eMedicine Specialties > Sports Medicine > Lower Limb

Slipped Capital Femoral Epiphysis

Author: Kevin D Walter, MD, FAAP, Assistant Professor of Orthopedics and Pediatrics, Department of Pediatric Orthopaedics, Department of Pediatrics, Medical College of Wisconsin; Member of Children's Specialty Group of Children's Hospital of Wisconsin
Coauthor(s): David Y Lin, MD, Fellow, Department of Orthopedic Surgery, Section of Pediatrics, University of Tennessee Campbell Clinic; Evan Schwartz, MD, Director of Orthopedic Surgery, New York Medical College; Assistant Professor, St John's Queens Hospital, Department of Surgery, Albert Einstein School of Medicine
Contributor Information and Disclosures

Updated: Aug 25, 2008

Introduction

Background

Slipped capital femoral epiphysis (SCFE) is one of the most important pediatric and adolescent hip disorders encountered in medical practice.^1,2,3,4 Although SCFE is a rare condition, an accurate diagnosis combined with immediate treatment is critical.^5,6  Despite the fact that the underlying defect may be multifactorial (eg, mechanical and constitutional factors), SCFE represents a unique type of instability of the proximal femoral growth plate. Clinically, the patient may report hip pain, medial thigh pain, and/or knee pain; an acute or insidious onset of a limp; and decreased range of motion of the hip.

On plain radiographs, the femoral head is seen displaced, posteriorly and inferiorly in relation to the femoral neck and within the confines of the acetabulum.⁷ Treatment is primarily operative internal fixation. The goal is to prevent complications such as avascular necrosis (AVN).^2,8,9,10

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.

Related eMedicine topics:
Avascular Necrosis, Femoral Head [in the Radiology section]
Femoral Head Avascular Necrosis [in the Sports Medicine section]
Slipped Capital Femoral Epiphysis [in the Orthopedic Surgery section]
Slipped Capital Femoral Epiphysis [in the Radiology section]

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Resource Center Exercise and Sports Medicine
Resource Center Joint Disorders
Specialty Site Orthopaedics
CME/CE Evidence-Based Pain Management Practices in Older Adults in Multiple Practice Settings: A Challenge of Translation
MR Imaging of Femoroacetabular Impingement

Frequency

United States

The overall incidence for SCFE in the United States is 10.8 cases per 100,000 children.¹¹  The incidence rate in boys (13.35/100,000) is higher than in girls (8.07/100,000). When compared with white children, black children have a higher incidence rate at 3.94 times, and Hispanic children have a 2.54 times higher incidence rate.

There are higher rates per 100,000 children of SCFE in the Northeast (17.15) and West (12.70) than the Midwest (7.69) and South (8.12). There is also evidence that points to a seasonal variation in SCFE occurrence. In areas north of 40º latitude, 57.4% of SCFEs occurred during the summer, whereas in areas south of 40º latitude, 57.3% of SCFEs occurred during the winter months.¹¹

SCFE mainly occurs between the ages of 10-16 years.^1,11  There has been a slight downward trend for average ages over several years, with some data finding the average age for boys at 12.7 years and girls at 11.2 years. This change could be due to the phenomenon of children maturing at a younger age.

In general, about 20% of patients have bilateral involvement at the time of presentation. It is felt that an additional 20-40% will subsequently progress to bilateral slips. When the presentation is sequential, the second hip usually presents within 18 months of the first SCFE.^12,13

There is an increased risk in children who are obese, as well as in children with other medical issues: hypothyroidism, low growth hormone level, pituitary tumors, craniopharyngioma, Down syndrome, renal osteodystrophy, and adiposogenital syndrome.

International

In a study by Benson et al, the investigators reexamined the incidence of SCFE in New Mexico (previous studies had reported almost a 5-fold lower incidence of SCFE in New Mexico compared with Connecticut). The discharge databases for the 11 major medical centers in New Mexico from 1995 to 2006 were analyzed by comparison with the 2000 New Mexico census data. The incidence data are reported as cases per 100,000 boys aged 10-17 years and girls aged 8-15 years, as per the earlier study data.¹⁴

The investigators found an incidence rate of SCFE in New Mexico for the study period was 5.99, which was a statistically significant change that was more than double the reported incidence in the 1960s (2.13). Obesity was noted as a patient factor that changed since 1971 (tripled), although the national incidence of SCFE appeared to have remained fairly constant at 10.8 per 100,000. Benson et al theorized that "increased obesity in children and improved access to pediatric orthopaedic evaluation may have contributed to a significant increase in reported incidence of SCFE in New Mexico."¹⁴

Functional Anatomy

SCFE results from a Salter-Harris type physeal fracture. In patients with SCFE, the epiphyseal growth plate is unusually widened, primarily due to expansion of the zone of hypertrophy. The hypertrophic zone, which constitutes 15-30% of the normal physis, can account for up to 80% of the width of the physeal plate in affected patients. Histologically, abnormal cartilage maturation, endochondral ossification, and perichondral ring instability occur. This leads to less organization of the normal cartilaginous columnar architecture. Slippage occurs through this weakened area.

The position of the proximal physis normally changes from horizontal to oblique during preadolescence and adolescence, redirecting hip forces from compression forces to shear forces. There is an association between femoral neck retroversion and a reduced neck-shaft angle with SCFE. These changes can increase the shear forces across the hip, leading to SCFE.¹⁵  Other concomitant findings in the hip include inflammatory synovitis and disorganized collagen fibrils with accumulations of proteoglycans and glycoproteins within the growth plate; however, whether these changes are a cause or a result of SCFE remains undetermined.

Clinical

History

• Slipped capital femoral epiphysis (SCFE) is most common in the adolescent period (ie, boys aged 10-16 y, girls aged 12-14 y). Males have 2.4 times the risk compared with females.
• The left hip is affected more commonly than the right.
• Obesity is a risk factor because it places more shear forces around the proximal growth plate in the hip at risk.^16,17
• The duration, location, and radiation of pain are important, as is the ability to bear weight.
• Genetics may play a role in SCFE because the rate of familial involvement is 5-7%, with a large variability in penetrance.
• In patients younger than 10 years, SCFE is associated with metabolic endocrine disorders (eg, hypothyroidism, panhypopituitarism, hypogonadism, renal osteodystrophy, growth hormone abnormalities).^1,18,19 Bilaterality is more common in these younger patients.
• The chronicity of the condition should be determined.
  • Prodromal symptoms (eg, hip or knee pain, limp, decreased range of motion) for less than 3 weeks are deemed acute.
  • Prodromal symptoms for longer than 3 weeks are deemed chronic.
  • If a patient reports symptoms of greater than 3 weeks' duration but presents with an acute exacerbation of pain, limp, inability to bear weight, or decreased range of motion with or without an associated traumatic episode, the SCFE is categorized as acute on chronic.
  • Determine if a traumatic episode occurred.
• It is important to determine if the lesion is stable or unstable.
  • "Stable" SCFEs allow the patient to ambulate with or without crutches.⁶
  • "Unstable" SCFEs do not allow the patient to ambulate at all; these cases carry a higher rate of complication, particularly of AVN.⁶

Physical

• If a patient reports knee pain, always examine the hip, because knee pain may be referred pain from the hip via the obturator nerve.
• Obesity increases a clinician's index of suspicion for SCFE.
• Patients often hold their affected hip in passive external rotation.
• Determine the patient's ability to bear weight (stable vs unstable).
• If the patient is ambulatory, determine the his or her gait pattern:
  • Antalgic – Shortened stance phase on the affected side
  • Out-toeing
• Always examine both hips. Assess the active and passive range of motion in both hips. In patients with unilateral complaints, this comparison allows the clinician to compare the affected and unaffected sides for differences. Internal and external rotation are best tested with the patient in the prone position with the knees flexed to 90 º.
  • If SCFE is present, the lower extremity may externally rotate and abduct with gentle passive hip flexion.
  • Internal rotation is decreased in nearly all hips with SCFE. Internal rotation is often painful.

• Search for CME/CE on This Topic »

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