Decade-long Trends in Incidence of Slipped Capital Femoral Epiphysis in the United States: A Nationwide Database Analysis of Over 33 Million Patients.

PURPOSE: Slipped capital femoral epiphysis (SCFE) is a prevalent pediatric hip disorder linked to severe complications, with childhood obesity as a crucial risk factor. Despite the rising obesity rates, contemporary data on SCFE's epidemiology remain scarce in the United States. This study examined SCFE incidence trends and demographic risk factors in the United States over a decade. METHODS: A decade-long (2011 to 2020) retrospective cohort study was undertaken using the Healthcare Cost and Utilization Project National Inpatient Sample. Patients aged younger than 18 years were identified and further analyzed if diagnosed with SCFE through ICD-9 or ICD-10 codes. Key metrics included demographics variables, with multivariate regression assessing demographic factors tied to SCFE, and yearly incidence calculated. RESULTS: Of 33,180,028 pediatric patients, 11,738 (0.04%) were diagnosed with SCFE. The incidence escalated from 2.46 to 5.96 per 10,000 children, from 2011 to 2020, mirroring childhood obesity trends. Lower socioeconomic status children were predominantly affected. Multivariate analysis revealed reduced SCFE risk in female patients, while Black and Hispanic ethnicities, alongside the Western geographic location, had an increased risk. CONCLUSION: This study underscores a twofold increase in SCFE incidence over the past decade, aligning with childhood obesity upsurge. Moreover, SCFE disproportionately affects lower SES children, with male sex, Black and Hispanic ethnicities amplifying the risk. This calls for targeted interventions to mitigate SCFE's effect, especially amidst the vulnerable populations.

Slipped capital femoral epiphysis after tumor prosthesis implantation in a patient receiving chemotherapy.

While the usual etiology of slipped capital femoral epiphysis (SCFE) is idiopathic, there are many other factors that increase the predisposition to slippage. Chemotherapy can be one of them. In this article, we report a rare case of acute SCFE after tumor prosthesis implantation in a patient who received chemotherapy. A 10-year-old girl with osteosarcoma of the right distal femur underwent (neo-) adjuvant chemotherapy, wide tumor resection, and reconstruction using a growing tumor prosthesis and a short non-cemented femoral stem. Half a year after implantation, she developed aseptic loosening. Revision surgery was performed using a hydroxyapatite (HA)-coated cementless femoral stem. Postoperative plain radiographs revealed SCFE that was treated by closed reduction and screw fixation. The patient recovered without complications, and unaffected hip showed no radiographic signs of slippage on follow-up. The forces of implanting a tumor prosthesis, particularly with a non-cemented stem, can increase the risk of an acute SCFE. The controversy over prophylactic pinning of the uninvolved hip in chemotherapy-associated SCFE is unresolved. Pinning can be considered only in the presence of abnormal prodromal radiological findings.

Bilateral Slipped Capital Femoral Epiphysis in a Young Girl Treated With Chemotherapy: A Case Report.

CASE: A 1-year-old girl was treated with chemotherapy and hematopoietic stem cell transplantation because of CD40 ligand deficiency. Four years later, she presented with pain in her right leg, diagnosed as atypical acute slipped capital femoral epiphysis, without a clear cause, besides chemotherapy possibly. She was treated with fixation of the epiphysis with a cannulated screw. Two years later, the same diagnosis was made for the left hip and the same surgery was applied. After the 2-year follow-up, clinical outcomes were good. CONCLUSION: Chemotherapy may be a risk factor for atypical slipped capital femoral epiphysis, even without the combination with radiotherapy.

ChatGPT Responses to Common Questions About Slipped Capital Femoral Epiphysis: A Reliable Resource for Parents?

BACKGROUND: We sought to evaluate the ability of ChatGPT, an AI-powered online chatbot, to answer frequently asked questions (FAQs) regarding slipped capital femoral epiphysis (SCFE). METHODS: Seven FAQs regarding SCFE were presented to ChatGPT. Initial responses were recorded and compared with evidence-based literature and reputable online resources. Responses were subjectively rated as "excellent response requiring no further clarification," "satisfactory response requiring minimal clarification," "satisfactory response requiring moderate clarification," or "unsatisfactory response requiring substantial clarification." RESULTS: ChatGPT was frequently able to provide satisfactory responses that required only minimal clarification. One response received an excellent rating and required no further clarification, while only 1 response from ChatGPT was rated unsatisfactory and required substantial clarification. CONCLUSIONS: ChatGPT is able to frequently provide satisfactory responses to FAQs regarding SCFE while appropriately reiterating the importance of always consulting a medical professional.

Investigating pelvic drop gait abnormality in adolescent hip pathology patients.

BACKGROUND: Trendelenburg gait describes contralateral pelvic drop during single leg stance (SLS) with occasional lateral trunk lean compensation over the stance limb. However, quantitative research on 'uncompensated Trendelenburg' gait (pelvic drop independent of lateral trunk lean) remains sparse among populations that commonly utilize this gait pattern, such as adolescent hip pathology patients. RESEARCH QUESTION: How prevalent is uncompensated Trendelenburg among various adolescent hip pathologies and how is it related to hip load, hip abduction strength, and self-reported hip pain? METHODS: Gait, strength, and pain data were collected among 152 pre-operative patients clinically diagnosed with acetabular hip dysplasia, femoroacetabular impingement, Legg-Calvé-Perthes, or slipped capital femoral epiphysis (SCFE). Patients with ≥ 5.4° of dynamic pelvic drop in SLS were divided into a 'pelvic drop' group and screened to exclude those with excessive ipsilateral trunk lean. They were then compared to the 'stable pelvis' patients using a Mann-Whitney test. RESULTS: Dysplasia patients represented the highest proportion of the pelvic drop group (46%). The pelvic drop group showed a significant increase in self-reported hip pain (p = 0.011), maximum hip abductor moment (p = 0.002), and peak coronal power absorption at the affected hip during SLS loading response, (p < 0.001) while showing no difference in abduction strength (p = 0.381). SIGNIFICANCE: Uncompensated Trendelenburg gait may lead to increased loading of the affected hip in adolescent hip pathology patients. Disadvantageous hip biomechanics can create increased abductor muscle demand among these pathological populations, with dysplasia patients showing the highest prevalence. Maximal abduction strength did not correlate with pelvic drop. Future work should aim to identify and quantify causal factors. Increased coronal hip power absorption during weight acceptance warrants clinical attention, as there may be a detrimental, over-reliance on passive hip structures to support load among a population that that is already predisposed to hip osteoarthritis.

Intraoperative Epiphyseal Perfusion Monitoring Does Not Reliably Predict Osteonecrosis Following Treatment of Unstable SCFE.

BACKGROUND: Avascular necrosis (AVN) remains the most dreaded complication of unstable slipped capital femoral epiphysis (SCFE) treatment. Newer closed reduction techniques (with perfusion monitoring) have emerged as a technically straightforward means to address residual SCFE deformity while still minimizing the risk of osteonecrosis. However, limited data exists regarding the reliability of intraoperative epiphyseal perfusion monitoring to predict the development of AVN. The purpose of this study was to evaluate its reliability. METHODS: We retrospectively reviewed all patients with unstable SCFE who underwent closed or open reduction with epiphyseal perfusion monitoring using an intracranial pressure (ICP) probe from 2015 to 2023 at a single institution with a minimum 6-month radiographic follow-up. Demographic, clinical, and radiographic data were recorded, including duration of symptoms, type of reduction, capsulotomy performed, presence of a waveform on ICP monitoring after epiphyseal fixation, and development of AVN on follow-up radiographs. RESULTS: Our cohort included 33 hips (32 patients), of which 60.6% (n=20) were male. The average age was 12.5±1.8 years, with a median follow-up of 15.8 months. Eleven hips were treated with open reduction using the modified Dunn technique (10 hips) or anterior approach (1 hip), and 22 hips were treated with inadvertent (5 hips) or purposeful closed reduction using the Leadbetter technique (17 hips). Overall, 8 of the 33 hips in our series (24.2%) developed AVN, 6 of which (20%) had a pulsatile waveform on intraoperative epiphyseal perfusion monitoring. The overall rate of AVN after closed reductions was 31.8% (7 of 22 hips); the incidence of AVN after closed reduction with a detectable waveform was 30% (6 of 20 hips). There was no significant association between time to surgery ( P =0.416) or type of reduction ( P =0.218) and the incidence of AVN. CONCLUSIONS: In this series, intraoperative epiphyseal perfusion monitoring did not reliably predict the development of osteonecrosis. To our knowledge, this is the first study to report AVN after demonstrable intraoperative epiphyseal perfusion following closed reduction of unstable slips. LEVEL OF EVIDENCE: Level IV: case series-therapeutic study.

A Role for Thyroid Testing in Slipped Capital Femoral Epiphysis? 32% Rate of Abnormal Values in Tested Patients.

BACKGROUND: Hypothyroidism is a known risk factor for slipped capital femoral epiphysis (SCFE), and prior studies of hypothyroid-associated SCFE have demonstrated an incidence of up to 6%. However, there is limited evidence and no formal practice guidelines regarding whether patients presenting with SCFE should undergo screening for endocrine disorders. This study aims to investigate the incidence of abnormal thyroid function studies in patients presenting with SCFE. METHODS: This was a retrospective review of all patients aged 0 to 18 years treated for SCFE at a single pediatric hospital from January 2015 to July 2022. On presentation, patients' BMI, thyroid-stimulating hormone (TSH), free T4, vitamin D, creatinine, BUN, and HbA1c levels were documented. Follow-up and treatment for any identified endocrinopathies were noted. In addition, the chronicity, stability, and severity of their slips were recorded. RESULTS: Ninety-eight patients with 106 hips were included in this study. TSH was obtained at the time of initial presentation in 66% (n=65/98) of patients. Median TSH was 2.99 (range: 0.02 to 919, std dev: 132.4). The normal reference range for our institution is 0.5 to 4.5 mcIU/mL. Thirty-two percent (n=21/65) of patients with a documented TSH had an abnormal value. Of those patients who had an elevated TSH, 3 were diagnosed with clinical hypothyroidism and went on to treatment with levothyroxine (n=3/19, 16%), 2 patients had been started on levothyroxine before presentation (n=2/19, 11%), and 2 patients were followed in endocrinology clinic until their TSH levels had normalized without further intervention (n=2/19, 11%). CONCLUSIONS: Screening of our SCFE population revealed a 32% incidence of thyroid abnormalities which affected treatment in 24% of those patients. This is a much higher incidence of hypothyroid-associated SCFE than previously demonstrated in the literature and has prompted us to start including thyroid screening studies as a routine part of our workup for all patients with SCFE. LEVEL OF EVIDENCE: Level III.

Association of Relative Skeletal Immaturity of the Triradiate Cartilage with Increased Proximal Femoral Deformity in Prophylactic Fixation for Slipped Capital Femoral Epiphysis: A Radiographic Study.

INTRODUCTION: The purpose of this study was to describe proximal femoral deformity after contralateral hip prophylactic fixation of slipped capital femoral epiphysis (SCFE) in patients and the association of relative skeletal immaturity with this deformity. METHODS: A retrospective review of patients presenting with a SCFE was conducted from 2009 to 2015. Inclusion criteria were (1) radiographic evidence of a unilateral SCFE treated with in situ fixation, (2) contralateral prophylactic fixation of an unslipped hip, and (3) at least 3 years of follow-up. Measurements were made on radiographs and included greater trochanter height relative to the center of the femoral head, femoral head-neck offset, and femoral neck length. Skeletal maturity was evaluated by assessing the status of the proximal femoral physis and triradiate cartilage (TRC) of the hip, in addition to the length of time to closure of these physes. Values were compared from initial presentation to final follow-up. Statistical analysis included descriptive statistics and linear regression. RESULTS: Twenty-seven patients were included. Bivariable linear regression demonstrated that an increased relative trochanteric overgrowth was associated with TRC width (ß = 3.048, R = 0.585, P = 0.001) and an open TRC (ß = -11.400, R = 0.227, P = 0.012). Time to proximal femoral physis closure (ß = 1.963, R = 0.444, P = 0.020) and TRC closure (ß = 1.983, R = 0.486, P = 0.010) were predictive of increased deformity. In addition, multivariable elimination linear regression demonstrated that TRC width (ß = 3.048, R = 0.585, P = 0.001) was predictive of an increased relative trochanteric overgrowth. DISCUSSION: Patients with an open TRC and increased TRC width are associated with increased relative trochanteric overgrowth when undergoing prophylactic fixation for a unilateral SCFE. Increased caution should be exercised when considering contralateral hip prophylactic fixation in skeletally immature patients presenting with a unilateral SCFE. LEVEL OF EVIDENCE: Level IV, case series.

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.

Limited angular remodelling after in-situ fixation for slipped capital femoral epiphysis : A study on radiographs from the Swedish pediatric orthopaedic quality registry for SCFE.

BACKGROUND: In Sweden, most children with slipped capital femoral epiphysis (SCFE) are operated on with a single smooth pin or a short-threaded screw, allowing further growth of the femoral neck. Using the Swedish Pediatric Orthopaedic Quality registry, SPOQ, we investigated whether angular remodelling occurs adjacent to the proximal femoral epiphysis after fixation of SCFE using implants, allowing continued growth of the femoral neck. METHODS: During 2008-2010 a total national population of 155 children were reported to the SPOQ registry. Following our strict inclusion criteria, radiographs of 51 hips were further assessed. The lateral Head Shaft Angle (HSA), the Nötzli 3-point α-angle, the anatomic α-angle, and the Anterior Offset Ratio (AOR) on the first postoperative radiographs and at follow-up were measured to describe the occurrence of remodelling. Slip severity was categorised as mild, moderate or severe according to postoperative HSA. RESULTS: Mean and SD values for the change in HSA were 3,7° (5,0°), for 3-point α-angle 6,8° (8,9°), and anatomic α-angle 13,0° (16,3°). The overall increase in AOR was 0,038 (0.069). There were no significant differences between the slip severity groups. CONCLUSIONS: We found limited angular remodelling after in situ fixation with smooth pins or short threaded screws for SCFE. The angular remodelling and the reduction of the CAM deformity was less than previously described after fixation of SCFE with similar implants. Results about the same magnitude with non-growth sparing techniques suggest that factors other than longitudinal growth of the femoral neck are important for angular remodelling.

The Effect of Human Growth Hormone Treatment on the Development of Slipped Capital Femoral Epiphysis: A Cohort Analysis With 6 Years of Follow-up.

BACKGROUND: Slipped capital femoral epiphysis (SCFE) is a common hip disorder in adolescents that can result in substantial complications, impacting the quality of life. Human Growth Hormone (HGH) administration may elevate the risk of SCFE, though the relationship remains unclear. Clarifying this association could enable better monitoring and earlier diagnosis of SCFE in patients receiving HGH. The aim of the study is to investigate the association between HGH administration and the incidence of SCFE. METHODS: This retrospective cohort study utilized data from the TriNetX research database from January 2003 to December 2022. The study included 2 cohorts: an HGH cohort including 36,791 patients aged below 18 years receiving HGH therapy and a control group consisting of patients who did not receive HGH therapy. A 1:1 propensity score matching technique was employed to ensure comparability between the HGH and no-HGH cohorts. The primary outcome measure was the development of SCFE identified by International Classification of Diseases codes. For comparative analysis, both risk ratios (RR) and hazard ratios were computed to evaluate the association between HGH therapy and the development of SCFE. RESULTS: The HGH cohort had an increased risk of SCFE compared with the no-HGH cohort (RR: 3.5, 95% CI: 2.073, 5.909, P <0.001) and had an increased hazard of developing SCFE (hazard ratio: 2.627, 95% CI: 1.555, 4.437, P <0.001). Patients with higher exposure to HGH (defined as >10 prescriptions) had an RR of 1.914 (95% CI: 1.160, 3.159, P =0.010) when compared with their counterparts with ≤10 prescriptions. CONCLUSIONS: In the largest study to date, HGH administration was associated with an elevated risk of SCFE in children in a dose-dependent manner. LEVEL OF EVIDENCE: Level III-therapeutic retrospective cohort study.

Incidence and Clinical Characteristics of Slipped Capital Femoral Epiphysis in Patients with Endocrinopathy: A Population-Based Cohort Study.

BACKGROUND: Endocrinopathy is a risk factor for slipped capital femoral epiphysis (SCFE). We aimed to determine (1) the incidence of endocrinopathy-associated SCFE compared with that of non-endocrinopathy-associated SCFE, (2) whether the incidence of SCFE increases with the number of deficient hormones, and (3) the clinical characteristics of endocrinopathy-associated SCFE. METHODS: We conducted a population-based cohort study using a nationwide database in South Korea. All new diagnoses of endocrinopathy or SCFE between 2002 and 2019 in children born between 2002 and 2005 were identified. The incidence of SCFE was calculated for each type of endocrinopathy. The trend of the incidence of SCFE relative to the number of deficient hormones was analyzed. The male:female ratio was compared between endocrinopathy-associated SCFE and non-endocrinopathy-associated SCFE. For endocrinopathy-associated SCFE, the time between the diagnoses of SCFE and endocrinopathy was evaluated. RESULTS: The incidence of SCFE was higher in children with endocrinopathy than in those without endocrinopathy (37.1/100,000 versus 9.0/100,000 children) (relative risk, 4.1 [95% confidence interval, 2.8-6.1]). Among various endocrinopathies, growth hormone deficiency showed the highest incidence of SCFE (583.8/100,000 children). The Cochran-Armitage test showed a linear trend, with an increased number of deficient hormones being associated with a higher incidence of SCFE (p < 0.001). Male sex was dominant in the non-endocrinopathy-associated SCFE group (73%; 117 of 161), whereas female sex was dominant in the endocrinopathy-associated SCFE group (53%; 16 of 30) (p = 0.009). Twenty-two of the 30 cases of endocrinopathy-associated SCFE were diagnosed after the diagnosis of endocrinopathy, with a median time of 3.6 years between the diagnoses. Six (27%) of these 22 children developed SCFE >5 years after the diagnosis of endocrinopathy. CONCLUSIONS: The incidence of SCFE was approximately 4 times higher in children with endocrinopathy than in those without endocrinopathy. The risk of SCFE increased with an increased number of deficient hormones. Long-term monitoring of SCFE occurrence in children with endocrinopathies is strongly recommended. LEVEL OF EVIDENCE: Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.

[Evaluation of care for slipped capital femoral epiphysis (SCFE) in Germany]. / Analyse der Versorgungssituation bei Epiphyseolysis capitis femoris (ECF) in Deutschland.

INTRODUCTION: The treatment concept for slipped capital femoral epiphysis is still controversial. According to studies, there is currently no recommendation for a universal approach. Therefore, the aim of this study is to analyze the care reality of children with ECF in Germany. METHODS: The evaluation of the study is performed based on a questionnaire sent to physicians tending to ECF in 2021. Data is compared to the literature. RESULTS: 36 of 47 questionnaires sent out were included. Overall, no significant difference in ECF care was proven in terms of annual caseload or the size of hospital. CONCLUSION: A high variance in operative SCFE treatment is reported. According to current literature, the modified Dunn procedure is considered the best therapeutic option to date, especially for patients with severe or chronic ECF. However, compared with alternative care options, this is not feasible in every hospital due to its complicating and challenging nature. Central registration, minimum volume regulation, and expansion of continuing education measures can contribute to optimization.

Quantifying Risk Factors for Slipped Capital Femoral Epiphysis and Postslip Osteonecrosis.

BACKGROUND: Slipped capital femoral epiphysis (SCFE) is a disorder of the proximal femoral physis occurring in late childhood and adolescence. Previously postulated risk factors include obesity and endocrinopathies. The purpose of this investigation was to identify risk factors for developing SCFE, as well as postslip osteonecrosis (ON), among the United States pediatric population. METHODS: A national database investigation was performed using PearlDiver Technologies, Inc., queried for SCFE and ON using International Classification of Disease codes (2010 to 2020). Regression analyses to determine the risk of developing a SCFE, and ON after a patient has already been diagnosed with a SCFE ("postslip"). Propensity matching between SCFE and control groups generated a pseudo-randomization model to compare the relative risk. RESULTS: There were 11,465 patients with SCFE available in the database, matched with 134,680 controls. After matching, vitamin D deficiency, obesity, hypothyroidism, and growth hormone use were risk factors for developing SCFE [relative risk ranges from 1.42 (95% CI: 1.21-1.39, vitamin D deficiency) to 3.45 (95% CI: 3.33-3.57, obesity)]. ON risk factors were vitamin D deficiency [1.65 (1.26-2.14)] and hypothyroidism [1.49 (1.10-2.07)]. CONCLUSIONS: This United States national database study quantified risk factors of developing an SCFE and postslip ON. Obesity is the most significant risk factor for the development of a slip, but not ON. Growth hormone use, hypothyroidism, and vitamin D deficiency are also risk factors for SCFE development, whereas only the latter two were associated with ON. These findings demonstrate the public health implications of obesity and comorbid conditions in pediatric hip pathology. LEVEL OF EVIDENCE: Level III.

The Effects of Residual Femoral Deformity on Computed Contact Mechanics in Patients Treated With In Situ Fixation for Slipped Capital Femoral Epiphysis.

OBJECTIVE: In situ fixation for treatment of slipped capital femoral epiphysis (SCFE) can stabilize the epiphysis and prevent further joint deformation but often leaves residual deformity that may adversely affect intra-articular contact mechanics. The purpose of this study was to investigate the relationship between residual deformity and contact mechanics in the post-SCFE hip. METHODS: Patient-specific hip models were created for 19 patients with SCFE treated with in situ fixation. For each model, discrete element analysis was used to compute cumulative acetabular and femoral contact stress exposure during a walking gait cycle. Slip severity was evaluated for each patient using the two-dimensional Southwick angle and a novel three-dimensional (3D) assessment of multiplanar femoral deformity (3D slip angle). RESULTS: Of the SCFE cases, 2/7 mild (Southwick angle ≤30 degrees) had peak cumulative femoral exposures equivalent to that of severe (Southwick angle ≥60 degrees) cases. Severe SCFE cases had higher peak ( P = 0.015) and mean ( P = 0.028) femoral contact stress exposure and lower cumulative femoral contact area ( P = 0.003) than mild (Southwick angle ≤30 degrees) SCFE cases. Mean femoral contact stress exposure was also higher in severe SCFE cases than in moderate SCFE cases ( P = 0.027). Acetabular and femoral contact mechanics metrics typically demonstrated stronger correlations with 3D slip angle than two-dimensional Southwick angle. CONCLUSIONS: Increased slip severity adversely impacts intra-articular femoral contact mechanics. Contact mechanics metrics demonstrate higher correlations with 3D slip angle, indicating that this novel measurement may better describe global deformity and its relationship to intra-articular mechanics; however, the modest strength of these correlations may also imply that global impingement-generating deformity is not the primary factor driving contact mechanics in the post-SCFE hip. CLINICAL RELEVANCE: Greater slip severity adversely impacts contact mechanics in the post-SCFE hip. However, focal regions of high contact stress were seen even in mild SCFE deformities, suggesting some type of deformity correction should be considered even for mild slips to alleviate secondary impingement, address focal incongruities, and reduce osteoarthritis development/progression.

In situ fixation of slipped capital femoral epiphysis carries a greater than 40% risk of later total hip arthroplasty during a long-term follow-up.

Aims: We aimed to assess the cumulative risk of total hip arthroplasty (THA) from in situ fixation for slipped capital femoral epiphysis (SCFE) after a follow-up of almost 50 years. Methods: In this study, 138 patients with 172 affected hips treated with in situ fixation were evaluated retrospectively. A total of 97 patients (70%) were male and the mean age was 13.6 years (SD 2.1); 35 patients (25%) had a bilateral disease. The median follow-up time was 49 years (interquartile range 43 to 55). Basic demographic, stability, and surgical details were obtained from patient records. Preoperative radiographs (slip angle; SA) were measured, and data on THA was gathered from the Finnish National Arthroplasty Register. Results: The preoperative SA was a mean of 39° (SD 19°). At follow-up, 56 of the patients had undergone THA for a hip previously fixed in situ for SCFE (41%) and 64 of all affected hips had been replaced (37%). Kaplan-Meier analysis gave a median prosthesis-free postoperative survival of 55 years (95% confidence interval (CI) 45 to 64) for the affected hips. In a multivariate analysis, female patients had a two-fold risk for THA (hazard ratio (HR) 2.42 (95% CI 1.16 to 5.07)) and a greater preoperative SA increased the risk of THA (HR 1.03 for every increment of 1° (95% CI 1.01 to 1.05)), while patient age at surgery, slip laterality, stability of slip, or diagnostic delay did not have a statistically significant effect on the risk of THA. Conclusion: SCFE treated primarily with in situ fixation may lead to THA in more than 40% of affected hips at a near 50-year follow-up. This risk is approximately 15-times the reported lifetime risk in the Finnish general population. Female sex and increasing preoperative SA significantly predicted higher risk of THA.

3D printed patient-specific fixation plates for the treatment of slipped capital femoral epiphysis: Topology optimization vs. conventional design.

Orthopedic plates are commonly used after osteotomies for temporary fixation of bones. Patient-specific plates have recently emerged as a promising fixation device. However, it is unclear how various strategies used for the design of such plates perform in comparison with each other. Here, we compare the biomechanical performance of 3D printed patient-specific bone plates designed using conventional computer-aided design (CAD) techniques with those designed with the help of topology optimization (TO) algorithms, focusing on cases involving slipped capital femoral epiphysis (SCFE). We established a biomechanical testing protocol to experimentally assess the performance of the designed plates while measuring the full-field strain using digital image correlation. We also created an experimentally validated finite element model to analyze the performance of the plates under physiologically relevant loading conditions. The results indicated that the TO construct exhibited higher ultimate load and biomechanical performance as compared to the CAD construct, suggesting that TO is a viable approach for the design of such patient-specific bone plates. The TO plate also distributed stress more evenly over the screws, likely resulting in more durable constructs and improved anatomical conformity while reducing the risk of screw and plate failure during cyclic loading. Although differences existed between finite element analysis and experimental testing, this study demonstrated that finite element modelling can be used as a reliable method for evaluating and optimizing plates for SCFE patients. In addition to enhancing the mechanical performance of patient-specific fixation plates, the utilization of TO in plate design may also improve the surgical outcome and decrease the recovery time by reducing the plate and incision sizes.

Comparison of three radiographic assessment methods for detecting slipped capital femoral epiphyses in cats: Klein's line, modified Klein's line and the S-sign.

OBJECTIVES: The aim of the present study was to investigate whether diagnostic assessment methods used on radiographs in humans with slipped capital femoral epiphysis (SCFE) can be used in cats. METHODS: The ventrodorsal (VD) extended-leg and VD frog-leg pelvic radiographs of 20 cats with SCFE without fully displaced femoral capital epiphyses (FCE), eight cats with fully displaced FCE and five control cats with normal pelvic anatomy were assessed by five observers on two separate occasions 3 months apart. The Klein's line and modified Klein's line were assessed on each VD extended-leg radiograph, and the S-sign was assessed on each VD extended-leg and VD frog-leg radiograph. RESULTS: Excluding cases of fully displaced FCE, the S-sign on the VD frog-leg radiographs more accurately diagnosed SCFE than the S-sign on the VD extended-leg radiographs and the Klein's line (92.4% vs 88.8% vs 60.6%, respectively), and had the greatest sensitivity (93.9% vs 79.2% vs 30.6%, respectively). The S-sign on the VD extended-leg radiographs had greater specificity than the Klein's line and S-sign on the VD frog-leg radiographs (99.2% vs 97.9% vs 90.9%, respectively). The modified Klein's line detected SCFE in 40.2% of cases that were negative for the Klein's line. CONCLUSIONS AND RELEVANCE: The S-sign in both VD extended-leg and VD frog-leg views successfully detected SCFE in cats and can be used to increase early diagnosis and treatment in cats with SCFE that have only subtle radiographic changes.