Slipped Capital Femoral Epiphysis 

Updated: Dec 03, 2018
Author: Kevin D Walter, MD, FAAP; Chief Editor: Craig C Young, MD 

Overview

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, 5, 6] Although SCFE is a rare condition, an accurate diagnosis combined with immediate treatment is critical.[7, 8] 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.[9] Treatment is primarily operative internal fixation. The goal is to prevent complications such as avascular necrosis (AVN).[2, 10, 11, 12, 13]

A Klein line is a line drawn along the superior bo A Klein line is a line drawn along the superior border of the femoral neck that would normally pass through a portion of the femoral head. If not, slipped capital femoral epiphysis is diagnosed.
X-ray of a hip following operative percutaneous fi X-ray of a hip following operative percutaneous fixation of a slipped capital femoral epiphysis.

Epidemiology

Frequency

United States

The overall incidence for SCFE in the United States is 10.8 cases per 100,000 children.[14] The incidence rate in boys (13.35 per 100,000) is higher than in girls (8.07 per 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.

Rates of SCFE per 100,000 children are higher in the Northeast (17.15) and West (12.70) than in the Midwest (7.69) and South (8.12).[15] Evidence also 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.[14]  A study by Loder et al reported new seasonal variation findings in 10,350 cases of slipped capital femoral epiphysis. The study found a peak in August/September in both the Southern and Northern US with a second peak in March/April found only in the Southern US. Areas with more seasonal variability in temperature, humidity and sunlight were more likely to have greater variability.[16]  

SCFE mainly occurs between the ages of 10 and 16 years.[1, 14] A slight downward trend has occurred 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.[17]

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.[18, 19]

The risk of SCFE is increased in children who are obese, as well as in children with other medical issues such as 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.[20]

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."[20]

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.[21] 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.

 

Presentation

History

See the list below:

  • 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.[22, 23]

    • A study by Perry et al that included BMI data from 597,017 children reported that children 5-6 years of age with severe obesity had almost 6 times the risk for SCFE and children 11-12 years of age with severe obesity had 17 times the risk compared to children with normal BMI.[37]

  • 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, 24, 25] 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.[8]

    • "Unstable" SCFEs do not allow the patient to ambulate at all; these cases carry a higher rate of complication, particularly of AVN.[8]

Physical

See the list below:

  • 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.

 

DDx

 

Workup

Laboratory Studies

Routine hormonal screening of children with slipped capital femoral epiphysis (SCFE) is not indicated.

Appropriate laboratory tests should be completed for endocrinopathies and medical disorders (hypothyroidism, low growth hormone level, pituitary tumors, craniopharyngioma, Down syndrome, renal osteodystrophy, and adiposogenital syndrome) in patients with an atypical presentation or other findings on history and physical examination that are consistent with endocrinologic disorders. Atypical presentation is considered for children who present with SCFE who are younger than age 10 years or older than 16 years, as well as for children who present with SCFE and short stature. It is also worth considering endocrinology laboratory testing for a patient who is not obese but who falls within the 10- to 16-year age range.

Imaging Studies

Obtain anteroposterior and frog-lateral radiographs of the pelvis or bilateral hips.

  • Determine the amount of head displacement off the femoral neck as a percentage to classify the degree of slippage.

    • Type I slippage is less than 33% displacement.

    • Type II slippage is between 33% and 50% displacement.

    • Type III slippage is greater than 50% displacement.

  • Note any bony changes of the femoral neck and head because they may demonstrate chronic adaptive changes during alterations in hip biomechanics as the femoral head displaces.

  • AP radiograph: The Klein line is drawn straight up the superior aspect of the femoral neck. This should intersect the epiphysis. If not, then it is likely an SCFE (see the image below).

    A Klein line is a line drawn along the superior bo A Klein line is a line drawn along the superior border of the femoral neck that would normally pass through a portion of the femoral head. If not, slipped capital femoral epiphysis is diagnosed.
  • Frog leg radiograph: A straight line through the center of the femoral neck proximally should be at the center of the epiphysis. If not, and the line is anterior in the epiphysis, it is likely an SCFE.

  • Assess radiographs for signs of underlying medical disorders (rickets, renal osteodystrophy, etc).

Bone scanning, magnetic resonance imaging (MRI),[26] and computed tomography (CT) scanning are not routinely performed, but these imaging modalities may be helpful to confirm the diagnosis of SCFE or more accurately measure the degree of displacement and epiphyseal perfusion.

  • A report by Tins et al suggests that pretreatment MRI in established cases of SCFE has a role with prognostic implications for the treatment approach and outcome of this condition.[27] The investigators noted that synovitis, periphyseal edema, and joint effusion are regular features of SCFE; however, "the clinical history and findings are unreliable for the classification of SCFE," and "radiographs underestimate the severity of SCFE." On the other hand, Tins et al stated that "MRI can potentially identify unstable, reducible slips. If the mode of surgical treatment depends on the particular nature of the SCFE, then MRI contributes to surgical decision-making."[27]

 

Treatment

Acute Phase

Medical Issues/Complications

Treatment of slipped capital femoral epiphysis (SCFE) is emergent; therefore, early and accurate diagnosis is paramount. There is no role for observation or attempts at closed reduction.

Classification schemes are as follows:

  • Determine whether the SCFE is acute (< 3 weeks), chronic (3+ weeks), or acute on chronic (3+ weeks of symptoms with acute exacerbation or change).

  • Determine whether the SCFE stable (able to bear weight) or unstable (non-weight bearing). This determination has become more important than acute versus chronic due to the fact that unstable patients have been found to have a high complication rate.

  • Determine the radiographic classification. This is determined by the percentage of displacement of the hip in relation to the neck. Type I is less than 33% displacement, type II is 33-50% displacement, and type III is greater than 50% displacement.

Prophylactic treatment of the asymptomatic hip remains controversial. In Europe, the majority of patients receive prophylactic fixation of the contralateral hip. Each case should be approached individually, and the benefits and risks should be weighed when contemplating surgery on the unaffected hip.

In a review of the literature, prophylactic treatment may be considered in patients younger than 10 years or patients affected by various endocrinopathies because these individuals have higher relative risks for bilateral involvement. Prophylactic treatment should also be considered in a patient or family that is unreliable. In a typical patient who presents with unilateral SCFE, the parents should be warned of possible sequential bilateral involvement. The need for close follow-up and early operative intervention if the other hip becomes symptomatic must be understood by the family.

Delays in diagnosis or treatment can be very detrimental to the patient's outcome. The slip may progress, and increased severity of SCFE leads to early degenerative arthritis. With a diagnostic or treatment delay, stable slips may become unstable, which leads to higher rates of AVN.

Surgical Intervention

At this time, immediate internal fixation in-situ using a single cannulated screw is the treatment of choice of SCFE. Fixation allows early stabilization of the slippage, enhancement of physeal closure, prevention of further slippage, and amelioration of symptoms with minimal morbidity.[28, 29] Unstable or grade III slips may require gentle repositioning to improve alignment. Revision of the screw fixation may be needed if the child "outgrows" the screw, placing the child at risk for a repeat slip.

Prophylactic fixation of the unaffected hip in unilateral SCFE remains controversial.[3, 30] Each case should be approached individually. However, stronger consideration for the prophylactic fixation should be given to patients with endocrinologic or metabolic comorbidities, or patients who fall outside of the usual age range (10-16 y).

Wensaas et al evaluated the long-term natural history of untreated contralateral hips to see if there is a consensus regarding prophylactic fixation of the contralateral hip in SCFE. 40 patients treated for unilateral SCFE without evidence of subsequent contralateral slip during adolescence were reviewed with a mean follow-up of 36 years (range 21-50 years). The authors concluded that since the natural history showed good long-term radiographic and clinical outcome in 35 of 40 patients, that routine prophylactic fixation of the contralateral hip is not indicated.[31]

Evidence suggests that if surgical intervention occurs within 24 hours of SCFE onset, significantly fewer complications occur (7% AVN). However, if surgical intervention occurs between 24 and 48 hours, the AVN rate dramatically increases (87.5%). This risk decreases to 32% if the procedure is performed after 48 hours. True cause and effect among onset, diagnosis, and intervention cannot be truly ascertained; thus, urgency with surgical intervention is still the unquestioned rule. A study by Kohno et al found that patients with unstable slipped capital femoral epiphysis who underwent a closed reduction and pinning procedure between 24 hours to 7 days after the onset of symptoms were at significantly higher risk for AVN.[32]

Osteotomy of the proximal femur is not indicated as the primary procedure for SCFE. However, it may be needed as a secondary procedure for repositioning of the femoral head to improve functional range of motion, or as a primary procedure for patients with severe morphologic displacement.

Bone-graft epiphysiodesis in combination with internal fixation or casting is advocated by some surgeons, but the procedure is associated with a high learning curve, a high prevalence of AVN and chondrolysis, poor initial fixation, prolonged operative time, increased intraoperative blood loss, and loss of epiphyseal position.[31]

Historically, spica casts were used[33] ; however, because of the high morbidity (eg, AVN, chondrolysis) and difficulty in applying and maintaining these casts, especially in patients who are obese, spica casts have fallen out of favor.

Two techniques to correct moderate and/or severe SCFE have been evaluated[34, 35] :

Witbreuk et al performed epiphysiodesis combined with early Imhauser intertrochanteric osteotomy in 28 patients (32 hips) to downgrade moderate and severe SCFE to diminish mechanical impingement and prevent osteoarthritis.[34] At a median follow-up of 8 years (range, 2-25 y), the patients were performing well clinically, functionally, and socially. In addition, there were no radiologic signs of chondrolysis or avascular necrosis, and greater than 80% of the patients did not have signs of osteoarthritis.[34]

Lawane et al retrospectively evaluated the Dunn procedure in adolescents aged 10-15 years with severe SCFE (epiphyseal slippage of 60-90 degrees) with regard to avascular necrosis of the femoral head.[35] Of the 25 cases, 15 achieved good clinical and radiologic results, but 10 had immediate or late complications, for a 40% complication rate. Of the 8 immediate complications (32%), 4 were necroses (16%), 2 of which resulted in arthritis; 3 were chondrolyses, all of which progressed to arthritis; and 1 was mechanical.[35] Before 10-year follow-up, 2 arthrodeses and 3 hip replacements were performed. At long-term follow-up, an additional 2 late deteriorations occurred despite initial favorable clinical and radiologic outcomes.

The investigators concluded that although the Dunn procedure limits the vascular risk of surgical correction of the SCFE displacement, there are issues of concern, including "tricky" technical aspects of the procedure and the risk of necrotic complication, at rates up to 17% in other reported series.[35] Lawane et al reported a necrosis rate of 16%, which they found unacceptable in view of the immediate loss of joint function in the adolescent patients. Their preferred approach to severe SCFE is arthrotomy followed by a direct approach to the displacement with associated anterior cuneiform neck resection.[35]

A multicenter study of 186 cases of SCFE that evaluated the results of various treatment strategies for severe SCFE reported favorable results with the "anterior" Dunn procedure with regards to stopping the slip and preventing osteoarthritis while having a relatively low complication rate.[36]

Consultations

Orthopedic surgery consultation should be immediate in cases of SCFE.

Endocrinology consultation may be indicated for patients presenting earlier than age 10 years of or later than age 16 years. Also, if there are any concerns for endocrinopathy found on history or physical examination, consultation may be necessary to help evaluate for a potential disorder.

 

Medication

Medication Summary

No medical therapy is available for the treatment of slipped capital femoral epiphysis (SCFE) except symptomatic pain relief. Medications may include acetaminophen, nonsteroidal anti-inflammatory drugs, or narcotics, depending on the physician's preference.

Analgesics/Antipyretics

Class Summary

Pain control is essential to quality patient care. Analgesics ensure patient comfort and have sedating properties, which are beneficial for patients who have sustained trauma or who have sustained injuries.

Acetaminophen (Tylenol, Feverall, Tempra)

DOC for pain in patients with documented hypersensitivity to aspirin or NSAIDs, with upper GI disease, or who are taking oral anticoagulants.

Hydrocodone and acetaminophen (Vicodin, Lorcet, Lortab)

Drug combination for moderate to severe pain.

Codeine/acetaminophen (Tylenol With Codeine #2, #3, #4)

Indicated for mild to moderate pain. Opioid and analgesic.

Acetaminophen and codeine content of Tylenol products is as follows:

Tylenol #2: 300 mg acetaminophen/15 mg codeine

Tylenol #3: 300 mg acetaminophen/30 mg codeine

Tylenol #4: 300 mg acetaminophen/60 mg codeine

Nonsteroidal Anti-inflammatory Drugs (NSAIDs)

Class Summary

NSAIDs have analgesic, anti-inflammatory, and antipyretic activities, which make these ideal agents for treating ankle injuries. The mechanism of action of NSAIDs is not known, but they may inhibit cyclooxygenase activity and prostaglandin synthesis. Other mechanisms may exist as well, such as inhibition of leukotriene synthesis, lysosomal enzyme release, lipoxygenase activity, neutrophil aggregation and various cell membrane functions.

Ibuprofen (Motrin, Advil)

DOC for mild to moderate pain. Inhibits inflammatory reactions and pain by decreasing prostaglandin synthesis.

Ketoprofen (Orudis, Actron, Oruvail)

Indicated for mild to moderate pain and inflammation.

Small initial doses are indicated in small and elderly patients and in those with renal or liver disease.

Doses >75 mg do not increase the therapeutic effects. Administer high doses with caution, and closely observe the patient for the response.

Naproxen (Naprelan, Anaprox, Naprosyn)

Indicated for mild to moderate pain; inhibits inflammatory reactions and pain by decreasing the activity of cyclooxygenase, which results in a decrease of prostaglandin synthesis.

 

Follow-up

Return to Play

Following fixation of slipped capital femoral epiphysis (SCFE), the patient is given crutches with protected weight bearing for 6-8 weeks. Physical therapy for strengthening, proprioception, balance, and endurance training may be helpful. Most children can then return to full activity once they are pain free with full strength. However, some literature advocates for not allowing a return to contact sports until the physis has closed.

Radiographic follow-up is often continued until physeal closure is achieved to ensure the slippage has not progressed and to ensure there is no contralateral hip involvement. Loss of fixation of the slip can occur but is rare.

Complications

Untreated SCFE may result in progressive deformity and pain, destabilization of the femoral epiphysis, and decreased range of motion of the hip joint.

AVN of the femoral head is thought to result from vascular damage during the time of the initial traumatic event, but it may result from forceful reduction during the time of surgery. The amount of energy, magnitude of epiphyseal damage and displacement, level of increased intra-articular pressure, and degree of vascular occlusion have been implicated in this process. The risk of AVN is up to 47% with an unstable SCFE. Treatment options are limited (eg, bone grafting, osteotomy to change the position of the femoral head), but often these patients will eventually need a total hip replacement.

Chondrolysis is the destruction of articular cartilage, which can cause joint space narrowing. Intra-articular penetration of hardware and violation of the joint has been associated with chondrolysis. It is believed to occur irrespective of the method of treatment; however, chondrolysis has occurred in patients who have not undergone any treatment.

Osteoarthritis is a late complication. There is evidence that increased risk of early degenerative change may result from AVN, chondrolysis, or alterations of the hip biomechanics following slippage. In general, the more severe the deformity and/or SCFE, the higher risk of developing arthritis. Mild deformities may have few consequences.

Leg-length inequality may result from incomplete reduction, AVN, chondrolysis, or secondary coxa vara.

Hardware failure and "outgrowing" hardware may cause loss of fixation. Although rare, postoperative infection may occur.

Prognosis

Most patients with SCFE who are treated with urgent in situ fixation do well. However, in those cases with severe slippage and resultant deformity, long-term sequelae may result (eg, AVN, chondrolysis, leg-length discrepancy, stiffness, osteoarthritis). Although conservative modalities (eg, therapy, analgesics, orthotics, assistive aids) are used initially for symptomatic relief, urgent operative intervention is indicated. Young patients with unremitting pain, loss of motion, and stiffness secondary to chondrolysis, AVN, or osteoarthritis may require salvage hip arthrodeses. In hips that are incompletely damaged, proximal osteotomies may aid in redirecting the joint forces to less damaged areas of the articular femoral head.

 

Questions & Answers

Overview

What is slipped capital femoral epiphysis (SCFE)?

What is the prevalence of slipped capital femoral epiphysis (SCFE) in the US?

What is the functional anatomy of slipped capital femoral epiphysis (SCFE)?

Presentation

Which clinical history findings are characteristic of slipped capital femoral epiphysis (SCFE)?

Which physical exam findings are characteristic of slipped capital femoral epiphysis (SCFE)?

DDX

What are the differential diagnoses for Slipped Capital Femoral Epiphysis?

Workup

What is the role of lab testing in the workup of slipped capital femoral epiphysis (SCFE)?

What is the role of imaging studies in the workup of slipped capital femoral epiphysis (SCFE)?

Treatment

What is slipped capital femoral epiphysis (SCFE) treated?

What is the role of surgery in the treatment of slipped capital femoral epiphysis (SCFE)?

Which specialist consultations are beneficial to patients with slipped capital femoral epiphysis (SCFE)?

Medications

What is the role of medications in the treatment of slipped capital femoral epiphysis (SCFE)?

Which medications in the drug class Nonsteroidal Anti-inflammatory Drugs (NSAIDs) are used in the treatment of Slipped Capital Femoral Epiphysis?

Which medications in the drug class Analgesics/Antipyretics are used in the treatment of Slipped Capital Femoral Epiphysis?

Follow-up

How is return-to-play determined following the treatment of slipped capital femoral epiphysis (SCFE)?

What are the possible complications of slipped capital femoral epiphysis (SCFE)?

What is the prognosis of slipped capital femoral epiphysis (SCFE)?