You are in: eMedicine Specialties > Radiology > PEDIATRICS Slipped Capital Femoral EpiphysisArticle Last Updated: Mar 18, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: Brent Adler, MD, Chief of Musculoskeletal Imaging, Department of Radiology, Children's Hospital Brent Adler is a member of the following medical societies: American College of Radiology, Radiological Society of North America, and Society for Pediatric Radiology Editors: Beverly P Wood, MD, MS, PhD, Professor, Departments of Radiology and Pediatrics, Division of Medical Education, Keck School of Medicine, University of Southern California; Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; Marta Hernanz-Schulman, MD, FAAP, Professor, Radiology, Radiological Sciences, and Pediatrics, Director, Department of Pediatric Radiology, Radiologist-in-Chief, Director, Department of Diagnostic Imaging, Vanderbilt University Medical Center, Vanderbilt Children's Hospital; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; Felix S Chew, MD, MBA, EdM, Professor, Department of Radiology, Vice Chairman for Radiology Informatics, Section Head of Musculoskeletal Radiology, University of Washington Author and Editor Disclosure Synonyms and related keywords: SCFE, hip abnormality, early osteoarthritis, proximal femoral physis, Salter-Harris type 1 fracture, hip pain INTRODUCTIONSection 2 of 11
  BackgroundSlipped capital femoral epiphysis (SCFE) is the most common hip abnormality presenting in adolescence and is a primary cause of early osteoarthritis. Unfortunately, SCFE frequently is misdiagnosed, and it has symptoms that can be misleading.1 Early treatment leads to better outcome but is confounded by frequent delays in diagnosis.2 PathophysiologySCFE is a Salter-Harris type 1 fracture through the proximal femoral physis. Stress around the hip causes a shear force to be applied at the growth plate. Certainly, trauma has a role in the manifestation of the fracture, but an intrinsic weakness in the physeal cartilage also is present. The almost exclusive incidence of SCFE during the adolescent growth spurt indicates a hormonal role. Obesity is another key predisposing factor in the development of SCFE.3 The fracture occurs at the hypertrophic zone of the physeal cartilage. Stress on the hip causes the epiphysis to move posteriorly and medially. By convention, position and alignment in SCFE is described by referring to the relationship of the proximal fragment (capital femoral epiphysis) to the normal distal fragment (femoral neck). Because the physis has yet to close, the blood supply to the epiphysis still should be derived from the femoral neck; however, this late in childhood, the supply is tenuous and frequently lost after the fracture occurs. Manipulation of the fracture frequently results in osteonecrosis and chondrolysis because of the tenuous nature of the blood supply.4, 5, 6 FrequencyUnited StatesThe incidence is 1 case per 100,000 people. SCFE occurs most frequently in adolescents, with a slightly greater incidence in males than in females. SCFE typically occurs just after the onset of puberty, frequently in overweight and slightly skeletally immature boys. African American children are affected slightly more commonly than are others. Additional underlying risks include malnutrition, endocrine abnormalities, and prior developmental dysplasia of the hip. Chemotherapy, irradiation, and renal failure also predispose individuals to SCFE. Slippage is bilateral in 20-37% and synchronous in 9-18% of patients, and they almost always appear in the first 2 years after initial presentation. Mortality/MorbiditySCFE is a fracture through the physis. Unlike typical Salter-Harris type I fractures, SCFE has a high propensity for morbidity. The nutrient vessels of the epiphysis are beginning to penetrate the physis as it closes, and when the physis is disrupted, avascular necrosis of the head may result, particularly if the head is manipulated. The tilted epiphysis is mechanically unfavorable and increases weight bearing on the lateral edge.
RaceAfrican American children are affected slightly more often than others. SexThe incidence is slightly greater in boys than in girls. AgeSCFE typically occurs just after the onset of puberty, frequently in overweight and slightly skeletally immature boys. It is often seen in children in whom puberty is delayed. Girls who present are slightly younger than boys who present, and the condition is never seen in children who have a closed growth plate. The inclination of the growth plate from the horizontal toward the vertical also leads to an increase in vertical shear forces, promoting slippage. AnatomySCFE is a disease exclusively of the proximal femur. The fracture occurs through the hypertrophic zone of physeal cartilage. Abductors around the hip tend to pull the femur laterally and anteriorly. The epiphysis remains in place, and when the femur moves back to neutral, the epiphysis appears to have slipped medially and posteriorly. Clinical DetailsClinical presentation often is misleading, with only 50% of patients presenting with hip pain and 25% presenting with knee pain. Diagnostic errors are typical, and 26% of patients experience delay in treatment. The most common misdiagnoses include muscle strain, Osgood-Schlatter disease, and flat feet. Moderate-to-severe slips are present 50% of the time; the outcome of SCFE is related directly to the severity of the slip at treatment. The treatment of SCFE entails stabilizing the hip. Pins, screws, and wires have been used to cross the physis and fix the epiphysis.7 The goal is to avoid further damage to the penetrating vessels by stabilizing the fracture. The physis always closes after treatment. Most patients will not lose much growth potential since this physis would soon have closed. Most frequently, the bones are left with the tilt seen at presentation, and manipulation is attempted only in patients in whom the tilt impedes function. Manipulation almost always results in avascular necrosis. Chondrolysis also occurs frequently, more often in African-American children. Some complications appear to arise from synovitis, which may accompany the slip. These complications may result in early development of osteoarthritis of the hip.8 Preferred ExaminationDiagnosis is made using anteroposterior (AP) pelvis and lateral frog-leg radiographs.9 CT is a sensitive method of measuring the degree of tilt and detecting early disease, but it is rarely needed. CT may be performed with low doses, and reconstructions may allow viewing of the relationship of the femoral head to the metaphysis in three planes. MRI depicts the slippage earliest, and MRI can demonstrate early marrow edema and slippage. MRI may be helpful in follow-up studies of the contralateral hip.10 Limitations of TechniquesRadiographs are the easiest images to obtain and provide an excellent screening examination for hip pain in any patient. In patients with SCFE, advanced stages of the disease are easy to identify; however, subtle changes early in the course are more difficult to detect. Before the femoral epiphysis actually has become displaced, only a slight widening of the affected physis may be evident. A metaphyseal blanch is an increase in density in the proximal metaphysis. It is presumed that metaphyseal blanch represents an attempt at healing that occurs before there is visible displacement of the epiphysis. MRI or CT may be able to detect SCFE in early cases. DIFFERENTIALSSection 3 of 11
Femoral Neck, Fractures Juvenile Rheumatoid Arthritis Knee, Extensor Mechanism Injuries (MRI) Legg-Calve-Perthes Disease Musculoskeletal Tumors, Staging And Treatment Planning Osgood-Schlatter Disease Osteoarthritis, Primary Osteochondritis Dissecans Osteoid Osteoma Osteomyelitis, Acute Pyogenic Septic Arthritis Sickle Cell Anemia, Skeletal Other Problems to Be ConsideredFlat feet
RADIOGRAPHSection 4 of 11
FindingsDiagnosis is made using AP pelvis and lateral frog-leg radiographs. Abduction of the femur for the frog-leg view may result in increased slippage and should be performed with caution (see Images 1-6). On AP radiographs, close attention should be paid to the physis. Early in SCFE, the physis may widen. Increased opacity in the metaphysis, described as blanching, may occur as an early healing response, and the epiphysis may appear smaller because it is tilted dorsally. The lateral radiograph demonstrates slippage earliest because the slippage begins with posterior displacement and progresses with medial rotation. The Southwick method can be used by creating an axis for the femoral neck and determining whether the epiphysis is tilted (see Image 4). An additional method is to draw a line along the lateral aspect of the femoral neck on the AP view; this line, known as the line of Klein, should intersect a portion of the femoral head.11 Degree of ConfidenceDegree of confidence in radiographic findings of SCFE is high. False Positives/NegativesWhen the aforementioned constellation of findings is present, false-positive and false-negative findings do not occur. CT SCANSection 5 of 11
FindingsCT is a sensitive method for measuring the degree of tilt and detecting disease, but it is rarely needed. Usually, CT is performed only at the request of the treating physician for documenting the severity of the tilt. MRISection 6 of 11
FindingsThe earliest way to detect SCFE is by using MRI. With MRI, early marrow edema and slippage can be demonstrated. This is demonstrated with increased signal on T2-weighted and water-sensitive images. MRI can be considered in patients for whom the clinical suspicion of SCFE is high and in whom the radiographs appear normal. MRI can be considered for follow-up imaging of the contralateral hip. False Positives/NegativesMarrow edema is a nonspecific finding, and while it can indicate early bone changes in SCFE, it has numerous other causes, such as infection or even tumor. Those diagnoses are rarely considered with the proper clinical evaluation. ULTRASOUNDSection 7 of 11
FindingsUltrasonographic findings are rarely specific, and the sensitivity of sonography is unknown. Hip effusions of blood often have been reported and are suggestive of fracture. NUCLEAR MEDICINESection 8 of 11
FindingsThe radionuclide bone scan is sometimes used during workup but prior to diagnosis. Accumulation of the bone scanning agents can be decreased after fixation and in patients with an acute slip and significant displacement. The decrease is usually limited to the epiphysis. The decreased accumulation is associated with increased incidence of chondrolysis. INTERVENTIONSection 9 of 11
Patient Education: For excellent patient education resources, visit eMedicine's Foot, Ankle, Knee, and Hip Center and Sports Injury Center. Also, see eMedicine's patient education article Repetitive Motion Injuries. Medical/Legal Pitfalls
See also the Medscape topic Medical Malpractice and Legal Issues. MULTIMEDIASection 10 of 11
REFERENCESSection 11 of 11
Slipped Capital Femoral Epiphysis excerpt Article Last Updated: Mar 18, 2008 | ||||||||||||||||||||||||||||||||||||||||||
