Bilateral slipped capital femoral epiphysis: predictive factors for contralateral slip

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Shedding light on slipped capital femoral epiphysis: a nationwide study on Turkish population

OBJECTIVES

This comprehensive study aimed to describe the epidemiologic and demographic distribution of slipped capital femoral epiphysis (SCFE) in Türkiye, a condition that globally presents at a rate of 10.8 cases per 100 000 children. Utilizing data from the Ministry of Health, we examined the specifics of SCFE in Türkiye, comparing the findings with those of other populations to clarify the country's unique epidemiological profile.

METHODS

In this retrospective analysis, the Ministry of Health's database was used to extract medical records of children under the age of 16 diagnosed with SCFE from 2016 to 2023. Patients were evaluated based on sex, age at diagnosis, comorbidities, complications, time of diagnosis and BMI.

RESULTS

Our analysis identified 720 children with SCFE, with the average age at diagnosis being 12.9 years. The prevalence of SCFE in Türkiye was found to be 0.005% for the year 2022. The occurrence of SCFE showed no correlation with seasons. It was noted that the majority of patients received treatment at university and high-level hospitals (59.9%), with none being treated at lower-level public hospitals. A total of 58 patients were found to have additional growth and developmental diseases. Notably, only 33 cases (4.6%) involved avascular necrosis during follow-up.

CONCLUSION

This study provides the first epidemiological and demographic analysis of SCFE in Türkiye. Interestingly, our data suggest that male patients are twice as likely to develop SCFE compared to their female counterparts.

Idiopathic Slipped Capital Femoral Epiphysis: Demographic Differences and Similarities between Stable, Unstable, and Valgus Types

Idiopathic slipped capital femoral epiphysis (SCFE) is a known disorder in pre/adolescent children with vague hip/knee pain. We wished to study the demographic differences between stable varus, unstable varus, and valgus idiopathic SCFEs using a retrospective review over a 10-year period of SCFE children seen at a tertiary children's hospital. Standard demographic data was collected, and radiographs were measured to determine the Southwick angle and status of the tri-radiate cartilage. There were 190 patients; 138 had stable varus SCFEs, 45 unstable varus SCFEs, and 7 valgus SCFEs. All unstable SCFEs were varus, and all valgus SCFEs were stable. There were significant differences between the three groups by age at diagnosis, sex, race, SCFE severity, weight percentile, and duration of symptoms. The average age at diagnosis was 11.0 ± 1.2, 11.8 ± 1.8, and 12.3 ± 1.7 years for the valgus, unstable varus, and stable varus groups (p = 0.019), and similarly, SCFE severity was 25° ± 15°, 48° ± 18°, and 35° ± 19° (p = 0.0002) for the three same groups. Patients with valgus SCFEs were mostly female (86%) compared to the stable varus (39.9%) and unstable (47%) groups (p = 0.05) and mostly non-White (86%) (0.011). The duration of symptoms was 4.1 ± 4.1, 2.3 ± 5.0, and 4.5 ± 5.0 months for the valgus, unstable varus, and stable varus groups (p = 0.00005). These three types of idiopathic SCFEs demonstrated differences by age at diagnosis, sex, race, weight percentile, and duration of symptoms.

Presence and magnitude of anterior physeal separation in slipped upper femoral epiphysis helps identifying those at high risk for avascular necrosis

AIMS

We sought to determine if the magnitude of anterior physeal separation (APS) in slipped upper femoral epiphysis was a predictor for the subsequent development of avascular necrosis (AVN). Anterior Physeal Separation (APS) is defined as the distance between the anterior lip of the bony capital epiphysis and the lateral corresponding point of the adjacent bony metaphysis on the Lauenstein radiographic view. It represents hinging of the posterior aspect of the metaphysis with the anterior epiphysis lifting away from its adjacent metaphysis, indicating instability and potential vulnerability of the vessels.

PATIENTS AND METHODS

A retrospective review of all patients treated regionally for slipped upper femoral epiphysis over a 9 year period (2010-2018 inclusive) were identified. Data regarding demographics, radiological parameters and outcomes was recorded. APS was measured on a Launestein radiograph view, with the patient supine, the hip and knee are flexed to 40°, and the hip externally rotated 45°, with film-focus distance of 100 cm. Analysis of the APS was performed to validate a threshold above which AVN occurs.

RESULTS

We identified 147 hips in 142 patients, of which 5 had bilateral slips at the time of presentation. Average anterior physeal separation was 3.8 ± 1.8 mm, with higher grade slips having significantly greater APS values. Increased APS values were seen with Loder "unstable" slips. Seven hips (4.8%) developed AVN, and in these cases the APS was significantly larger than those who did not (8.5 ± 1.4 Vs 3.9 ± 1.7; p < 0.001). Receiver operator curve analysis demonstrated a critical value of 7.5 mm was associated with a 100% sensitivity and 98.6% specificity for AVN. We identified some grade II/moderate slips with high APS values had similar outcomes to grade III/severe slips, and therefore suggest that APS may serve to alert the surgeon on counselling patients on the risk of developing AVN and to consider strategies to minimise the risk of AVN.

CONCLUSIONS

APS is sensitive, specific, accurate and reliable for the association with AVN in SUFE. Its values closely reflect the high AVN rates seen in acute and unstable SUFE. This risk is greatest if the magnitude of APS exceeds the critical value of 7.5 mm.

The contralateral hip in slipped capital femoral epiphysis: Is there an easy-to-use algorithm to support a decision for prophylactic fixation?

PURPOSE

To identify a specific factor that can support the decision for prophylactic fixation in unilateral slipped capital femoral epiphysis.

METHODS

This retrospective cohort study included a total national population of 379 children diagnosed with slipped capital femoral epiphysis from 2007 to 2013. Regression analysis used information on slip severity, clinical classification of the index hip, age, sex, age-adjusted body mass index, the difference in epiphyseal-diaphyseal angle, and comorbidity to identify any risk factor for the subsequent development of a slip in the contralateral hip. Four observers evaluated the triradiate cartilage following the modified Oxford bone score grade. The occurrence of later development of a contralateral slip in different stage of physeal closure was used to analyze the sensitivity and specificity for this method.

RESULTS

This study's only predictor for a subsequent contralateral slip was chronological age. At age 13 years or older, 1/15 in girls and 3/65 in boys suffered from a slip in the contralateral hip. Thus, when using age <13 years as a test for deciding when to do prophylactic fixation, the sensitivity would be 88% and specificity 51% for preventing contralateral slip. However, the correlation between the four different observers was too low to be considered useful when assessing the triradiate cartilage for skeletal maturity.

CONCLUSION

We would advocate a prophylactic fixation for children <13 years diagnosed with a unilateral slipped capital femoral epiphysis as an easy-to-use algorithm.

LEVEL OF EVIDENCE

level II.

Telescoping screw fixation compared to traditional in situ screw fixation for slipped capital femoral epiphysis: clinical, radiographic and patient-reported outcomes

This study compares clinical, radiographic and patient-reported outcomes among telescoping and traditional screws for the treatment of slipped capital femoral epiphysis (SCFE). We hypothesized that telescoping screws would prevent slip progression and result in preserved femoral neck growth and improved patient-reported outcomes. Traditional screws were compared to telescoping screws in a 2:1 matched cohort based on age at initial surgery, length of radiographic follow-up and whether or not the hip was pinned prophylactically or as a treatment for SCFE. Neck length and telescoping screw length were measured. The patient-reported outcomes were obtained at routine clinic visits. Total 42 hips were included with a mean follow-up of 24.5 ± 3.3 months. No patients developed avascular necrosis, chondrolysis or needed revision surgical procedures. Telescoping screws increased in length for the entire cohort by a mean of 6.0 ± 4.3 mm. Neck length change was not different in SCFE hips when treated with traditional screws vs. telescoping screws (P = 0.527). However, there was a difference in neck length change between the two groups when comparing prophylactically treated hips (P = 0.001). There were no significant differences in patient-reported outcomes among hips treated with telescoping screws compared to traditional screws. Traditional and telescoping screws are both effective for the treatment of SCFE. Telescoping screws have an advantage when prophylactically treating hips that are at risk of slipping as they don't lead to the coxa breva that is seen with traditional screws. However, both treatment methods had similar patient-reported outcomes.

Slipped capital femoral epiphysis: an epidemiological Nationwide study in Italy from 2001 to 2015

BACKGROUND

Slipped capital femoral epiphysis (epiphysiolysis of the femoral head, SCFE) is the most common pediatric hip disease in 10-14 years old children. The most used procedure to correct a stable form of SCFE is in situ pinning. Instead, the proper treatment for unstable forms is controversial. The first purpose of this study was to estimate annual admissions for SCFE in Italian patients from 2001 to 2015, basing on the hospitalization reports. The second aim was to assess the difference between regions regarding SCFE procedures. Lastly, a statistical prediction of the volume of SCFE procedures performed in Italy based on data from 2001 to 2015 was performed.

METHODS

Data of this study were collected from the National Hospital Discharge Reports (SDO) reported at the Italian Ministry of Health regarding the years of this paper. The yearly number of hospital admission for SCFE, the percentage of males and females, the average age, days of hospitalization, primary diagnoses and primary procedures in the whole Italian population were calculated using descriptive statistical analyses.

RESULTS

From 2001 to 2015, 4893 hospitalizations for SCFE were recorded in Italy, with a mean incidence of 2.9 (cases/100.000 inhabitants). The majority of patients treated by SCFE were males (70.6%).

CONCLUSION

National health statistics for SCFE are attractive for an international audience, as different approaches to screening are reported between countries. These differences allow comparing outcomes internationally. Moreover, sharing national statistics and correlating those to other countries protocols, could be helpful to compare outcomes for different procedures internationally. However, further studies are required to understand the specific reasons for regional variation for SCFE procedures in Italy.

LEVEL OF EVIDENCE

III.

Posterior sloping angle of the capital femoral physis in slipped capital femoral epiphysis has poor clinical utility and should not guide treatment on prophylactic fixation

BACKGROUND

Prophylactic pinning of the uninvolved side after unilateral slipped capital femoral epiphysis (SCFE) is controversial as it balances increased surgical risks against the possibility of protecting a normal hip from initial slip and deformity. A posterior sloping angle (PSA) of greater than 12-14.5° has been proposed by various authors as a treatment threshold to predict for contralateral hip progression and prophylactic pinning.

METHODS

A retrospective review of a 10-year series of patients with the diagnosis of SCFE and follow-up of 18 months was conducted. Patients were divided into two groups, those with Isolated Unilateral Slips and those who subsequently underwent Subsequent Contralateral Progression. PSA measurements were performed by two clinicians and assessed for inter-observer reliability. Data collected included age, sex, ethnicity, Loder class, endocrinopathy, renal impairment, radiation exposure, and PSA.

RESULTS

There were no significant differences between the distribution of gender, site of slip, age of onset, Loder class, and presence of medical comorbidities between the Isolated Unilateral Slip and Subsequent Contralateral Progression groups (p > 0.05). The mean PSA value was not significantly higher in the Subsequent Contralateral Progression group (17.9 ± 4.32 (10.5-23.5)) compared to the Isolated Unilateral Slip group (15.8 ± 5.31 (6-26)) (p = 0.32). The receiver operator coefficient-derived ideal treatment threshold of 16.5° gave a sensitivity of 0.71, specificity of 0.64, and number needed to treat of 3.

CONCLUSION

PSA differences between the Subsequent Contralateral Progression and Isolated Unilateral Slip groups were not statistically significant in this series. All proposed treatment thresholds had poor specificity. Prophylactic pinning should not be based on isolated PSA values.

LEVEL OF EVIDENCE

III.

Safely Reducing the Incidence of Contralateral Slipped Capital Femoral Epiphysis: Results of a Prospectively Implemented Prophylactic Fixation Protocol Using the Posterior Sloping Angle

BACKGROUND

Bilateral slipped capital femoral epiphysis (SCFE) is common. The management of the contralateral hip in unilateral SCFE remains controversial. The aim of this study was to report on the clinical outcomes using a posterior sloping angle (PSA) threshold of 14.5 degrees for prophylactic fixation in preventing contralateral SCFE.

METHODS

Having previously established through a retrospective study that PSA was predictive of future slip, the authors put in place a protocol where patients with unilateral SCFE who had a PSA ≥14.5 degrees on the contralateral side were offered prophylactic fixation. Those with unilateral SCFE presenting between January 2008 and December 2018 with a minimum of 12-month follow-up were included. Patients with renal or endocrine disorders were excluded. Primary outcomes were the number of slips prevented, the number needed to treat, and the complication rate.

RESULTS

Of the 219 patients who were included, 114 (52.1%) underwent prophylactic fixation.A PSA threshold of 14.5 degrees prevented 77% of subsequent slips with a number needed to treat of 2.4 in our population. There were no cases of chondrolysis, avascular necrosis, or periprosthetic fracture associated with prophylactic pinning.

CONCLUSIONS

Prophylactic fixation using a PSA of 14.5 degrees is safe, decreases unnecessary intervention, and reduces 77% of subsequent SCFE. The PSA can increase over time and the authors recommend that the protocol be applied for the duration of follow-up.

LEVEL OF EVIDENCE

Level III.

Probability analysis of sequential SCFE (PASS score)

PURPOSE

The study aimed to develop a scoring system based on clinical and radiological findings to predict the risk of a sequential slipped capital femoral epiphysis (SCFE).

METHODS

Paediatric patients with unilateral SCFE and at least two years of radiographic follow-up were screened for inclusion. Medical records were reviewed for multiple variables including age, gender, body mass index (BMI), stability of SCFE, and time to sequential presentation. Radiographic analysis included triradiate physeal status, Risser staging, superior epiphyseal extension ratio (EER), posterior epiphyseal angle (PEA), posterior sloping angle (PSA) and slip severity.

RESULTS

In total, 163 patients (88 male, 54%, 75 female, 46%) met inclusion criteria. Of those, 65 (40%) with a mean age of 11.9 ± 1.3 years developed sequential SCFE at a mean of 9.8 ± 6.4 months after the initial slip. Eight independent variables were statistically different (p < 0.05) between unilateral and sequential groups. Following multivariate analysis, Risser stage and triradiate status were no longer significant and did not influence the strength of the final model (overall area under the curve (AUC) = 0.954) and were consequently excluded. We developed the PASS score using three radiographic parameters using chosen cut-off values that were close to their maximized value and weighted the point value assigned to each parameter based on the strength of predictor.

CONCLUSION

A PASS score of three or higher predicts a high probability of sequential SCFE with 95% confidence and may warrant prophylactic screw fixation. PASS score calculation can be used to predict a sequential SCFE and provide an objective method to determine the utility prophylactic screw fixation.

LEVEL OF EVIDENCE

II.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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 OF EVIDENCE

Level II.

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.].

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.

Osteonecrosis After Contralateral in Situ Prophylactic Pinning for a Slipped Capital Femoral Epiphysis: A Case Report

CASE

We report the case of an 11-year-old girl who developed osteonecrosis of the femoral head in the radiographically normal, asymptomatic left hip that had been fixed prophylactically in the context of a slipped capital femoral epiphysis (SCFE) that had been detected on the contralateral hip. The etiology of the osteonecrosis remains unknown.

CONCLUSION

This case report demonstrates that prophylactic fixation of a radiographically normal, asymptomatic hip in the context of an SCFE on the contralateral side has the potential for substantial complications. Therefore, the risk of osteonecrosis in the prophylactically pinned hip should be carefully considered because this complication may have devastating functional consequences.

What Is the Prevalence of Cam Deformity After Prophylactic Pinning of the Contralateral Asymptomatic Hip in Unilateral Slipped Capital Femoral Epiphysis? A 10-year Minimum Followup Study

BACKGROUND

Prophylactic pinning of the asymptomatic and normal-appearing contralateral hip in patients with unilateral slipped capital femoral epiphysis (SCFE) remains controversial. Understanding the minimal 10-year clinical, functional, and radiographic outcomes of the contralateral asymptomatic hip in unilateral SCFE may be helpful in the decision regarding whether the benefits associated with potentially preventing a SCFE are outweighed by the risk of additional surgery.

QUESTIONS/PURPOSES

Among patients with SCFE treated with prophylactic pinning of the asymptomatic and contralateral hip, we sought (1) to determine the complications and reoperations; (2) to evaluate the development of cam deformities and the frequency and severity of osteoarthritis progression; and (3) to characterize hip pain and function as measured by the Harris hip score (HHS) and the Hip Disability and Osteoarthritis Outcome Score (HOOS) at minimal 10-year followup.

METHODS

Between 1998 and 2005 all patients with SCFE seen at our institution were treated with the modified Dunn procedure and all were offered prophylactic pinning of the contralateral asymptomatic hip. Of the 41 patients who underwent the unilateral modified Dunn procedure and who had an asymptomatic contralateral hip, 37 patients (90%) underwent pinning of that contralateral hip. Of those, 33 patients (80%) were available for clinical and radiographic evaluation for this retrospective study at a minimum of 10 years (mean followup 12 ± 2 years) after surgery. Three patients of the 37 patients only had 10-year clinical followup, including questionnaires sent by mail and telephone, because they refused further radiographic followup and one patient was lost to followup. The group included 19 males and 17 females whose age at surgery was a mean of 13 ± 2 years. Medical charts were reviewed and patients were asked about complications and additional surgical procedures. Most recent postoperative radiographs were evaluated for measurement of the alpha angle, head-neck offset, epiphysis orientation, and osteoarthritis grading according to Tönnis classification and minimum joint space width. The presence of a cam deformity was defined by an alpha angle measurement > 60° on the AP radiograph and/or > 55° on the lateral radiograph. Hip function and pain were assessed by the HHS and HOOS outcome measures.

RESULTS

No complications with prophylactic in situ pinning were recorded. Four of 36 (11%) patients underwent subsequent surgical treatment for cam-type femoroacetabular impingement (FAI), and hardware removal was performed in four hips (11%). The mean alpha angle was 53° ± 8° on the AP radiograph and 49° ± 8° on the lateral view at followup. In total, 10 of 33 hips (30%) had a cam morphology at the femoral head-neck junction and four (12%) were symptomatic and underwent FAI surgery. Six of 33 patients (18%) developed an asymptomatic cam morphology at the femoral head-neck junction; in three of 33 hips (9%), the cam deformity instead of lesion were visible only on the lateral projection, and 9% were visible on both the AP and lateral projections. The preoperative offset of the femoral head-neck junction was 10 ± 3 mm on the AP view and 11 ± 4 mm on the lateral view. At followup, the AP offset was 7 ± 3 mm and the lateral offset was 6 ± 3 mm, and on the lateral view, the offset was < 10 mm in eight hips (22%). No patient had radiographic signs of hip osteoarthritis (Tönnis Grade 0). The mean minimum joint space width was 4 ± 0.4 mm. The mean HHS for the 32 patients who did not undergo subsequent surgery was 97 ± 5 at latest followup. The mean postoperative HOOS was 94 ± 8 for the 32 patients at latest followup.

CONCLUSIONS

At a minimum followup of 10 years after prophylactic pinning of a contralateral asymptomatic hip, most patients achieve excellent hip scores; however, a substantial proportion will develop a symptomatic cam deformity despite prophylactic pinning. No patient had signs of osteoarthritis at a minimum of 10 years, but almost one-third of the patients who underwent prophylactic pinning developed a cam deformity.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

MRI in idiopathic, stable, slipped capital femoral epiphysis: evaluation of contralateral pre-slip

PURPOSE

Early diagnosis and treatment of slipped capital femoral epiphysis (SCFE) is important to prevent slip progression and avoid complications. We sought to determine if MRI findings in patients with unilateral SCFE could indicate 'pre-slip' or predict future SCFE in the contralateral hip.

METHODS

A prospective study evaluated patients with unilateral SCFE over a two-year period. MRI of the asymptomatic hip was performed within the perioperative period. Patients were followed with radiographs until a contralateral slip occurred or until physeal closure. Demographics, clinical stability, severity, posterior slope angle (PSA), modified Oxford Bone Score (mOBS) and patency of the triradiate cartilage were recorded and statistical analysis performed.

RESULTS

In all, 33 of 54 patients with unilateral SCFE were enrolled into the study. In all, 29 (87.8%) had complete follow-up. Five of the enrolled patients (15.2%) developed a sequential slip requiring in situ pinning. Six of 33 (18.2%) patients had positive MRI findings: four of which proceeded to sequential SCFE and two which did not. One sequential slip had a negative MRI. PSA predicted 1/11 sequential slips (sensitivity 9.09%, specificity 81.4%, positive predictive value (PPV) 11.1%, negative predictive value (NPV) 77.8%) and mOBS predicted 5/11 sequential slips (sensitivity 45.5%, specificity 93%, PPV 62.5%, NPV 87%). An open triradiate cartilage was present in 8/11 patients with sequential slips (sensitivity 72.7%, specificity 81.4%, PPV 50%, NPV 92.1%).

CONCLUSION

MRI findings consistent with 'pre-slip' were present in 66.7% of patients who developed a sequential SCFE. Further study on the utility/sensitivity of MRI in predicting sequential SCFE is warranted.

LEVEL OF EVIDENCE

II, diagnostic.

Outcomes after slipped capital femoral epiphysis: a population-based study with three-year follow-up

PURPOSE

To evaluate outcomes three years after treatment for slipped capital femoral epiphysis (SCFE): development of avascular necrosis (AVN), subsequent surgery, hip function and the contralateral hip.

METHODS

This prospective cohort study included a total national population of 379 children treated for SCFE between 2007 and 2013. A total of 449 hips treated for SCFE and 151 hips treated with a prophylactic fixation were identified. The Barnhöft questionnaire, a valid patient-reported outcome measure (PROM), was used.

RESULTS

In all, 90 hips had a severe slip, 61 of these were clinically unstable. AVN developed in 25 of the 449 hips. Six of 15 hips treated with capital realignment developed AVN. A peri-implant femur fracture occurred in three slipped hips and in two prophylactically pinned hips. In three of these five hips technical difficulties during surgery was identified. In 43 of 201 hips scheduled for regular follow-up a subsequent SCFE developed in the contralateral hip. Implant extraction after physeal closure was performed in 156 of 449 hips treated for SCFE and in 51 of 151 prophylactically fixed hips. Children with impaired hip function could be identified using the Barnhöft questionnaire.

CONCLUSION

Fixation in situ is justified to remain as the primary treatment of choice in SCFE. Overweight is more common in children with SCFE than in the average population. Prophylactic fixation is a safe procedure when performed using a correct technique. The number of patients who developed AVN after capital realignment is of concern. We recommend rigorous follow-up of both hips, including PROM evaluation, until physeal closure.

LEVEL OF EVIDENCE

II - prospective cohort study.

Asynchronous slipped capital femoral epiphysis in a patient with a seizure disorder: case report and review of the literature

Debate remains about the appropriate treatment of the asymptomatic side following treatment of a unilateral slipped capital femoral epiphysis (SCFE). A 12-year-old boy with a seizure disorder presented with an unstable SCFE on the left hip following a seizure. He underwent percutaneous pinning of the left only. At 8 months postoperatively, he returned with an unstable slip of the right hip, again following a seizure. No literature discussing the treatment of patients with risk of SCFE and seizure disorders was identified. Further study may identify an increased incidence of contralateral slip following an initial slip in this population. If a greater risk exists, contralateral prophylactic fixation at time of index surgery may be indicated.

Magnetic resonance imaging at primary diagnosis cannot predict subsequent contralateral slip in slipped capital femoral epiphysis

OBJECTIVE

Prophylactic fixation of the contralateral hip in slipped capital femoral epiphysis (SCFE) is controversial, and no reliable method has been established to predict subsequent contralateral slip. The main purpose of this study was to evaluate if magnetic resonance imaging (MRI) performed at primary diagnosis could predict future contralateral slip.

MATERIALS AND METHODS

Twenty-two patients with unilateral SCFE were included, all had MRI of both hips taken before operative fixation. Six different parameters were measured on the MRI: the MRI slip angle, the greatest focal widening of the physis, the global widening of the physis measured at three locations (the midpoint of the physis and 1 cm lateral and medial to the midpoint), periphyseal (epiphyseal and metaphyseal) bone marrow edema, the presence of pathological joint effusion, and the amount of joint effusion measured from the lateral edge of the greater trochanter. Mean follow-up was 33 months (range, 16-63 months). Six patients were treated for contralateral slip during the follow-up time and a comparison of the MRI parameters of the contralateral hip in these six patients and in the 16 patients that remained unilateral was done to see if subsequent contralateral slip was possible to predict at primary diagnosis.

RESULTS

All MRI parameters were significantly altered in hips with established SCFE compared with the contralateral hips. However, none of the MRI parameters showed any significant difference between patients who had a subsequent contralateral slip and those that remained unilateral.

CONCLUSIONS

MRI taken at primary diagnosis could not predict future contralateral slip.

Slipped capital femoral epiphysis: a population-based study

BACKGROUND

Slipped capital femoral epiphysis (SCFE) is the most common hip disorder in children 9-15 years old. This is a population-based study in Sweden presenting the epidemiology for SCFE.

METHODS

In a prospective cohort study, we analysed pre- and postoperative radiographs, medical records for all children treated for SCFE in Sweden 2007-2013, demographic data, severity of slip and surgical procedures performed.

RESULTS

We identified 379 Swedish children with primary SCFE 2007-2013; 162 girls, median age 11.7 (7.2-15.4) years, and 217 boys, median age 13 (3.8-17.7) years. The average annual incidence was 4.4/10000 for girls and 5.7/10000 for boys 9-15 years old. Obesity or overweight was found in 56% of the girls and in 76% of the boys. As an initial symptom, 66% of the children had hip/groin pain and 12% knee pain. At first presentation, 7% of the children had bilateral SCFE. Prophylactic fixation was performed in 43%. Of the remaining children, 21% later developed a contralateral slip. Fixation with implants permitting further growth was used in >90% of the children. Femoral neck osteotomy was performed for 11 hips.

CONCLUSIONS

The annual average incidence 2007-2013 in Sweden showed a mild increase for girls. The male-to-female ratio was lower than previous regional data from Sweden. Overweight or obesity is one major characteristic for boys with SCFE but to a less extent for girls. Knee pain as initial symptom cause a delay in diagnosis. Most hospitals in Sweden treat <2 children annually.

Opinion survey of members of British Society of Children's Orthopaedic Surgery related to specific case scenarios in slipped capital femoral epiphysis

The aim of this study was to assess contemporary management of slipped capital femoral epiphysis (SCFE) by surveying members of the British Society of Children's Orthopaedic Surgery (BSCOS). A questionnaire with five case vignettes was used. Two questions examined the timing of surgery for an acute unstable SCFE in a child presenting at 6 and 48 h after start of symptoms. Two further questions explored the preferred method of fixation in mild and severe stable SCFE. The final question examined the management of the contralateral normal hip. Responses were entered into an Excel spreadsheet and the data was analysed using a χ-test. The response rate was 56% (110/196). Overall, 88% (97/110) responded that if a child presented with an acute unstable SCFE within 6 h, they would treat it within 24 h of presentation, compared with 41% (45/110) for one presenting 48 h after the onset of symptoms (P<0.0001). Overall, 53% (58/110) of surveyed BSCOS members would offer surgery for an unstable SCFE between 1 and 7 days after onset of symptoms. Single screw fixation in situ for mild stable SCFE was advocated by 96% (106/110) with 71% (78/110) using this method for the treatment of severe stable SCFE. Corrective osteotomy is used by 2% (2/110) and 25% (28/110) of respondents for mild and severe stable SCFE, respectively (P<0.0001). Surgeons preferring osteotomy are more likely to perform an intracapsular technique. Prophylactic fixation of the contralateral normal hip was performed by 27% (30/110) of respondents. There are significant differences in opinions between BSCOS members as to the optimal management of SCFE. This reflects the variable recommendations and quality in the current scientific literature. Further research is therefore required to determine best practice and enable consensus to be reached.

[Slipped capital femoral epiphysis]

Slipped capital femoral epiphysis (SFCE) is a disorder of the hip, characterized by a displacement of the capital femoral epiphysis from the metaphysic through the femoral growth plate. The epiphysis slips posteriorly and inferiorly. SCFE occurs during puberty and metabolic and epidemiologic risk factors, such as obesity are frequently found. Most chronic slips are diagnosed late. Sagittal hip X-rays show epiphysis slip. In case of untreated SCFE, a slip progression arises with an acute slip risk. Treatment is indicated to prevent slip worsening. The clinical and radiological classification is useful to guide treatment and it is predictive of the prognosis. In situ fixation of stable and moderately displaced SCFE with cannulated screws gives excellent results. Major complications are chondrolysis and osteonecrosis and the major sequelae are femoroacetabular impingement and early arthritis.

Current Practice in the Management of Slipped Capital Femoral Epiphysis

BACKGROUND

The most widely used treatment for slipped capital femoral epiphysis (SCFE) is in situ fixation. In an attempt to reduce the chances of impingement, osteoarthritis, and osteonecrosis, surgeons have started adopting newer surgical techniques. The purpose of this study was to determine the current pattern of treating SCFE.

METHODS

A questionnaire was sent electronically to all of the members of the Pediatric Orthopaedic Society of North America. The data were analyzed dividing surgeons into academic versus private practice, years of practice, and number of SCFEs treated per year.

RESULTS

Of 990 members, 277 (28%) responded to the survey.Type of practice (academic, n=181 vs. private, n=51): For unstable severe SCFE, surgeons in academic practice use the surgical hip dislocation (SHD) approach significantly more frequently (35.7% vs. 14.9%; P=0.02). A radiolucent table is used significantly more frequently in academic practice for both stable (50.6% vs. 29.8%; P=0.01) and unstable (39.6% vs. 15.2%; P=0.002) SCFE. Fully threaded cannulated screws (44.4% vs. 27.1%; P=0.03), open capsular decompression (63.9% vs. 32.4%; P=0.001), contralateral pinning (79% vs. 58.7%; P=0.005), and postoperative magnetic resonance imaging (MRI) (15.5% vs. 3.9%; P=0.03) are significantly more frequent in academic practice.Years of practice (≤15 y, n=124 vs. >15 y, n=140): For severe stable SCFE, surgeons practicing for ≤15 years do acute osteotomies significantly less frequently (1.8% vs. 9%; P=0.004) and perform SHD significantly more frequently (20.2% vs. 8.2%; P=0.004). For unstable moderate SCFE, SHD is utilized significantly more frequently by surgeons ≤15 years in practice (29.8% vs. 16.5%; P=0.04). Bilateral frog-leg lateral views (86.4% vs. 73.7%; P=0.04), preoperative MRI (36.1% vs. 20.6%; P=0.006), open capsular decompression (69.3% vs. 51.7%; P=0.01) are significantly more frequent among surgeons ≤15 years in practice.Number of SCFE treated per year (<10, n=129 vs. ≥10, n=136): For unstable severe SCFE, surgeons treating ≥10/y perform SHD significantly more frequently (38.6% vs. 26.1%; P=0.02) and do in situ fixation with manual reduction significantly less frequently (11.8% vs. 21.8%; P=0.02). Radiolucent table (54.3% vs. 38%; P=0.01), 7.5 mm screw versus 6.5 mm (62% vs. 45.4%; P=0.01), contralateral pinning (78.9% vs. 67.8%; P=0.04), postoperative MRI (17.6% vs. 9.3%; P=0.04), and postoperative computed tomography (14.7% vs. 7%; 0.04) are significantly more frequent among surgeons doing ≥10/y. Elective implant removal is more common among surgeons treating <10/y (16.2% vs. 6.9%; P=0.02).

CONCLUSIONS

Treatment of SCFE varies significantly depending on the surgeon's type of practice, years in practice, and numbers treated per year. Surgeons in academic practice, surgeons with ≤15 years in practice, and surgeons treating greater number of SCFEs are more likely to use SHD to acutely reduce the slip.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

These biomechanical data support the threshold of 15-degree PSA as an objective measure for prophylactic fixation of the contralateral hip in SCFE.

CLINICAL RELEVANCE

The number needed to treat with (minimally invasive) prophylactic fixation to prevent contralateral SCFE can be minimized if the above-mentioned threshold is used.

Outcome of the unaffected contralateral hip in unilateral slipped capital femoral epiphysis: a report comparing prophylactic fixation with observation

This was a retrospective review of 80 patients with unilateral slipped capital femoral epiphysis treated with either prophylactic fixation or observation. The unaffected hip of 44 patients (mean age 12.6 years) were subjected to simultaneous prophylactic fixation and 36 patients (mean age 13.4 years) were managed by observation. Fisher's exact test showed a significantly high incidence of sequential slip of unaffected hips in the observation group in comparison with prophylactic fixation (P=0.002). No cases had avascular necrosis or chondrolysis. Prophylactic fixation significantly reduces the incidence of sequential slip. It outweighs the minimal surgical risks compared with its benefit in the prevention of further sequential slip.

Complications Related to the Treatment of Slipped Capital Femoral Epiphysis

Slipped capital femoral epiphysis (SCFE) is a condition of the immature hip in which mechanical overload of the proximal femoral physis results in anterior and superior displacement of the femoral metaphysis relative to the epiphysis. The treatment of SCFE is surgical, as the natural history of nonsurgical treatment is slip progression and early arthritis. Despite advances in treatment, much controversy exists regarding the best treatment, and complication rates remain high. Complications include osteonecrosis, chondrolysis, SCFE-induced impingement, and related articular degeneration, fixation failure and deformity progression, growth disturbance of the proximal femur, and development of bilateral disease.

Biomechanical Comparison of Perpendicular Versus Oblique In Situ Screw Fixation of Slipped Capital Femoral Epiphysis

BACKGROUND

Percutaneous in situ single screw fixation is the preferred treatment for stable and unstable slipped capital femoral epiphysis (SCFE). The recommended screw placement is in the center of the epiphysis and perpendicular to the physis, which necessitates an anterior starting point for most SCFEs. A recent clinical study has shown good clinical results with a laterally based screw for SCFE, which is oblique to the physis. We sought to biomechanically compare these 2 techniques for load to failure and hypothesized that the laterally based oblique screw is equivalent or superior to an anteriorly based perpendicular screw.

METHODS

Twenty-two paired immature porcine femurs were used to compare the techniques. A SCFE model was created in all femurs using a previously published technique by performing a 30-degree posterior closing wedge osteotomy through the proximal physis. In the control group, a screw was placed perpendicular to the slip with an anterior starting point. In the experimental group, the screw was started as close to the mid-lateral cortex of the proximal femur as possible while maintaining the screw anterior to the posterior cortex of the femoral neck and ending at the apex of the epiphysis ignoring the resultant angle to the physis for the experimental group. The specimens were then potted and loaded in a physiologically relevant posteroinferior direction (30 degrees posterior from vertical) to determine load to failure (N) and stiffness (N/mm).

RESULTS

No statistical difference was found between the 2 groups in maximum load to failure or stiffness (P>0.05).

CONCLUSIONS

A laterally based screw oblique to the physis for in situ fixation in mild SCFE is not significantly different than an anteriorly based screw perpendicular to the physis in load to failure and stiffness in our study model.

CLINICAL RELEVANCE

In light of no difference in load to failure of these 2 constructs, surgeons may be more comfortable with the traditional lateral entry point while still aiming for screw placement in the center of head.

Fracture prevention by prophylactic femoroplasty of the proximal femur--metallic compared with cemented augmentation

OBJECTIVES

To compare 2 different femoral neck augmentation techniques at improving the mechanical strength of the femoral neck.

METHODS

Twenty pairs of human cadaveric femora were randomly divided into 2 groups. In 1 group, the femora were augmented with a steel spiral; the other group with the cemented technique. The untreated contralateral side served as an intraindividual control. Fracture strength was evaluated using an established biomechanical testing scenario mimicking a fall on the greater trochanter (Hayes fall).

RESULTS

The peak load to failure was significantly higher in the steel spiral group (P = 0.0024) and in the cemented group (P = 0.001) compared with the intraindividual controls. The peak load to failure showed a median of 3167 N (1825-5230 N) in the spiral group and 2485 N (1066-4395 N) in the spiral control group. The peak load to failure in the cemented group was 3698 N (SD ± 1249 N) compared with 2763 N (SD ± 1335 N) in the cement control group. Furthermore, fracture displacement was clearly reduced in the steel spiral group.

CONCLUSIONS

Femoral augmentations using steel spirals or cement-based femoroplasty are technically feasible procedures. Our results demonstrate that a prophylactic reinforced proximal femur has higher strength when compared with the untreated contralateral limb. Prophylactic augmentation has potential to become an auxiliary treatment option to protect the osteoporotic proximal femur against fracture.

Slipped capital femoral epiphysis: what's new?

Slipped capital femoral epiphysis (SCFE) is a common hip disorder among adolescents, whereby the epiphysis is displaced posteriorly and inferiorly to the metaphysis. Treatment modalities aim to stabilize the epiphysis, prevent further slippage, and avoid complications associated with long-term morbidity, such as osteonecrosis and chondrolysis. Controversy exists with SCFE regarding prophylactic fixation of the contralateral, painless, normal hip, the role of femoroacetabular impingement with SCFE, and whether in situ fixation is the best treatment method for SCFE. This article presents and discusses the latest diagnostic and treatment modalities for SCFE.

A reduction in body mass index lowers risk for bilateral slipped capital femoral epiphysis

BACKGROUND

Slipped capital femoral epiphysis (SCFE) is occurring in greater numbers, at increasingly younger ages, and more frequently bilaterally (BL-SCFE). Obesity is one risk factor for SCFE. However, it is unclear whether postoperative decreases or increases in body mass index (BMI) alter the risk of subsequent contralateral SCFE.

QUESTIONS/PURPOSES

We therefore determined whether (1) BMI percentile was a risk factor for BL-SCFE; and (2) postoperative increases and/or decreases in BMI percentile influenced the risk for BL-SCFE.

METHODS

We retrospectively reviewed the records of 502 patients surgically treated for SCFE and identified 138 (27%) with BL-SCFE and 364 (73%) with unilateral SCFE (UL-SCFE); 173 patients, 60 (35%) with BL-SCFE and 113 (65%) with UL-SCFE met our inclusion criteria. Risk factors included sex, age, slip stability, slip chronicity, slip angle, and obesity. Percentile BMI was recorded at the time of first SCFE surgery, at the time of last followup for patients undergoing UL-SCFE, and at the time of second SCFE surgery for patients undergoing BL-SCFE.

RESULTS

Sex, age, slip stability, and slip angle were not associated with BL-SCFE. Postoperative obesity (odds ratio [OR], 3.5; 95% confidence interval [CI], 1.2-9.7) and acute slip chronicity (OR, 2.9; 95% CI, 1.3-6.7) had higher risks for sequential BL-SCFE. Obese patients who became nonobese postoperatively had a decreased risk of sequential BL-SCFE compared with those who remained obese (OR, 0.16; 95% CI, 1.2-116.5).

CONCLUSIONS

Only postoperative obesity and an acute slip were risk factors for sequential BL-SCFE. BMI reduction to lower than the 95% percentile after SCFE surgery was associated with lower risk for BL-SCFE development. The data suggest early supervised therapeutic weight management programs for patients treated for UL-SCFE are important to reduce risk of subsequent SCFE.

LEVEL OF EVIDENCE

Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

[Slipped capital femoral epiphysis]

Slipped capital femoral epiphysis (SCFE) is characterized by displacement of the capital femoral epiphysis from the metaphysis through the physis. The term is confusing, because the metaphysis moves upward and outward while the epiphysis remains in the acetabulum. The SCFE is considered stable when the child is able to walk with or without crutches, and it is considered unstable when the child cannot walk with or without crutches. Patients with SCFE present with pain in the groin, knee and limp. The current treatment of stable SCFE is in situ stabilization with a single screw.

Klein line on the anteroposterior radiograph is not a sensitive diagnostic radiologic test for slipped capital femoral epiphysis

OBJECTIVE

To correlate the amount of slipped capital femoral epiphysis (SCFE) that results in an abnormality of the Klein line. In mild slips, the Klein line on the anteroposterior (AP) radiograph may remain normal, potentially leading to a delay in diagnosis and emphasizing the importance of obtaining a frog lateral radiograph in patients with a suspected SCFE.

STUDY DESIGN

A retrospective review of 55 patients with SCFE was performed from January 2004-March 2009. Of the 55 patients, 32 were missing radiographs and were excluded, leaving 23. The 23 sets of radiographs were reviewed.

RESULTS

Of the 23 hips studied with SCFE, only 9 (39%) were able to be diagnosed on the AP radiograph using the classic definition of the Klein line. Twenty cases (87%) of SCFE were identified on the AP radiograph using the modified Klein line. All 23 cases (100%) of SCFE were identified on frog lateral radiographs.

CONCLUSIONS

Relying on the Klein line will fail to identify many mild or moderate slips. An AP and a frog lateral pelvic radiograph should be obtained in any child when an SCFE is suspected to accurately identify the disorder and to prevent delays in diagnosis.

Effects of the grade, stability, chronological classification and being either unilateral or bilateral of the slip on the treatment by in situ single screw fixation of patients with slipped capital femoral epiphysis

PURPOSE

The effects of the grade, stability, chronological classification and being either unilateral or bilateral of the slip on the outcomes of the treatment by in situ single screw fixation of the Slipped capital femoral epiphysis were investigated.

METHODS

34 hips of 24 patients (7 girls, 17 boys; mean age 12.04 years; range 9-14; 14 slips acute, 7 slips acute on chronic, 13 slips chronic; 22 slips stable, 12 slips unstable; 20 slips Grade 1, 13 slips Grade 2, 1 slips Grade 3) between 2003 and 2009 were involved in the study. During the controls; range of motion, walking abnormalities, Trendelenburg test, use of assistive devices during mobilization, existence of pain and complications were evaluated. The evaluation of clinical results was made according to the average Harris Hip Score.

RESULTS

10 of 24 patients showed evidence of a slip of the contralateral hip on average 10.6 (6-16) months after the initial operation. At mean 41.52 ± 8.08 months controls, the Harris Hip Score was found 77.41 ± 14.66, hip-joint motions, flexion 120° (70°-140°), abduction 40° (20°-60°), internal rotation 25° (10°-40°). Evaluation at the last follow-up showed significant differences between single hip slip than both hip slip, stable slip than unstable slip and Grade 1 slip than Grade 2 slip. In the last control of one patient with a Grade 3 slip, avascular necrosis has been observed. Considering the effect on the clinical results of the chronological classification of the no slip, significant differences have been seen between the clinical outcomes of the acute, chronic or acute on chronic slips.

DISCUSSION

The outcomes of the treatment by in situ single screw fixation are negatively affected by increase in the grade of slip, instability of the slip and existence of slip at both hips.

The asymptomatic contralateral hip in unilateral slipped capital femoral epiphysis: morbidity of prophylactic fixation

Prophylactic contralateral fixation in unilateral slipped capital femoral epiphysis (SCFE) remains a controversial issue. In this study, 66 patients treated for unilateral SCFE (July 1997-April 2009) were screened for complications with need for surgical reintervention in the asymptomatic contralateral hip. Except for one patient, prophylactic fixation was performed in all cases. Major complications such as avascular necrosis were not seen; minor complications such as wound revision occurred in 4.6% (three of 65). In 16.9% (11/65) secondary loss of fixation with need for second fixation occurred. As the need for second fixation arose mostly bilaterally (10.7%, 7/65), only four patients (6.2%) required an additional surgical procedure for second fixation. Children who needed second fixation were significantly younger (11.8 years) than those who did not (13.1 years, P=0.013). In conclusion, this retrospective analysis shows that prophylactic contralateral fixation in SCFE is a safe procedure with no major complications and an acceptable rate of minor complications. When Kirschner wires are used for prophylactic pinning, there is a possibility of secondary loss of fixation due to length growth at the level of the physis. To avoid the need for secondary fixation, screw epiphysiodesis might be considered.

Management of the contralateral hip in patients with unilateral slipped upper femoral epiphysis: to fix or not to fix--consequences of two strategies

In the majority of patients with slipped upper femoral epiphysis only one hip is involved at primary diagnosis. However, the contralateral hip often becomes involved over time. There are no reliable factors predicting a contralateral slip. Whether or not the contralateral hip should undergo prophylactic fixation is a matter of controversy. We present a number of essential points that have to be considered both when choosing to fix the contralateral hip prophylactically as well as when refraining from surgery and instead following the patients with repeat radiographs.

The epidemiology and demographics of slipped capital femoral epiphysis

The etiology of slipped capital femoral epiphysis (SCFE) is unknown with many insights coming from epidemiologic/demographic information. A systematic medical literature review regarding SCFE was performed. The incidence is 0.33/100,000 to 24.58/100,000 children 8 to 15 years of age. The relative racial frequency, relative to Caucasians at 1.0, is 5.6 for Polynesians, 3.9 for Blacks, and 2.5 for Hispanics. The average age is 12.0 years for boys and 11.2 years for girls. The physiologic age when SCFE occurs is less variable than the chronologic age. The average symptom duration is 4 to 5 months. Most children are obese: >50% are >95th percentile weight for age with average BMI is 25-30 kg/m(2). The onset of SCFE is in the summer when north of 40°N. Bilaterality ranges from 18 to 50%. In children with bilateral involvement, 50-60% present with simultaneous SCFEs and those who present with a unilateral SCFE and subsequently develop a contralateral SCFE do so within 18 months. The age at presentation is younger for those who present with a unilateral SCFE and later develop a contralateral SCFE. The age-weight, age-height, and height test are useful to differentiate between an idiopathic and atypical SCFE.

Treatment of SCFE in a healthy 5-year-old child: case report and review

Slipped capital femoral epiphysis is a common adolescent hip disorder and when patients present at an age younger than 10 years, it is atypical and there is often some identifiable associated metabolic or endocrinologic abnormality. We present the case of a 5-year-old boy with idiopathic bilateral slipped capital femoral epiphysis. This patient underwent staged bilateral pinning in situ using a uniquely modified screw where the distal threads were machined-off for smooth fixation across the physis. The patient had an unremarkable postoperative course and showed evidence of remodeling and patent physes at 1-year follow-up.

Bilateral unstable slipped capital femoral epiphysis: a look at risk factors

Unstable slipped capital femoral epiphysis can have disastrous complications including osteonecrosis and chondrolysis. It has been shown that 20% to 80% of patients may develop a contralateral slip ≤18 months after diagnosis. The purpose of this article is to report and characterize patients who developed bilateral unstable slips. After Institutional Review Board approval, the patients included were only those with bilateral unstable slipped capital femoral epiphyses. A minimum 2-year follow-up was required. Seven patients, all female, were included in the study, with an average age of 11.4 years at the time of their first slips. The interval between slips averaged 127 days (range, 0-245 days). All but 1 patient presented with a severe slip. The second slip was also severe in 3 patients and less severe in 4 patients. The triradiate cartilage was open in 3 patients. Two patients required corrective osteotomies. Chondrolysis developed in 2 patients with no osteonecrosis reported. The incidence of bilateral unstable slips ranged from 4% to 20% of all unstable slipped capital femoral epiphyses based on our findings. Skeletal immaturity was not a risk factor. The surgeon must be vigilant for the possibility of bilateral slips. The family must be instructed on precautions patients must take while recuperating from unstable slipped capital femoral epiphyses. Contralateral fixation of the unaffected side may be warranted in patients with initial severe unstable slipped capital femoral epiphyses to prevent this condition.

In situ fixation of slipped capital femoral epiphysis with Steinmann pins

BACKGROUND AND PURPOSE

Slipped capital femoral epiphysis (SCFE) is often treated by surgical fixation; however, no agreement exists regarding technique. We analyzed the outcome of in situ fixation with Steinmann pins.

PATIENTS AND METHODS

All 67 subjects operated for slipped capital femoral epiphysis at Haukeland University Hospital during the period 1990-2007 were included. All were treated by in situ fixation with 2 or 3 parallel Steinmann pins (8 mm threads at the medial end). The follow-up evaluation consisted of clinical examination and hip radiographs. Radiographic outcome was based on measurements of slip progression, growth of the femoral neck, leg length discrepancy, and signs of avascular necrosis and chondrolysis.

RESULTS

67 subjects (41 males) were operated due to unilateral slips (n = 47) or bilateral slips (n = 20). Mean age at time of diagnosis was 13 (7.2-16) years. Mean age at follow-up was 19 (14-30) years, with a mean postoperative interval of 6.0 (2-16) years. The operated femoral neck was 9% longer at skeletal maturity than at surgery, indicating continued growth of the femoral neck. At skeletal maturity, 12 subjects had radiographic features suggestive of a previous asymptomatic slip of the contralateral hip. The total number of bilateral cases of SCFE was 32, i.e half of the children had bilateral SCFE. 3 subjects required additional surgery and mild avascular necrosis of the femoral head was seen in 1 patient. None had slip progression or chondrolysis.

INTERPRETATION

In situ pinning of SCFE with partly threaded Steinmann pins appears to be a feasible and safe method, with few complications. The technique allows further growth of the femoral neck.

The utility of posterior sloping angle in predicting contralateral slipped capital femoral epiphysis

PURPOSE

Prophylactic pinning of the uninvolved side after unilateral slipped capital femoral epiphysis (SCFE) is controversial. The posterior sloping angle (PSA) has previously been proposed to predict contralateral slip. The purpose of this study was to determine whether the PSA can predict subsequent slip after unilateral SCFE, and if so, whether a sex difference exists.

METHODS

A retrospective case-control study was performed comparing 51 patients who initially presented with unilateral SCFE and subsequently developed contralateral slip (Bilateral) with 51 patients who had unilateral SCFE only (Unilateral). Data collected included age, sex, ethnicity, and PSA.

RESULTS

The patients in the Bilateral group had significantly higher PSA (14.5±6.1 vs. 10.6±5.3, P=0.001) and were younger (11.3±1.5 vs.12.3±1.2, P<0.001) than the patients in the Unilateral group. A receiver-operating characteristic curve demonstrated that the threshold for pinning a contralateral hip with PSA >12.66 yields an area under the curve of 67%. When the analysis was repeated with respect to sex, girls in the Bilateral group had significantly higher PSA (15.9±6.3 vs. 10.1±6.0, P=0.002) and were younger (10.7±1.1 vs.11.9±1.0, P<0.001) than the girls in the Unilateral group. Among boys, these associations were not significant. A receiver-operating characteristic curve demonstrated that the threshold for pinning a contralateral hip with PSA >13 in girls yields an area under the curve of 76%.

CONCLUSIONS

PSA is predictive of contralateral slip in patients presenting with unilateral SCFE. However, it is more predictive in girls, and we recommend considering prophylactic pinning in girls with PSA >13.

LEVEL OF EVIDENCE

Level III.

Obesity in pediatric orthopaedics

Obesity is a rapidly expanding health problem in children and adolescents and is the most prevalent nutritional problem for children in the United States. Some believe that obesity has become a major epidemic in American children, with the prevalence having more than doubled since 1980. This epidemic has led to a near-doubling in hospitalizations with a diagnosis of obesity between 1999 and 2005 and an increase in costs from $125.9 million to $237.6 million between 2001 and 2005. This article describes some of the orthopaedic conditions commonly encountered in overweight/obese children and adolescents, classically infantile and adolescent tibia vara and slipped capital femoral epiphysis. Also discussed are genu valgum, which has been associated with obesity, and other difficulties encountered in providing orthopaedic care to obese children.

Prognostic significance of stability in slipped upper femoral epiphysis: a systematic review and meta-analysis

OBJECTIVE

To examine associations of major complications after surgical treatment of slipped upper femoral epiphysis (SUFE) with condition- and treatment-related risk factors.

STUDY DESIGN

This systematic review and meta-analysis of observational studies used an electronic literature search of Embase and Medline supplemented by a manual search of bibliographies. The studies enrolled children and adolescents with SUFE, defined stable and unstable disease, and reported at least 3 primary endpoints: avascular necrosis (AVN), chondrolysis, and reoperation. Random-effects meta-regression analysis was performed when possible.

RESULTS

The weighted risk for AVN, derived from intercept-only meta-regression, was estimated as 5.3% (95% confidence interval [CI], 3.4%-7.2%). Patients with unstable slips had a 9.4-fold greater risk of developing AVN. Instability proved to be an independent predictor for AVN. The weighted risk of chondrolysis was 0.8% (95% CI, 0.2%-1.4%), associated with unstable slips and osteotomies. The risk of reoperation was estimated at 5.5% (95% CI, 1.7%-9.3%). Loss of fixation was the primary reason for reoperation.

CONCLUSIONS

Current evidence indicates that unstable slips are at a significantly higher risk for AVN than stable slips, regardless of the attempted surgical approach. Little clinical information is available regarding chondrolysis and reoperation in relation to the stability of the physis.