summary Slipped Capital Femoral Epiphysis, is a common condition of the proximal femoral physis that leads to slippage of the metaphysis relative to the epiphysis, and is most commonly seen in adolescent obese males. Diagnosis can be confirmed with radiographs of the hip. Treatment is usually percutaneous pin fixation. Contralateral pinning is indicated for patients at high risk, such as those with an initial slip at age < 10, obese males, and those with endocrine disorders. Epidemiology Incidence most common disorder affecting adolescent hips 10 per 100,000 Demographics more common in obese children males login to view 1 more bullet specific ethnicities including African Americans, Pacific islanders, Latinos periods of rapid growth login to view 1 more bullet average age range is 12-13.4 for boys 11.2-12.2 for girls occurs when going through puberty Anatomic location left hip is a more common location can be bilateral in 17% to 50% (average of 25%) Risk factors obesity single greatest risk factor recent data shows a trend towards younger age and increased frequency of bilateral presentation login to view 1 more bullet acetabular retroversion and femoral retroversion secondary to increased mechanical shearing forces at the physis history of previous radiation therapy to the femoral head region elevated leptin levels 4.9x increased in the odds of developing a SCFE in patients with elevated leptin, even when controlling for obesity status, sex and race Etiology Pathophysiology mechanism occurs due to axial and rotational mechanical forces which act on a susceptible physis direction of slip/angulation login to view 2 more bullets pathoanatomy slippage occurs though the hypertrophic zone of the physis login to view 2 more bullets increased risk in adolescence because: login to view 5 more bullets similar to Salter-Harris type I fracture, but may differ based on login to view 4 more bullets Associated conditions endocrine disorders associated conditions login to view 7 more bullets endocrine workup indicated if login to view 2 more bullets Down syndrome ANATOMY Osteology normal proximal femur neck shaft-angle is 130 +/- 7° normal proximal femur anteversion is 10 +/- 7° proximal femur consists of tensile and compressive trabecular groups proximal femoral physis is where pathology occurs with slip of epiphysis and metaphysis Ligaments iliofemoral, ischiofemoral and pubofemoral ligaments attach to outer hip capsule and help to prevent excessive hip motion Blood supply a confluence of arteries which forms an extracapsular arterial ring that divides into the ascending cervical arteries which supply the femoral neck and head via perforators main blood supply in adolescents and adults is the lateral epiphyseal artery which is derived from the medial femoral circumflex artery lateral femoral circumflex contributes to anterior arterial ring superior and inferior gluteal arteries also give small contributions to arterial ring artery of ligamentum teres comes from obturator or medial femoral circumflex login to view 1 more bullet initial slip as well as iatrogenic causes are thought to increase the risk of damage to blood supply unstable SCFE at greater risk for blood supply injury Biomechanics in double-leg stance, the force vector through hip is vertical and in single-leg stance it is parallel to the neck and head axial/rotational forces through physis place stress on weak hypertrophic zone in population at risk Classification Loder classification Loder Classification Based on ability to bear weight Stable Able to bear weight with or without crutches Minimal risk of osteonecrosis (<10%) Unstable Unable to ambulate (not even with crutches) High risk of osteonecrosis (24-47%) Temporal classification Temporal Classification Based on duration of symptoms; rarely used; no prognostic information Acute Symptoms that persist for less than 3 weeks Chronic Symptoms that persist for more than 3 weeks Acute on Chronic Acute exacerbation of long-standing symptoms Southwick Slip Angle Classification epiphyseal-diaphyseal angle can be measured on both AP and frog lateral pelvis radiographs slip angle classification is based on the degree of difference between the affected and unaffected hip if bilateral hips are involved, use 145° as "unaffected" hip reference for AP and 10° as "unaffected" hip reference for lateral Southwick Slip Angle Classification Based on femoral epiphyseal-diaphyseal angle difference Mild < 30° Moderate 30-50° Severe > 50° Grading system Grading System Based on percentage of slippage Grade I 0-33% of slippage Grade II 34-50% of slippage Grade III >50% of slippage Presentation History most commonly atraumatic, although some present after an injury pain has often been present for several months Symptoms pain in hip (52%), groin (14%) and thigh (35%) pain is most common presenting symptom knee pain 15-50% present with knee pain login to view 2 more bullets patients prefer to sit in a chair with affected leg crossed over the other duration symptoms are usually present for weeks to several months before diagnosis is made login to view 1 more bullet Physical exam inspection abnormal gait / limp login to view 1 more bullet abnormal leg alignment externally rotated foot progression angle motion login to view 3 more bullets neurovascular weakness and thigh atrophy no true neurovascular compromise usually seen Imaging Radiographs recommended views AP & frog-leg lateral of both hips login to view 2 more bullets findings Klein's line login to view 4 more bullets "S" sign login to view 2 more bullets epiphysiolysis (growth plate widening or lucency) login to view 1 more bullet blurring of proximal femoral metaphysis login to view 2 more bullets MRI indications may help diagnose a preslip condition when radiographs are negative findings growth plate widening edema in metaphysis login to view 1 more bullet STUDIES Labs if patient is <10 years old, pre-pubertal or has short stature or weight below 50th percentile for age. consist of: TSH free T4 BUN serum creatinine DIFFERENTIAL Septic arthritis/transient synovitis Osteomyelitis Legg-Calve-Perthes disease Developmental dysplasia of hip (DDH) Traumatic injuries adductor strain, AIIS avulsion, pelvic/femur fractures Treatment Operative percutaneous in situ fixation indications login to view 1 more bullet technique login to view 7 more bullets outcomes login to view 3 more bullets contralateral hip prophylactic fixation indications login to view 6 more bullets open epiphyseal reduction and fixation indications (controversial) login to view 1 more bullet technique login to view 2 more bullets outcomes login to view 3 more bullets Operative management of symptoms after initial in situ fixation osteochondroplasty indications login to view 2 more bullets techniques login to view 3 more bullets outcomes login to view 3 more bullets proximal femoral osteotomy indications login to view 3 more bullets technique login to view 6 more bullets outcomes login to view 3 more bullets Techniques Percutaneous in situ fixation goal to stabilize the epiphysis from further slippage approach percutaneous wire insertion to anterior/lateral thigh using radiographic localization technique reduction login to view 2 more bullets number of screws login to view 2 more bullets screw insertion login to view 5 more bullets screw position login to view 4 more bullets imaging login to view 7 more bullets postoperatively login to view 2 more bullets complications osteonecrosis of femoral head residual deformity & limb length discrepancy chondrolysis login to view 1 more bullet Surgical hip dislocation, open capital realignment and fixation (Modified Dunn procedure) goal to correct the acute proximal femoral deformity and stabilize the epiphysis while protecting the femoral head blood supply technique surgical hip dislocation using the Ganz technique login to view 10 more bullets develop retinacular soft tissue flaps login to view 3 more bullets mobilize epiphysis login to view 2 more bullets debride metaphysis login to view 1 more bullet reduce epiphysis to metaphysis fixation login to view 5 more bullets postoperatively login to view 1 more bullet complications osteonecrosis of femoral head login to view 1 more bullet Osteochondroplasty goal to address pain and loss of motion related to hip impingement from prominent metaphyseal bump in mild to moderate chronic SCFE deformity technique arthroscopy login to view 3 more bullets limited anterior arthrotomy login to view 2 more bullets surgical hip dislocation login to view 5 more bullets Flexion intertrochanteric (Imhauser) femoral osteotomy goal to correct symptomatic proximal femoral deformity in moderate to severe chronic SCFE deformity technique lateral approach login to view 3 more bullets transverse osteotomy just proximal to lesser trochanter correction login to view 3 more bullets postoperative login to view 1 more bullet complications osteonecrosis arthritis Complications Osteonecrosis of femoral head incidence low in stable slips, 24-47% in unstable slips login to view 1 more bullet risk factors initial trauma operative complication (4-6%) login to view 1 more bullet treatment symptomatic management, core decompression, arthroplasty Contralateral hip SCFE incidence 20-80% after unilateral hip fixation most common complication after unilateral surgical fixation risk factors male, obesity, young age of initial slip (< 10 years old, open triradiate cartilage), endocrine disorders treatment/prevention surgical fixation of contralateral hip as needed weight loss programs login to view 1 more bullet Chondrolysis incidence 0-2% seen with narrowed joint space, pain, and decreased motion risk factors unrecognized implant penetration of the articular surface occurring in 0-2% of cases login to view 3 more bullets spica cast immobilization Residual proximal femoral deformity & limb length discrepancy risk factors increased α-angle associated with symptomatic impingement login to view 2 more bullets treatment intertrochanteric osteotomy (Imhauser) login to view 1 more bullet subtrochanteric osteotomy (Southwick) femoral neck cuneiform osteotomy (controversial due to high rate of osteonecrosis and arthritis) Slip progression incidence 1-2% of cases following single screw fixation Delayed diagnosis risk factors increased slip severity knee/thigh pain vs. hip pain stable slips Medicaid insurance Infection incidence 0-2% Chronic pain incidence 5-10% Degenerative arthritis Labral tearing and degeneration risk factors seen with high anterior and medial 2nd screw in-situ fixation login to view 1 more bullet