Contralateral Slipped Capital Femoral Epiphysis Research Articles

Rate and Risk Factors for Contralateral Slippage in Adolescents Treated for Slipped Capital Femoral Epiphysis: A Comprehensive Analysis of 3,528 Cases.

After a unilateral slipped capital femoral epiphysis (SCFE), the contralateral hip is at risk for a subsequent SCFE. However, further information with regard to risk factors involved in the development of contralateral SCFE must be investigated. The purpose of this study was to report the rate and risk factors for subsequent contralateral SCFE in adolescents treated for unilateral SCFE by exploring a mix of known and potential risk factors. A case-control study utilizing aggregated multi-institutional electronic medical record data between January 2003 and March 2023 was conducted. Patients <18 years of age diagnosed with SCFE who underwent surgical management were included. Variables associated with contralateral SCFE were identified using multivariable logistic regression models that adjusted for patient characteristics and time of the surgical procedure, providing adjusted odds ratios (ORs). The false discovery rate was accounted for via the Benjamini-Hochberg method. In this study, 15.3% of patients developed contralateral SCFE at a mean (and standard error) of 296.53 ± 17.23 days and a median of 190 days following the initial SCFE. Increased thyrotropin (OR, 1.43 [95% confidence interval (CI), 1.04 to 1.97]; p = 0.022), diabetes mellitus (OR, 1.67 [95% CI, 1.22 to 2.49]; p = 0.005), severe obesity (OR, 1.81 [95% CI, 1.56 to 2.57]; p < 0.001), history of human growth hormone use (OR, 1.85 [95% CI, 1.10 to 3.38]; p = 0.032), low vitamin D (OR, 5.75 [95% CI, 2.23 to 13.83]; p < 0.001), younger age in boys (under 12 years of age: OR, 1.85 [95% CI, 1.37 to 2.43]; p < 0.001) and in girls (under 11 years of age: OR, 1.47 [95% CI, 1.05 to 2.02]; p = 0.026), and tobacco exposure (OR, 2.43 [95% CI, 1.49 to 3.87]; p < 0.001) were significantly associated with increased odds of developing contralateral SCFE. In the largest study on this topic, we identified the rate, odds, and risk factors associated with development of contralateral SCFE. We found younger age, hypothyroidism, severe obesity, low vitamin D, diabetes mellitus, and a history of human growth hormone use to be independent risk factors. Our findings can aid clinical decision-making in at-risk patients. Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Surgeon Preference for Prophylactic Contralateral Fixation in Slipped Capital Femoral Epiphysis (SCFE) Patients: A Nationwide POSNA Survey Study.

It is estimated that 11% to 60% of unilateral slipped capital femoral epiphysis (SCFE) patients will develop contralateral pathology, usually within 18 months after the first event. Despite this, prophylactic fixation remains controversial, and there is significant variability in surgeon preferences. Thus, this study aimed to determine which factors predict surgeon preferences for prophylactic contralateral pinning in SCFE patients. We designed a survey for pediatric orthopedic surgeons to collect data on (1) surgeon and hospital characteristics, (2) individual preference for contralateral SCFE pinning in three disparate hypothetical scenarios, and (3) personal risk-aversion traits. The questionnaire was distributed across the United States by the POSNA Evidence-Based Orthopaedics Committee. All POSNA members were eligible to respond. We performed analyses to evaluate the role of patient risk factors in hypothetical surgical decision-making and to determine if surgical training, hospital characteristics, and geographic region influenced prophylactic pinning in a surgeon's real-life practice. A total of 126 POSNA members responded to the survey. In the last year, a median of 6.5 SCFE patients was seen per surgeon (1243 patients total). A median of 10% of those patients underwent prophylactic contralateral fixation. In multiple analyses, surgeons were influenced by body mass index, open triradiate cartilage, patient race, various endocrine abnormalities, and specific radiographic measurements when deciding to fix the contralateral side prophylactically. Moreover, in multivariate regression, more years in practice and a hospital size of 500+ beds predicted fewer prophylactic fixation procedures (all P <0.05). Surgeons practicing in the South Atlantic, New England, and Mountain regions of the United States estimated the highest rate of contralateral pinning. This study's findings suggest that multiple factors influence surgeons' decisions to prophylactically fix the contralateral side in SCFE patients. Surgical training, hospital characteristics, and geographical regions played a role in decision-making. N/A.

Which factor is more reliable considering prophylactic pinning of contralateral hip of unilateral SCFE patients?

This study evaluates the radiological parameters of developing subsequent contralateral slips in unilateral slipped capital femoral epiphysis (SCFE) patients at the time of initial presentation. The study group included the review of unilateral SCFE patients treated between June 2007 and August 2018. Age, gen-der, side, stability, posterior slope angle, grade of slip, modified Oxford bone age score (mOBAS), the Risser classification, and the ap-pearance of the triradiate cartilage were evaluated retrospectively. Data were analyzed between two groups: subsequent contralateral SCFE (SCFESC) patients that developed contralateral slip during follow-up and unilateral SCFE (SCFEU) patients that did not develop contralateral slip up to skeletal maturity. Descriptive statistics were used to compare risk factors between groups. This study included 48 patients and 6 patients (12.5%) developed a SCFESC. Only mOBAS was significantly different be-tween groups. The mOBAS scores in SCFESC were 18 in 2 patients (33.3%), 19 in 4 patients (66.7%). The mOBAS scores in SCFEU were 18 in 1 patient (2.4%), 19 in 24 patients (57.1%), and >20 in 17 patients (40.5%). In the SCFESC group, all patients had a Risser score of 0 and all had open triradiate cartilage. Patients with unilateral SCFE are at risk for SCFESC, and the mOBAS is the best predictor of risk assessment. We agree that mOBAS score of 16,17 or 18 patients' contralateral hips can be prophylactically pinned. We also suggest pinning or close screening of mOBAS 19 patients that some carry relatively high risk of subsequent contralateral slip.

Orthopaedic Diagnoses in the Black Pediatric Population.

The Black pediatric population is one that has been historically underserved and continues to have unmet needs. Factors including lack of diversity in orthopaedic studies and in historical standards, such as bone age, may inadvertently lead to inferior care. There are certain conditions in this population for which the practicing orthopaedic surgeon should have a higher degree of suspicion, including slipped capital femoral epiphysis, Blount disease, and postaxial polydactyly. Systemic diseases with higher rates in this population have orthopaedic manifestations, including sickle cell disease, vitamin D deficiency, and obesity. Racial discrepancies in access to prenatal care can have orthopaedic consequences for babies, especially cerebral palsy and myelodysplasia. Racial discrepancy exists in evaluation for nonaccidental trauma. Increased awareness of these issues better prepares practitioners to provide equitable care.

Prophylactic fixation of the unaffected contralateral side in children with slipped capital femoral epiphysis seems favorable: A systematic review.

BACKGROUNDSlipped capital femoral epiphysis (SCFE) occurs in adolescents and has an incidence of around 10 per 100000 children. Children presenting with a unilateral SCFE are 2335 times more likely to develop a contralateral SCFE than the general population. Prognostic factors that have been suggested to increase the risk of contralateral slip include a younger patient, an underlying endocrine disorder, growth hormone use and a higher radiographic posterior sloping angle. However, there is still much debate on the advantages and disadvantages of prophylactic fixation of the unaffected side in an otherwise healthy patient. AIMTo investigate the risk rate of contralateral SCFE and assess the (dis)advantages of prophylactic fixation of the contralateral hip.METHODSA systematic literature search was performed in the Embase, Medline, Web of Science Core Collection and Cochrane databases. Search terms included ‘slipped capital femoral epiphysis,’ ‘fixation,’ ‘contralateral,’ and derivatives. The eligibility of the acquired articles was independently assessed by the authors and additional relevant articles were included through cross-referencing. Publications were considered eligible for inclusion if they presented data about otherwise healthy children with primarily unilateral SCFE and the outcomes of prophylactically pinning their unaffected side, or about the rates of contralateral slips and complications thereof. The study quality of the included articles was assessed independently by the authors by means of the methodological index for non-randomized studies criteria.RESULTSOf 293 identified unique publications, we included 26 studies with a total of 12897 patients. 1762 patients (14%) developed a subsequent symptomatic contralateral slip. In addition, 38% of patients developed a subsequent slip on the contralateral side without experiencing clinical symptoms. The most outspoken advantage of prophylactic fixation of the contralateral hip in the literature is prevention of an (asymptomatic) slip, thus reducing the increased risk of avascular necrosis (AVN), cam morphology and osteoarthritis. Disadvantages include an increased risk of infection, AVN, peri-implant fractures, loss of fixation as well as migration of hardware and morphologic changes as a consequence of growth guidance. These risks, however, appeared to only occur incidentally and were usually mild compared to the risks involved with an actual SCFE. CONCLUSIONThe advantages of prophylactic pinning of the unaffected side in otherwise healthy patients with unilateral SCFE seem to outweigh the disadvantages. The final decision for treatment remains to be patient-tailored.

The British Orthopaedic Surgery Surveillance study: slipped capital femoral epiphysis: the epidemiology and two-year outcomes from a prospective cohort in Great Britain.

AimsThe aim of this study was to inform the epidemiology and treatment of slipped capital femoral epiphysis (SCFE).MethodsThis was an anonymized comprehensive cohort study, with a nested consented cohort, following the the Idea, Development, Exploration, Assessment, Long-term study (IDEAL) framework. A total of 143 of 144 hospitals treating SCFE in Great Britain participated over an 18-month period. Patients were cross-checked against national administrative data and potential missing patients were identified. Clinician-reported outcomes were collected until two years. Patient-reported outcome measures (PROMs) were collected for a subset of participants.ResultsA total of 486 children (513 hips) were newly affected, with a median of two patients (interquartile range 0 to 4) per hospital. The annual incidence was 3.34 (95% confidence interval (CI) 3.01 to 3.67) per 100,000 six- to 18-year-olds. Time to diagnosis in stable disease was increased in severe deformity. There was considerable variation in surgical strategy among those unable to walk at diagnosis (66 urgent surgery vs 43 surgery after interval delay), those with severe radiological deformity (34 fixation with deformity correction vs 36 without correction) and those with unaffected opposite hips (120 prophylactic fixation vs 286 no fixation). Independent risk factors for avascular necrosis (AVN) were the inability of the child to walk at presentation to hospital (adjusted odds ratio (aOR) 4.4 (95% CI 1.7 to 11.4)) and surgical technique of open reduction and internal fixation (aOR 7.5 (95% CI 2.4 to 23.2)). Overall, 33 unaffected untreated opposite hips (11.5%) were treated for SCFE by two-year follow-up. Age was the only independent risk factor for contralateral SCFE, with age under 12.5 years the optimal cut-off to define ‘at risk’. Of hips treated with prophylactic fixation, none had SCFE, though complications included femoral fracture, AVN, and revision surgery. PROMs demonstrated the marked impact on quality of life on the child because of SCFE.ConclusionThe experience of individual hospitals is limited and mechanisms to consolidate learning may enhance care. Diagnostic delays were common and radiological severity worsened with increasing time to diagnosis. There was unexplained variation in treatment, some of which exposes children to significant risks that should be evaluated through randomized controlled trials.Cite this article: Bone Joint J 2022;104-B(4):519–528.

Intraobserver and Interobserver Reliability of the Peritubercle Lucency Sign in Slipped Capital Femoral Epiphysis.

An area of enlargement of the metaphyseal socket around the epiphyseal tubercle, termed the peritubercle lucency sign, has recently been introduced as a possible predictor of contralateral slipped capital femoral epiphysis in patients with previous unilateral slipped capital femoral epiphysis. This study aimed to assess intraobserver and interobserver reliability for detecting the presence or absence of the peritubercle lucency sign. Thirty-five radiographs were presented to 6 fellowship-trained pediatric orthopaedic surgeons on 2 separate occasions 30 days apart, ensuring that the images were shown in a different order on the second exposure. Both times the reviewers recorded whether the peritubercle lucency sign was present or absent in each of the radiographs. Statistical analysis was performed to determine the intraobserver and interobserver reliability. In the intraobserver analysis, percent agreement between the first and second time the radiographs were reviewed varied between 62.9% and 85.7%, for an average intraobserver agreement of 74.8%. κ values for the 6 reviewers varied between 0.34 and 0.716, with an average intraobserver κ value of 0.508. The interobserver percent agreement was 40.0% for the first time the radiographs were reviewed, 42.9% the second time, and the overall interobserver percent agreement was 29%. The interobserver κ value was 0.44 the first time the radiographs were reviewed, 0.45 the second time, and the overall interobserver κ value was 0.45. On the basis of our findings, the peritubercle lucency has modest intraobserver and interobserver reliability at best and should be used with other currently used factors, such as age, presence of endocrinopathy, status of triradiate cartilage, posterior sloping angle, and modified Oxford score, in determining the need for prophylactic pinning. Further refinement of the definition of the peritubercle lucency sign may be needed to improve agreement and reliability of the sign. Level III-prognostic study.

Contralateral slip after unilateral slipped capital femoral epiphysis is associated with acetabular retroversion but not increased acetabular depth and overcoverage.

Overcoverage of the femoral head by the acetabulum, increased acetabular depth and retroversion have been associated with the etiology of slipped capital femoral epiphysis (SCFE). However, limited evidence exists about the impact of the acetabular morphology on the development of a contralateral slip following an initial presentation of unilateral SCFE. We aimed to investigate whether acetabular overcoverage as assessed by an increased lateral center-edge angle (LCEA) and low Tönnis angle, increased acetabular depth assessed by the acetabular depth-width ratio (ADR) and the presence of coxa profunda; and acetabular retroversion assessed by the presence of the crossover sign were associated with a contralateral slip in patients presenting with unilateral SCFE. We evaluated 250 patients with initial diagnosis of unilateral SCFE (average age, 12.5 ± 1.7 years), who had not undergone prophylactic fixation on the contralateral hip for a median follow-up of 49 months (interquartile range: 25-76 months). Endpoints were the development of a contralateral slip (70 patients, 28%) or skeletal maturity assessed by complete closure of the proximal femoral growth plate (180 patients, 72%). We measured the LCEA, Tönnis angle, ADR, and the coxa profunda sign on an anteroposterior pelvic radiograph. The crossover sign was assessed in 208 hips who had a secondary ossification center in the posterior acetabular rim. For each additional degree of LCEA, the odds of contralateral slip decreased 8% [odds ratio = 0.92; 95% confidence interval (CI), 0.87-0.98; P = 0.009]. Tönnis angle (P = 0.11), ADR (P = 0.20) and coxa profunda (p = 0.37) had no association with a contralateral slip. The presence of crossover sign increased two and half times the odds for a contralateral slip (odds ratio = 2.5; 95% CI = 1.12-5.64; P = 0.03). Acetabular retroversion, but not acetabular overcoverage or increased acetabular depth, was associated with contralateral SCFE development in patients with unilateral SCFE. Level of evidence: prognostic level II.

Predicting subsequent contralateral slipped capital femoral epiphysis: an evidence-based approach.

PurposeThe purpose of this study was to identify risk factors for developing a subsequent contralateral slipped capital femoral epiphysis (SCFE) and provide a prediction score to quantify risk of subsequent slip at the time of initial presentation.MethodsThis retrospective study included patients that presented with a unilateral SCFE between 2006 and 2017. Chart and radiographic review were performed to collect demographic, clinical and radiographic risk factors. Descriptive statistics, univariate analyses and multivariate regression analysis were used to compare risk factors between patients that did or did not develop a subsequent contralateral SCFE.ResultsThis study included 183 patients and 33 patients (18%) developed a subsequent contralateral SCFE. Younger age at time of initial presentation, lower modified Oxford Score and smaller difference in epiphyseal-diaphyseal angle between both sides during index presentation were significant predictors of subsequent contralateral SCFE. Specifically, age ≤ 11 years, modified Oxford Score ≤ 20 and difference in epiphyseal-diaphyseal angle of ≤ 21° between both hips were predictive of a contralateral slip (Area Under the Curve = 0.78; p < 0.05). The presence of each risk factor increased the risk of subsequent contralateral SCFE and having all three risk factors increased the risk to 73%.ConclusionThere is a significant risk of subsequent contralateral SCFE in patients with unilateral SCFE, and predictive risk factors include younger age, lower modified Oxford Score and smaller difference in epiphyseal-diaphyseal angle between the affected and unaffected hips.Level of EvidenceLevel III

Capital Femoral Epiphyseal Cupping and Extension May Be Protective in Slipped Capital Femoral Epiphysis: A Dual-center Matching Cohort Study.

Peripheral cupping of the capital femoral epiphysis over the metaphysis has been reported as a precursor of cam morphology, but may also confer stability of the epiphysis protecting it from slipped capital femoral epiphysis (SCFE). The purpose of this study was to investigate the relationship between a novel morphologic parameter of inherent physeal stability, epiphyseal cupping, and the development of SCFE in a dual-center matched-control cohort study. We performed a dual-center age-matched and sex-matched cohort study comparing 279 subjects with unilateral SCFE and 279 radiographically normal controls from 2 tertiary children's hospitals. All SCFE patients had at least 18 months of radiographic follow-up for contralateral slip surveillance. Anteroposterior and frog lateral pelvis radiographs were utilized to measure the epiphyseal cupping ratio and the current standard measure of inherent physeal stability, the epiphyseal extension ratio. Control hips were found to have greater epiphyseal cupping than the contralateral uninvolved hip of SCFE subjects both superiorly (0.28±0.08 vs. 0.24±0.06; P<0.001) and anteriorly (0.22±0.07 vs. 0.19±0.06; P<0.001). The 58/279 (21%) subjects who went on to develop contralateral slip had decreased epiphyseal cupping superiorly (0.25±0.07 vs. 0.23±0.05; P=0.03) and anteriorly (0.20±0.06 vs. 0.17±0.04; P<0.001). When we compared controls with hips that did not progress to contralateral slip and hips that further developed a contralateral SCFE, 1-way ANOVA demonstrated a stepwise decrease in epiphyseal cupping and epiphyseal extension ratio in the anterior and superior planes from control hips to contralateral hips without subsequent slip to contralateral hips that developed a SCFE (P<0.01 for each). This study provides further evidence that epiphyseal cupping around the metaphysis is associated with decreased likelihood of SCFE and may reflect increased inherent physeal stability. Epiphyseal cupping may represent an adaptive mechanism to stabilize the epiphysis during adolescence at the long-term cost of the eventual development of associated cam-femoroacetabular impingement deformity. Level III-prognostic Study.

The Atypical Patient With Slipped Capital Femoral Epiphyses May Be at Increased Risk for a Missed Contralateral Slip.

Slipped capital femoral epiphysis (SCFE) is a commonly encountered hip disorder. The goal of this study was to describe the incidence of missed contra-lateral SCFE as well as to identify risk factors. The authors hypothesized that contralateral slips are more often missed in patients with severe involvement of the treated side. After institutional review board approval was obtained, a retrospective chart review was performed of all pediatric patients who were treated for sequential and bilateral SCFE at a single institution during an 18-year period. Medical records were reviewed for demographic features and attending surgeon. Radiographs were reviewed for skeletal maturity, Klein's line, and severity of the treated slip. All radiographs were reviewed by 3 pediatric orthopedists. Contralateral SCFE was deemed present when consensus was achieved. Comparisons were made with Fisher's exact test, and P<.05 was considered significant. Of the records that were reviewed, 56 patients met the study criteria. Of these, 19 patients had bilateral involvement and 5 missed slips were identified (8.9%). The patients with missed disease tended to be younger (mean age, 10.8 vs 11.4 years), with a lower body mass index. Fellowship-trained pediatric surgeons were more likely to identify bilateral disease compared with orthopedists without pediatric training (P=.0065). A contralateral slip was more likely to be present in patients who had a positive finding for Klein's line (P<.0001). Severity of the treated slip did not increase the likelihood of missing a contralateral slip. Although Klein's line is a useful tool in the diagnosis of SCFE, a false-negative rate of 40% was observed. The authors recommend increased vigilance when an "atypical" patient with SCFE presents with unilateral disease. [Orthopedics. 2020;43(2):e114-e118.].

Risk Factors for Contralateral Slipped Capital Femoral Epiphysis: A Meta-analysis of Cohort and Case-control Studies.

Slipped capital femoral epiphysis (SCFE) is an important cause of hip pain and disability in pediatric patients. SCFE occurs bilaterally in 12% to 80% of cases, and the risk of contralateral SCFE is noted to be 2335 times higher than the index SCFE. Several studies have reported risk factors for contralateral SCFE; however, these studies have not been systematically analyzed. The purpose of this systematic review and meta-analysis was to review and analyze risk factors for subsequent contralateral SCFE and identify the strongest risk factors for a subsequent slip. A systematic review was performed of all observational studies focusing on risk factors for subsequent contralateral SCFE indexed in Medline, Embase, and Cochrane databases. Data extraction was performed and summarized using descriptive statistics. Meta-analysis was performed for risk factors with sufficient constituent study data. Quality assessment was performed using the Newcastle-Ottawa Scale, and funnel plots were generated to assess publication bias. The initial search strategy identified 226 references, and after exclusions, 20 studies were included in this analysis. Demographic risk factors included age, sex, weight, body mass index, ethnicity, and urban/rural residence; clinical risk factors included endocrine abnormality, duration of symptoms, slip stability, and slip chronicity; and radiographic risk factors included slip angle, triradiate cartilage, alpha angle, posterior sloping angle (PSA), physeal sloping angle, modified Oxford score, and bone age. Younger patient age, body mass index≥95th percentile, presence of an endocrine abnormality, higher PSA of the unaffected hip, and lower modified Oxford score have been noted to be significant risk factors for contralateral SCFE. Meta-analysis showed that younger age (-0.9; confidence interval, -1.1, -0.6), and higher PSA (4.7 degrees; 95% confidence interval, 3.3-6.2 degrees) of the unaffected hip were predictive of subsequent contralateral SCFE. The majority of studies were of good quality. There are several risk factors for subsequent contralateral SCFE. On the basis of the available data, younger patients with a high PSA of the unaffected hip would most likely benefit from prophylactic fixation of the unaffected hip. Level II.

Rates of Contralateral SCFE in the United States: Analysis of the Pediatric Health Information System.

Slipped capital femoral epiphysis (SCFE) is relatively common in pediatric patients. Subsequent contralateral SCFE is also common and rates of bilateral SCFE have been reported to range from 12% to 80% in the literature. The purpose of this study was to determine the rates of subsequent contralateral SCFE in patients who present with unilateral SCFE in the United States and determine risk factors for the development of subsequent contralateral SCFE. The authors performed a retrospective study using data from the Pediatric Health Information System (PHIS). Patients who underwent in situ pinning of a unilateral SCFE between 2004 and 2016 were included in this study and followed prospectively to determine subsequent contralateral SCFE. They excluded patients who underwent bilateral pinning at index admission. Descriptive, univariate, and multivariate statistics were used to determine rates of subsequent contralateral SCFE and identify factors associated with contralateral SCFE. This study included 9755 patients who underwent in situ pinning for unilateral SCFE. The mean age at the time of index SCFE was 11.9 years (SD, 1.7) and ~62% of patients were male individuals. Subsequent contralateral SCFE occurred in 1077 (11%) patients at an average of 277 days (range, 7 to 1523 d) after the index procedure. Patients who developed a subsequent contralateral SCFE were younger at the time of index SCFE than patients who did not develop a contralateral SCFE (11.3 vs. 12 y old, P<0.01). In multivariate analysis, older children had a lower risk of subsequent contralateral SCFE (adjusted odds ratio, 0.8; 95% confidence interval, 0.77-0.83), and the odds of subsequent contralateral SCFE decreased by 20% with each increasing year in age. The rate of subsequent contralateral SCFE is ~11% in the United States, and younger patients are more likely to develop a contralateral SCFE than older patients. Prophylactic pinning should be considered in younger patients with unilateral SCFE, and patients should be followed until skeletal maturity to monitor for subsequent contralateral SCFE. Level III.

Alpha Angle as a Predictor of Impending Contralateral Slipped Capital Femoral Epiphysis in an Asian Population.

BackgroundProphylactic pinning of the uninvolved side after unilateral slipped capital femoral epiphysis (SCFE) is controversial. The alpha angle, a measurement of femoral head-neck aspherity, was proposed as a predictor of progression of contralateral SCFE with a treatment threshold of greater than 50.5°. The aim of this study was to evaluate its validity in our cohort of patients.MethodsA retrospective review of a 10-year series of patients who presented with unilateral SCFE was conducted. Minimum follow-up duration to identify contralateral progression was 18 months. Age, sex, ethnicity, and endocrinopathies were noted. Alpha angle measurements of the unaffected hip were performed by two independent observers. The average values of measurements were used for analysis. Univariate and multivariate logistic regression analyses were performed to identify predictors of contralateral progression. A receiver operating characteristic (ROC) curve was generated.ResultsThere were 43 patients with unilateral SCFE. Seven patients (16.3%) developed contralateral SCFE. There were 31 males (72.1%) and 12 females (27.9%). The mean duration from index surgery to contralateral fixation was 43.9 weeks (range, 16.2 to 77 weeks). The mean alpha angle was significantly higher in the patients with contralateral progression (mean, 50.7°; standard deviation [SD], 5.4°; range, 43.8° to 58.5°) than in the patients without progression (mean, 43.0°; SD, 4.2°; range, 33.0° to 52.5°; p < 0.001). The alpha angle was also identified as a statistically significant predictor of contralateral progression on multivariate analysis (p = 0.02). The intraclass correlation coefficient for interobserver reliability was moderately strong at 0.76 (95% confidence interval, 0.55 to 0.87). The area under the ROC curve was 0.88. The treatment threshold of 50.5° had a sensitivity of 0.43, specificity of 0.94, and number needed to treat (NNT) of 2.7. The ideal treatment threshold derived from the ROC curve was 49.0°, which had a sensitivity of 0.71, specificity of 0.89, and an NNT of 1.7.ConclusionsAlpha angle is a potential predictor of contralateral hip involvement in children with SCFE who may benefit from prophylactic hip fixation. Results from our series suggest a treatment threshold be 49.0°. However, given the limited sample size and moderately strong interobserver reliability, larger studies are needed to validate our findings.

Prophylactic pinning should be considered in patients at risk for slipped capital femoral epiphysis.

Background: The use of prophylactic contralateral pinning for slipped capital femoral epiphysis (SCFE) remains controversial. This study evaluated the outcome of SCFE treatment and examined the use of prophylactic pinning.Methods: The study included 44 patients (33 men, 11 women; 54 hips [right, 31; left, 23]), with mean age of 12.9 (7.3–29) years, who underwent treatment between 1986 and 2017, with follow-up for more than 6 months. Patients were divided into 3 groups: group 1 had bilateral SCFE at first presentation, group 2 developed contralateral side SCFE during follow-up, and group 3 had unilateral SCFE until final follow-up. Three patients who received prophylactic pinning were excluded. Univariate and multivariate logistic analyses were performed.Results: Overall, 93% (50/54) of hips underwent positional reduction and in situ fixation and 7.4% (4/54) underwent open reduction. Mean follow-up period was 4.8 (0.5–25) years. Groups 1, 2, and 3 had 7, 3, and 31 cases, respectively. Sex, age, and follow-up period showed no significant differences among the groups. The Rohrer index was significantly higher in group 1, the affected side posterior sloping angle (PSA) was significantly higher in group 3, and the contralateral side PSA and percentage with endocrinopathy were significantly higher in group 2. In multivariate logistic analysis, age, sex, Rohrer index, affected side PSA, and endocrinopathy were significantly correlated with bilateral SCFE.Conclusion: We recommend prophylactic contralateral side pinning in patients with risk factors of obesity, high PSA before slipping, and endocrinopathy. Careful observation until growth plate closure is required in patients without risk factors.

The Peritubercle Lucency Sign is a Common and Early Radiographic Finding in Slipped Capital Femoral Epiphysis.

A rotational mechanism of slipped capital femoral epiphysis (SCFE) in which the epiphyseal tubercle acts as a fulcrum has been recently described. However, there is limited radiographic evidence supporting this theory. We aimed to investigate whether a radiographic lucency around the epiphyseal tubercle (peritubercle lucency sign) could be observed before or at the diagnosis of a subsequent slip in patients initially presenting with unilateral SCFE. We evaluated 70 patients with unilateral SCFE who were followed until a contralateral slip was diagnosed, and 180 patients with unilateral SCFE who had no contralateral slip until skeletal maturity between 2000 and 2017. We revised anteroposterior and lateral radiographs from the initial presentation, surveillance, and diagnosis of a contralateral SCFE. The presence or absence of the peritubercle lucency sign in the contralateral initially uninvolved hip was recorded for every radiograph. The presence of hip pain, and the presence of classic radiographic parameters for SCFE diagnosis (epiphyseal tilt and Klein's line) were recorded when the peritubercle lucency sign became noticeable. The peritubercle lucency sign was observed in 84% [59/70; 95% confidence interval (CI), 73%-92%] of the patients who developed contralateral slip. Most patients (46/59=78%; 95% CI, 65%-87%; P<0.001) had the peritubercle lucency sign visible within 9 months after the initial diagnosis of unilateral SCFE. The sign preceded the definitive diagnosis of the contralateral slip at a median of 9 weeks (interquartile range, 0 to 10 wk). At the time of first observation of the peritubercle lucency sign, 36% (25/70; 95% CI, 25%-48%) of the patients were asymptomatic and 49% (34/70; 95% CI, 36%-61%) of the hips showed no abnormalities in the tilt angle or the Klein line. Among patients who did not experience a contralateral slip (n=180), the sign was observed in 2 patients (1.1%; 95% CI, 0.2%-4.4%). The sensitivity was 84% and specificity was 99%. A peritubercle lucency is an early imaging sign, present in >80% of contralateral slips following an initial presentation of unilateral SCFE. The presence of the peritubercle lucency sign may be helpful for contralateral hip surveillance. Future studies are necessary to establish the clinical validity of the peritubercle lucency sign and whether it may serve as a predictor of contralateral involvement. Diagnostic level III.

Morphologic Features of the Contralateral Femur in Patients With Unilateral Slipped Capital Femoral Epiphysis Resembles Mild Slip Deformity: A Matched Cohort Study

AbstractBackgroundHip osteoarthritis has been reported in the contralateral hip in patients who had been treated for unilateral slipped capital femoral epiphysis (SCFE) during adolescence. Although this might be related to the presence of a mild deformity, the morphologic features of the contralater

Severity of Asynchronous Slipped Capital Femoral Epiphyses in Skeletally Immature Versus More Skeletally Mature Patients

Routine prophylactic screw fixation for skeletally immature patients with slipped capital femoral epiphysis (SCFE) continues to be debated. The purpose of this study was to assess the slip severity of a second SCFE in skeletally immature versus more mature patients and determine necessity of contralateral hip prophylactic screw fixation. All patients treated for SCFE at 3 pediatric hospitals over a 10-year time period (January 1, 2002 to December 31, 2011) were evaluated. Patients were included if they had a unilateral SCFE and a contralateral asynchronous SCFE, and were divided into immature (Oxford triradiate score 1) versus more mature (Oxford triradiate score 2 and 3) groups. Data evaluation included age, time between slips, body mass index, Southwick angles of first then second SCFEs, and follow-up duration. There were a total of 45 patients: 16 patients in the skeletally immature and 29 patients in the more mature group. Average age at first SCFE in immature patients was 10.9 years and in more mature patients 12.1 years (P=0.70). Age at second SCFE in immature patients was 11.5 years and in more mature patients 13.0 years (P=0.023). Average time between SCFEs was 6.6 months for immature and 11.4 months for more mature patients (P=0.093). Southwick angles for immature patient first and second SCFEs were 25 and 12.9 degrees, respectively, and for more mature patient first and second SCFEs were 31 and 21 degrees, respectively. Southwick angles were higher at first and second slips in the more mature group, significant only at the second slip (P=0.032). SCFE severity at initial event was predictive of severity of second SCFE regardless of maturity (P=0.043). Regression analysis of slip severity against multiple patient factors demonstrated triradiate score was not a factor assessing subsequent SCFE magnitude (P=0.099). There was no significant difference between first and second SCFEs regardless of skeletal maturity but severity of initial SCFE did correlate with severity of the second SCFE. Deciding not to prophylactically pin an unaffected hip does not lead to worse deformity if a second SCFE occurs in skeletally immature or more mature patients, unless the initial event is severe. Prophylactic pin fixation in skeletally immature patients should occur as a shared decision between patient, guardians, and treating surgeon. Level III-retrospective comparative study.

Biomechanics of Slipped Capital Femoral Epiphysis: Evaluation of the Posterior Sloping Angle

The posterior sloping angle (PSA) has been shown to be an objective and reproducible predictor of the risk of patients developing contralateral slipped capital femoral epiphysis (SCFE); however, prophylactic fixation remains controversial. This in vitro study investigates the biomechanical basis of using a 15-degree PSA as a threshold for prophylactic fixation. Synthetic bone in vitro models of the proximal femur were constructed with a PSA of 10 degrees as a control (normal) group (n=6) by performing an osteotomy at the physis and gluing the head back onto the neck. SCFE groups were created with a PSA of 15, 20, 25, 30, 50, or 60 degrees, by excising a wedge from the posterior neck and gluing them back at the new angle with corresponding posterior translation proportional to the slip angle, and loaded superoinferiorly in compression, to failure. Ultimate strength, energy to failure, and stiffness were recorded. Increasing the PSA from 10 to 15 degrees only reduced ultimate strength by 13% (P>0.05; CI, -0.21 to -0.06), though a significantly lesser energy to failure was required (-58%, P<0.05; CI, -0.68 to -0.48). Increasing the angle to 20 degrees resulted in a further significant decrease in strength (-19%, P<0.05; CI, -0.28 to -0.10) and energy to failure (-45%, P<0.05; CI, -0.53 to -0.84). The severe SCFE (60-degree PSA) was significantly weaker and less rigid that the control, and the mild and moderate SCFE models (P<0.01). These biomechanical data support the threshold of 15-degree PSA as an objective measure for prophylactic fixation of the contralateral hip in SCFE. The number needed to treat with (minimally invasive) prophylactic fixation to prevent contralateral SCFE can be minimized if the above-mentioned threshold is used.

The alpha angle as a predictor of contralateral slipped capital femoral epiphysis.

PurposeContralateral hip involvement in slipped capital femoral epiphysis (SCFE) is common. Femoral head−neck asphericity, as measured by an elevated alpha angle, has not previously been assessed with respect to SCFE risk. Our aim was to assess the utility of the alpha angle in predicting contralateral SCFE.MethodsWe retrospectively reviewed 168 patients (94 males) managed surgically for unilateral SCFE between 2001 and 2013 who had a minimum of 18 months follow-up. The alpha angle, the posterior sloping angle (PSA), and the modified Oxford score were recorded for every patient at the time of initial SCFE presentation. Follow-up clinical records and radiographs were assessed to determine the presence of absence of contralateral SCFE.ResultsForty-five patients (27 %) developed a contralateral SCFE. Patients who developed a contralateral SCFE had a significantly higher alpha angle (51° vs 45°, p < 0.001) than patients who did not develop a contralateral SCFE. There was no significant difference in PSA or modified Oxford score (both p > 0.10) between patients who developed a contralateral SCFE and those who did not. Using a proposed alpha angle of 50.5° as a threshold for prophylactic fixation, 26 (58 %) of the 45 cases of contralateral SCFE in our study would have been prevented and 18 (15 %) of 123 patients would have undergone fixation unnecessarily.ConclusionsWe found the alpha angle to positively correlate with contralateral SCFE risk. Patients with significantly elevated alpha angles may be at greater risk of contralateral SCFE and benefit from further investigation or prophylactic hip fixation.