Environmental factors associated with incidence of developmental dysplasia of the hip: a systematic review and meta-analysis.

BACKGROUND: Established associated factors for DDH include female sex, breech presentation, family history, congenital malformations, oligohydramnios, and maternal hyperthyroidism. However, evidence for environmental factors that may contribute to DDH is limited and inconsistent. METHODS: A systematic review of medical literature was conducted to collect data on environmental factors, including latitude, longitude, average yearly precipitation, average yearly temperature, minimum monthly temperature, and maximum monthly temperature, from all institutions that published articles on DDH. Univariate linear regression analysis was used to examine the correlation between environmental factors and DDH incidence, while multiple regression analysis was conducted to identify significant associated factors for DDH incidence. RESULTS: Data from a total of 93 unique manuscripts were analyzed, revealing a significant negative correlation between DDH incidence and temperature, including average yearly temperature (r = -0.27, p = 0.008), minimum monthly temperature (r = -0.28, p = 0.006), and maximum monthly temperature (r = -0.23, p = 0.029). Additionally, there was a significant positive correlation between DDH incidence and latitude (r = 0.27, p = 0.009), and a significant negative correlation between DDH incidence and average yearly precipitation (r = -0.29, p = 0.004). In the final multiple regression analysis, temperature, including average yearly temperature, minimum monthly temperature, and maximum monthly temperature, were identified as significant associated factors for DDH incidence. CONCLUSION: The findings of this study suggest an association between cold weather and DDH incidence. Further research should explore the link between cold weather and DDH incidence, offering insights into potential interventions for cold climates.

Soft Tissue Releases With Simultaneous Guided Growth Decrease Risk of Spastic Hip Displacement Recurrence.

BACKGROUND: Soft tissue release (STR) is an established treatment for spastic hip displacement, but recurrence of hip displacement is not uncommon. This study aims to (1) evaluate the recurrence of hip displacement after STR, (2) define associated factors of recurrence, and (3) elucidate the effects of guided growth on hip displacement recurrence. METHODS: The study subjects included 66 individuals with spastic cerebral palsy treated by STR with or without guided growth for hip displacement. The treatment goal was the maintenance of migration percentage (MP) to <40%. Recurrence was defined by a rebound of the MP by 5% or more after the first postoperative year. Children with recurrence were compared with those without recurrence using the Mann-Whitney U test and the χ 2 test. The risk factors for recurrence were evaluated using multiple logistic regression analysis. RESULTS: Nineteen individuals (29%) had a recurrence of hip displacement after the first postoperative year. They sustained a 2-fold increase in the rate of treatment failure ( P < 0.001) and reoperation ( P = 0.04). Age, sex, motor function, and preoperative radiographic parameters were comparable between individuals with and without recurrence. The use of guided growth was associated with less risk of recurrence than without (5% and 39%, respectively, odds ratio = 0.01 to 0.45, respectively) despite the similar risk of failure (35% and 48%, respectively, odds ratio = 0.15 to 4.82). CONCLUSIONS: Recurrence of the MP >5% after the first postoperative year is an important early indicator for failure to control MP to <40% and reoperation. Guided growth not only decreases coxa valga but also reduces the risk of recurrent hip displacement after STR. LEVEL OF EVIDENCE: Level III; case-control study.

Prediction of Surgical Outcomes of Radial Polydactyly From the Wassel-Flatt Type and Symmetry of Duplication.

BACKGROUND: The Wassel classification is commonly used for cases of radial polydactyly but has not been used to predict surgical outcomes. This study aimed to investigate the predictive factors of surgical outcomes using the Wassel type and symmetry of duplication. METHODS: Forty-five patients with 47 radial polydactylies were reviewed using the Japanese Society for Surgery of the Hand (JSSH) scores 4.6 years after minor thumb excision and reconstructive surgery. The symmetry index was defined as the metaphyseal width ratio of the minor thumb to the dominant thumb. The relationships between the JSSH scores and operation age, sex, side, follow-up duration, Wassel type, symmetric index, divergent angle, and joint angulation were analyzed by linear regression. RESULTS: The mean JSSH score of the 47 thumbs was 18.3 points (range, 15-20). Five thumbs had fair or poor outcomes (scores <17), all of which were Wassel type IV. The hypoplastic type had a better JSSH score (19.4) than other Wassel types. The symmetric index had a negative relationship with JSSH scores, especially for Wassel type IV (r=-0.68, P =0.001). Linear regression revealed that the symmetric index was the only independent factor significantly associated with JSSH scores among Wassel type IV polydactylies ( P <0.05). The receiver operating characteristic curve suggested a symmetric index <0.74 could predict good or excellent outcomes. CONCLUSION: The symmetry of the 2 duplicated thumbs is an important factor for surgical outcomes. The Wassel type IV polydactylies with a symmetric index >0.74 are at greater risk of fair or poor outcomes after excision and reconstruction, and further studies are warranted to confirm whether the Bilhaut-Cloquet procedure is a good choice. LEVEL OF EVIDENCE: Level IV-Case-control study.

Distal Femur Growth Modification Surgery Is Associated With Higher Surgical Wound Complication Rate.

BACKGROUND: Orthopaedic wound complications are often associated with extensive surgeries and patient medical conditions. However, we noticed wound complications in minor growth modification surgeries in children, including guided growth and epiphysiodesis. Herein, we report the complication rate and risk factors associated with pediatric growth modification surgeries. METHODS: This retrospective study reviewed surgical wound complications in 622 pediatric orthopaedic patients who underwent growth modification surgeries (418 children) or osteotomies (204 children) in the lower extremities in a single center between 2007 and 2019. The grades II and III complications assessed using the modified Clavien-Dindo-Sink complication classification system were compared between growth modification and osteotomy. Risk factors for complications, including the type of surgery, age, body mass index, neuromuscular disease, operation time, surgical sites per patient, surgical location, and implant types, were analyzed using the logistic regression. RESULTS: The complication rate was 6.9% per patient and 3.6% per surgical site (29 sites in 29 patients comprising 21 grade II and 8 grade III) in the growth modification group, which was >1.0% per patient and 0.6% per site in the osteotomy group (2 sites in 2 patients comprising 2 grade III infections; P =0.001). Among 418 patients with 797 surgical sites in the growth modification group, wound complications were associated with surgical location (5.2% at distal femur vs. 1.0% at proximal tibia, P =0.002) and implant type (0.5% using transphyseal screw vs. 4.3-10.5% using plates or staples, P =0.011). CONCLUSION: Surgical wound complication was associated with growth modification surgeries using plates or staples at the distal femur. Our results alert orthopaedic surgeons to this minor but unneglectable problem. Transphyseal screws may be the implant of choice for guided growth and epiphysiodesis at the distal femur in older children, considering the lower risks of wound complication. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Genu Valgum After Distal Femur Extension Osteotomy in Children With Cerebral Palsy.

BACKGROUND: Distal femur extension osteotomy (DFEO) is a common treatment for knee flexion contracture and crouch gait in patients with cerebral palsy (CP), but skeletally immature patients tend to develop genu valgum deformities after DFEO. This study aimed to report the tendency of valgus changes after DFEO and determine the risk factors for subsequent surgery for excessive genu valgum. METHODS: This retrospective case-control study included 25 children with CP who underwent DFEO in 44 limbs for knee flexion contractures ≥15 degrees at a mean age of 11.0 years. Radiologic measurements included the anatomic lateral distal femoral angle (aLDFA), anatomic tibiofemoral angle (aTFA), medial proximal tibia angle, and plate-condyle angle, postoperatively and at the latest follow-up. Age, sex, preoperative knee flexion contracture angle, Gross Motor Function Classification System level, and radiographic measurements were compared between children with and without subsequent guided growth for genu valgum. RESULTS: A significant valgus change was observed at the distal femur in the first postoperative year (aLDFA from 83.6 to 80.1 degrees, P<0.001; aTFA from 176.1 to 172.5 degrees, P<0.01; plate-condylar angle from 5.3 to 9.5 degrees, P<0.001). Valgus changes occurred in 36 of the 44 limbs (82%) by an average of -4.6 degrees in the aLDFA, and subsequent guided growth was performed in 5 patients (20%). Guided growth for genu valgum was associated with a greater postoperative valgus angle (aLDFA: 78.0 vs. 84.9 degrees, P<0.01) but not with age, Gross Motor Function Classification System level, or preoperative flexion contracture. CONCLUSIONS: Distal metaphyseal osteotomies and distally placed angled plates near the physis are associated with valgus changes following growth. We recommend making a slight varus alignment during DFEO to compensate for subsequent valgus changes. LEVEL OF EVIDENCE: Level III-therapeutic, retrospective comparative study.

Development of Joint Activity Angle Measurement and Cloud Data Storage System.

In this study, we developed a range of motion sensing system (ROMSS) to simulate the function of the elbow joint, with errors less than 0.76 degrees and 0.87 degrees in static and dynamic verification by the swinging and angle recognition modules, respectively. In the simulation process, the É£ correlation coefficient of the Pearson difference between the ROMSS and the universal goniometer was 0.90, the standard deviations of the general goniometer measurements were between ±2 degrees and ±2.6 degrees, and the standard deviations between the ROMSS measurements were between ±0.5 degrees and ±1.6 degrees. With the ROMSS, a cloud database was also established; the data measured by the sensor could be uploaded to the cloud database in real-time to provide timely patient information for healthcare professionals. We also developed a mobile app for smartphones to enable patients and healthcare providers to easily trace the data in real-time. Historical data sets with joint activity angles could be retrieved to observe the progress or effectiveness of disease recovery so the quality of care could be properly assessed and maintained.

Application of Simulated Arms with Real-Time Pressure Monitor in Casting and Splinting by Physiological Sensors.

In the real condition, the small sensor found it difficult to detect the position of the pressure sore because of casting displacement clinically. The large sensor will detect the incorrect pressure value due to wrinkles without close to arm. Hence, we developed a simulated arm with physiological sensors combined with an APP and a cloud storage system to detect skin pressure in real time when applying a short arm cast or splint. The participants can apply a short arm cast or splint on the simulative arm and the pressure in the cast or splint could be immediately displaced on the mobile application. The difference of pressure values from six pressure detection points of the simulated arm between the intern and the attending physician with 20-year working experience were 22.8%, -7.3%, 25.0%, 8.6%, 38.2%, 49.6%, respectively. It showed that the difference of pressure values in two farthest points, such as radius stab and ulnar styloid, was maximal. The pressures on the skin surface of the short arm cast were within acceptable range. Doctors would obtain reliable reference data and instantly understand the tightness of the swathed cast which would enable them to adjust it at any time to avoid complications.

Development of a System for Real-Time Monitoring of Pressure, Temperature, and Humidity in Casts.

Cast fixation is a general clinical skill used for the treatment of fractures. However, it may cause many complications due to careless treatment procedures. Currently, swathing a cast for a patient can only be determined by a doctors' experience; however, this cannot be determined by the value of pressure, temperature, or humidity with objective and reliable equipment. When swathing a cast for a patient, the end result is often too tight or too loose. Hence, in this paper we developed a sensor for detecting pressure, temperature, and humidity, respectively. This could provide reliable reference cast data to help physicians to understand the tightness of cast swathing and to adjust the tightness of cast swathing instantly to alleviate a patient's complications caused by excessive pressure or overheating. In this paper, six pressure sensors and one temperature-humidity sensor are used to detect the pressure, temperature, and humidity in an arm swathed with a cast to confirm whether the tightness of the cast is fixing the fracture efficiently, while avoiding causing any damage by using excessive pressure. Currently, the variation in temperature and humidity can be detected by the inflammation of the wound, displaying secretions, and fever in the cast. Based on the experiments, the voltage and power conversion coefficients of the developed sensors could be compensated for by the nonlinear error of the sensor. The experimental results could be instantly displayed on a human interface, such as a smart mobile device. The average skin pressure in a swathed cast was 12.14 g and ranged from 5.0 g to 17.5 g. A few casts exceeded 37.50 g. The abnormal pressure of wrinkles produced during swathing a cast often ranged from 22.50 g to 38.75 g. This shows that cast wrinkles cause pressure on the skin. The pressure caused by cast wrinkles on bone protrusions ranged from 56.5 g to 84.4 g. Compared to other parts that lacked soft skin cushioning, the pressure of cast wrinkles that occurred in the ulna near the protrusion of the wrist bone increased averagely. The pressure error value was less than 2%, the temperature error was less than 1%, and the humidity error was less than 5%. Therefore, they were all in line with the specifications of commercially available products. The six pressure detection points and one temperature and humidity detection point in our newly designed system can accurately measure the pressure, temperature, and humidity inside the cast, and instantly display the corresponding information by mobile APP. Doctors receive reliable reference data and are instantly able to understand the tightness of the swathed cast and adjust it at any time to avoid complications caused by pressure or overheating due to excessive pressure.

Guided Growth of the Proximal Femur for Hip Displacement in Children With Cerebral Palsy.

BACKGROUND: Guided growth by 1 eccentric transphyseal screw has been used to correct lower limb deformities. Pilot animal studies showed encouraging results in producing varus deformity in the proximal femur. The purpose of this study was to report the preliminary results of guided growth surgery to treat spastic hip displacement. METHODS: This case series study included consecutive patients who received soft-tissue release and guided growth at the proximal femur from January 2004 to May 2012 with minimal 2-year follow-up. Surgical indications were children with spastic cerebral palsy aged 4 to 10 years, a gross motor function classification system level IV or V, and hip displacement on 1 or both sides. Study outcomes were Reimer's migration percentage (MP) and the head-shaft angle (HSA). RESULTS: Nine children with 13 spastic displaced hips received surgery at the age of 6.2 years and were followed up for a mean of 45.6 months. The mean MP improved significantly from 52.2% preoperatively to 45.8% at 3 months, 40.3% at 1 year, and 37.1% at 2 years after operation. HSA was unchanged in the first 3 months, and deceased from 173.3 to 166.4 degrees at 1 year (P<0.01) and to 162.7 degrees at 2 years postoperatively. The screw was usually backed out from the femoral epiphysis in the second postoperative year, and no radiologic bony bar or other surgical complications occurred. CONCLUSIONS: The immediate postoperative improvement of MP was the result of soft-tissue release. From postoperative 3 months to 2 years, the HSA was reduced by 10.6 degrees and the MP further improved by 8.7%. Less surgical dissection, faster recovery of motion, and less comorbidity than varus osteotomy make guided growth surgery a treatment option for coxa valga in spastic hip displacement in nonambulant cerebral palsy children. LEVEL OF EVIDENCE: Level IV-therapeutic, case series.

Determinants of Hip Displacement in Children With Cerebral Palsy.

BACKGROUND: Coxa valga and femoral anteversion often are seen in patients with spastic hip displacement and osteotomy is recommended. However, the relationship between femoral deformities and hip displacement has not been clearly defined and other factors, such as joint motion and posture, should be considered before recommending treatment. QUESTIONS: For children with cerebral palsy with Gross Motor Function Classification System Level IV or V, we questioned (1) whether hip abduction range correlates with hip displacement, (2) what the relationships are between proximal femoral deformities and hip displacement, and (3) whether the patient with a windblown posture has greater degrees of femoral anteversion? METHODS: We retrospectively studied 31 consecutive children with cerebral palsy with Level IV or V gross motor function who underwent three-dimensional CT for preoperative assessment of hip displacement between January 2010 and December 2013. Among the children, 23 had a windblown posture and eight had symmetric hip motion. Femoral anteversion and true neck-shaft angle were measured from the three-dimensional CT images. Migration percentage was the dependent variable we chose to study in relation to femoral anteversion, neck-shaft angle, maximal hip abduction, and hip flexion contracture, using correlations and multiple linear regressions. Using ANOVA and Scheffé's post hoc tests, we analyzed and compared the data of 23 abducted hips and 23 adducted hips in the 23 children with windblown posture and in 16 displaced hips in the eight children with symmetric hip abduction. RESULTS: Greater migration percentage was associated with less hip abduction range (r = -0.86; p < 0.001). Femoral anteversion had a weak correlation (r = 0.28; p < 0.05) to migration percentage, and the association became insignificant after considering hip abduction motion. Adducted windblown hips had greater femoral anteversion than the symmetric displaced hips and abducted windblown hips (46° vs 36° and 38°, respectively; p < 0.05). CONCLUSIONS: Our study results did not support a relationship between femoral deformities and hip displacement after considering gross motor function and hip abduction motion. Greater femoral anteversion was noted in the adducted hips of patients with windblown posture, and derotation osteotomy is especially recommended. LEVEL OF EVIDENCE: Level III, diagnostic study.

Surgical Outcomes of Developmental Dysplasia of the Hip With or Without Prior Failed Closed Reduction.

BACKGROUND: Osteonecrosis of the femoral head is a major complication in the treatment of developmental dysplasia of the hip (DDH). Redislocation and secondary surgeries were regarded as risk factors of osteonecrosis. This study aims to clarify whether prior failed closed reduction is a risk factor of osteonecrosis in subsequent surgery. METHODS: We retrospectively studied 124 patients treated by open reduction and pelvic osteotomy for unilateral DDH before 3 years old. Twenty-five patients had failed closed reduction before the surgery (secondary surgery group), and the other 99 patients had the same surgery as the first treatment (primary surgery group). Osteonecrosis was defined by broadening of femoral neck and fragmentation of epiphysis in the first 3 years after operation. The background data and rate of osteonecrosis were compared between the 2 groups using t test and χ2 test. RESULTS: Age at surgery and Tönnis grade were not significantly different between the 2 groups. Broadening of the femoral neck was observed in 63 of the 99 hips (63.6%) in the primary surgery group and 7 of the 25 hips (28.0%) in the secondary surgery group (P=0.001). Rate of epiphyseal fragmentation was 34% in primary surgery group and 24% in secondary surgery group (P=0.323). CONCLUSIONS: Soft tissue tension could be reduced by previous closed reduction, and redislocation would not carry a greater risk of osteonecrosis in the subsequent open reduction.

A prospective comparative study of pin site infection in pediatric supracondylar humeral fractures: daily pin care vs. no pin care.

INTRODUCTION: Pin site infection is a critical issue for patients' safety in skeletal fixation using percutaneous pins or wires. Closed reduction and percutaneous Kirschner wires fixation are the mainstay of treatment in pediatric supracondylar humeral fractures. Little information is available in the literature about the optimal regimen of pin site care in children. MATERIALS AND METHODS: We performed a prospective comparative study of 61 children with supracondylar humeral fractures between June 2011 and March 2013 after approval by the institutional review board. They were allocated into two groups of different postoperative pin site care methods by the emergency department arrival date and received fracture fixation within 24 h. Postoperatively, 30 children underwent pin site cleaning every day whereas the other 31 patients did not have the pin sites cleaned until the pins removal 4-6 weeks later. RESULTS: Demographic data were not significantly different between the two groups. The infection rate was significantly higher in patients who underwent daily pin site care (90.3 vs. 53.3 %, p = 0.001). Of the 144 pin sites, infection occurred at 42 (57.5 %) pin sites in the daily care group and at 19 (26.8 %) pin sites in the non-care group. The number of telephone consultations for postoperative care was significantly higher in the daily care group (1.0 vs. 0.27 call/case, p = 0.007). CONCLUSIONS: Daily pin site care was associated with a higher infection rate and greater stress in postoperative care that required more telephone consultations. The study results could not support daily pin site care. Careful observation of pin sites was recommended in the treatment of pediatric supracondylar humeral fractures.

Classification of radial polydactyly based on physical characteristics.

BACKGROUND: Previous classifications in polydactyly of the thumb were by the level of duplication on radiography. This study aimed to develop a practical algorithm based on physical characteristics for treatment guidelines. METHODS: The polydactylies were stratified using four physical characteristics: floating, symmetry, dominant side, and joint angulation/nail size. The algorithm identified the hypoplastic type and then stratified the polydactylies as symmetric and asymmetric. The asymmetric type was divided into ulnar dominant and radial dominant. The symmetric type was divided into adequate type and inadequate type. The prediction of treatments was studied retrospectively by the distribution of surgical procedures in 500 patients with 545 affected thumbs, by the new classification and the Wassel-Flatt classification. RESULTS: Of the 545 polydactylies, 78 (14.5%) were categorized as the hypoplastic type, 369 (67.5%) as the ulnar-dominant type, 8 (1.5%) as the radial-dominant type, 70 (12.8%) as the symmetric adequate nail type, and 20 (3.7%) as the symmetric inadequate type. Treatments were excision and reconstruction in 403 polydactylies (73.9%), simple excision in 135 polydactylies (24.8%), and the Bilhaut-Cloquet procedure, ray amputation, and on-top plasty procedures were only performed in 7 polydactylies (1.3%). The distribution of surgical procedures was distinct among the new classification types and was similar among the Wassel-Flatt types. CONCLUSIONS: The new classification stratified polydactylies by physical findings in a stepwise manner. Though surgical technical details are not included, this simple classification is useful for paediatricians and parents to understand how a surgical decision is made. LEVEL OF EVIDENCE: Diagnostic Level IV.

Automatic and human level Graf's type identification for detecting developmental dysplasia of the hip.

BACKGROUND: Developmental dysplasia of the hip (DDH) is a common congenital disorder that may lead to hip dislocation and requires surgical intervention if left untreated. Ultrasonography is the preferred method for DDH screening; however, the lack of experienced operators impedes its application in universal neonatal screening. METHODS: We developed a deep neural network tool to automatically register the five keypoints that mark important anatomical structures of the hip and provide a reference for measuring alpha and beta angles following Graf's guidelines, which is an ultrasound classification system for DDH in infants. Two-dimensional (2D) ultrasonography images were obtained from 986 neonates aged 0-6 months. A total of 2406 images from 921 patients were labeled with ground truth keypoints by senior orthopedists. RESULTS: Our model demonstrated precise keypoint localization. The mean absolute error was approximately 1 mm, and the derived alpha angle measurement had a correlation coefficient of R = 0.89 between the model and ground truth. The model achieved an area under the receiver operating characteristic curve of 0.937 and 0.974 for classifying alpha <60° (abnormal hip) and <50° (dysplastic hip), respectively. On average, the experts agreed with 96% of the inferenced images, and the model could generalize its prediction on newly collected images with a correlation coefficient higher than 0.85. CONCLUSIONS: Precise localization and highly correlated performance metrics suggest that the model can be an efficient tool for assisting DDH diagnosis in clinical settings.

Artificial Intelligence Image Recognition System for Preventing Wrong-Site Upper Limb Surgery.

Our image recognition system employs a deep learning model to differentiate between the left and right upper limbs in images, allowing doctors to determine the correct surgical position. From the experimental results, it was found that the precision rate and the recall rate of the intelligent image recognition system for preventing wrong-site upper limb surgery proposed in this paper could reach 98% and 93%, respectively. The results proved that our Artificial Intelligence Image Recognition System (AIIRS) could indeed assist orthopedic surgeons in preventing the occurrence of wrong-site left and right upper limb surgery. At the same time, in future, we will apply for an IRB based on our prototype experimental results and we will conduct the second phase of human trials. The results of this research paper are of great benefit and research value to upper limb orthopedic surgery.

Double diapering facilitates hip maturation in newborns.

BACKGROUND: Double diapering may help to maintain a baby's hips in flexion and abduction posture, but the efficacy in facilitating hip maturation has never been verified. We investigated whether double diapering results in greater improvement of the alpha angle in newborn babies. METHODS: This prospective study enrolled newborns with Graf type IIa immature hips and assigned them to the double-diaper or single-diaper group by the day of birth in a week. Parents were instructed on proper hip positioning, except for diapering. Change in the alpha angle from newborn to 1 month after birth, rate of improvement to bilateral Graf type I hips in 1 month, and number of ultrasound examinations and orthopaedic clinic visits in the first year were compared between the two groups. RESULTS: Seventy newborns with 102 type IIa hips were included from January to December 2017. They were allocated to the double-diaper group (n = 33) and single-diaper group (n = 37). With a comparable sex ratio, gestational age, and newborn alpha angle, the double-diaper group had a greater increase of alpha angles in 1 month than the single-diaper group (+7.9° vs. +5.2°, t-test, p = 0.011). Twenty-eight babies in the double-diaper group (84.8%) and 20 babies in the single-diaper group (54.1%) improved to having bilateral Graf type I hips (chi-square test, p = 0.006). Under the same clinical management pathway, subsequent clinical visits and hip ultrasounds before 1 year were significantly reduced in the double-diaper group. CONCLUSION: Double diapering enhances hip maturation and reduces clinical costs in newborns with physiological immature hips, but the therapeutic role for hip dysplasia requires further study.

Cold Weather as a Risk Factor for Late Diagnosis and Surgery for Developmental Dysplasia of the Hip.

BACKGROUND: Newborn hip screening aims to prevent the late diagnosis of and subsequent surgical procedures for developmental dysplasia of the hip (DDH). Weather may affect how parents swaddle their babies in early life, but weather has never been formally regarded as a risk factor in hip screening. This study investigates the association between the incidence of surgically treated DDH and the outdoor temperature. METHODS: Surgical procedures for late-diagnosed DDH were investigated in 12 birth-year cohorts (1999 to 2010) using the Taiwan National Health Insurance Research Database. The number of children who underwent a DDH-related surgical procedure between 6 months and 5 years of age per total live births was evaluated as an outcome of hip screening. Trend and regression analyses were used to determine the association between the incidence of surgically treated DDH and birth year, birth month, and the temperature during the birth month and first 3 months of life. RESULTS: The mean incidence of surgically treated DDH was 0.48 per 1,000 live births (1,296 surgically treated patients per 2,712,002 live births). The incidence of surgically treated DDH among babies born in winter months (0.70 per 1,000) was significantly higher than that among babies born in summer months (0.32 per 1,000), and it was significantly correlated with mean temperature in the first 3 months of life (r2 = 0.91; p < 0.0001) and birth month (r2 = 0.68; p < 0.001). Multivariable regression revealed that external temperature in the first 3 months of life was the most significant factor (ß = -0.034 [95% confidence interval, -0.042 to -0.022]; p < 0.001) for the incidence of surgically treated DDH (adjusted r2 = 0.485). The trend of seasonal differences remained the same throughout the study years following implementation of the hip-screening policy. CONCLUSIONS: As the incidence of surgically treated DDH is the ultimate outcome of newborn hip screening, cold weather should be regarded as a risk factor and should be incorporated into future screening programs. Weather patterns of different geographical areas should be studied to determine if children born in the winter are at an increased risk for requiring a surgical procedure for DDH, and newborn hip-screening programs should be revised accordingly. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Predictive value for femoral head sphericity from early radiographic signs in surgery for developmental dysplasia of the hip.

BACKGROUND: Avascular necrosis after treatment for late developmental dysplasia of the hip can result in deformity of the femoral head and long-term morbidity. This study aims to analyze the clinical and radiographic factors that are associated with femoral head deformity in the early stage of avascular necrosis. METHODS: Thirty patients with unilateral developmental dysplasia of the hip treated by the same operation before 3 years of age and who developed early signs of avascular necrosis, were studied. Avascular necrosis was diagnosed by either broadening of the femoral neck, fragmentation of the capital epiphysis, or the presence of a metaphyseal growth disturbance line in the first postoperative year. After 10-year follow-up, the hips were classified into spherical head or deformed head by irregularity <2 mm or more to analyze the associated factors. RESULTS: Sixteen hips had spherical femoral heads and the other 14 hips had deformed femoral heads. Age, sex, side, Tonnis classification, and preoperative or postoperative acetabular index were not associated with the outcome after avascular necrosis. Among the early signs of avascular necrosis, fragmentation of the capital epiphysis was significantly associated with later head deformity. Fragmentation was a sign with high sensitivity (79%) and high specificity (88%) in predicting a deformed head. Broadening of femoral neck had a high sensitivity (93%), but a low specificity (38%) in outcome prediction. CONCLUSIONS: Fragmentation and flattening of the femoral epiphysis are the worst radiographic signs indicating subsequent growth disturbance and deformity of the proximal femur. Broadening of the femoral neck exhibited high sensitivity in predicting later deformity, and physicians should be alerted to subsequent epiphyseal fragmentation. A metaphyseal growth disturbance line is a sign of avascular necrosis, but the predictive value is limited. LEVEL OF EVIDENCE: Diagnostic level 3.

Acetabular deficiency in spastic hip subluxation.

BACKGROUND: The direction of spastic hip subluxation is generally agreed to be posterolateral; however, the location of acetabular deficiency is still controversial. This study aims to define the degree and location of acetabular deficiency that is crucial in choosing acetabuloplasty method. METHODS: Twenty-five children with spastic cerebral palsy, average aged 7.1 years (range, 4.4 to 9.6 y), underwent 3-dimensional computed tomography (CT) studies of the pelvis. Mean Reimers migration percentage of the 50 hips was 32.6% (range, 16% to 66%). Twenty-eight hips were nonsubluxated and the other 22 hips were subluxated (migration percentage > 30%). The 3-dimensional image of pelvis was realigned and a series of 9 section planes were formed to represent the whole iliac root. The CT acetabular indexes were measured and compared to define the deficiency. The data of 5 children without hip problem was retrieved as control. RESULTS: Spastic nonsubluxated hips had similar CT acetabular indexes to normal hips. The differences between spastic subluxated hips and normal hips, from anterosuperior to posterosuperior aspects of acetabulum, were 14.8 degrees (A60 degrees), 11.2 degrees (A45 degrees), 10.8 degrees (A30 degrees), 9.9 degrees (A15 degrees), 9.7 degrees (0 degree), 9.5 degrees (P15 degrees), 9.8 degrees (P30 degrees), 9.8 degrees (P45 degrees), and 5.3 degrees (P60 degrees). The differences were significant in all directions and greater in the anterior aspect of the acetabulum. CONCLUSIONS: The definition of pathology is defined by the deviation from normal physiological status. Acetabular dysplasia in spastic hip subluxation is global and more apparent in the anterior aspect. LEVEL OF EVIDENCE: Diagnostic II.

Tension band plates have greater risks of complications in temporary epiphysiodesis.

PURPOSE: This study aimed to compare the efficacy of decreasing leg-length discrepancy (LLD) and postoperative complications between tension band plates (TBP) and percutaneous transphyseal screws (PETS). METHODS: This retrospective study reviewed LLD patients who underwent temporary epiphysiodesis at the distal femur and/or proximal tibia from 2010 to 2017 (minimum two years follow-up). Efficacy of decreasing LLD was assessed one and two years postoperatively. Complications were classified with the modified Clavien-Dindo-Sink complication classification system. Knee deformities were assessed by percentile and zone of mechanical axis across the tibial plateau. RESULTS: In total, 53 patients (25 boys, 28 girls) underwent temporary epiphysiodesis (mean age, 11.4 years). The efficacy of decreasing LLD at two years between the TBP (n = 38) and PETS (n = 15) groups was comparable. Seven grade III complications were recorded in six TBP patients and in one PETS patient who underwent revision surgeries for knee deformities and physis impingement. Four grade I and two grade II complications occurred in the TBP group. The mechanical axis of the leg shifted laterally in the PETS group and medially in the TBP groups (+7.1 percentile versus -4.2 percentile; p < 0.05). Shifting of the mechanical axis by two zones was noted medially in four TBP patients and laterally in two PETS patients. CONCLUSION: More implant-related complications and revision surgeries for angular deformities were associated with TBP. A tendency of varus and valgus deformity after epiphysiodesis using TBP and PETS was observed, respectively. Patients and families should be informed of the risks and regular postoperative follow-up is recommended. LEVEL OF EVIDENCE: Level III.