Intraoperative 3D Fluoroscopy During Open Reduction for DDH: An Effective Alternative to Postoperative CT/MRI.

BACKGROUND: Computed tomography CT or magnetic resonance imaging (MRI) has been the most used imaging modality to assess hip reduction in developmental dysplasia of the hip (DDH) after open reduction (OR). In 2015, intraoperative 3D fluoroscopy (3D) was introduced at our center as an alternative to CT/MRI. 3D offers the advantage that if hip reduction is insufficient, it can be addressed at the time of surgery. The purpose of this study was to assess the efficacy of 3D in comparison to CT/MRI. METHODS: This was a single-centre, retrospective comparative study of two consecutive cohorts: those with OR and 3D between 2015 and 2017 and those with OR and CT/MRI between 2012 and 2014. Time to imaging, re-imaging, length of stay (LOS), re-operation, and redislocation or subluxation after cast removal were evaluated. RESULTS: Forty-two patients (46 hips) had 3D, and 30 patients (32 hips) had CT/MRI. Significant differences were found between groups in time to imaging, cast changes, and LOS. All 3D was intraoperative (46 hips), and only 69% (22 hips) of CT/MRI was on the day of surgery (P<0.01). In the 3D group, 1 hip (2%) had a cast change under the same anesthetic, and 4 hips (13%) from CT/MRI had cast changes in subsequent surgery (P=0.03). The mean LOS in days for 3D was 1.72 and 2.20 for CT/MRI (P=0.03). There were no statistically significant differences between groups in further imaging and subluxations or re-dislocations at cast removal. Two hips (4%) in the 3D group had MRI, but with no further intervention (P=0.51), and at cast removal, there were 3 subluxations in each group (P=0.69) and 1 redislocation in the 3D group (P=1.00). CONCLUSIONS: Intraoperative 3D improved time to imaging, allowed for cast changes at surgery and had a shorter LOS. Moreover, there were no significant differences found in adverse outcomes between those who underwent 3D versus CT/MRI. 3D should thus be considered an effective alternative to CT/MRI for assessing hip reduction during OR for DDH. LEVEL OF EVIDENCE: Diagnostic Study, level II.

The impact of public health lockdown measures during the COVID-19 pandemic on the epidemiology of children's orthopedic injuries requiring operative intervention.

BACKGROUND: In March 2020, Ontario instituted a lockdown to reduce spread of the SARS-CoV-2 virus. Schools, recreational facilities, and nonessential businesses were closed. Restrictions were eased through 3 distinct stages over a 6-month period (March to September 2020). We aimed to determine the impact of each stage of the COVID-19 public health lockdown on the epidemiology of operative pediatric orthopedic trauma. METHODS: A retrospective cohort study was performed comparing emergency department (ED) visits for orthopedic injuries and operatively treated orthopedic injuries at a level 1 pediatric trauma centre during each lockdown stage of the pandemic with caseloads during the same date ranges in 2019 (prepandemic). Further analyses were based on patients' demographic characteristics, injury severity, mechanism of injury, and anatomic location of injury. RESULTS: Compared with the prepandemic period, ED visits decreased by 20% (1356 v. 1698, p < 0.001) and operative cases by 29% (262 v. 371, p < 0.001). There was a significant decrease in the number of operative cases per day in stage 1 of the lockdown (1.3 v. 2.0, p < 0.001) and in stage 2 (1.7 v. 3.0; p < 0.001), but there was no significant difference in stage 3 (2.4 v. 2.2, p = 0.35). A significant reduction in the number of playground injuries was seen in stage 1 (1 v. 62, p < 0.001) and stage 2 (6 v. 35, p < 0.001), and there was an increase in the number of self-propelled transit injuries (31 v. 10, p = 0.002) during stage 1. In stage 3, all patient demographic characteristics and all characteristics of operatively treated injuries resumed their prepandemic distributions. CONCLUSION: Provincial lockdown measures designed to limit the spread of SARS-CoV-2 significantly altered the volume and demographic characteristics of pediatric orthopedic injuries that required operative management. The findings from this study will serve to inform health system planning for future emergency lockdowns.

Surgical waitlist management: Perspectives from surgeons on surgical prioritization at a paediatric hospital.

Globally exacerbated surgical waitlists have provided the opportunity to reflect on prioritization and resource allocation decisions. The unique circumstances of paediatric surgery and consequences of surgical delay prompted the study reported in this paper. As part of a larger project to attend to prioritization in our surgical waitlists, we conducted a Quality Improvement study, the purpose of which is to understand surgeon's perspectives regarding the ethical and practical realities of surgical prioritization at our institution. The study comprises semi-structured interviews with nine full-time paediatric surgeons from a variety of subspecialties conducted at our institution, which is a tertiary paediatric hospital with ten surgical subspecialties in a publicly funded healthcare system. Participants articulated how they prioritize their waitlists, and how they understand ethical prioritization. These findings resonate with the growing public concern for ethical practice in healthcare delivery and transparency in prioritization and resource allocation practices. Specifically, more transparency, consistency, and support is required in prioritization practices. This work highlights the importance of institutional dialogue regarding surgical case prioritization. Because quality improvement work is necessarily site-specific, concrete generalizations cannot be offered. However, the insights gleaned from these interviews and the process by which they were gleaned are a valuable knowledge-sharing resource for any institution that is interested in ongoing quality improvement work. The objectives here were to clarify the goals of prioritization within the institution, improve prioritization practices, and make them more ethical and transparent.

Prolonged Brace Treatment Does Not Result in Improved Acetabular Indices in Infantile Dislocated Hips.

BACKGROUND: The Pavlik harness (PH) is commonly used to treat infantile dislocated hips. However, significant variability exists in the duration of brace treatment after successful reduction of the dislocated hip. The purpose of this study was to evaluate the effect of prescribed time in brace on acetabular index (AI) at two years of age using a prospective, international, multicenter database. METHODS: We retrospectively studied prospectively enrolled infants with at least 1 dislocated hip that were initially treated with a PH and had a recorded AI at 2-year follow-up. Subjects were treated at 1 of 2 institutions. Institution 1 used the PH until they observed normal radiographic acetabular development. Institution 2 followed a structured shorter brace treatment protocol. Hip dislocation was defined as <30% femoral head coverage at rest on the pretreatment ultrasound or International Hip Dysplasia Institute (IHDI) grade III or IV on the pretreatment radiograph. RESULTS: Fifty-three hips met our inclusion criteria. Hips from Institution 1 were treated with a brace ×3 longer than hips from institution 2 (adjusted mean 8.9±1.3 vs. 2.6±0.2 mo) (P<0.001). Institution 1 had an 88% success rate and institution 2 had an 85% success rate at achieving hip reduction (P=0.735). At 2-year follow-up, we observed no significant difference in AI between Institution 1 (adjusted mean 25.6±0.9 degrees) compared with Institution 2 (adjusted mean 23.5±0.8 degrees) (P=0.1). However, 19% of patients from Institution 1 and 44% of patients from Institution 2 were at or below the 50th percentile of previously published age-matched and sex-matched AI normal data (P=0.049). Also, 27% (7/26) of hips from Institution 1 had significant acetabular dysplasia (more than 2 SD from the mean), compared with a 22% (6/27) from Institution 2 (P=0.691). We found no correlation between age at initiation of bracing and AI at 2-year follow-up (P=0.071). CONCLUSIONS: The PH brace can successfully treat dislocated infant hips, however, prolonged brace treatment was not found to result in improved acetabular development at 2-year follow-up. LEVEL OF EVIDENCE: Level III.

Femoral Lengthening in Children: A Comparison of Motorized Intramedullary Nailing Versus External Fixation Techniques.

BACKGROUND: Femoral lengthening is associated with high complication rates often related to the type of surgical device used to perform the lengthening. The advent of intramedullary lengthening devices has promised a reduction in complications when compared with external fixation systems. The purpose of this study was to compare the clinical outcomes of femoral lengthening in children using a motorized intramedullary nail (Precice) versus an external fixation system (Taylor Spatial Frame-TSF; or Monolateral Rail System-MRS) at a single institution, single surgeon practice. METHODS: This study is a retrospective comparison of pediatric patients who had previously undergone femoral lengthening (±deformity correction). Patients ages 8 to 18 years of age were included and grouped based on whether they had undergone Precice nailing or external fixation (TSF or MRS) between 2010 and 2019. RESULTS: Twenty-seven patients (32 femurs) were included. Thirteen patients (15 femurs) had undergone Precice nailing and 14 patients (17 femurs) had undergone external fixation. The Precice group had significantly fewer problems, obstacles, and complications than the external fixation group, Precice 6.6%, 0%, 0%, respectively, and external fixation 47.1%, 29.4%, 0% respectively (P<0.01). Unplanned return to the operating room occurred in 4 cases, solely in the external fixation group. There were no differences in percentage of goal length achieved, Precice (mean 93.6%, range: 66.7% to 114.3%), external fixation (mean 96%, range: 76.9% to 117.5%) P=0.31 and total length achieved, Precice (mean: 44 mm, range: 20 to 80 mm), external fixation (mean: 46 mm, range: 10 to 70 mm) P=0.72. There was no difference in consolidation index, Precice (24.1 d/cm), external fixation (28.5 d/cm) P=0.36. The Precice group had a significantly shorter length of stay (mean: 2.2 d, range: 1 to 4 d), compared with the external fixation group (mean: 3.7 d, range: 2 to 8), P=0.01. CONCLUSIONS: Femoral lengthening in children using a motorized intramedullary nail was associated with a markedly reduced rate of complications and shorter length of stay compared with external fixation. LEVEL OF EVIDENCE: Level III.

Interobserver and Intraobserver Reliability in the Salter Classification of Avascular Necrosis of the Femoral Head in Developmental Dysplasia of the Hip.

BACKGROUND: Avascular necrosis (AVN) of the femoral head is a concerning complication that can result from treatments for developmental dysplasia of the hip (DDH). AVN can lead to degenerative osteoarthritis, persistent acetabular dysplasia, reduced function, and continuing hip pain. The incidence of AVN reported in the DDH literature is widely varied (0% to 73%). This variability may arise from lack of consensus on what constitutes true AVN in this patient population, and lack of clear criteria provided in studies reporting incidence rates. METHODS: A multicentre, prospective database of infants diagnosed with DDH between 2010 and 2014 from 0 to 18 months of age was analyzed for patients treated by closed reduction (CR). Twelve pediatric orthopaedic surgeons completed 2 rounds of AVN assessments. Deidentified anteroposterior radiographs at most recent follow-up were provided to surgeons along with patient age at radiographic assessment, length of follow-up, ands affected hip. Ten of 12 surgeons completed a third round of assessments where they were provided with 1 to 2 additional radiographs within the follow-up period. Radiographic criteria for total AVN described by Salter and colleagues were used. Surgeons rated the presence of AVN as "yes" or "no" and kappa values were calculated within and between rounds. RESULTS: A total of 69 hips in 60 patients were assessed for AVN a median of 22 months (range: 12 to 36) post-CR. Interobserver kappa values for rounds 1, 2, and 3 were 0.52 (range: 0.11 to 0.90), 0.61 (range: 0.21 to 0.90), and 0.53 (range: 0.10 to 0.79), respectively. Intraobserver agreement for AVN diagnosis was an average of 0.72 (range: 0.31 to 0.96). CONCLUSIONS: Despite using the most commonly referenced diagnostic criteria, radiographic diagnosis of AVN following CR in DDH patients demonstrated only moderate agreement across surgeons. The addition of sequential radiographs did not improve cross-observer reliability, and while substantial agreement was seen within observers, the range of intraobserver kappa values was large. LEVEL OF EVIDENCE: Level I-diagnostic study.

The Gait Outcomes Assessment List for Children With Lower Limb Difference (GOAL-LD): Assessment of Reliability and Validity.

BACKGROUND: The Gait Outcomes Assessment List for children with Lower Limb Difference (GOAL-LD) is a patient and parent-reported outcome measure that incorporates the framework of the International Classification of Functioning, Disability, and Health. This prospective multicenter cohort study evaluates the validity and reliability of the GOAL-LD and the differences between parent and adolescent report. METHOD: One hundred thirty-seven pediatric patients aged over 5 years attending limb reconstruction clinics at the participating sites were assessed at baseline, and a self-selected cohort also completed an assessment 2 to 6 weeks later. Construct and criterion validity were assessed by comparing GOAL-LD scores with a measure of limb deformity complexity (LLRS-AIM) and the Pediatric Outcomes Data Collection Instrument, using Spearman correlation coefficients. Face and content validity were determined through ratings of item importance. Test-retest reliability was reported as an intraclass correlation coefficient and internal consistency using Cronbach α. Adolescent reports were compared with their parents using paired t tests. RESULTS: The GOAL-LD demonstrated a moderate negative correlation with the LLRS-AIM (r=-0.40, P<0.001) and was able to discriminate between deformity complexity groups as defined by the LLRS-AIM (χ2=11.43, P=0.022). Internal consistency was high across all domains (α≥0.68 to 0.97). Like domains of the Pediatric Outcomes Data Collection Instrument and the GOAL-LD were well correlated. Parents reported a lower total GOAL-LD score when compared with adolescents (mean difference 3.04; SE 1.06; 95% confidence interval, 0.92-5.16; P<0.01); however this difference was only significant for body image and self-esteem (Domain F) and gait appearance (Domain D). Test-retest reliability remained high over the study period (intraclass correlation coefficient 0.85; SE 0.03; 95% confidence interval, 0.77-0.91). CONCLUSIONS: The GOAL-LD is a valid and reliable self and parent-reported outcome measure for children with lower limb difference. Parents report a lower level of function and attribute a higher importance to items when compared with their children. The GOAL-LD helps to communicate parent and child perspectives on their function and priorities and therefore has the capacity to facilitate family centered treatment planning and care. LEVEL OF EVIDENCE: Level II-diagnostic. Prospective cross-sectional and a longitudinal cohort design.

Management of Irreducible Hip Dislocations in Infants With Developmental Dysplasia of the Hip Diagnosed Below 6 Months of Age.

BACKGROUND: Infants with dislocated irreducible (D/I) hips can be substantially harder to treat than infants with dislocated but reducible hips. The purpose of this study was to compare treatment methods and outcomes for infants with D/I hips in order to optimize management of this difficult patient cohort. METHODS: A multicenter prospective hip dysplasia study database was analyzed from 2010 to 2016. Infants aged below 6 months with clinically and radiologically confirmed D/I hips were included in the study. Teratological hips (syndromic/neuromuscular) were excluded. RESULTS: In total, 59 hips in 52 patients were included. All hips were clinically Ortolani negative and radiologically dislocated but irreducible on presentation and had at least 20 months of follow-up. Mean age at diagnosis was 1.9 months (range, 0.1 to 5.9 mo). There were 33 left hips, 12 right hips, and 14 bilateral hips (7 patients). In total, 48 of 59 hips were treated in Pavlik harness. The remainder were treated by alternative braces or primary closed or open reductions. Pavlik treatment was successful in 27 of 48 hips. Pavlik treatment was abandoned in 21 D/I hips, 3 due to femoral nerve palsy and the remainder due to failure to achieve reduction. There was no statistical correlation between Pavlik success and age at diagnosis (P=0.22), patient sex (P=0.61), or bilateral compared with unilateral D/I hips (P=0.07). Left hips were more likely to be successfully reduced in Pavlik harness than right hips (P=0.01). Five complications occurred: 3 patients developed femoral nerve palsy in Pavlik harness, while 2 patients developed avascular necrosis, both after failed Pavlik treatment and subsequent surgery. CONCLUSIONS: Pavlik harness treatment has been demonstrated to be a safe and sensible first-line treatment for infants with D/I hips. Left hips were more likely to be successfully reduced in Pavlik harness than right hips, but age, sex, and bilaterality were not correlated. The outcomes demonstrated from this multicentre prospective database inform management of this complex patient cohort. LEVEL OF EVIDENCE: Level II-prognostic study: less-quality prospective study.

Closed Reduction for Developmental Dysplasia of the Hip: Early-term Results From a Prospective, Multicenter Cohort.

BACKGROUND: Closed reduction (CR) is a common treatment for infantile developmental dysplasia of the hip. The purpose of this observational, prospective, multicenter study was to determine the early outcomes following CR. METHODS: Prospectively collected data from an international multicenter study group was analyzed for patients treated from 2010 to 2014. Baseline demographics, clinical exam, radiographic/ultrasonographic data, and history of previous orthotic treatment were assessed. At minimum 1-year follow-up, failure was defined as an IHDI grade 3 or 4 hip and/or need for open reduction. The incidence of avascular necrosis (AVN), residual dysplasia, and need for further surgery was assessed. RESULTS: A total of 78 patients undergoing CR for 87 hips were evaluated with a median age at initial reduction of 8 months (range, 1 to 20 mo). Of these, 8 hips (9%) were unable to be closed reduced initially. At most recent follow-up (median 22 mo; range, 12 to 36 mo), 72/79 initially successful CRs (91%) remained stable. The likelihood of failure was unaffected by initial clinical reducibility of the hip (P=0.434), age at initial CR (P=0.897), or previous treatment in brace (P=0.222). Excluding those hips that failed initial CR, 18/72 hips (25%) developed AVN, and the risk of osteonecrosis was unaffected by prereduction reducibility of the hip (P=0.586), age at CR (P=0.745), presence of an ossific nucleus (P=0.496), or previous treatment in brace (P=0.662). Mean acetabular index on most recent radiographs was 25 degrees (±6 degrees), and was also unaffected by any of the above variables. During the follow-up period, 8/72 successfully closed reduced hips (11%) underwent acetabular and/or femoral osteotomy for residual dysplasia. CONCLUSIONS: Following an initially successful CR, 9% of hips failed reduction and 25% developed radiographic AVN at early-term follow-up. History of femoral head reducibility, previous orthotic bracing, and age at CR did not correlate with success or chances of developing AVN. Further follow-up of this prospective, multicenter cohort will be necessary to establish definitive success and complication rates following CR for infantile developmental dysplasia of the hip. LEVEL OF EVIDENCE: Level II-prospective observational cohort.

Tibial hemimelia associated with GLI3 truncation.

Tibial hemimelia is a rare, debilitating and often sporadic congenital deficiency. In syndromic cases, mutations of a Sonic hedgehog (SHH) enhancer have been identified. Here we describe an ~5 kb deletion within the SHH repressor GLI3 in two patients with bilateral tibial hemimelia. This deletion results in a truncated GLI3 protein that lacks a DNA-binding domain and cannot repress hedgehog signaling. These findings strengthen the concept that tibial hemimelia arises because of failure to restrict SHH activity to the posterior aspect of the limb bud.

Ischiofemoral Impingement in Children: Imaging With Clinical Correlation.

OBJECTIVE: The purpose of this study is to correlate the MRI finding of quadratus femoris edema in children with established measures of ischiofemoral impingement in adults and to determine their clinical significance. MATERIALS AND METHODS: A case-control retrospective review was performed of MR images of 12 hips of nine children (mean age, 10 years) that showed abnormal signal intensity in the quadratus femoris muscle. The findings were compared with those for 13 hips in 13 control subjects (mean age, 9.8 years). Two musculoskeletal radiologists independently measured the ischiofemoral space, quadratus femoris space, inclination angle, and hamstring tendon area. Quadratus femoris muscle edema, tears, or fatty replacement were assessed visually. Statistical analysis determined inter- and intraobserver variability and statistical differences between the two subject groups. RESULTS: Subjects with abnormal signal in the quadratus femoris muscle had a statistically significantly narrower ischiofemoral space (mean, 11.5 vs 20.7 mm; p < 0.05) and quadratus femoris space (mean, 7.2 vs 14.3 mm, p < 0.05) compared with control subjects. Inclination angles were statistically significantly larger in affected subjects (145.5° vs 138.7°; p < 0.05). No statistically significant difference was found in hamstring tendon area. Four of 12 patient hips had no symptoms or symptoms unrelated to the abnormality. Inter- and intraobserver variability scores were strong for all continuous variables. CONCLUSION: Ischiofemoral impingement is a cause of hip pain in children and should be considered with the combination of quadratus femoris muscle edema and narrowing of ischiofemoral space and quadratus femoris space. Coxa valga may contribute to narrowing of these parameters and predispose to ischiofemoral impingement. The MRI features of ischiofemoral impingement, however, are nonspecific and may be seen in patients with pain localized to that hip or in patients with symptoms unrelated to the abnormality.

What Is the Impact of Center Variability in a Multicenter International Prospective Observational Study on Developmental Dysplasia of the Hip?

BACKGROUND: Little information exists concerning the variability of presentation and differences in treatment methods for developmental dysplasia of the hip (DDH) in children < 18 months. The inherent advantages of prospective multicenter studies are well documented, but data from different centers may differ in terms of important variables such as patient demographics, diagnoses, and treatment or management decisions. The purpose of this study was to determine whether there is a difference in baseline data among the nine centers in five countries affiliated with the International Hip Dysplasia Institute to establish the need to consider the center as a key variable in multicenter studies. QUESTIONS/PURPOSES: (1) How do patient demographics differ across participating centers at presentation? (2) How do patient diagnoses (severity and laterality) differ across centers? (3) How do initial treatment approaches differ across participating centers? METHODS: A multicenter prospective hip dysplasia study database was analyzed from 2010 to April 2015. Patients younger than 6 months of age at diagnosis were included if at least one hip was completely dislocated, whereas patients between 6 and 18 months of age at diagnosis were included with any form of DDH. Participating centers (academic, urban, tertiary care hospitals) span five countries across three continents. Baseline data (patient demographics, diagnosis, swaddling history, baseline International Hip Dysplasia Institute classification, and initial treatment) were compared among all nine centers. A total of 496 patients were enrolled with site enrolment ranging from 10 to 117. The proportion of eligible patients who were enrolled and followed at the nine participating centers was 98%. Patient enrollment rates were similar across all sites, and data collection/completeness for relevant variables at initial presentation was comparable. RESULTS: In total, 83% of all patients were female (410 of 496), and the median age at presentation was 2.2 months (range, 0-18 months). Breech presentation occurred more often in younger (< 6 months) than in older (6-18 months at diagnosis) patients (30% [96 of 318] versus 9% [15 of 161]; odds ratio [OR], 4.2; 95% confidence interval [CI], 2.3-7.5; p < 0.001). The Australia site was underrepresented in breech presentation in comparison to the other centers (8% [five of 66] versus 23% [111 of 479]; OR, 0.3, 95% CI, 0.1-0.7; p = 0.034). The largest diagnostic category was < 6 months, dislocated reducible (51% [253 of 496 patients]); however, the Australia and Boston sites had more irreducible dislocations compared with the other sites (ORs, 2.1 and 1.9; 95% CIs, 1.2-3.6 and 1.1-3.4; p = 0.02 and 0.015, respectively). Bilaterality was seen less often in older compared with younger patients (8% [seven of 93] versus 26% [85 of 328]; p < 0.001). The most common diagnostic group was Grade 3 (by International Hip Dysplasia Institute classification), which included 58% (51 of 88) of all classified dislocated hips. Splintage was the primary initial treatment of choice at 80% (395 of 496), but was far more likely in younger compared with older patients (94% [309 of 328] versus 18% [17 of 93]; p < 0.001). CONCLUSIONS: With the lack of strong prognostic indicators for DDH identified to date, the center is an important variable to include as a potential predictor of treatment success or failure.

A Reliable and Valid Objective Structured Assessment of Technical Skill for the Application of a Pavlik Harness Based on International Expert Consensus.

BACKGROUND: The use of competency-based training is increasing in medical education as it offers individualized learning opportunities to master required skills. Inherent to this method of teaching is the need for standardized and objective assessments of skill mastery. In orthopaedic surgery, educational programs have focused on surgical skills with lesser emphasis on nonoperative techniques. Accordingly, formal evaluation tools specific to Pavlik Harness application do not exist, despite its widespread use and potential complications from inappropriate application. This study sought to develop a reliable and valid evaluation tool based on international expert consensus to standardize and evaluate Pavlik Harness application for developmental dysplasia of the hip. METHODS: Consensus was sought from 10 content experts using Delphi methodology. Resulting items formed the Objective Structured Assessment of Technical Skill (OSATS). Thirty-five participants were selected into 3 a priori groups (expert, intermediate and novice) based on Pavlik Harness experience. On 2 occasions, 3 content experts assessed randomized and deidentified videotapes of each participant applying a Pavlik Harness to an infant model using the OSATS and global rating scales (GRS). The reliability and validity of the OSATS was determined with intraclass (ICC) and Pearson correlations and analysis of variance (ANOVA). RESULTS: Consensus was obtained after 2 rounds of structured surveying and resulted in a 25-item OSATS. The reliability of the OSATS was excellent with an ICC of 0.96 for interrater and 0.98 for test-retest reliability. Construct validity was excellent with high correlations between OSATS and GRS (>0.90). In addition, the OSATS discriminated between expert, intermediate, and novice users. CONCLUSIONS: We have developed a competency-based evaluation tool for Pavlik Harness application based on consensus from international experts. The OSATS has been shown to be a reliable and valid method for assessing Pavlik Harness application that can discriminate between expert, intermediate, and novice users. LEVEL OF EVIDENCE: Level II.

Intraoperative assessment of closed reduction for developmental dislocation of the hip using 3-dimensional fluoroscopy.

BACKGROUND: Postoperative imaging for operatively treated developmental dislocation of the hip typically uses computed tomography or a magnetic resonance imaging (MRI). Neither imaging modality offers the ability to intervene intraoperatively. The 3-dimensional (3D) C-arm provides an attractive alternative providing immediate intraoperative feedback on the quality of a hip reduction. Our primary research question was to determine whether 3D fluoroscopy could assess hip position after closed reduction and spica casting. Secondary questions included whether reduction was maintained postoperatively when compared with postoperative MRI, and to determine the radiation dose received by the infant. METHODS: We retrospectively identified 16 patients from 2010 to 2013 who underwent closed reduction and spica casting for a developmentally dislocated hip who underwent both intraoperative 3D fluoroscopy and postoperative MRI imaging. Scans were retrieved and assessed by a blinded pediatric orthopaedic fellow. Assessment of hip reduction was graded based on the modified Shenton line of the pelvis in axial plane images. Effective radiation doses between imaging modalities were compared using an anthropomorphic phantom. RESULTS: All hips were reduced on 3D fluoroscopic images. Comparing the intraoperative 3D scans with the postoperative MRI images all 16 hips were in the same position. At 12 weeks all hips were reduced and no signs of subluxation were identified on the plain anteroposterior radiograph. 3D fluoroscopy achieved the lowest effective dose of radiation per study measuring 0.3 mSv compared with 0.5 mSv for low-dose CT and 0.48 mSv for 60 seconds of live fluoroscopy. CONCLUSIONS: Accurate assessment of the quality of hip reduction is possible in the axial plane using 3D fluoroscopy with no significant loss of reduction in the early postoperative period. When comparing the effective radiation exposure to limited-cut computed tomography protocols, 3D fluoroscopy offers a low-dose alternative that may facilitate cost savings and early discharge. LEVEL OF EVIDENCE: Diagnostic studies-investigating a diagnostic test; study of nonconsecutive patients with consistently applied gold standard; level III.

Resolving residual acetabular dysplasia following successful brace treatment for developmental dysplasia of the hip in infants.

Aims: Radiological residual acetabular dysplasia (RAD) has been reported in up to 30% of children who had successful brace treatment of infant developmental dysplasia of the hip (DDH). Predicting those who will resolve and those who may need corrective surgery is important to optimize follow-up protocols. In this study we have aimed to identify the prevalence and predictors of RAD at two years and five years post-bracing. Methods: This was a single-centre, prospective longitudinal cohort study of infants with DDH managed using a published, standardized Pavlik harness protocol between January 2012 and December 2016. RAD was measured at two years' mean follow-up using acetabular index-lateral edge (AI-L) and acetabular index-sourcil (AI-S), and at five years using AI-L, AI-S, centre-edge angle (CEA), and acetabular depth ratio (ADR). Each hip was classified based on published normative values for normal, borderline (1 to 2 standard deviations (SDs)), or dysplastic (> 2 SDs) based on sex, age, and laterality. Results: Of 202 infants who completed the protocol, 181 (90%) had two and five years' follow-up radiographs. At two years, in 304 initially pathological hips, the prevalence of RAD (dysplastic) was 10% and RAD (borderline) was 30%. At five years, RAD (dysplastic) decreased to 1% to 3% and RAD (borderline) decreased to < 1% to 2%. On logistic regression, no variables were predictive of RAD at two years. Only AI-L at two years was predictive of RAD at five years (p < 0.001). If both hips were normal at two years' follow-up (n = 96), all remained normal at five years. In those with bilateral borderline hips at two years (n = 21), only two were borderline at five years, none were dysplastic. In those with either borderline-dysplastic or bilateral dysplasia at two years (n = 26), three (12%) were dysplastic at five years. Conclusion: The majority of patients with RAD at two years post-brace treatment, spontaneously resolved by five years. Therefore, children with normal radiographs at two years post-brace treatment can be discharged. Targeted follow-up for those with abnormal AI-L at two years will identify the few who may benefit from surgical correction at five years' follow-up.

Comparison of brace to observation in stable, radiological developmental dysplasia of the hip: a protocol for a global multicentre non-inferiority randomised trial.

INTRODUCTION: Brace treatment is common to address radiological dysplasia in infants with developmental dysplasia of the hip (DDH); however, it is unclear whether bracing provides significant benefit above careful observation by ultrasound. If observation alone is non-inferior to bracing for radiological dysplasia, unnecessary treatment may be avoided. Therefore, the purpose of this study is to determine whether observation is non-inferior to bracing for infants with radiological dysplasia. METHODS AND ANALYSIS: This will be a multicentre, global, randomised, non-inferiority trial performed under the auspices of a global prospective registry for infants and children diagnosed with DDH. Patients will be included if they present with radiological dysplasia (centred hip, alpha angle 43-60°, percent femoral head coverage greater than 35% measured on ultrasound) of a clinically stable hip under 3 months old. Patients will be excluded if they present with clinical hip instability, have received prior treatment or have known/suspected neuromuscular, collagen, chromosomal or lower-extremity congenital abnormalities or syndromic-associated hip abnormalities. Patients will be enrolled and randomised to undergo observation alone or brace treatment with a Pavlik harness for a minimum of 6 weeks. Follow-up visits will occur at 6 weeks, 1 year and 2 years post-enrolment. The primary outcome will be the norm-referenced acetabular index measured on the 2-year radiograph with a 3° non-inferiority margin. A total of 514 patients will be included.The study is anticipated to start in April 2024 and end in September 2028.The primary outcome will be compared between arms with a mixed-effects model with a random intercept for study centre, and a single covariate for the treatment group. If the lower bound of the 95% CI lies within 3° of the mean, we will treat this as evidence for non-inferiority. ETHICS AND DISSEMINATION: Ethics approval has been obtained from the lead site's ethics board (University of British Columbia, Children's and Women's Research Ethics Board). Ethics approval will be obtained from the local ethics committees or institutional review boards at each institution prior to patient enrolment. It is intended that the results of this study shall be published in peer-reviewed journals and presented at suitable conferences. TRIAL REGISTRATION NUMBER: NCT05869851.

Management of hip instability in trisomy 21.

The unstable hip in Trisomy 21 presents with a spectrum of hip instability with different problems at different ages. What links this multiphase problem, in many patients, is the final common pathway of untreated instability, that of a stiff, dislocated, and often-painful hip, leading to significant functional disability. Historically, the results of treating hip instability in Trisomy 21 were variable with a notable frequency of poor results. With an improved understanding of the Trisomy 21 hip in terms of its pathoanatomy and a more contemporary surgical approach to hip reconstruction, much improved results can be expected and indeed have recently been shown. The mainstay of treatment for the habitual dislocation group presenting before 8 years of age is the femoral varus derotation osteotomy. The older group presenting with painful subluxation often show signs of secondary acetabular dysplasia and thus are best treated with redirectional acetabular osteotomy with or without the use of femoral varus derotation osteotomy. The presence of radiographic features of degenerative arthritis in the fixed dislocation group precludes the use of joint-preserving techniques for hip reconstruction, and these patients can achieve excellent results with total joint arthroplasty. The natural history, historical results, assessment, treatment, and management of complications of hip instability in Trisomy 21 are addressed in this paper.

Aspect elucidation of a physicochemical pretreatment for continuous decrystallization.

The purpose of this study is to understand the operating conditions of a physicochemical pretreatment process for lignocellulosic biomass using homogeneous acid catalysts. Four parameters were studied: moisture content, acid catalyst, type of biomass and reactor morphology. The different types of biomass (perennial grasses: sugarcane bagasse, corn stover; flowering plants: cannabis (stalks and leaves); hardwoods (pulp and bark): poplar, sugar maple; softwood bark) were processed in a meat grinder with sulfuric acid. Furthermore, softwood bark was used to change the moisture content, acid catalyst and reactor morphology. Biomass moisture above 17 wt% yielded less than 50 wt% glucose. Sulfuric acid, by far, had the best performance with a 74.5 wt% glucose yield in the meat grinder. The glucose yield showed a direct relationship with the non-carbohydrate components of biomass (lignin, ash, etc).

The true pelvic volume change with various corrective osteotomy techniques for exstrophy-epispadias complex spectrum: the value of computer-assisted virtual surgery.

Pelvic osteotomies are essential to approximate widened symphysis pubis in the exstrophy-epispadias complex, yet it is unknown which osteotomy type has the greatest effect on pelvic volume. We therefore used virtual surgery to study pelvic volume change with anterior, oblique, and posterior iliac osteotomies. Preoperative CT scans of two cloacal and one classic bladder exstrophy patients were used. Simulations were free-hand or constrained to keep minimal strain in the sacrospinous SSL and sacrotuberous STL ligaments. Changes in inter-pubic distance, pelvic volume, SSL and STL strains were measured. Mean pelvic volume decreased by 10% with free hand compared to 23% with constrained simulations (P = 0.171) and decreased by 7% with posterior, 17% with diagonal and 26% with horizontal osteotomies (P = 0.193). SSL and STL were strained by 20% and 26%, respectively, with free-hand simulations. A statistically significant moderate positive correlation was found between the decrease in inter-pubic distance and reduction in pelvic volume (r = 0.6, P = 0.004). Mean pelvic volume decreased 0.05, 0.37 and 0.62% for each mm of pubic symphysis approximation with posterior, diagonal and horizontal osteotomies, respectively. Differences in effect on pelvic volume were identified between the osteotomies using virtual surgery which predicted residual diastasis in actual cloacal exstrophy surgical reconstructions. Oblique osteotomies are a compromise, avoiding difficulties with posterior osteotomies and excessive pelvic volume reduction with horizontal osteotomies. Understanding how osteotomy type affects pelvic morphology with virtual surgery may be an effective adjunct to pre-operative planning in exstrophy spectrum.