Comparison of Contrast-enhanced Ultrasound and Contrast-enhanced Magnetic Resonance Imaging in the Assessment of Infant Hip Perfusion and Prediction of Proximal Femoral Growth Disturbance Following Closed and Open Reduction for Developmental Dysplasia of the Hip: A Preliminary Study.

OBJECTIVE: Proximal femoral growth disturbance (PFGD) is a significant complication associated with surgical treatment of infant hip dislocation. Contrast-enhanced magnetic resonance imaging (CEMRI) has been utilized to assess perfusion in these hips and avoid PFGD. Contrast-enhanced ultrasound (CEUS) is an imaging technique utilized to evaluate perfusion in other organs. The aims of this study were to compare perfusion of dysplastic infant hips with CEUS and CEMRI after surgical treatment and to determine whether CEUS was as effective as CEMRI at predicting PFGD. METHODS: A retrospective analysis of patients undergoing closed or open reduction for infant hip dislocation between 2012 and 2019 was performed. All patients underwent intraoperative CEUS and postoperative CEMRI to assess femoral epiphyseal perfusion using intravenous contrast. Perfusion status was rated as normal, partially decreased, or globally decreased in both modalities. Agreement in perfusion status between CEUS and CEMRI was assessed. Patients were followed for a minimum of 2 years postoperatively and assessed for PFGD. RESULTS: Eighteen patients (28% males) underwent closed or open reduction at an average age of 8 months (3 to 16 mo). The agreement in perfusion status between CEUS and CEMRI was substantial (α = 0.74). Patients were followed for a median of 3 years. PFGD developed in 3 hips (17%). For the detection of PFGD, both imaging modalities performed very well and with no difference in the diagnostic utility of CEUS compared with CEMRI. Considering normal perfusion alone the accuracy, sensitivity, and specificity for CEUS were 83%, 100%, and 80%, and for CEMRI were 78%, 100%, and 73%, respectively. Considering global decreased perfusion alone, the accuracy, sensitivity, and specificity for CEUS were 94%, 67%, and 100%, and for CEMRI were 89%, 67%, and 93%, respectively. CONCLUSIONS: CEUS is a viable intraoperative method to assess infant hip perfusion. This pilot study appears to be comparable to CEMRI at visualizing perfusion of infant hips and as good or better in predicting PFGD after hip reduction. Prospective studies of this imaging technique should be performed to confirm the findings of this retrospective review. LEVEL OF EVIDENCE: Level II-development diagnostic criteria on the basis of consecutive patients (with generally preferred standard).

A Prospective, Multicenter Study of Developmental Dysplasia of the Hip: What Can Patients Expect After Open Reduction?

BACKGROUND: Although there are several predominantly single-center case series in the literature, relatively little prospectively collected data exist regarding the outcomes of open hip reduction (OR) for infantile developmental dysplasia of the hip (DDH). The purpose of this prospective, multi-center study was to determine the outcomes after OR in a diverse patient population. METHODS: The prospectively collected database of an international multicenter study group was queried for all patients treated with OR for DDH. Minimum follow-up was 1 year. Proximal femoral growth disturbance (PFGD) was defined by consensus review using Salter's criteria. Persistent acetabular dysplasia was defined as an acetabular index >90th percentile for age. Statistical analyses were performed to compare preoperative and operative characteristics that predicted re-dislocation, PFGD, and residual acetabular dysplasia. RESULTS: A cohort of 232 hips (195 patients) was identified; median age at OR was 19 months (interquartile range 13 to 28) and median follow-up length was 21 months (interquartile range 16 to 32). Re-dislocation occurred in 7% of hips (n=16/228). The majority (81%; n=13/16) occurred in the first year after initial OR. Excluding patients with repeat dislocation, 94.5% of hips were IHDI 1 at most recent follow-up. On the basis of strict radiographic review, some degree of PFGD was present in 44% of hips (n=101/230) at most recent follow-up. Seventy-eight hips (55%) demonstrated residual dysplasia compared with established normative data. Hips that had a pelvic osteotomy at index surgery had about half the rate of residual dysplasia (39%; n=32/82) versus those without a pelvic osteotomy with at least 2 years follow-up (78%; n=46/59). CONCLUSIONS: In the largest prospective, multicenter study to date, OR for infantile DDH was associated with a 7% risk of re-dislocation, 44% risk of PFGD, and 55% risk of residual acetabular dysplasia at short term follow-up. The incidence of these adverse outcomes is higher than previous reports. Patients treated with concomitant pelvic osteotomy had lower rates of residual dysplasia. These prospectively collected, multicenter data provide better generalizable information to improve family education and appropriately set expectations. LEVEL OF EVIDENCE: Level II, prospective comparative study.

Barriers to Discharge After Hip Reconstruction Surgery in Non-ambulatory Children With Neurological Complex Chronic Conditions.

BACKGROUND: Hip reconstruction surgery in patients with neurological complex chronic conditions (CCC) is associated with prolonged hospitalization and extensive resource utilization. This population is vulnerable to cognitive, developmental, and medical comorbidities which can increase length of stay (LOS). The aims of this study were to characterize barriers to discharge for a cohort of children with neurological CCC undergoing hip reconstruction surgery and to identify patient risk factors for prolonged hospitalization and delayed discharge. METHODS: Retrospective chart review of nonambulatory patients with neurological CCC undergoing hip reconstruction surgery between 2007-2016 was conducted. Hospitalization ≥1 day past medical clearance was characterized as delayed discharge. Barriers were defined as unresolved issues at the time of medical clearance and categorized as pertaining to the caregiver and patient education, durable medical equipment, postdischarge transportation/placement, and patient care needs. RESULTS: The cohort of 116 patients was 53% male, 16% non-English speaking, and 49% Gross Motor Function Classification System (GMFCS) V with the mean age at surgery of 9.1±3.64 years. Median time from admission to medical clearance was 5 days with median LOS of 6 days. Approximately three-quarters of patients experienced delayed discharge (73%) with barriers identified for 74% of delays. Most prevalent barriers involved education (30%) and durable medical equipment (29%). Postdischarge transportation and placement accounted for 26% of barriers and 3.5 times longer delays ( P <0.001). Factors associated with delayed discharge included increased medical comorbidities ( P <0.05) and GMFCS V ( P <0.001). Longer LOS and medical clearance times were found for female ( P =0.005), older age ( P <0.001), bilateral surgery ( P =0.009), GMFCS V ( P =0.003), and non-English-speaking patients ( P <0.001). CONCLUSIONS: Patients with neurological CCC frequently encounter postoperative barriers contributing to increased LOS and delayed discharge. Patients that may be at higher risk for prolonged hospitalization and greater resource utilization include those who are female sex, adolescent, GMFCS V, non-English speaking, have additional comorbidities, and are undergoing bilateral surgery. Standardized preoperative assessment of educational needs, perioperative equipment requirements, and posthospital transportation may decrease the LOS, reduce caregiver and patient burden/distress, cost, and ultimately reduce variation in care delivery. LEVEL OF EVIDENCE: Level III, Retrospective Case Series.

Epidural Analgesia Versus Lumbar Plexus Blockade After Hip Reconstruction Surgery in Children With Cerebral Palsy and Intrathecal Baclofen Pumps: A Comparison of Safety and Efficacy.

BACKGROUND: Epidural analgesia is commonly used for pain control after reconstructive hip surgery, but its use is controversial in the presence of an intrathecal baclofen pump (ITB). The purpose of this retrospective study was to investigate the rate of serious anesthetic and postoperative complications as well as the efficacy of epidural analgesia compared with lumbar plexus blocks (LPBs) for pain management after neuromuscular hip reconstruction in children with cerebral palsy (CP) and ITB. METHODS: Pediatric patients with CP and ITB undergoing hip reconstructive surgery from 2010 to 2019 were retrospectively identified. Patients receiving epidural analgesia were compared with those receiving LPB. Morphine milligram equivalents per kilogram were used as a surrogate measure for pain-related outcomes, as pain scores were reported with wide ranges (eg, 0 to 5/10), making it unfeasible to compare them across the cohort. Postoperative complications were graded using the modified Clavien-Dindo classification. RESULTS: Forty-four patients (26/44, 59% male) underwent surgery at an average age of 10.3 years (SD=3.4 y, range: 4 to 17 y). The majority utilized LPB (28/44, 64%) while the remaining utilized epidural (16/44, 36%). There were no differences in rates of serious complications, including no cases of ITB malfunction, damage, or infection. During the immediate postoperative course, patients who received LPB had higher morphine milligram equivalents per kilogram requirements than patients who received epidural analgesia. CONCLUSIONS: In patients with CP undergoing hip reconstruction surgery with an ITB in situ, epidural anesthesia was associated with improved analgesia compared with LPB analgesia, with a similar risk for adverse outcomes. Epidural catheters placed using image-guided insertion techniques can avoid damage to the ITB catheter while providing effective postoperative pain control without increasing rates of complications in this complex patient population. LEVEL OF EVIDENCE: Level III.

Incidence of Pediatric Venous Thromboembolism After Elective Spine and Lower-Extremity Surgery in Children With Neuromuscular Complex Chronic Conditions: Do we Need Prophylaxis?

BACKGROUND: The incidence of venous thromboembolism (VTE) after elective surgery in children with mobility impairments, including those with a neuromuscular complex chronic condition (NCCC), is unknown. Therefore, our objectives were to assess the incidence of VTE after elective spine and lower-extremity surgery in children with NCCC. METHODS: A retrospective analysis of children with NCCC undergoing elective lower-extremity and/or spinal surgeries from 2005 to 2009 included in the Pediatric Health Information Systems Plus (PHIS+) database. VTE during hospitalization for surgery was assessed through abstraction and review of ultrasound (U/S) and computed tomography results by 2 independent reviewers. VTEs related to pre-existing central venous catheters were excluded. RESULTS: There were 4,583 children with NCCC who underwent orthopaedic surgery during the study period at 6 centers. Most were male (56.3%), non-Hispanic whites (72.7%), and had private insurance (52.2%). The most common NCCC diagnoses were cerebral palsy (46.7%), brain and spinal cord malformations (31.1%), and central nervous system degenerative conditions (14.5%). Forty children (0.9%) underwent U/S to assess VTE. Eighteen children (0.4%) underwent computed tomography to assess VTE. Four children (with cerebral palsy) had a positive U/S for a lower-extremity VTE (10-18 y of age), yet 2 had their VTE before surgery. Therefore, the adjusted VTE rate for children with NCCC undergoing orthopaedic lower-extremity or spine surgery was 4 per 10,000 (2 cases per 4583 surgeries). Each of the 2 cases had a known coagulation disorder preoperatively. Only 10% of the cohort used compression devices, 3% enoxaparin, and 1.6% aspirin for prophylaxis. CONCLUSION: The rate of non-central-venous-catheter-related VTE associated with orthopaedic surgery in children with NCCC is very low and lower than rates reported in healthy children. SIGNIFICANCE: To our knowledge, this is the first multi-institutional study reporting the incidence of VTE in children with NCCCs undergoing elective hip and spine surgery. These data support no additional prophylaxis is required in children with NCCC undergoing elective hip and spine surgery unless other known risk factors are also present.

Should I Plan to Open? Predicting the Need for Open Reduction in the Treatment of Developmental Dysplasia of the Hip.

BACKGROUND: Closed reduction is generally attempted on children under 18 months of age who present as older infants or who fail nonoperative management for developmental dysplasia of the hip (DDH). However, many of these patients will not achieve concentric reduction by closed means and will ultimately require open reduction (OR). Limited evidence exists to predict which patients can be adequately closed reduced versus those who will need open treatment. METHODS: Prospectively collected data from 4 select centers of an international multicenter study group sharing a common treatment approach were reviewed for all DDH infants under 18 months old that required operative management. Patients were categorized into 2 groups: those whose hips were successfully closed reduced or those who ultimately required OR. Factors were compared between the closed reduction and OR groups for 2 separate cohorts-those presenting early in life with ultrasound (US) data, and those presenting later with radiographic data. RESULTS: A total of 154 patients (166 hips) were included in the analysis. Overall, 87.3% were female. In the early-presenting cohort, purposeful entry multivariate regression revealed that patients with Graf IV hips on US had 3.8 times higher odds of requiring an OR. For the later cohort, hips that were clinically irreducible (ie, negative Ortolani sign) had 3.3 times higher odds of requiring OR. Patients with International Hip Dysplasia Institute (IHDI) grade IV hips had 2.5 times higher odds of needing an OR versus those with grade III hips and 15.4 times higher odds than those with grade II hips. Children with an IHDI grade IV hip and a negative Ortolani sign had 4.4 times higher odds of needing OR. CONCLUSION: Children younger than 18 months with dislocated hips who require OR are more likely to have a high-grade radiographic dislocation (IHDI grade IV), negative preoperative Ortolani sign, and a Graf IV classification on initial US. This information may help surgeons budget the use of operating room time and better counsel parents about intraoperative expectations. LEVEL OF EVIDENCE: Level III-Prognostic.

The Use of Tranexamic Acid (TXA) in Neuromuscular Hip Reconstruction: Can We Alter the Need for Blood Transfusion?

BACKGROUND: Children with neuromuscular complex chronic conditions (NMCCC) frequently undergo hip reconstruction surgery requiring blood transfusion. The purpose of this study is to examine the efficacy of tranexamic acid (TXA) to reduce blood loss and transfusion requirement in NMCCC children undergoing hip reconstruction surgery. METHODS: Children with NMCCC undergoing hip reconstruction surgery between 2013 and 2018 were identified. Two cohorts were identified: those who received TXA and those who did not. Patient and surgical characteristics between cohorts were used for propensity matching. Patients were matched on the basis of comorbid factors, bilateral involvement, pelvic osteotomy, open reduction, and surgeon. Comparative outcomes between cohorts were analyzed for intraoperative and postoperative blood loss and transfusion requirements and length of hospital stay (LOS). RESULTS: A total of 166 patients underwent hip surgery at an average of 9.6 years (SD, 4.0). Propensity matching utilized 72% of the cohort including 47 TXA and 72 non-TXA subjects. There were no differences in patient or surgical characteristics across matched groups. Fifteen (15/47, 32%) TXA subjects required a postoperative blood transfusion compared with the 47% (34/72) of non-TXA subjects who required a transfusion and intraoperative transfusion rates were similar between the 2 groups. There was no significant difference in complication rate (TXA, 79%; non-TXA, 86%), reported estimated blood loss (median=200 mLfor both) or LOS (median=6 d for both). Hematocrit levels were slightly higher in TXA subjects intraoperatively (P=0.047), at the end of surgery (P=0.04), and for the overall lowest perioperative level (P=0.04). The overall percent loss of estimated blood volume was less for those who were given TXA compared with those who were not (P=0.001). CONCLUSIONS: The use of TXA during hip reconstruction surgery in NMCCC children significantly reduced the percent loss of estimated blood volume and postoperative transfusion rate. Further prospective multicenter studies are needed to verify the positive effects and safety of TXA in the setting of hip reconstruction surgery in NMCCC children. LEVEL OF EVIDENCE: Level III-retrospective comparative study.

Vascular Supply to the Femoral Head in Patients With Healed Slipped Capital Femoral Epiphysis.

BACKGROUND: Slipped capital femoral epiphysis (SCFE) is one of the most common hip disorders. The vascularity of the lateral epiphyseal vessels supplying the femoral head in patients with healed SCFE has not been well defined. The purpose of this study was to characterize the location and number of lateral epiphyseal vessels in young adults with healed SCFE. METHODS: This was a retrospective study of 17 patients (18 hips) with a diagnosis of SCFE and a matched control group of 17 patients (17 hips) with developmental dysplasia of the hip. All patients underwent high-resolution contrast-enhanced magnetic resonance imaging to visualize the path of the medial femoral circumflex artery and the lateral epiphyseal arterial branches supplying the femoral head. RESULTS: There were 5 unstable SCFEs and 13 stable SCFEs with an average slip angle of 31 degrees. (All patients had been treated with in situ pinning and screw removal). Average age at time of magnetic resonance imaging was 24.5 years (range, 15 to 34 y). The lateral epiphyseal vessels reliably inserted on the posterior-superior aspect of the femoral neck from the superior-anterior to the superior-posterior position in both the SCFE and control groups. An average of 2 (±0.8) retinacular vessels were identified in the SCFE group compared with 5.2 (±0.7) retinacular vessels in the control group (P<0.001). CONCLUSIONS: In healed SCFE, the lateral epiphyseal vessels reliably insert in the same anatomic region as patients with hip dysplasia; however, the overall number of vessels is significantly lower.

Hip Reconstruction in Nonambulatory Children With Cerebral Palsy: Identifying Risk Factors Associated With Postoperative Complications and Prolonged Length of Stay.

BACKGROUND: The purpose of this study is to examine the relationship between preoperative comorbidities, surgical complications, and length of stay (LOS) after hip reconstruction in nonambulatory children with cerebral palsy (CP). METHODS: This single-center retrospective cohort study included 127 patients undergoing hip surgery between 2007 and 2016 who were diagnosed with CP (GMFCS IV/V). The cohort was 54% Gross Motor Function Classification System (GMFCS) V with an average age at surgery of 9 years (range, 3-19 y). Preoperative comorbidities included: presence of a gastrostomy tube, respiratory difficulty requiring positive-pressure ventilation or tracheostomy, history of seizures, and nonverbal status. Complications were dichotomized into major and minor complications according to severity. Multivariable general linear modeling was used to identify factors associated with complications and prolonged LOS. RESULTS: The median LOS in the hospital was 6 days (intequartile range, 5-9 d). The majority of procedures (72%) involved both the femur and acetabulum and 82% of surgeries were performed bilaterally. Patients who experienced a major complication were mostly GMFCS level V and were more likely to spend time in intensive care unit than postanesthetic care unit (P=0.001). Multivariable analysis for a major complication determined that the addition of each comorbid risk fact increased the odds of developing a major complication by 2.6 times (odds ratio, 2.64; 95% confidence interval, 1.56-4.47; P<0.001) regardless of GMFCS level. Multivariable analysis for prolonged LOS determined that major complications (P<0.001), bilaterality (P=0.01), age (P=0.02), female sex (P=0.01), and GMFCS V (P<0.001) were all factors that increased LOS. Migration percentage, acetabular index odds ratio, and pelvic obliquity were not associated with prolonged LOS or the presence of a major complication. CONCLUSIONS: From our analysis, the authors found that a patient's premorbid comorbidities were more predictive of the likelihood of sustaining a major complication than their GMFCS level. Identifying high-risk patients preoperatively may help reduce complications and LOS, which ultimately will improve the quality of care the authors deliver to nonambulatory children with CP undergoing hip reconstruction surgery. LEVEL OF EVIDENCE: Level III-retrospective cohort study.

Measuring the Reliability and Construct Validity of the Pediatric Evaluation of Disability Inventory-Computer Adaptive Test (PEDI-CAT) in Children With Cerebral Palsy.

OBJECTIVE: The purpose of this study was to (1) investigate the construct validity and (2) test-retest reliability of the Pediatric Evaluation of Disability Inventory-Computer Adaptive Test (PEDI-CAT) in children with cerebral palsy (CP). DESIGN: A prospective convenience cross-sectional sample. SETTING: Multidisciplinary CP clinic in a tertiary level pediatric children's hospital. PARTICIPANTS: English- and Spanish-speaking school-aged children (N=101) with a diagnosis of CP, stratified by Gross Motor Function Classification System level, who presented to our multidisciplinary clinic. Participants were excluded if they underwent recent surgery (<6mo) or botulinum neurotoxin A injection (<3mo). A subset of 17 families participated in retest reliability. MAIN OUTCOME MEASURES: Convergent and divergent validity were evaluated using Spearman correlation coefficient analysis; test-retest reliability was assessed using intraclass correlation coefficients (ICCs). RESULTS: Mean age was 12±3.7 years. Convergent validity was established between Mobility (PEDI-CAT) and Functional Mobility Scale (FMS) (5 m, r=0.85; 50 m, r=0.84; 500 m, r=0.76; P<.001). In ambulant children, convergent validity was established between Daily Activities (PEDI-CAT vs Pediatric Quality of Life CP [PedsQL-CP] [r=0.85, P<.001]) and between Social/Cognitive (PEDI-CAT) and Speech and Communication (PedsQL-CP) (r=0.42, P<.001). In nonambulant children, convergent validity was established between Daily Activities (PEDI-CAT) and Personal Care (Caregiver Priorities and Child Health Index of Life with Disabilities [CPCHILD]) (r=0.44, P<.001) and between social/cognitive (PEDI-CAT) and Communication (CPCHILD) (r=0.64, P<.001). A lack of correlation between Daily Activities, Social/Cognitive, and Responsibility (PEDI-CAT) and FMS and between the Mobility (PEDI-CAT) and Communication (PedsQL) domains confirmed divergent validity. Test-retest reliability was excellent for all domains of the PEDI-CAT (ICC=0.96-0.99). CONCLUSIONS: The PEDI-CAT is an outcome measure that demonstrates strong construct validity and reliability in children with CP.

Developmental Dysplasia of the Hip From Birth to Arthroplasty: Clear Indications and New Controversies.

Developmental dysplasia of the hip is the all-encompassing term used to describe the wide spectrum of disorders of the development of the hip that manifest in various forms and at different ages. Developmental dysplasia of the hip often evolves over time because the structures of the hip are normal during embryogenesis but gradually become abnormal. Such variability in pathology is associated with a similarly wide range in management options and recommendations aimed at preventing hip joint arthrosis. These options may be instituted at any time between birth and adulthood as techniques aimed at preserving the native hip or replacing the arthritic hip. Many of these management options are clearly indicated and considered standard practice. However, with the evolution of the understanding of hip biomechanics, better knowledge of the long-term outcomes of hip joint-preserving surgeries, and ever-improving technology influencing hip arthroplasty come new controversies, especially whether to preserve or replace the mature hip.

Radiation Prophylaxis for Hip Salvage Surgery in Cerebral Palsy: Can We Reduce the Incidence of Heterotopic Ossification?

BACKGROUND: Heterotopic ossification (HO) is a well-recognized complication of proximal femoral resection (PFR) surgery in children with cerebral palsy (CP). Although single-dose radiation prophylaxis (SDRP) has been shown to be effective at lowering the rates of HO following adult total hip arthroplasty; there has been limited study examining the efficacy of SDRP for HO prevention in children with CP undergoing PFR. The purpose of this study was to assess the efficacy of SDRP in children with CP undergoing PFR. METHODS: This retrospective case control series identified all patients from one tertiary children's hospital undergoing PFHR. Patients were dichotomized into (1) SDRP and (2) non-SDRP groups. In SDRP, radiation was delivered preoperatively at a dose of 7.5 Gy utilizing a 6 MV photon beam. The incidence of HO in the SDRP cohort was compared to historic data using binomial testing. The size of HO lesions was compared using Wilcoxon signed-rank test. McCarthy, Brooker, and Anatomic Classifications of HO were compared using repeated measures logistic regression. RESULTS: Twenty-three patients (mean age, 15.5) and 35 hips (17 SDRP, 18 Non-SDRP) were included in the analysis. There were 17 females and 6 males in the cohort with the majority classified as GMFCS V, 21/23 (91%). HO was seen in 6 of the SDRP cohort (6/17, 35%) and 15 of the non-SDRP cohort (15/18, 83%) (P=0.015). The average size of HO at maturity was 282.7 mm in the SDRP cohort compared with 1221.5 mm in the Non-SDRP cohort (P=0.026). Radiation treatment was associated with a 938.9 mm decrease in HO size at maturity (P= 0.026). Multivariate repeated measures logistic regression analysis found that non-SDRP hips had 13 times higher odds of developing HO (P=0.015). There were no significant differences in infection rates between the 2 cohorts and there were no radiation-associated complications. CONCLUSIONS: Short-term follow up demonstrates that SDRP is a safe and efficacious intervention in decreasing the incidence and size of HO in children with CP undergoing PFR. LEVELS OF EVIDENCE: Level III-Case control cohort study.

Ultrasound Characteristics of Clinically Dislocated But Reducible Hips With DDH.

BACKGROUND: Although ultrasound (US) is frequently used in diagnosis and management of infantile developmental dysplasia of the hip, precise ultrasonographic parameters of what constitutes a dislocation, subluxation etc remain poorly defined. The purpose of this study was (1) to describe the ultrasonographic characteristics of a large cohort of clinically dislocated but reducible hips and (2) to begin to develop ultrasonographic definitions for what constitutes a hip dislocation. METHODS: A retrospective review of prospectively collected data from an international multicenter study group on developmental dysplasia of the hip was conducted on all patients under 6 months of age with hip(s) that were dislocated at rest but reducible based on initial physical examination (ie, Ortolani positive). Femoral head coverage (FHC), alpha angle (α), and beta angle (ß) were measured on pretreatment US by the individual treating surgeon, and were recorded directly into the database. RESULTS: Based on 325 Ortolani positive hips, the median FHC on presentation was 10% with an interquartile range of 0% to 23%. A total of 126 of the 327 hips (39%) demonstrated 0% FHC. The 90th percentile was found to be at 33% FHC. Of 264 hips with sufficient α data, the median α was 43 degrees with an interquartile range from 37 to 49 degrees. The 90th percentile for α was at 54 degrees. A total of 164 hips had documented ß with a median of 66 degrees and an interquartile range of 57 to 79 degrees; the 90th percentile was at 94 degrees. CONCLUSIONS: Analysis of a large cohort of patients with dislocated but reducible hips reveals a median percent FHC of 10%, a median α of 43 degrees, and a median ß of 66 degrees on initial US. Using a threshold at the 90th percentile, a sensible ultrasonographic definition of a dislocated hip seems to be FHC≤33%, implying that FHC between 34% and 50% may be reasonably termed a subluxation. Although these findings are consistent with previous, smaller reports, further prospective research is necessary to validate these thresholds. LEVEL OF EVIDENCE: Level IV-diagnostic 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.

Acute Exertional Compartment Syndrome in Young Athletes: A Descriptive Case Series and Review of the Literature.

OBJECTIVES: Acute exertional compartment syndrome (AECS) is a rare presentation of acute compartment syndrome (ACS) after exertion without injury. Unfamiliarity with this entity can lead to delay in diagnosis. The purpose of this study was to increase awareness of AECS and illustrate the morbidities associated with delayed diagnosis. METHODS: With institutional review board approval, we conducted a retrospective chart review of all patients who underwent emergent fasciotomies for AECS from 1997-2013 at our institution. Male patients with sports-related closed fractures of the tibia leading to ACS were identified for comparison. Demographic variables, patient-specific factors, treatment, and outcome characteristics were analyzed. RESULTS: Seven male patients (mean age, 17 years) presented to our institution with AECS from 1997-2013, and 9 patients with fracture-related ACS were selected for comparison. All cases of AECS occurred in the leg. In the AECS group, the mean time from symptom onset to diagnosis was 97 hours. Four patients initially had a missed diagnosis. On presentation, 6 of 7 patients experienced neurologic symptoms (motor or sensory deficit), although none had perfusion deficits. The mean compartment pressure was 91 mm Hg. They all underwent isolated anterior and lateral compartment releases (except for 1 patient who required a 4-compartment release) and required a mean of 4 surgeries. The mean follow-up was 270 days. Of the 4 patients with missed diagnoses, 2 had significant neurologic and functional deficits at final follow-up. The other 5 patients had a full recovery. Fracture-related ACS patients were younger, with quicker time from symptom onset to surgery, and required more compartments to be decompressed at surgery. CONCLUSIONS: Despite the rarity of AECS, orthopedists as well as primary care, emergency medicine, and sports medicine physicians should maintain a high index of suspicion when examining a patient with leg pain out of proportion to examination after exertion. Delay in diagnosis of AECS is associated with substantial muscle necrosis and morbidity.

Survivorship of the Bernese Periacetabular Osteotomy: What Factors are Associated with Long-term Failure?

BACKGROUND: The Bernese periacetabular osteotomy (PAO) continues to be a commonly performed nonarthroplasty option to treat symptomatic developmental hip dysplasia, but there are few long-term followup studies evaluating results after PAO. QUESTIONS/PURPOSES: (1) What is the long-term survivorship of the hip after PAO? (2) What were the validated outcomes scores among patients who had PAO more than 14 years ago? (3) What factors are associated with long-term failure? METHODS: One hundred fifty-eight dysplastic hips (133 patients) underwent PAO between May 1991 and September 1998 by a single surgeon. Of those, 37 hips (34 patients [26%]) were lost to followup; an additional seven patients (5% [eight hips]) had not been seen in the last 5 years. The 121 hips (in 99 patients) were retrospectively evaluated at a mean of 18 years (range, 14-22 years). Survivorship was assessed using Kaplan-Meier analysis with total hip arthroplasty (THA) as the endpoint. Hips were evaluated for activity, pain, and general health using the UCLA Activity Score, modified Harris hip score, WOMAC, and Hip disability and Osteoarthritis Outcome Score (HOOS). Failure was defined as a WOMAC pain subscale score ≥ 10 or having undergone THA. Hips were divided into three groups: asymptomatic (did not meet any failure criteria at any point in time), symptomatic (met WOMAC pain failure criteria at previous or most recent followup), and replaced (having undergone THA). A multinomial logistic regression model using a general estimating equations approach was used to assess factors associated with failure. RESULTS: Kaplan-Meier analysis with THA as the endpoint revealed a survival rate (95% confidence interval [CI]) of 74% (66%-83%) at 18 years. Twenty-six hips (21%) underwent THA at an average of 9 ± 5 years from the surgery. Sixty-four hips (53%) remained asymptomatic and did not meet any failure criteria at most recent followup. Thirty-one hips (26%) were symptomatic and considered failed based on a WOMAC pain score of ≥ 10 with a mean ± SD of 11 ± 4 out of 20 at most recent followup. Although some failed initially by pain, their most recent WOMAC score may have been < 10. Of the 16 symptomatic hips that failed early by pain (reported a WOMAC pain subscale score ≥ 10 in the prior study), two were lost to followup, two underwent THA at 16 and 17 years, four still failed because of pain at most recent followup, and the remaining eight had WOMAC pain scores < 10 at most recent followup. Asymptomatic hips reported better UCLA Activity Scores (asymptomatic: mean ± SD, 7 ± 2; symptomatic: 6 ± 2, p = 0.001), modified Harris hip scores (pain, function, and activity sections; asymptomatic: 80 ± 11; symptomatic: 50 ± 15, p < 0.001), WOMAC (asymptomatic: 2 ± 2, symptomatic: 11 ± 4, p < 0.001), and HOOS (asymptomatic: 87 ± 11, symptomatic: 52 ± 20, p < 0.001) compared with symptomatic hips at long-term followup. Age older than 25 years at the time of PAO (symptomatic: odds ratio [OR], 3.6; 95% CI, 1.3-9.8; p = 0.01; replaced: OR, 8.9; 95% CI, 2.6-30.9; p < 0.001) and a preoperative joint space width ≤ 2 mm (replaced: OR, 0.3; 95% CI, 0.12-0.71; p = 0.007) or ≥ 5 mm (replaced: OR, 0.121; 95% CI, 0.03-0.56; p = 0.007) were associated with long-term failure while controlling for poor or fair preoperative joint congruency. CONCLUSIONS: This study demonstrates the durability of the Bernese PAO at long-term followup. In a subset of patients, there was progression to failure over time. Factors of progression to THA or more severe symptoms include age older than 25 years, poor or fair preoperative hip congruency, and a preoperative joint space width that is less than 2 mm or more than 5 mm. Future studies should focus on evaluating the two failure groups that we have identified in our study: those that failed early and went on to THA and those that are symptomatic at long-term followup. LEVEL OF EVIDENCE: Level III, therapeutic study.

Fracture Table Application for Pediatric Femur Fractures: Incidence and Risk Factors Associated With Adverse Outcomes.

BACKGROUND: Flexible elastic nails, submuscular plating, and rigid locked intramedullary nails are common methods of fixation for pediatric femur fractures (PFF) in which the fracture table is used to aid reduction. Little is known about complications associated with fracture table application in PFF. The purpose of this study was to determine the incidence and risk factors associated with adverse outcomes related to fracture table application for the treatment of PFF. METHODS: A retrospective chart review of all children (younger than 18 y) treated for a femur fracture with the use of the fracture table between 2004 and 2015 at a single tertiary pediatric hospital was performed. Data on demographics, mechanism of injury, treatment modality, radiographic characteristics, and fracture table-related complications were gathered. Complications of interest included nerve palsy, skin breakdown/ulceration, vascular injury, and compartment syndrome. Penalized likelihood logistic regression was used to determine risk factors associated with adverse outcomes. RESULTS: In total, 260 patients were included. There were 8 patients with nerve palsies related to positioning and traction on the fracture table (1 bilateral and 6 ipsilateral peroneal nerve palsies, 1 contralateral tibial nerve palsy; incidence of 3.1%). No other fracture table-related complications were recorded. Patients who developed a nerve palsy were significantly heavier (78.7 vs. 44.3 kg, P<0.001) and had a significantly longer mean surgical time (188.6 vs. 117.0 min, P<0.001). Multivariate analysis demonstrated weight to be the only significant risk factor for complications, with a 5% increase in odds of complication with each additional kilogram (odds ratio, 1.05; confidence interval, 1.03-1.08; P<0.001). CONCLUSIONS: Nerve palsy related to the use of the fracture table during the fixation of PFF occurred in 3.1% of patients in our series. Patients who developed nerve palsies were significantly heavier and had significantly longer surgical times. Although the use of the fracture table for fixation of PFF is safe, every effort should be made to minimize time in traction to avoid iatrogenic nerve palsy, particularly in heavier children (>80 kg). LEVEL OF EVIDENCE: Level III.

What Risk Factors and Characteristics Are Associated With Late-presenting Dislocations of the Hip in Infants?

BACKGROUND: Most infants with developmental dysplasia of the hip (DDH) are diagnosed within the first 3 months of life. However, late-presenting DDH (defined as a diagnosis after 3 months of age) does occur and often results in more complex treatment and increased long-term complications. Specific risk factors involved in late-presenting DDH are poorly understood, and clearly defining an associated set of factors will aid in screening, detection, and prevention of this condition. QUESTIONS/PURPOSES: Using a multicenter database of patients with DDH, we sought to determine whether there were differences in (1) risk factors or (2) the nature of the dislocation (laterality and joint laxity) when comparing patients with early versus late presentation. METHODS: A retrospective review of prospectively collected data from a multicenter database of patients with dislocated hips was conducted from 2010 to 2014. Baseline demographics for fetal presentation (cephalic/breech), birth presentation (vaginal/cesarean), birth weight, maternal age, maternal parity, gestational age, family history, and swaddling history of patients were compared among nine different sites for patients who were enrolled at age younger than 3 months and those enrolled between 3 and 18 months of age. A total of 392 patients were enrolled at baseline between 0 and 18 months of age with at least one dislocated hip. Of that group, 259 patients were younger than 3 months of age and 133 were 3 to 18 months of age. The proportion of patients with DDH who were enrolled and followed at the nine participating centers was 98%. RESULTS: A univariate/multivariate analysis was performed comparing key baseline demographics between early- and late-presenting patients. After controlling for relevant confounding variables, two variables were identified as risk factors for late-presenting DDH as compared with early-presenting: cephalic presentation at birth and swaddling history. Late-presenting patients were more likely to have had a cephalic presentation than early-presenting patients (88% [117 of 133] versus 65% [169 or 259]; odds ratio [OR], 5.366; 95% confidence interval [CI], 2.44-11.78; p < 0.001). Additionally, late-presenting patients were more likely to have had a history of swaddling (40% [53 of 133] versus 25% [64 of 259]; OR, 2.053; 95% CI, 1.22-3.45; p = 0.0016). No difference was seen for sex (p = 0.63), birth presentation (p = 0.088), birth weight (p = 0.90), maternal age (p = 0.39), maternal parity (p = 0.54), gestational age (p = 0.42), or family history (p = 0.11) between the two groups. Late presenters were more likely to present with an irreducible dislocation than early presenters (56% [82 of 147 hips] versus 19% [63 of 333 hips]; OR, 5.407; 95% CI, 3.532-8.275; p < 0.001) and were less likely to have a bilateral dislocation (11% [14 of 133] versus 28% [73 of 259]; OR, 0.300; 95% CI, 0.162-0.555; p = 0.002). CONCLUSIONS: Those presenting with DDH after 3 months of age have fewer of the traditional risk factors for DDH (such as breech birth), which may explain the reason for a missed diagnosis at a younger age. In addition, swaddling history was more common in late-presenting infants. A high index of suspicion for DDH should be maintained for all infants, not just those with traditional risk factors for DDH. Further investigation is required to determine if swaddling is a risk factor for the development of hip dislocations in older infants. More rigorous examination into traditional screening methods should also be performed to determine whether current screening is sufficient and whether late-presenting dislocations are present early and missed or whether they develop over time. LEVEL OF EVIDENCE: Level III, retrospective study.

Medial versus anterior open reduction for developmental hip dislocation in age-matched patients.

BACKGROUND: The difference between medial (MAOR) and anterior (AAOR) approaches for open reduction of developmental hip dysplasia in terms of risk for avascular necrosis (AVN) and need for further corrective surgery (FCS, femoral and/or acetabular osteotomy) is unclear. This study compared age-matched cohorts undergoing either MAOR or AAOR in terms of these 2 primary outcomes. Prognostic impact of presence of ossific nucleus at time of open reduction was also investigated. METHODS: Institutional review board approval was obtained. Nineteen hips (14 patients) managed by MAOR were matched with 19 hips (18 patients) managed by AAOR based on age at operation (mean 6.0; range, 1.4 to 14.9 mo). Patients with neuromuscular conditions and known connective tissue disorders were excluded. Primary outcomes assessed at minimum 2 years' follow-up included radiographic evidence of AVN (Kalamchi and MacEwen) or requiring FCS. RESULTS: MAOR and AAOR cohorts were similar regarding age at open reduction, sex, laterality, and follow-up duration. One hip in each group had AVN before open reduction thus were excluded from AVN analysis. At minimum 2 years postoperatively (mean 6.2; range, 1.8 to 11.7 y), 4/18 (22%) MAOR and 5/18 (28%) AAOR met the same criteria for AVN (P=1.0). No predictors of AVN could be identified by regression analysis. Presence of an ossific nucleus preoperatively was not a protective factor from AVN (P=0.27). FCS was required in 4/19 (21%) MAOR and 7/19 (37%) AAOR hips (P=0.48). However, 7/12 (54%) hips failing closed reduction required FCS compared with 4/26 (16%) hips without prior failed closed reduction (P=0.024). Cox regression analysis showed that patients who failed closed reduction had an annual risk of requiring FCS approximately 6 times that of patients without a history of failed closed reduction (hazard ratio=6.1; 95% CI, 1.5-24.4; P=0.009), independent of surgical approach (P=0.55) or length of follow-up (P=0.78). CONCLUSIONS: In this study of age-matched patients undergoing either MAOR or AAOR, we found no association between surgical approach and risk of AVN or FCS. In addition, we identified no protective benefit of a preoperative ossific nucleus in terms of development of AVN. However, failing closed reduction was associated with a 6-fold increased annual risk of requiring FCS. SIGNIFICANCE: To the best of our knowledge, this is the first study comparing these 2 surgical techniques in an age-matched manner. It further corroborates previous studies stating that there may be no difference in risk of AVN based on surgical approach or presence of ossific nucleus preoperatively. LEVEL OF EVIDENCE: Level III-retrospective comparative study.

Complications after modified Dunn osteotomy for the treatment of adolescent slipped capital femoral epiphysis.

BACKGROUND: Modified Dunn osteotomy has gained popularity over the past decade in the treatment of moderate to severe adolescent slipped capital femoral epiphysis. The purpose of this study was to retrospectively evaluate a consecutive series of adolescent slipped capital femoral epiphysis patients treated with the modified Dunn procedure at a single institution. We analyze the indications for the procedure as well as the complications after surgical treatment. METHODS: Forty-three adolescent patients (18 boys and 25 girls) were treated with the modified Dunn procedure at our institution between September 2001 and August 2012. The average follow-up for this cohort was 2.6 years (range, 1 to 8 y). Complications were graded according to the modified Dindo-Clavien classification. RESULTS: Twenty-six patients (60%) had an unstable injury with an inability to ambulate with our without crutches. Seventeen patients (40%) had an acute injury with duration of symptoms <3 weeks. Thirty-seven patients (86%) had a severe slip based on a Southwick slip angle of >50 degrees. Twenty-two complications occurred in 16 patients (37%) in this cohort. Fifteen revision procedures were performed for femoral head avascular necrosis, fixation failure with deformity progression, or postoperative hip dislocation. Two patients developed end-stage degenerative joint disease and severe femoral head avascular necrosis and were referred for a total hip arthroplasty. CONCLUSIONS: The complication rate in this series is higher than most previous reports. This may be in part because of the fact that as a tertiary referral center our patient population was more complex. However, we identified a clear inverse relationship between surgeon-volume and patient-outcomes. On the basis of our results we have modified our practice. A high-volume surgeon must be present during each modified Dunn procedure, and only patients that have sustained an acute severe (>50 degrees) epiphyseal displacement with mild chronic remodeling of the metaphysis that can be addressed within 24 hours of the slip may be treated with the modified Dunn technique. LEVEL OF EVIDENCE: Level IV-therapeutic study.