Pediatric Hip Disorders Research Articles

Pediatric hip disorders are not associated with an increased 10-year revision risk after total hip arthroplasty under the age of 55: results from the Dutch Arthroplasty Register.

Developmental dysplasia (DDH) and Legg-Calvé-Perthes disease (LCPD) are common indications for total hip arthroplasty (THA) at a young age, and may be associated with increased revision risk. We aimed to investigate the 10-year cumulative aseptic cup revision and overall revision risk of THA, and investigated whether these are increased compared with THA for primary osteoarthritis (OA) in patients below 55 years. All THAs (2007-2019) in patients under the age of 55 for the indications OA, DDH, and LCPD were extracted from the Dutch Arthroplasty register. The 10-year cumulative incidences of aseptic cup failure and overall revision were assessed for the 3 groups, with death as a competing risk. Cox regression analysis was used. 24,263 THAs were identified: 20,645 (85%) for OA, 3,032 (13%) for DDH, and 586 (2%) for LCPD. The 10-year cumulative revision risk for aseptic cup failure was 3.4% (95% confidence interval [CI] 3.0-3.8) for OA, 3.4% (CI 2.4-3.4) for DDH, and 1.7% (CI 0.2-3.1) for LCPD. The 10-year cumulative overall revision risk was 6.0% (CI 5.6-6.5) for OA, 6.0% (CI 4.9-7.2) for DDH, and 5.1% (2.7-7.5) for LCPD. The multivariable Cox regression analysis for aseptic cup failure yielded hazard ratios of 0.7 (0.5-1.2) for DDH, and 0.8 (0.3-2.1) for LCPD compared with OA. No statistically significant differences for overall revision were found. THA performed for DDH or LCDP in patients under the age of 55 was not associated with a statistically significant increased risk of aseptic cup revision or overall revision, compared with THA performed for primary OA in the same age group.

Imaging of Disease and Normal Variant Patterns in Pediatric Hips.

The pediatric hip undergoes significant changes from infancy through adolescence. Proper maturation is crucial for the development of a stable and functional hip joint. Imaging interpretation of the pediatric hip requires distinguishing normal variants and maturation patterns from pathology. We review femoral ossification centers, variants, and conditions that affect the proximal femur, such as Legg-Calvé-Perthes disease; the acetabulum, such as developmental hip dysplasia; the acetabular labrum, such as femoroacetabular impingement; and synovial pathology in children through adolescence. Understanding the spectrum of hip conditions and using advanced imaging techniques are essential for the accurate diagnosis and effective management of pediatric hip disorders.

Does spinopelvic alignment affect femoral head cartilage and the proximal femoral physis in slipped capital femoral epiphysis? A finite element analysis

BackgroundSlipped capital femoral epiphysis is a prevalent pediatric hip disorder. Recent studies suggest the spine's sagittal profile may influence the proximal femoral growth plate's slippage, an aspect not extensively explored. This study utilizes finite element analysis to investigate how various spinopelvic alignments affect shear stress and growth plate slip. MethodsA finite element model was developed from CT scans of a healthy adult male lumbar spine, pelvis, and femurs. The model was subjected to various sagittal alignments through reorientation. Simulations of two-leg stance, one-leg stance, walking heel strike, ascending stairs heel strike, and descending stairs heel strike were conducted. Parameters measured included hip joint contact area, stress, and maximum growth plate Tresca (shear) stress. FindingsPosterior pelvic tilt cases indicated larger shear stresses compared to the anterior pelvic tilt variants except in two leg stance. Two leg stance resulted in decreases in the posterior tilted pelvi variants hip contact and growth plate Tresca stress compared to anterior tilted pelvi, however a combination of posterior pelvic tilt and high pelvic incidence indicated larger shear stresses on the growth plate. One leg stance and heal strike resulted in higher shear stress on the growth plate in posterior pelvic tilt variants compared to anterior pelvic tilt, with a combination of posterior pelvic tilt and high pelvic incidence resulting in the largest shear. InterpretationOur findings suggest that posterior pelvic tilt and high pelvic incidence may lead to increased shear stress at the growth plate. Activities performed in patients with these alignments may predispose to biomechanical loading that shears the growth plate, potentially leading to slip.

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

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. 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. 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. 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.

Pediatric Hip Disorders

Developmental dysplasia of the hip is a condition characterized by hip joint instability due to acetabular dysplasia in infancy, necessitating precise ultrasound examination. Legg-Calvé-Perthes disease is caused by a temporary disruption in blood flow to the femoral head during childhood, progressing through avascular, fragmentation, re-ossification, and residual stages. Slipped capital femoral epiphysis is a condition where the femoral head shifts medially along the epiphyseal line during adolescence due to stress, such as weight-bearing. Differentiating between transient hip synovitis and septic arthritis may require joint fluid aspiration. Osteomyelitis can be associated with soft tissue edema and osteolysis. When multiple lesions are present, it is essential to distinguish between Langerhans cell histiocytosis and metastatic neuroblastoma. This review will introduce imaging techniques and typical findings for these conditions.

Temporal trends in surgical implants for in situ fixation of stable slipped capital femoral epiphysis.

Stable slipped capital femoral epiphysis (SCFE) is a pediatric hip disorder managed with in situ fixation of the proximal femoral epiphysis, otherwise known as 'pinning the hip'. The objective of this study was to characterize how the choice of implant for in situ fixation of stable SCFE has changed over time. A systematic review of publications concerning in situ fixation of stable SCFE from January 1993 to November 2021 was conducted. The change in the type, diameter, and number of implants used in publications over time and the age of their respective patient cohorts was evaluated. A total of 207 articles met inclusion criteria. There was an increase in publications using cannulated screws over time ( P = 0.0113). As the yearly percentage of publications using threadless non-cannulated implants decreased ( P = 0.0309), the percentage using cannulated screws increased ( P = 0.0047). Single-implant fixation also increased ( P = 0.0409). While there was no difference in the rate of increase of implants < 7 mm or ≥ 7 mm in diameter ( P = 0.299), patients with larger-diameter implants were, on average, older than patients with smaller-diameter implants ( P = 0.0462). In general, the age of patients undergoing in situ fixation of stable SCFE has not changed ( P = 0.595). Irrespective of patient-specific considerations, single cannulated screws have become the implant of choice for in situ fixation of stable SCFE. There has not been a consensus on the optimal implant diameter; instead, patient-specific considerations are of paramount importance in this decision.

Clinical aspects of imaging the hip in infants, children and adolescents

When achild with ahip problem is clinically evaluated, it is usually possible to make apresumptive diagnosis which is subsequently confirmed. The most important tool for confirmation in pediatric hip disorders is radiological imaging. Vice versa changes on sonogram, native X‑ray or magnetic resonance images (MRI) can often only be interpreted when the history and current clinical findings are known. In this constellation, it is desirable that all colleagues who are confronted with achild's hip problem know the most common and important pediatric hip disorders and use the same terminology. The aim of this article is to present ashort outline of the pathogenesis and clinical aspects of congenital and neurogenic hip dysplasia, coxitis fugax, septic coxitis, Perthes' disease, infantile and adolescent femoroacetabular impingement, apophysiolyses, and slipped capital femoral epiphysis.

Functional and Patient-related Outcomes of Total Hip Arthroplasty in Patients Younger Than 20 Years.

Total hip arthroplasty (THA) in adolescent and young adults represent only about 10% of all THAs. Despite the advances in hip conservation surgery, there are still adolescents and young adults who progress to severe joint degeneration. THA seems to be the last solution in these cases. We aimed to assess the clinical and patient-related outcomes at short-term to midterm follow-up for THAs performed before the age of 20 years. We performed a retrospective monocentric study including all patients that underwent a THA before the age of 20 years between January 2008 and December 2018 at our tertiary orthopaedic center with a minimum follow-up of 2years. Demographic data were recorded. The Harris and Oxford hip scores were used to assess clinical and patient-related outcomes. A total of 11 patients (12 THAs) were included. Juvenile inflammatory arthritis and avascular necrosis due to slipped capital femoral epiphysis were the most commonly encountered etiologies. The mean age at surgery was 16 years (minimum 13, maximum 19 years). The mean follow-up duration was 6 years (minimum 2, maximum 9 years) without any revision. Regarding the Harris and Oxford hip scores, the mean score were 81 and 39.5 for clinical and patient-related outcomes respectively. The Spearman correlation test revealed a statistically significant positive correlation between the 2 scores of ρ= 0.811 with a P value < .001. THA in adolescents and young adults suffering from end-stage osteoarthritis due to pediatric hip disorders provides improved hip function and notable pain relief at short-term to midterm follow-up.

Surgical course of lateral femoral cutaneous nerve during anterior exposure of paediatric hips: an observational study.

Anterior approach to the hip joint is commonly used for paediatric hip disorders. Lateral femoral cutaneous nerve (LFCN) is always exposed and dissected in this approach before deep dissection is carried out. The course of this nerve has been described in adults but there is a lack of literature regarding this in the paediatric age group. This study aimed to find the surgical anatomy of LFCN in children during the anterior approach to the hip. A total of 51 paediatric hip surgeries were done in 45 children for various hip disorders. The anterior exposure was done by the Somerville approach (Bikini incision). During surgical exposure, LFCN was exposed and its relationship to anterior superior iliac spine (ASIS), inguinal ligament and sartorius muscle was observed. In most of the cases (45/51) it was found as a single trunk below the inguinal ligament and medial to the ASIS. In one hip, multiple branches of the nerve were found just below the inguinal ligament. In four hip exposures, the nerve was not found in the surgical field and in one case nerve was accidentally cut during surgery as it was lying adherent to ASIS. There was no significant correlation between the observational parameters of the nerve with anthropometric variables. Nerve was mostly seen in area 5-25 mm medial to ASIS and 10-50 mm below the ASIS in 80% of our surgical exposures where the nerve was isolated. We observed that once LFCN is dissected, the injury during further surgical procedures can be prevented.

Modernizing Our Understanding of Total Hip Arthroplasty in the Pediatric and Young Adult Patient: A Single-center Experience.

Pediatric hip disorders represent a broad range of pathology and remain a significant source of morbidity for children and young adults. Surgical intervention is often required for joint preservation, but when salvage is not possible, joint replacement may be indicated to eliminate pain and preserve function. Although there have been significant updates in the management of both pediatric hip disease and the field of total hip arthroplasty (THA), there is a paucity of literature reflecting advancements in the area of pediatric and young adult (PYA) arthroplasty. No study has investigated the impact of approach on outcomes after PYA THA. The purpose of this study is to describe the indications, techniques, and early outcomes of THA in the PYA population in a modern practice setting. We performed a retrospective descriptive analysis of all patients undergoing primary THA performed at a tertiary care children's hospital from 2004 to 2019. Ninety-three hips in 76 patients were evaluated. Demographics, intraoperative variables, postoperative pain and function ratings, and complication and revision rates were collected. Eighty-five hips in 69 patients were included. Patients were aged 12 to 23 years old, with males and females represented equally (33 vs. 36, respectively). The most common cause of hip pain was avascular necrosis (AVN, 56/85, 66%), most commonly due to slipped capital femoral epiphysis (13/56, 23%) idiopathic AVN (12/56, 21%), and chemotherapy (12/56, 21%). Half of all hips had been previously operated before THA (43/85). Thirty-six procedures were performed via the posterolateral approach (36/85, 42%), 33 were performed via direct anterior approach (33/85, 39%), and 16 were performed via the lateral approach (LAT, 16/85, 19%). At final follow-up, 98% (83/85) of patients had complete resolution of pain, 82% (70/85) had no notable limp, and 95% (81/85) had returned to all activities. There were 6 complications and 1 early revision. Average Hip disability and Osteoarthritis Outcomes Score for Joint Replacement scores increased by 37 points from 56 to 93. The overall revision-free survival rate for PYA THA was 98.8% (at average 19-mo follow-up). Modern PYA THA is dissimilar in indications and surgical techniques to historic cohorts, and conclusions from prior studies should not be generalized to modern practice. In our practice, PYA patients most commonly carry a diagnosis of AVN, and THA can be performed with modern cementless fixation with large cup and head sizes and ceramic-on-cross-linked polyethylene bearings utilizing any approach. Further study is required to better characterize middle-term and long-term results and patient-reported outcomes. Therapeutic Level IV-retrospective case series.

Management of Patients With Legg-Calvé-Perthes Disease at a Single Center in Jeddah, Saudi Arabia.

Background: Legg-Calvé-Perthes disease (LCPD) is an idiopathic pediatric hip disorder associated with avascular necrosis of the femoral head. Although there is no standardized and optimal treatment protocol for patients with LCPD, there are three primary treatment strategies: symptomatic treatment, nonsurgical containment using orthotic devices, and surgical containment.Objective: This study aimed to describe the demographic characteristics, management and outcome of pediatric patients with LCPD at our center between 2005 and 2015.Material and Methods: In this retrospective study, 23 patients with LCPD who represented all patients with LCPD treated at King Abdul-Aziz Medical City, Jeddah, Saudi Arabia between 2005 and 2015 were enrolled. Their demographic and clinical characteristics, treatment methods, and outcomes were evaluated.Results: Descriptive statistics showed that most of the patients were males (87.0%), with a mean age of 7.1±2.4 years. None of the patients had a family history of LCPD. Approximately two-thirds of the patients reported hip pain as the chief concern. LCPD was observed in the left hip in 60.9% of patients, the right hip in 21.7% of patients, and both hips in 17.4% of patients. Approximately half of the patients (55.3%) were treated with physiotherapy, and 10.6% were treated with orthotics. Despite that, 10 patients (43.4%) required surgical management after the conservative approach, and six of them underwent pelvic Salter innominate osteotomy.Conclusion: These results highlight the experience of a single center in managing patients with LCPD. Treatment was different based on patient age; non-surgical treatment, mainly physiotherapy, was predominant in younger children. However, regardless of the type of treatment, the earlier interventions have proven to provide better outcomes in patients with this health condition.

Treatment Options for End-Stage Hip Disease in Adolescents: To Replace, Fuse, or Reconstruct?

This paper aims to review the indications criteria for the surgical treatment of adolescents with hip osteoarthritis and summarize the contemporary techniques that orthopaedic surgeons can apply for hip reconstruction. Hip osteoarthritis remains a concerning burden to North American society. While the rate of total hip replacement (THR) in younger patients has increased in the last decades, younger patients may have a higher risk of revision hip replacement because of their increased level of activity and expected patient longevity compared with the elderly. Increased demand for multiple revision surgeries is a concern for the adolescent patient. Although in general THR has been increasingly recommended for the treatment of end-stage osteoarthritis secondary to pediatric hip disorders, hip arthrodesis remains a beneficial alternative for the treatment of severe hip disease secondary to infection and for patients who desire to engage in a very active lifestyle. Hip preservation procedures are ideally performed in the prearthritic stage or in hips with minimal degeneration to preserve the joint and achieve the most optimal outcomes. However, adolescents and young adults with moderate and rarely advanced arthritis may benefit from surgical treatment using hip preservation techniques. Treatment of adolescents with pain and dysfunction because of end-stage hip disease is challenging and controversial. THR and arthrodesis are the 2 principal alternatives. However, in particular circumstances, hip reconstruction may be recommended.

Functional Outcomes of Hip Arthroscopy for Pediatric and Adolescent Hip Disorders.

BackgroundThere is a paucity of literature on the use of hip arthroscopy for pathologic conditions in skeletally immature patients. Thus, the indications and safety of the procedure are still unclear. The purpose of this study was to investigate the safety and functional outcomes of hip arthroscopy for pediatric and adolescent hip disorders. We further attempted to characterize arthroscopic findings in each disease.MethodsWe retrospectively reviewed 32 children and adolescents with hip disorders who underwent 34 hip arthroscopic procedures at a tertiary care children's hospital from January 2010 to December 2016. We evaluated functional limitations and improvement after operation by using the modified Harris hip score (HHS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), subjective pain assessment with a visual analog scale (VAS), and range of hip motion as well as the complications of hip arthroscopy. Arthroscopic findings in each disease were recorded.ResultsHip arthroscopy was performed for Legg-Calvé-Perthes disease (n = 6), developmental dysplasia of the hip (n = 6), slipped capital femoral epiphysis (n = 5), idiopathic femoroacetabular impingement (n = 6), sequelae of septic arthritis of the hip (n = 3), hereditary multiple exostosis (n = 2), synovial giant cell tumor (n = 3), idiopathic chondrolysis (n = 2), and posttraumatic osteonecrosis of the femoral head (n = 1). Overall, there was a significant improvement in the modified HHS, WOMAC, VAS, and range of hip motion. Symptom improvement was not observed for more than 18 months in four patients who had dysplastic acetabulum with a labral tear (n = 2) or a recurrent femoral head bump (n = 2). There were no complications except transient perineal numbness in five patients.ConclusionsOur short-term follow-up evaluation shows that hip arthroscopy for pediatric and adolescent hip disorder is a less invasive and safe procedure. It appears to be effective in improving functional impairment caused by femoroacetabular impingement between the deformed femoral head and acetabulum or intra-articular focal problems in pediatric and adolescent hip disorders.

Benign Pediatric Tumors and Tumor-Like Conditions of the Hip

AbstractHip pain in the pediatric population can be a challenging presenting complaint to assess. An extensive differential list, including the possibility of infection, transient conditions, and malignancy, results in numerous questions that can render diagnosis difficult. As clinicians, it is imperative that we have the ability to recognize, properly diagnose, and possibly treat the multitude of potential pediatric hip disorders. Here the authors present the incidence, characteristics, and treatment of various benign tumors and tumor-like conditions of the pediatric hip.

Hip Arthroscopy in the Pediatric and Adolescent Athlete

Hip disorders are increasingly common in pediatric and adolescent athletes, being both idiopathic problems aggravated by sports and overuse injuries caused by sports. These disorders are a major cause of morbidity and their long-term consequences carry into adulthood. In the past these problems have been primarily treated with open surgery using a surgical hip dislocation, but due to improved instruments and techniques, hip arthroscopy is becoming a mainstay in their treatment. Arthroscopic management allows assessment and reconstructive treatment of most problems in practically all parts of the hip. Recent comparative studies have shown better clinical results, less complications and much faster recovery after arthroscopy when compared with open surgery for a number of indications, including impingement and labral tears. Typical pediatric hip disorders such as slipped capital femoral epiphysis (SCFE) and Legg-Calve-Perthes Disease (LCPD) may also benefit from hip arthroscopy. Analyzing complications, hip arthroscopy has also performed very well. What stands out as a risk factor is the need for experience in pediatric hip arthroscopy techniques, which have been described to be distinctly different from the approach to the adult hip. Also, an understanding of the growing anatomy is crucial. Finally, a thorough and well-directed postoperative therapy is pivotal to realize the best possible outcome.

3-dimensional metrics of proximal femoral shape deformities in Legg-Calvé-Perthes disease and slipped capital femoral epiphysis.

Legg-Calvé-Perthes disease (LCPD) and slipped capital femoral epiphysis (SCFE) are two common pediatric hip disorders that affect the 3-dimensional shape and function of the proximal femur. This study applied the principles of continuum mechanics to statistical shape modeling (SSM) and determined 3-D metrics for the evaluation of shape deformations in normal growth, LCPD, and SCFE. CT scans were obtained from 32 patients with asymptomatic, LCPD, and SCFE hips ((0.5-0.9 mm)2 in-plane resolution, 0.63 mm slice thickness). SSM was performed on segmented proximal femoral surfaces, and shape deformations were described by surface displacement, strain, and growth plate angle metrics. Asymptomatic normal femurs underwent coordinated, growth-associated surface displacements and anisotropic strains that were site-specific and highest at the greater trochanter. After size- and age-based shape adjustment, LCPD femurs exhibited large displacements and surface strains in the femoral head and neck, with associated changes in femoral head growth plate angles. Mild SCFE femurs had contracted femoral neck surfaces, and surface displacements in all regions tended to increase with severity of slip. The results of this paper provide new 3-D metrics for characterizing the shape and biomechanics of the proximal femur. Statement of Clinical Significance: Quantitative 3-D metrics of shape may be useful for understanding and monitoring disease progression, identifying target regions for shape modulation therapies, and objectively evaluating the success of such therapies. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1526-1535, 2018.

Indications for Hip Arthroscopy

Context:Hip arthroscopy is gaining popularity within the field of orthopaedic surgery. The development and innovation of hip-specific arthroscopic instrumentation and improved techniques has resulted in improved access to the hip joint and ability to treat various hip pathologies.Evidence Acquisition:Electronic databases, including PubMed and MEDLINE, were queried for articles relating to hip arthroscopy indications (1930-2017).Study Design:Clinical review.Level of Evidence:Level 4.Results:Initially used as a technique for loose body removal, drainage/debridement of septic arthritis, and treatment of pediatric hip disorders, hip arthroscopy is currently used to treat various hip conditions. The recognition of femoroacetabular impingement (FAI) as a source of hip pain in young adults has rapidly expanded hip arthroscopy by applying the principles of osseous correction that were previously described and demonstrated via an open surgical dislocation approach. Hip pathologies can be divided into central compartment, peripheral compartment, peritrochanteric space, and subgluteal space disorders.Conclusion:Although hip arthroscopy is a minimally invasive procedure that may offer decreased morbidity, diminished risk of neurovascular injury, and shorter recovery periods compared with traditional open exposures to the hip, it is important to understand the appropriate patient selection and indications.

The use of hip arthroscopy in the management of the pediatric hip.

Arthroscopy of the pediatric hip began in 1977 with a publication by Gross. Interest was relatively slow to develop in the 1980s and 1990s. Coupled with the success of hip arthroscopy in the adult, interest heightened in applying the procedure to a variety of pediatric hip disorders, given that the alternative was an open surgical hip dislocation. The success of this initial group of pediatric hip arthroscopist’s has further expanded the application of hip arthroscopy as the primary or adjunct procedure for the management of intra-articular problems of the pediatric hip.

Update on Selected Pediatric Hip Disorders

Several pediatric hip disorders are essential for the nurse practitioner to recognize, manage, and refer. In this study, the following selected hip disorders are described: developmental dysplasia of the hips; Legg-Calvé-Perthes disease; transient synovitis of the hip; and septic arthritis of the hip. Developmental dysplasia of the hips can occur congenitally or in early childhood. Legg-Calvé-Perthes disease is an avascular necrosis of the femoral head that occurs between 4 and 8 years of age. Transient synovitis of the hip is benign and self-limited, but its danger is that it can mimic septic arthritis of the hip. Septic arthritis of the hip is a medical emergency that requires operative intervention and intravenous antibiotics.

Ceramic-on-ceramic THA Implants in Patients Younger Than 20 Years.

Poor survival of THA implants in very young patients has been attributed to use of cemented implants, wear of conventional polyethylene, and the presence of morphologic deformities in the proximal femur or in the acetabulum. Few studies have reported the long-term results of ceramic-on-ceramic implants in THAs in patients younger than 20 years. We determined: (1) the proportion of patients who experienced complications related to the ceramic bearing (squeaking, fracture); (2) the survivorship free from loosening and free from revision for any reason; (3) whether patients with osteonecrosis had inferior survivorship compared with patients whose surgical indication was all other diagnoses including sequelae of pediatric hip disorders (developmental dysplasia of the hip, Legg-Calvé-Perthes disease, slipped capital femoral epiphysis); and (4) clinical function. Between 1979 and 2013, we performed 113 primary THAs in 91 patients younger than 20 years at the time of surgery. Of those, 105 THAs (83 patients) were done with ceramic-on-ceramic bearings (91% of the 91 patients); during that period, a ceramic-on-ceramic bearing couple was indicated in all patients younger than 20 years. In eight patients (eight hips), a cemented polyethylene cup was implanted because the diameter of the acetabulum was smaller than the smallest available ceramic cup (46 mm), or because adequate fixation of a ceramic press-fit cup could not be achieved despite careful reaming of the acetabulum. The most common diagnosis indicating THA was avascular necrosis of the femoral head (56.2%; 59 hips). Thirty-five patients (40 hips) had undergone previous operations before the replacement. Three patients (4%; four hips) died from unrelated causes, nine patients (11%; 13 hips) were lost to followup, and four patients (five hips) had a followup greater than 8.5 years but have not been seen in the last 5 years. Patients were assessed clinically (using the Merle d'Aubigne-Postel score, Hip disability and Osteoarthritis Outcome score (HOOS), and the SF-12(®) Health Survey, and radiographically for signs of radiolucencies, subsidence, or osteolysis on plain films. The mean followup was 8.8 ± 6.1 years (range, 2-34.4 years). Five patients experienced transient noise generation, defined as a snap in four patients and squeaking in one. Seventeen hips underwent revision surgery-16 for aseptic loosening and one for septic loosening. The implant survival rate at 10 years with aseptic loosening as the endpoint was 90.3% (95% CI, 82.4%-98.9%). No hip had acetabular or femoral osteolysis. Survivorship in patients with osteonecrosis did not differ from survivorship in patients with other diagnoses. The Merle d'Aubigne-Postel score increased from 10.1 ± 4.0 to 17.6 ± 1.1 (p < 0.01); the mean HOOS score was 79.3 ± 13.8 (range, 50.6-100); the mean SF-12(®) physical and mental component scores were 48.1 ± 7.9 (range, 21.4-57.6), and 47.4 ± 12.2 (range, 24.5-99.4), respectively. We found that patient-reported outcomes scores improved in most patients undergoing THA in this very young study group. Underlying diagnosis did not affect long-term survivorship. However, the revision-free survival rate at 10 years is lower than published estimates in older patients, and with 11% of patients lost to followup, our estimates may represent a best-case scenario. Therefore, we believe THA should be performed as a last resort in this population. Level IV, therapeutic study.