the same cutoff value as adult patients to them is unreasonable. PURPOSE/HYPOTHESIS: This study aimed to analyze the normative values of the TT-TG and tibial tubercle-posterior cruciate ligament (TT-PCL) distances in children with no patellofemoral instability and to propose the cutoff value of the TT-TG and TT-PCL distances predictive of increased risk of patellofemoral instability in pediatric patients. We hypothesized that the TT-TG and TT-PCL distances increase with age in children and adolescents. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Magnetic resonance imaging scans of the knee were collected from the patellar instability group and the control group. The TT-TG and TT-PCL distances were measured. The normalized values of the TT-TG and TT-PCL distances were calculated by dividing them by the femoral width. Segmented analysis with 1 breakpoint was performed for both the TT-TG and the TT-PCL distances. The optimal cutoff values of the TT-TG and TT-PCL distances were calculated by maximizing the sum of the sensitivity and specificity. RESULTS: A total of 87 patients had patellar instability, and 509 patients did not. The median values of TT-TG and TT-PCL distances in the control group (8.18 mm and 19.48 mm, respectively) were significantly smaller than those in the instability group (16.10 mm and 24.41 mm, respectively). For those aged <15 years, the TT-TG distance significantly increased by 0.39 mm as the age increased by 1 year. The TT-PCL distance increased by 1.14 mm/year until the age of 11 years. In our cohort, the cutoff value of the TT-TG distance of 14.90 mm yielded 66% sensitivity and 81.9% specificity for predicting an increased risk of patellar instability. The cutoff value of the TT-PCL distance of 23.68 mm yielded 63.9% sensitivity and 65.3% specificity for predicting an increased risk of patellar instability. CONCLUSION: In our cohort of 596 participants, we have documented the normative values of the TT-TG and TT-PCL distances in children aged <20 years. During the surgery for patellar instability in pediatric patients, orthopaedic surgeons should consider the normative values of the TT-TG and TT-PCL distances according to age to determine which patients need distal realignment surgery.

Epidemiology and demographics of slipped capital femoral epiphysis in South Korea: A nationwide cohort study.

BACKGROUND: This study investigated the epidemiology and demographics of slipped capital femoral epiphysis (SCFE) in South Korea using a nationwide population-based database. METHODS: Information on sex, age at onset, endocrine comorbidities, history of growth hormone therapy, history of radiation therapy, surgical methods, and complications in patients with SCFE aged younger than 18 years between 2007 and 2019 was retrieved from the Korean Health Insurance Review and Assessment Service database. RESULTS: Data were available for 586 children (429 boys, 157 girls). The average age at onset was 11.1 ± 1.8 years (boys, 11.3 ± 1.9; girls, 10.6 ± 1.5). Five hundred and twenty-nine (90.3%) patients were aged 9-14 years; the incidence rate in this age group was 6.0/100,000 (95% confidence interval, 5.5-6.6) and significantly higher in boys (8.4 vs 3.5, p<0.001). There was a significant increase in the annual incidence rate from 0.96/100,000 in 2009 to 2.05/100,000 in 2019 (p = 0.006). Ninety-five patients (16.2%) had endocrine comorbidities or a history of hormone/radiation therapy. Osteotomy and internal fixation were performed in 59 patients and in situ pinning in 527. Seventy-six patients developed postoperative complications. CONCLUSION: The annual incidence rate of SCFE in South Korea has increased since 2009.

National Trends in Pediatric CT Scans in South Korea: A Nationwide Cohort Study.

Purpose: This study evaluated the rates and annual trends of pediatric CT scans in South Korea using a nationwide population-based database. Materials and Methods: Data regarding pediatric CT scan usage between 2012 and 2017 were retrieved from the health insurance review and assessment service. Data on the age, sex, diagnosis, and the anatomical area of involved patients were also extracted. Results: A total of 576376 CT examinations were performed among 58527528 children aged below 18 years (9.8 scans/1000 children), and the number of CT examinations per 1000 children was noted to have increased by 23.2% from 9.0 in 2012 to 11.0 in 2017. Specifically, the number of CT examinations increased by 32.9% for the 6-12 years of age group (7.4/1000 to 9.8/1000) and by 34.0% for the 13-18 years of age group (11.4/1000 to 15.3/1000). Moreover, majority of the CT scans were limited to the head (39.1%), followed by the extremities (32.5%) and the abdomen (13.7%). Notably, the number of extremity CT scans increased by 83.6% (2.3/1000 to 4.2/1000), and its proportion as compared to other scans increased from 25.3% to 37.7%. Conclusion: CT scans in the pediatric population increased continuously from 2012 to 2017 at an annual rate of 4.4%. Therefore, physicians should balance the benefits of CT with its potential harms from associated radiation exposure in pediatric patients.

Development and Validation of a Mobile Application for Measuring Tibial Torsion.

BACKGROUND: Tibial torsion lacks a single and reliable method for its measurement. While physical examination, computed tomography (CT), and EOS imaging are used complementarily, three-dimensional (3D) CT is the most widely used method for intuitive documentation and visualization. However, concern regarding the associated radiation hazard limits its use in the evaluation of pediatric patients. Moreover, EOS machines are too expensive and too large to be placed in every clinic requiring the measurement of tibial torsion. Therefore, a new method for 3D reconstruction is needed. In the present study, we tested the validity and reliability of a novel reconstruction tool for the lower leg. METHODS: A statistical shape model and Laplacian constraint were adopted for the development of a new reconstruction tool for measuring tibial torsion. Tibial torsion measurements based on a 3D reconstruction application and CT images for 36 patients were evaluated for intraobserver and interobserver reliability. Tibial torsion measurements for 75 patients were compared for validation. RESULTS: A 3D reconstruction system for the lower leg was developed as a mobile application and was installed in a portable device for easy access in the clinical setting. In terms of interobserver reliability, the intraclass correlation coefficient among 3 clinicians was 0.896 (95% confidence interval [CI], 0.828 to 0.941). The correlation coefficient between tibial torsion measured with use of 3D CT and that measured with the mobile application was 0.865 (p < 0.001). CONCLUSIONS: The mobile application showed excellent reliability and validity for measuring tibial torsion. Concurrent utilization with mobile application for the femur allows visualization of the rotational profile of the leg without the need for CT or EOS. LEVEL OF EVIDENCE: Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.

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.

Usefulness of Bone SPECT/CT for Predicting Avascular Necrosis of the Femoral Head in Children with Slipped Capital Femoral Epiphysis or Femoral Neck Fracture.

OBJECTIVE: This study aimed to investigate the usefulness of bone single-positron emission tomography/computed tomography (SPECT/CT) of the hip in predicting the later occurrence of avascular necrosis (AVN) after slipped capital femoral epiphysis (SCFE) or femoral neck fracture in pediatric patients. The quantitative parameters of SPECT/CT useful in predicting AVN were identified. MATERIALS AND METHODS: Twenty-one (male:female, 10:11) consecutive patients aged < 18 years (mean age ± standard deviation [SD], 11.0 ± 2.7 years) who underwent surgery for SCFE or femoral neck fracture and postoperative bone SPECT/CT were included. The maximum standardized uptake value (SUV), mean SUV, and minimum SUV of the femoral head were measured. The ratios of the maximum SUV, mean SUV, and minimum SUV of the affected femoral head to the contralateral side were determined. Patients were followed up for > 1 year after the surgery. The SPECT/CT parameters were compared between patients who developed AVN and those who did not. The accuracy of SPECT/CT parameters for predicting AVN was assessed. RESULTS: Six patients developed AVN. There was a significant difference in the ratio of the mean SUV among patients who developed AVN (mean ± SD, 0.8 ± 0.3) and those who did not (1.1 ± 0.2, p = 0.018). However, there were no significant differences in the ratios of the maximum and minimum SUV between the groups (all p = 0.205). For the maximum, mean, and minimum SUVs, no significant differences were observed between the groups (p = 0.519, 0.733, and 0.470, respectively). The cutoff mean SUV ratio of 0.87 yielded a 66.7% sensitivity and 93.2% specificity for predicting AVN. CONCLUSION: Quantitative bone SPECT/CT is useful for evaluating femoral head viability in pediatric patients with SCFE or femoral neck fractures. Clinicians should consider the high possibility of later AVN development in patients with a decreased mean SUV ratio.

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.

What happens to the patella height in patients with cerebral palsy as they age.

We aimed to investigate the progression of patella alta (PA) in patients with cerebral palsy (CP) using the Koshino-Sugimoto (KS) index and assess associated risk factors. Participants in our retrospective study met the following inclusion criteria: patients with CP who visited our institute from May 2003 to December 2019, were ≤18 years of age, were followed up for >2 years and had at least two lateral knee radiographs. KS indices of both knee radiographs were measured for each patient. A linear mixed model was implemented. Our participants included 222 CP patients. KS index values were measured via 652 knee radiographs. Reference values of the KS index for those between 4 and 18 years of age were determined according to Gross Motor Function Classification System (GMFCS) levels. In all GMFCS levels, the KS index decreased with patients' ages (P < 0.0001). In groups where the KS index increased, GMFCS levels IV (P = 0.0045) and V (P = 0.0040) were statistically significant. Change in the KS index values indicates that PA improves as patients age within all GMFCS levels. However, in patients with GMFCS levels of IV and V, progressive PA is expected.

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.