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Slipped Capital Femoral Epiphysis: Early Intervention and Referral

      Abstract

      Slipped capital femoral epiphysis is the most common hip pathology in children aged 8–15 years old. Research has shown that when a nonorthopedic provider evaluates this patient population, there can be a significant delay in the appropriate treatment, which may have serious consequences for the prognosis of the patient. The delays are often caused by the practitioner's inability to put the clinical picture into focus with regard to how these patients typically present.. This article presents the demographics, clinical presentation, differential diagnosis, radiological and physical examination techniques, and prevention strategies to recognize this condition and provide early intervention.

      KEY WORDS

      INTRODUCTION

      Pediatric

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      • 1.
        Describe the clinical presentation of a slipped capital femoral epiphysis.
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        Identification of the at-risk population for a slipped capital femoral epiphysis.
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        Explain the evaluation techniques to make an accurate and timely diagnosis.
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        Identify the importance of treatment and referral as it relates to the prognosis for the patient.
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        State the potential differential diagnoses involved with pediatric hip pathology.
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      patients reporting with lower extremity pain can present a difficult diagnostic and evaluation challenge in the primary care setting. This population often presents with vague symptoms and may not provide a reliable history or mechanism of injury. When the clinician is presented with a patient reporting vague signs and symptoms, knowledge of common age-related pathology and differential diagnosis is of extreme importance for improved outcomes.
      Slipped capital femoral epiphysis (SCFE) is the most common hip pathology in children aged 8–15 years and often presents with vague complaints of hip, groin, thigh, or knee pain (
      • Peck D.M.
      • Voss L.M.
      • Voss T.T.
      Slipped capital femoral epiphysis: Diagnosis and management.
      ). The ambiguity of these complaints, in conjunction with the referral of the pain distally (one third with knee pain), leads to delay in diagnosis and prevents early treatment intervention (
      • Hosseinzadeh P.
      • Iwinski H.J.
      • Salava J.
      • Oeffinger D.
      Delay in the diagnosis of stable slipped capital femoral epiphysis.
      ). The patient will often report no certain mechanism of injury or may report a recent minor trauma that would not be considered significant enough to consider a fracture. The patient will typically present with progressive unilateral pain and limping (
      • Neville D.N.W.
      • Zuckerbraun N.
      Pediatric nontraumatic hip pathology.
      ;
      • Peck D.M.
      • Voss L.M.
      • Voss T.T.
      Slipped capital femoral epiphysis: Diagnosis and management.
      ).

      PATHOPHYSIOLOGY

      As a child develops, the ossification of the femoral head occurs between 2 and 8 months of age and fuses with the femoral neck in adolescence. This ossification usually occurs in females aged between 14 and 20 years and between 15 and 21 years in males (
      • Staheli L.T.
      Hip and femur.
      ). The proximal femoral physis is a vulnerable region as it is nourished by a fragile blood supply and is an area of rapid cellular proliferation, vulnerable to instability, particularly during the hormonal changes of puberty (
      • Neville D.N.W.
      • Zuckerbraun N.
      Pediatric nontraumatic hip pathology.
      ). The femoral head and proximal femur are especially susceptible to injury, especially when excessive mechanical loading is present or high shear forces occur (
      • Staheli L.T.
      Hip and femur.
      ). An SCFE is an abnormal separation between the head of the femur and the epiphyseal plate of the metaphysis; this causes rotation of the femur while the head stays in the acetabulum (
      • Herngren B.
      • Stenmarker M.
      • Vavruch L.
      • Hagglund G.
      Slipped capital femoral epiphysis: A population-based study.
      ).

      ADVERSE ADULT OUTCOMES

      The importance of early recognition and immediate intervention in this population cannot be overstated because of the potential adverse outcomes lasting into adulthood. As severity of the SCFE increases, the likelihood of successful intervention decreases, which could have dire consequences for the future. Patients with a history of SCFE may develop other hip pathologies such as early osteoarthritis and femoral acetabular impingement (
      • Helgesson L.
      • Johansson P.K.
      • Aurell Y.
      • Tiderius C.J.
      • Kärrholm J.
      • Riad J.
      Early osteoarthritis after slipped capital femoral epiphysis.
      ). The current literature suggests that patients with preexisting hip pathology will require a total hip arthroplasty at a younger age. The most common preexisting hip diagnoses include early-onset osteoarthritis and avascular necrosis of the femoral head (
      • Mei X.Y.
      • Gong Y.J.
      • Safir O.
      • Gross A.
      • Kuzyk P.
      Long-term outcomes of total hip arthroplasty in patients younger than 55 years: A systematic review of the contemporary literature.
      ).
      Total hip arthroplasty is an expensive and invasive surgery that may be required because of arthritic changes associated with the presence of an SCFE. Early identification, referral, and timely treatment could potentially limit the damage caused by a missed SCFE; however, even with appropriate intervention, the damage to the cartilage could still occur. If an SCFE patient requires a total hip arthroplasty, there may be extensive scar tissue and hardware that should be removed for the procedure (
      • Mei X.Y.
      • Gong Y.J.
      • Safir O.
      • Gross A.
      • Kuzyk P.
      Long-term outcomes of total hip arthroplasty in patients younger than 55 years: A systematic review of the contemporary literature.
      ). Adult patients have also reported a lower quality of life and decreased hip function because of cartilage changes, secondary to having an SCFE diagnosis as a child (
      • Helgesson L.
      • Johansson P.K.
      • Aurell Y.
      • Tiderius C.J.
      • Kärrholm J.
      • Riad J.
      Early osteoarthritis after slipped capital femoral epiphysis.
      ).

      EPIDEMIOLOGY AND RISK FACTORS

      SCFE occurs in 10 per 10,000 children in the United States and is often diagnosed in both hips, despite unilateral presentation (

      Swarup, I., Goodbody, C., Goto, R., Sankar, W. N., Fabricant, P. D. (2020). Risk factors for contralateral slipped capital femoral epiphysis: A meta-analysis of cohort and case-control studies. Journal of Pediatric Orthopaedics, 40, e446–e453.

      ). Peak incidence for diagnosis is the age of 13 years in males and 11 years in females—occurring most commonly in obese males (
      • Staheli L.T.
      Hip and femur.
      ). The diagnosis of SCFE outside the typical age range is more likely to have an underlying endocrine pathology. These age groups most commonly affected by SCFE are in a period of rapid skeletal growth, and that growth spurt requires the presence of certain nutrients required for healthy bone growth. Vitamin D and calcium are known to be important nutrients required for bone modeling and skeletal growth (

      Dunn, A. M., Duderstadt, K. G. (2021). Nutrition. In D. G. Maaks et al. (Ed.), Burns’ pediatric primary care (7th ed.). (pp. 214–248). Amsterdam, the Netherlands: Elsevier.

      ). There are many factors that can contribute to a weakness in bone; however, there appears to be an inverse relationship with obesity and serum vitamin D concentration, further complicated by low intake of dietary calcium (
      • Farr J.N.
      • Dimitri P.
      The impact of fat and obesity on bone microarchitecture and strength in children.
      ). In conjunction with an imbalance of important nutrients required for healthy bone growth, the obese population is at greater risk because of increased mechanical loads from an elevated body mass index (BMI;
      • Farr J.N.
      • Dimitri P.
      The impact of fat and obesity on bone microarchitecture and strength in children.
      ). The force created by higher body weight may also lead to changes in gait biomechanics and a lack of coordination, further complicating the direction of detrimental shear forces across the joints (
      • Farr J.N.
      • Dimitri P.
      The impact of fat and obesity on bone microarchitecture and strength in children.
      ).
      In addition to the significant risk of developing SCFE associated with obesity, other factors include endocrine disorders, metabolic disorders, trauma, and renal osteodystrophy (
      • Perry D.C.
      • Metcalfe D.
      • Costa M.L.
      • Van Staa T.
      A nationwide cohort study of slipped capital femoral epiphysis.
      ;
      • Staheli L.T.
      Hip and femur.
      ). The suspicion of an SCFE in the contralateral hip should be increased in the presence of specific risk factors: a BMI greater than the 95th percentile for age and endocrine comorbidity (

      Swarup, I., Goodbody, C., Goto, R., Sankar, W. N., Fabricant, P. D. (2020). Risk factors for contralateral slipped capital femoral epiphysis: A meta-analysis of cohort and case-control studies. Journal of Pediatric Orthopaedics, 40, e446–e453.

      ). The most common endocrine disorders, found in conjunction with SCFE, are hypothyroidism and diabetes mellitus. Other, less common metabolic conditions associated with SCFE include hypogonadism, renal osteodystrophy, or exposure to radiation (
      • Halverson S.J.
      • Warhoover T.
      • Mencio G.A.
      • Lovejoy S.A.
      • Martus J.E.
      • Schoenecker J.G.
      Leptin elevation as a risk factor for slipped capital femoral epiphysis independent of obesity status.
      ). The presence of one of these comorbidities should increase the provider's suspicion of an atypical SCFE, especially if hip, groin, or knee pain is also a presenting clinical symptom. Atypical SCFE is defined as occurring because of a secondary medical condition, typically metabolic or endocrine. An atypical SCFE should be a consideration when evaluating the patient with vague lower extremity pain and a metabolic or endocrine disorder. Figure 1 shows a bilateral comparison of an anatomically normal hip, versus a pathological hip, with an SCFE present.
      FIGURE 1
      FIGURE 1Comparison of anatomically normal hip (left) vs. pathological hip (right)
      Source: https://orthoonedenver.com/service/scfe. This figure appears in color online at www.jpedhc.org.
      The severity of the SCFE falls into one of two categories—stable or unstable. If a patient can fully bear weight on the joint or off-load with crutches, it is considered stable. The inability to weight bear with the assistance of crutches is considered unstable and is directly correlated to the duration of symptoms (
      • Peck D.M.
      • Voss L.M.
      • Voss T.T.
      Slipped capital femoral epiphysis: Diagnosis and management.
      ).

      Clinical Presentation

      When a pediatric patient presents with vague hip, groin, thigh, or knee pain in conjunction with a nontraumatic limp, this diagnosis must be considered. It is a primary consideration when the patient is a male with an increased BMI such as being overweight (85th–94th percentile) or obese (greater or equal to the 95th percentile), who is between the ages of 8 and 15 years (
      • Peck D.M.
      • Voss L.M.
      • Voss T.T.
      Slipped capital femoral epiphysis: Diagnosis and management.
      ). This clinical presentation is important to identify because delays in diagnosis and treatment have shown poor outcomes, especially if the diagnosis is made at 8 weeks or greater from the onset of symptoms (
      • Hosseinzadeh P.
      • Iwinski H.J.
      • Salava J.
      • Oeffinger D.
      Delay in the diagnosis of stable slipped capital femoral epiphysis.
      ). When a patient with SCFE was evaluated by a nonorthopedic provider, treatment was delayed up to 3 months when compared with the orthopedic provider who diagnosed and initiated treatment within 3–17 days (
      • Hosseinzadeh P.
      • Iwinski H.J.
      • Salava J.
      • Oeffinger D.
      Delay in the diagnosis of stable slipped capital femoral epiphysis.
      ). Factors that have been shown to increase delay included the location of pain, failure to seek initial medical care because of socioeconomic factors, and type of insurance (
      • Hosseinzadeh P.
      • Iwinski H.J.
      • Salava J.
      • Oeffinger D.
      Delay in the diagnosis of stable slipped capital femoral epiphysis.
      ).

      Physical Examination

      When evaluating the patient, it is of extreme importance to perform a gait assessment to establish the presence of an out-toeing gait, abductor lurch gait, or a Trendelenburg gait (
      • Staheli L.T.
      Hip and femur.
      ). An abductor lurch is described as a trunk and hip extension while keeping the knee straight to compensate for the instability of the hip, which is more common in the SCFE patient than Trendelenburg (
      • Staheli L.T.
      Hip and femur.
      ). Trendelenburg gait is the dropping of the opposite hip during the stance phase of walking, which may suggest gluteus medius weakness or palsy of the gluteal nerve (
      • Staheli L.T.
      Hip and femur.
      ). The patient may also present with a varus or valgus deformity at the knees and a wider stance to maintain normal balance (
      • Horsak B.
      • Schwab C.
      • Baca A.
      • Greber-Platzer S.
      • Kreissl A.
      • Nehrer S.
      • Wondrasch B.
      Effects of a lower extremity exercise program on gait biomechanics and clinical outcomes in children and adolescents with obesity: A randomized controlled trial.
      ). Bilateral range of motion for comparison should be used unless the provider suspects bilateral involvement, but the most sensitive test would be the Drehmann sign. When the provider passively flexes the patient's hip, they will compensate with external rotation (
      • Peck D.M.
      • Voss L.M.
      • Voss T.T.
      Slipped capital femoral epiphysis: Diagnosis and management.
      ). Patients may also have external foot rotation, weak hip abduction, decreased hip flexion, and decreased internal rotation and can develop a flexion contracture over time (
      • Neville D.N.W.
      • Zuckerbraun N.
      Pediatric nontraumatic hip pathology.
      ). These physical examination findings should increase the provider's suspicion of SCFE, especially if the chief complaint is hip, thigh, knee, or groin pain.

      Radiology

      To correctly make or confirm the diagnosis of SCFE, radiographs are typically sufficient as long as the provider orders an anteroposterior of the pelvis, frog-leg lateral, and true lateral views. If an unstable SCFE is suspected, then the frog-leg should not be performed, and a cross-table view would suffice (
      • Peck D.M.
      • Voss L.M.
      • Voss T.T.
      Slipped capital femoral epiphysis: Diagnosis and management.
      ). Evaluation of the x-ray includes assessing for any widening of the growth plate, decreased height of the femoral head, steel sign, and assessing Klein's line (Figure 2;
      • Peck D.M.
      • Voss L.M.
      • Voss T.T.
      Slipped capital femoral epiphysis: Diagnosis and management.
      ).
      FIGURE 2
      FIGURE 2Radiologic signs of slipped capital femoral epiphysis. Data from
      • Peck D.M.
      • Voss L.M.
      • Voss T.T.
      Slipped capital femoral epiphysis: Diagnosis and management.
      .
      On plain film radiograph, if the lesser trochanter of the injured hip appears lower, or more prominent than the asymptomatic hip, the provider should suspect rotation of the femur away from the femoral head (
      • Peck D.M.
      • Voss L.M.
      • Voss T.T.
      Slipped capital femoral epiphysis: Diagnosis and management.
      ). Steel sign would show double density of the metaphysis because of the posterior displacement of the growth plate. Klein's line is drawn along the superior border of the femoral neck. The line should intersect with the growth plate to some degree; if it does not, it confirms a slip seen in SCFE (
      • Peck D.M.
      • Voss L.M.
      • Voss T.T.
      Slipped capital femoral epiphysis: Diagnosis and management.
      ). The severity of the injury can be evaluated by the graded displacement (Figure 3) on both views of the radiograph based on changes in head position on the anterior-posterior view and changes in angles on the lateral x-ray (
      • Staheli L.T.
      Hip and femur.
      ). As seen in Figure 3, mild would be 0–1/3, moderate 1/3–2/3, and severe would be 2/3 to complete. On the lateral view, 0°–30° would be mild, 30°–60° is moderate, and severe would be 60°–90° (
      • Staheli L.T.
      Hip and femur.
      ).
      FIGURE 3
      FIGURE 3Grading the severity of slipped capital femoral epiphysis
      Severity can be expressed as a grade based on the displacement seen in the anteroposterior projection. A more accurate measurement is the slip angle measured from a true lateral radiograph. Data from
      • Staheli L.T.
      Hip and femur.
      .
      Specialized imaging is not necessary in most cases for the diagnosis of SCFE and should be reserved in very mild cases that are not measurable on the plain film. If a bone scan were to be ordered for this patient, it would need to be high resolution and would show increased bony uptake in both femoral heads, if the patient had not been displaced (
      • Staheli L.T.
      Hip and femur.
      ). An ultrasound may show a step-off deformity at the fracture site, and a magnetic resonance imaging (MRI) could evaluate if any avascular necrosis was present, which is a complication of delayed diagnosis or an unstable SCFE (
      • Staheli L.T.
      Hip and femur.
      ).

      Differential Diagnosis

      Several considerations must be made before the diagnosis of a patient who presents with nontraumatic hip pain. There may even be a history of a small musculoskeletal injury that resolved and may be considered innocent, masking itself as an underlying joint pathology. The Table reviews the lists of conditions that often present similarly as a patient with an SCFE (
      • Peck D.M.
      • Voss L.M.
      • Voss T.T.
      Slipped capital femoral epiphysis: Diagnosis and management.
      ). Other nontraumatic hip disorders include osteomyelitis and arthritis caused by Lyme disease (
      • Neville D.N.W.
      • Zuckerbraun N.
      Pediatric nontraumatic hip pathology.
      ).
      TABLEDifferential diagnosis of hip pain in the young patient
      ConditionAge (years)Clinical featuresIncidenceDiagnosis
      Apophyseal avulsion fracture of the anterosuperior and anteroinferior iliac spine12–25Pain after sudden forceful movementCommonHistory of trauma; radiography
      Apophysitis of the anterosuperior and anteroinferior iliac spine12–25Activity-related hip painCommonHistory of overuse; radiography to rule out a fracture
      Transient synovitis< 10Limping or hip painCommonRadiography, laboratory testing, ultrasonography
      FractureAll agesPain after a traumatic eventLess commonHistory of trauma; radiography
      Slipped capital femoral epiphysis8–15Hip, groin, thigh, or knee pain; limpingLess commonBilateral hip radiography
      Legg-Calves-Perthes disease4–9Vague hip pain, decrease internal rotation of the hipUncommonHip radiography or magnetic resonance imaging
      Septic arthritisAll agesFever, limping, hip painUncommonRadiography, laboratory testing; joint aspiration
      Adductor muscle strain (groin pull)12–20Groin pain after activityVery uncommonRadiography to rule out fracture; physical examination
      Note. Source:
      • Peck D.M.
      • Voss L.M.
      • Voss T.T.
      Slipped capital femoral epiphysis: Diagnosis and management.
      .

      Legg-Calve-Perthes disease

      Legg-Calve-Perthes (LCP) disease is avascular necrosis of the femoral head of unknown etiology that can occur because of developmental changes in the vascularity of the femur (
      • Staheli L.T.
      Hip and femur.
      ). Variations in vascularity can be due to coagulation disorders, trauma, endocrine, and metabolic disorders (
      • Staheli L.T.
      Hip and femur.
      ). This disease presents most commonly in boys between the ages of 4 and 8 years but can occur in any stage of skeletal development once the patient begins to ambulate (
      • Staheli L.T.
      Hip and femur.
      ). The patient will present similarly to SCFE but is more likely to present with Trendelenburg's gait and limited abduction and internal rotation (
      • Neville D.N.W.
      • Zuckerbraun N.
      Pediatric nontraumatic hip pathology.
      ). On imaging, there will be changes or deformities in the femoral head and may require an MRI to establish blood flow and sphericity changes, with the primary goal being the prevention of osteoarthritis (
      • Neville D.N.W.
      • Zuckerbraun N.
      Pediatric nontraumatic hip pathology.
      ). Bilateral involvement in LCP is rare, and the patient should be referred to an orthopedic surgeon with experience in treatment, which includes both operative and nonoperative options based on the severity (
      • Staheli L.T.
      Hip and femur.
      ).

      Septic arthritis

      `Septic arthritis is an infection that enters the joint, usually from another source, and may also be present with osteomyelitis (
      • Neville D.N.W.
      • Zuckerbraun N.
      Pediatric nontraumatic hip pathology.
      ). This infection can occur in any age group and would present with signs and symptoms of an infection, which would differentiate it well from SCFE and LCP. The presence of referred pain to the knee would be a similar presentation; however, other clinical factors would allow for easy differentiation (
      • Neville D.N.W.
      • Zuckerbraun N.
      Pediatric nontraumatic hip pathology.
      ). This diagnosis should be considered emergent and referred to orthopedic surgery for management. An MRI would confirm septic arthritis from other nontraumatic hip pathology if it were ordered by the provider (
      • Neville D.N.W.
      • Zuckerbraun N.
      Pediatric nontraumatic hip pathology.
      ). Laboratory studies should be used as needed when attempting a differential diagnosis of septic arthritis, which includes complete blood count with differential, C-reactive protein, and erythrocyte sedimentation rate. If synovial fluid was aspirated, a culture with gram-stain could identify the presence of bacteria and sensitivity for treatment purposes (
      • Neville D.N.W.
      • Zuckerbraun N.
      Pediatric nontraumatic hip pathology.
      ).

      Autoimmune diseases

      Joint tenderness, arthralgias, and myopathy may be present in patients that have an underlying autoimmune disorder such as idiopathic juvenile arthritis, systemic lupus erythematosus, or poststreptococcal arthritis (
      • John R.M.
      • Brady M.A.
      Atopic, rheumatic and immunodeficiency disorders.
      ). These conditions must be considered and ruled out through a history of present illness and diagnosed by exclusion (
      • John R.M.
      • Brady M.A.
      Atopic, rheumatic and immunodeficiency disorders.
      ). Complaints of diffuse musculoskeletal pain that does not only localize to one joint would direct the provider away from a specific hip pathology to consider a systemic condition. Once diagnosed, the patient should be referred to the appropriate specialty for treatment.
      In this category, the provider must also consider Lyme disease, especially in an area endemic for the disease (
      • Neville D.N.W.
      • Zuckerbraun N.
      Pediatric nontraumatic hip pathology.
      ). In patients aged from 5 to 15 years, who are likely to be exposed to a tick bite, with complaints of musculoskeletal pain, the provider should consider testing for Lyme disease. Other signs or symptoms of Lyme disease can be present, such as a rash, facial palsy, or photosensitivity, which would lead the practitioner to this differential diagnosis (
      • Neville D.N.W.
      • Zuckerbraun N.
      Pediatric nontraumatic hip pathology.
      ).

      Malignancy

      When presenting with unilateral, nontraumatic hip pain, the presence of malignancy needs to be ruled out. Osteosarcoma and Ewing's sarcoma can occur during adolescence with the presentation in the hip joint (
      • Neville D.N.W.
      • Zuckerbraun N.
      Pediatric nontraumatic hip pathology.
      ). Leukemia may also be a consideration and often presents with the nontraumatic limp, hip, or knee pain but is typically found in conjunction with other traditional symptoms of cancer (
      • Neville D.N.W.
      • Zuckerbraun N.
      Pediatric nontraumatic hip pathology.
      ). The presence of a tumor can be seen on a radiograph, and complete blood count with differential can help confirm or rule out malignancy in the bone (
      • Neville D.N.W.
      • Zuckerbraun N.
      Pediatric nontraumatic hip pathology.
      ).

      Treatment

      The most important aspect of successful treatment is early diagnosis and referral to an orthopedic surgeon. Initial treatment involves the patient being non–weight-bearing to prevent the progression of the slip and its associated complications (
      • Peck D.M.
      • Voss L.M.
      • Voss T.T.
      Slipped capital femoral epiphysis: Diagnosis and management.
      ). Surgical intervention is required in the patient with an SCFE, and the type of procedure is determined by the severity and the patient's age (
      • Peck D.M.
      • Voss L.M.
      • Voss T.T.
      Slipped capital femoral epiphysis: Diagnosis and management.
      ). Stable SCFE patients are generally repaired via percutaneous pins or cannulated screws; if younger than 8 years, smooth pins will be used to allow continued growth of the epiphysis (
      • Peck D.M.
      • Voss L.M.
      • Voss T.T.
      Slipped capital femoral epiphysis: Diagnosis and management.
      ). Unstable SCFE patients would most likely be treated with an osteotomy to reposition and realign the head and neck of the femur; the type of osteotomy is determined by the severity of the slip and the best position for realignment (
      • Peck D.M.
      • Voss L.M.
      • Voss T.T.
      Slipped capital femoral epiphysis: Diagnosis and management.
      ). The surgery outcome goals are to stabilize the deformity and prevent future pathology into adulthood associated with SCFE, which includes osteoarthritis and hip impingement (
      • Örtegren J.
      • Peterson P.
      • Svensson J.
      • Tiderius C.J.
      Persisting CAM deformity is associated with early cartilage degeneration after slipped capital femoral epiphysis: 11-year follow-up including dGEMRIC.
      ). Prophylactic pinning of the contralateral hip is a topic of debate because there is potential that the procedure is unnecessary and costly. Research has shown that 12% to 80% of patients will develop an SCFE in the asymptomatic hip, and early intervention is considered, especially if presenting at a younger age with significant slip associated with the duration of symptoms. The history of a previous SCFE did not yield a faster diagnosis than a primary SCFE, but it was still an average of 30 days, which may allow for the same poor outcomes of a primary SCFE (
      • Hosseinzadeh P.
      • Iwinski H.J.
      • Salava J.
      • Oeffinger D.
      Delay in the diagnosis of stable slipped capital femoral epiphysis.
      ).

      ONGOING EVALUATION BY THE PRIMARY CARE PROVIDER

      Recognition of the clinical presentation of this patient is the most crucial aspect of a provider's ability to diagnose SCFE correctly. The patient history, habitus, and gait pattern will help direct a provider's differential diagnosis, to be confirmed with radiographs. It cannot be overemphasized how important early recognition and prompt treatment is to the prognosis for the SCFE patient; however, the diagnosis of SCFE may require further diagnostic work and treatment for the primary care provider (PCP). A pediatric patient who is obese is at a higher risk for many comorbidities, including developing an SCFE. A BMI in the 95th percentile, or higher, increases the risk of having bilateral SCFE pathology (

      Swarup, I., Goodbody, C., Goto, R., Sankar, W. N., Fabricant, P. D. (2020). Risk factors for contralateral slipped capital femoral epiphysis: A meta-analysis of cohort and case-control studies. Journal of Pediatric Orthopaedics, 40, e446–e453.

      ). Increased body weight can create forces greater than the strength of the growth plate, which creates the SCFE pathophysiology in the hip of the obese patient (
      • Perry D.C.
      • Metcalfe D.
      • Lane S.
      • Turner S.
      Childhood obesity and slipped capital femoral epiphysis.
      ). Research has also shown that obesity may lower the age of puberty, which is problematic in a skeletally immature child and the development of this condition (
      • Perry D.C.
      • Metcalfe D.
      • Lane S.
      • Turner S.
      Childhood obesity and slipped capital femoral epiphysis.
      ). Finally, there is a definite link between obesity and lower socioeconomic status, which endangers an already vulnerable population to the potential need for expensive surgical intervention. Knowing that there is an inherent risk for this condition because of obesity, there must be diligence in health literacy for this at-risk population. Even though there are greater shear forces placed on the hip because of increased BMI, there is also a lack of physical activity that contributes to obesity. The lack of activity reduces the exposure of stress on the hip that would normally increase osteoblast activity in response to normal bone stressors (
      • Lerner Z.F.
      • Browning R.C.
      Compressive and shear hip joint contact forces are affected by pediatric obesity during walking.
      ).
      The greatest risk for developing a contralateral SCFE was the presence of an underlying endocrine disorder and duration of symptoms before the slip (

      Swarup, I., Goodbody, C., Goto, R., Sankar, W. N., Fabricant, P. D. (2020). Risk factors for contralateral slipped capital femoral epiphysis: A meta-analysis of cohort and case-control studies. Journal of Pediatric Orthopaedics, 40, e446–e453.

      ). Endocrine disorders that may be preexisting or undiagnosed in the patient with an SCFE are hypothyroidism, hypopituitarism, and hypogonadism. Patients who have a preexisting condition of renal osteodystrophy are at risk for SCFE because there is false hyperparathyroidism secondary to decreased excretion of phosphate, which also affects the kidney's ability to release calcitriol, a precursor to vitamin D (
      • Herngren B.
      • Stenmarker M.
      • Vavruch L.
      • Hagglund G.
      Slipped capital femoral epiphysis: A population-based study.
      ). Albeit a rare disorder, there have been cases of primary hyperparathyroidism because of malignancy that have caused SCFE because of an imbalance of serum calcium and decreased bone mineral density (
      • George G.S.
      • Raizada N.
      • Jabbar P.K.
      • Chellamma J.
      • Nair A.
      Slipped capital femoral epiphysis in primary hyperparathyroidism - Case report with literature review.
      ). These disorders should be evaluated and considered if some other clinical signs or symptoms are suggestive of an endocrine disorder in the patient diagnosed with an SCFE.
      Metabolic disorders may also be present, including rickets or cancer, which would predispose a patient to an SCFE (
      • Staheli L.T.
      Hip and femur.
      ). Vitamin D is of extreme importance for bone growth and development as it regulates the absorption of calcium and phosphate—two minerals required for the physiological development of bone (

      Dunn, A. M., Duderstadt, K. G. (2021). Nutrition. In D. G. Maaks et al. (Ed.), Burns’ pediatric primary care (7th ed.). (pp. 214–248). Amsterdam, the Netherlands: Elsevier.

      ). Low bone mineral density is a known risk factor for fractures in pediatrics, and vitamin D supplementation is recommended for patients presenting with fractures (
      • Gorter E.A.
      • Oostdijk W.
      • Felius A.
      • Krijnen P.
      • Schipper I.B.
      Vitamin D deficiency in pediatric fracture patients: Prevalence, risk factors, and vitamin D supplementation.
      ).

      PREVENTION AND INTERVENTION

      The most important intervention that must be considered is the education of primary health care providers, parents, coaches, athletic trainers, and school nurses (
      • Hosseinzadeh P.
      • Iwinski H.J.
      • Salava J.
      • Oeffinger D.
      Delay in the diagnosis of stable slipped capital femoral epiphysis.
      ). This education should include understanding the typical age of onset, clinical presentation, and obesity or certain endocrinopathies, placing those patients at a higher risk of SCFE pathology (
      • Hosseinzadeh P.
      • Iwinski H.J.
      • Salava J.
      • Oeffinger D.
      Delay in the diagnosis of stable slipped capital femoral epiphysis.
      ). Patients should be screened based on the presence of a nontraumatic limp, obesity, and factors that would put them at risk for a nutritional deficiency. This screening should also create a low threshold for imaging, with the correct views and measurements, for the PCP if a patient presents with a concern for potential SCFE.

      IMPLICATIONS FOR PROVIDERS

      Diagnosis delay is the most important implication for the PCP; this delays appropriate treatment, which inevitably leads to complications and poorer prognosis and outcomes. This delay presents a major source of potential litigation because of the misdiagnosis and severity of the injury, which incurs a higher surgical cost for the patient (
      • Perry D.C.
      • Metcalfe D.
      • Costa M.L.
      • Van Staa T.
      A nationwide cohort study of slipped capital femoral epiphysis.
      ). Providers need to be aware that knee pain, without trauma, should alert them to evaluate the entire lower extremity. Knee pain as a chief complaint in SCFE, creates a significant increase in time to correct diagnosis, and should be considered with other risk factors that would predispose the patient to a hip pathology (
      • Hosseinzadeh P.
      • Iwinski H.J.
      • Salava J.
      • Oeffinger D.
      Delay in the diagnosis of stable slipped capital femoral epiphysis.
      ).
      A pediatric patient who presents with a nontraumatic limp and complaints of pain in the hip, groin, thigh, or knee needs to be evaluated for hip pathology. While ruling out other differential diagnoses, the practitioner's suspicion for SCFE will increase if this patient is an obese male between the ages of 8 and 15 years. Recognition of further evaluation and health promotion is the responsibility of the PCP if there is a comorbidity that has predisposed this patient to this condition. Dietary counseling, patient education, and appropriate referral for any subspecialty should be considered based on the presence of endocrine or metabolic disease.

      CONCLUSION

      SCFE is a diagnosis that can be confirmed on a radiograph by a PCP who is aware of the presentation, has knowledge of predisposing factors, and performs an appropriate clinical examination. The PCP who prompts early intervention and referral to orthopedics will help ensure a much better prognosis for the patient.

      References

      1. Dunn, A. M., Duderstadt, K. G. (2021). Nutrition. In D. G. Maaks et al. (Ed.), Burns’ pediatric primary care (7th ed.). (pp. 214–248). Amsterdam, the Netherlands: Elsevier.

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      Biography

      Alan W. Duncan, Graduate Student, Clemson University, and Orthopedic and Neurotrauma Operating Room Nurse, Prisma Health, Greenville, SC.
      Heide S. Temples, Associate Professor, and Pediatric Primary Care Nurse Practitioner, Clemson University, Clemson, SC.