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Pediatric Hip MCQs

Practice Set 53 of 104

This practice set contains high-yield board review questions covering key concepts in Pediatric Hip. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 1041

Topic: Pediatric Hip

A 7-year-old boy presents with a painless limp of 3 months duration. Radiographs confirm the diagnosis of Legg-Calve-Perthes disease. Which of the following is considered a 'head at risk' sign indicating a poorer prognosis and potential need for surgical intervention?

. Medial subluxation of the femoral head
. Gage sign
. Presence of a subchondral fracture (Crescent sign)
. Decreased alpha angle
. Acetabular dysplasia

Correct Answer & Explanation

. Gage sign

Explanation

Catterall described several 'head at risk' signs in Legg-Calve-Perthes disease that indicate a poor prognosis and a higher likelihood of femoral head deformity. These include Gage sign (a V-shaped radiolucency in the lateral portion of the epiphysis/metaphysis), lateral subluxation of the femoral head, calcification lateral to the epiphysis, horizontal growth plate, and metaphyseal cysts.

Question 1042

Topic: Pediatric Hip

A 13-year-old boy presents with severe right hip and thigh pain after a minor slip. He is unable to bear weight on the right leg. He reports a 2-month history of intermittent right knee pain prior to this event. On examination, attempted hip flexion results in obligatory external rotation. Radiographs confirm a displaced slipped capital femoral epiphysis (SCFE).

What is the most appropriate management to minimize the risk of avascular necrosis (AVN) in this patient?

. Urgent percutaneous in situ fixation within 24 hours
. Delayed percutaneous in situ fixation after 72 hours to allow swelling to subside
. Closed reduction and spica casting
. Skeletal traction for 1 week followed by in situ pinning
. Subtrochanteric derotational osteotomy

Correct Answer & Explanation

. Urgent percutaneous in situ fixation within 24 hours

Explanation

This patient has an unstable Slipped Capital Femoral Epiphysis (SCFE), defined by the Loder classification as the inability to bear weight even with crutches. Unstable SCFE carries a significantly higher risk of avascular necrosis (AVN) compared to stable SCFE (up to 50% vs. nearly 0%). Current evidence strongly supports urgent surgical intervention (within 24 hours of symptom onset) via in situ percutaneous pinning or an open procedure (like a modified Dunn) depending on the surgeon's expertise. Urgent decompression/pinning decreases the intracapsular pressure and stabilizes the physis, significantly lowering the AVN rate compared to delayed treatment. Traction and spica casting are historically associated with poor outcomes and are no longer standard of care.

Question 1043

Topic: Pediatric Hip

An 8-year-old boy is evaluated for an 8-month history of right hip pain and a painless limp.

AP pelvis radiographs demonstrate fragmentation of the right capital femoral epiphysis consistent with Legg-Calvé-Perthes disease. According to the Herring Lateral Pillar Classification, which of the following defines a Lateral Pillar Group C hip, which carries the poorest prognosis?

. No involvement of the lateral pillar with normal height
. Maintenance of >50% of the normal lateral pillar height
. Maintenance of <50% of the normal lateral pillar height
. A subchondral crescent sign extending >50% of the femoral head width
. Calcification lateral to the epiphyseal margin

Correct Answer & Explanation

. Maintenance of <50% of the normal lateral pillar height

Explanation

The Herring Lateral Pillar Classification is the most widely used prognostic radiographic classification for Legg-Calvé-Perthes disease, evaluated during the fragmentation stage on the AP radiograph. Group A involves no radiolucency or loss of height in the lateral third of the epiphysis (lateral pillar). Group B demonstrates a lucency but maintains >50% of the lateral pillar height. Group C involves a loss of >50% of the lateral pillar height (i.e., maintenance of <50%). Group C hips have the poorest prognosis, frequently leading to a flat, aspherical head and early-onset osteoarthritis.

Question 1044

Topic: Pediatric Hip

A 12-year-old obese boy presents with 3 weeks of vague knee pain and a limp. Examination reveals obligate external rotation of the hip during flexion. He is diagnosed with a stable slipped capital femoral epiphysis (SCFE).

What is the most appropriate position to place the hip during in situ single-screw fixation to minimize the risk of osteonecrosis?

. Maximum internal rotation to reduce the slip
. Maximum abduction and flexion
. Resting position without attempting reduction
. Anatomical neutral position regardless of the slip
. Maximum external rotation to distract the joint

Correct Answer & Explanation

. Resting position without attempting reduction

Explanation

For a stable slipped capital femoral epiphysis (SCFE), the standard of care is in situ fixation with a single cannulated screw. Attempting to forcefully reduce a stable SCFE significantly increases the risk of osteonecrosis (avascular necrosis) of the femoral head due to disruption of the delicate epiphyseal blood supply. Therefore, the hip should be pinned in its resting position without deliberate attempts at reduction.

Question 1045

Topic: Pediatric Hip

A 30-month-old girl is brought in by her parents who noticed she walks with a limp. She has not received any prior orthopedic care. Pelvic radiographs reveal a completely dislocated left hip with acetabular dysplasia and a false acetabulum.

What is the most appropriate definitive management?

. Application of a Pavlik harness
. Closed reduction and spica casting
. Open reduction, femoral shortening osteotomy, and pelvic osteotomy
. Open reduction and spica casting without osteotomies
. Observation until skeletal maturity

Correct Answer & Explanation

. Open reduction, femoral shortening osteotomy, and pelvic osteotomy

Explanation

In a child older than 2 years (24 months) presenting with untreated developmental dysplasia of the hip (DDH) and a high dislocation, closed reduction is rarely successful and carries an unacceptably high risk of osteonecrosis. The gold standard is open reduction. Because the soft tissues are contracted and the acetabulum is dysplastic, a femoral shortening osteotomy (to reduce tension and AVN risk) and a pelvic osteotomy (to address acetabular dysplasia) are typically required simultaneously.

Question 1046

Topic: Pediatric Hip

A 12-year-old boy presents to the emergency department unable to bear weight on his left leg for the past 2 days after jumping off a swing. He refuses to walk even with crutches. Figure 4 shows the AP pelvis radiograph.

He is diagnosed with a slipped capital femoral epiphysis (SCFE) and undergoes urgent single-screw in situ fixation. Which of the following is the most likely complication associated with this specific type of presentation compared to a patient who is able to bear weight?

. Chondrolysis
. Avascular necrosis
. Progressive slippage
. Femoroacetabular impingement
. Contralateral slip

Correct Answer & Explanation

. Avascular necrosis

Explanation

The patient has an unstable slipped capital femoral epiphysis (SCFE), defined by the Loder classification as the inability to bear weight with or without crutches. The most significant and common severe complication of an unstable SCFE is avascular necrosis (AVN) of the femoral head, with rates historically reported up to nearly 50%, compared to near 0% in stable SCFE. Urgent, gentle reduction or in situ pinning is required, though the risk of AVN remains high.

Question 1047

Topic: Pediatric Hip

An 18-month-old girl presents with a waddling gait and a painless limp. Figure 10 shows her AP pelvis radiograph demonstrating a dislocated left hip.

She is scheduled to undergo an open reduction of the hip. Which of the following structures represents an EXTRA-articular obstacle to reduction that typically requires division or lengthening?

. Transverse acetabular ligament
. Iliopsoas tendon
. Ligamentum teres
. Pulvinar
. Inverted limbus

Correct Answer & Explanation

. Iliopsoas tendon

Explanation

In Developmental Dysplasia of the Hip (DDH), surgical reduction must overcome both extra-articular and intra-articular obstacles. The iliopsoas tendon is a primary extra-articular obstacle, as it tents over the capsule and constricts it (creating an hourglass shape), preventing the femoral head from entering the true acetabulum. Intra-articular obstacles include the pulvinar (fibrofatty tissue), ligamentum teres, inverted limbus, and the transverse acetabular ligament, all of which may need to be excised, incised, or divided to seat the head concentrically.

Question 1048

Topic: Pediatric Hip
An 8-year-old boy presents with a 4-month history of a painless right-sided limp. Radiographs demonstrate fragmentation of the capital femoral epiphysis consistent with Legg-Calvé-Perthes disease. According to the Herring lateral pillar classification, greater than 50% loss of lateral pillar height is noted (Type C). Which of the following factors in this patient is most strongly associated with a poor prognosis and often dictates the need for surgical containment?
. Male gender
. Unilateral involvement
. Age at onset of 8 years or older
. Presence of a subchondral crescent sign
. Painless presentation

Correct Answer & Explanation

. Age at onset of 8 years or older

Explanation

In Legg-Calvé-Perthes disease, the two most critical prognostic factors are the age at onset and the degree of lateral pillar involvement (Herring classification). Children who develop the disease at 8 years of age or older have less time for the femoral head to remodel before skeletal maturity and generally have worse outcomes, particularly if they have lateral pillar B or C involvement. Surgical containment (e.g., femoral or pelvic osteotomy) is often indicated in this age group to maintain sphericity.

Question 1049

Topic: Pediatric Hip

A 12-year-old obese boy presents with 3 weeks of right knee pain and a limp. Examination demonstrates obligate external rotation with hip flexion. An AP pelvis radiograph is shown in Figure 1.

He is diagnosed with a stable slipped capital femoral epiphysis (SCFE) and is scheduled for in situ pinning. What is the most reliable technical maneuver to prevent the devastating complication of chondrolysis during this procedure?

. Pin placement in the anterosuperior quadrant of the epiphysis
. Utilization of a smooth, unthreaded pin
. Using the approach-withdrawal fluoroscopic technique
. Performing a routine open arthrotomy
. Advancing the screw to within 1 mm of the subchondral bone

Correct Answer & Explanation

. Using the approach-withdrawal fluoroscopic technique

Explanation

The most common cause of chondrolysis following SCFE fixation is unrecognized intra-articular hardware penetration. The approach-withdrawal technique utilizes continuous live fluoroscopy while rotating the hip to dynamically verify that the screw tip remains entirely within the bone and has not violated the joint space, thus preventing chondrolysis. Pin placement should ideally be in the center-center position, not anterosuperior.

Question 1050

Topic: Pediatric Hip

An 18-month-old boy presents with a painless limp and leg length discrepancy. Examination reveals a positive Galeazzi sign on the right and limited right hip abduction. Pelvic radiographs demonstrate a completely dislocated right hip with a dysplastic acetabulum (acetabular index of 38 degrees).

What is the most recommended treatment plan for this child?

. Pavlik harness application
. Closed reduction and spica casting
. Open reduction and pelvic osteotomy, followed by spica casting
. Proximal femoral derotation osteotomy alone
. Observation until age 4, then single-stage reconstruction

Correct Answer & Explanation

. Open reduction and pelvic osteotomy, followed by spica casting

Explanation

In a walking child older than 18 months with developmental dysplasia of the hip (DDH), closed reduction has a high failure rate and an increased risk of avascular necrosis. Additionally, the remaining potential for acetabular remodeling is significantly diminished. Therefore, the standard of care is open reduction combined with a pelvic osteotomy (e.g., Salter or Pemberton) to correct the acetabular dysplasia, often accompanied by a femoral shortening osteotomy to reduce joint reaction forces and AVN risk.

Question 1051

Topic: Pediatric Hip

A 12-year-old boy presents to the emergency department with severe left hip pain and an inability to bear weight on the affected limb for 2 days. He reports a preceding 2-month history of mild, intermittent groin pain. AP and frog-leg lateral radiographs demonstrate a slipped capital femoral epiphysis (SCFE) with a 60% displacement. Which of the following is the most significant risk factor for the development of avascular necrosis (AVN) in this patient?

. The duration of his prodromal symptoms
. The chronicity of the slip prior to the acute episode
. The instability of the slip (inability to bear weight)
. The degree of epiphyseal displacement
. The use of a single cannulated screw for fixation

Correct Answer & Explanation

. The instability of the slip (inability to bear weight)

Explanation

Instability is the most significant risk factor for the development of avascular necrosis (AVN) in SCFE. A stable SCFE is defined clinically as the patient being able to bear weight, with or without crutches. An unstable SCFE means the patient is unable to bear weight. The rate of AVN in stable slips is close to 0%, whereas in unstable slips it ranges from 24% to 47%. While the severity of the slip increases the risk of chondrolysis and subsequent cam-type impingement, instability remains the primary predictor of AVN.

Question 1052

Topic: Pediatric Hip

A 13-year-old obese male presents to the emergency department after a minor slip. He is unable to bear weight on his right leg, even with crutches. Radiographs reveal a severe slipped capital femoral epiphysis (SCFE). Which of the following interventions during surgical treatment has been shown to potentially decrease the risk of osteonecrosis in this specific clinical scenario?

. Open reduction and internal fixation via surgical dislocation without capsulotomy
. Urgent closed reduction with forceful manipulation to achieve anatomical alignment
. Spica cast application
. Prophylactic pinning of the contralateral hip
. Capsular decompression (capsulotomy) prior to pinning

Correct Answer & Explanation

. Capsular decompression (capsulotomy) prior to pinning

Explanation

The patient has an unstable SCFE, defined by the inability to bear weight. Unstable SCFE has a significantly higher rate of osteonecrosis (up to 50%) compared to stable SCFE. Urgent capsular decompression (capsulotomy) to relieve intracapsular hematoma tamponade, followed by gentle or no reduction prior to pinning, has been shown to lower the risk of avascular necrosis. Forceful closed reduction is strictly contraindicated as it further disrupts the delicate blood supply.

Question 1053

Topic: Pediatric Hip

An 8-year-old boy is diagnosed with Legg-Calve-Perthes disease. Anteroposterior pelvic radiographs demonstrate sclerosis and fragmentation of the left capital femoral epiphysis. According to the Herring lateral pillar classification, which of the following radiographic findings indicates a Group C classification, which is associated with the poorest prognosis?

. No involvement of the lateral pillar
. Maintenance of >50% of lateral pillar height
. Maintenance of <50% of lateral pillar height
. Presence of a subchondral radiolucent line (crescent sign)
. Metaphyseal cysts

Correct Answer & Explanation

. Maintenance of <50% of lateral pillar height

Explanation

The Herring lateral pillar classification assesses the height of the lateral pillar of the capital femoral epiphysis on the AP radiograph during the fragmentation phase. Group A has no involvement; Group B maintains >50% of the lateral pillar height; Group C maintains <50% of the lateral pillar height. Group C is associated with the poorest clinical and radiographic outcomes, and patients in this group who are >8 years of age typically benefit from surgical containment.

Question 1054

Topic: Pediatric Hip

A 3-year-old girl is diagnosed with a neglected developmental dysplasia of the left hip. Radiographs show a high dislocation of the femoral head. What is the standard surgical management for this patient?

. Closed reduction and spica casting
. Open reduction and spica casting
. Open reduction and femoral shortening osteotomy
. Open reduction, femoral shortening osteotomy, and pelvic osteotomy
. Pelvic osteotomy alone

Correct Answer & Explanation

. Open reduction, femoral shortening osteotomy, and pelvic osteotomy

Explanation

In children older than 2 to 3 years with a neglected developmental dysplasia of the hip, the risk of redislocation and avascular necrosis is high due to soft tissue contractures and secondary acetabular dysplasia. The standard of care typically involves an open reduction, a femoral shortening osteotomy (to relieve soft tissue tension and reduce the risk of AVN), and a pelvic osteotomy (e.g., Dega or Salter) to address acetabular dysplasia and provide stable coverage.

Question 1055

Topic: Pediatric Hip

A 14-year-old boy is evaluated for hip pain and severe stiffness 6 months after undergoing in situ pinning for a stable slipped capital femoral epiphysis (SCFE) of the right hip. On examination, he has globally restricted range of motion of the right hip. Radiographs reveal narrowing of the joint space to less than 3 mm, osteopenia, and no evidence of hardware penetration into the joint. What is the most likely diagnosis?

. Avascular necrosis
. Septic arthritis
. Chondrolysis
. Cam impingement
. Hardware failure

Correct Answer & Explanation

. Chondrolysis

Explanation

Chondrolysis is characterized by acute cartilage necrosis, presenting with severe stiffness, pain, and globally restricted range of motion. Radiographically, it is defined by a joint space of less than 3 mm. Although historically associated with unrecognized hardware penetration, it can occur in unpinned SCFEs or following in situ pinning without joint penetration. AVN typically presents with sclerosis and collapse of the femoral head rather than isolated symmetric joint space narrowing.

Question 1056

Topic: Pediatric Hip
An 8-year-old boy presents with a painless limp of 3 months' duration. Radiographs show fragmentation of the femoral head consistent with Legg-Calvé-Perthes disease. According to the Herring Lateral Pillar classification, which of the following radiographic findings portends the worst prognosis?
. Greater than 50% maintenance of the lateral pillar height
. Less than 50% maintenance of the lateral pillar height
. Central pillar depression
. Subchondral radiolucent line (crescent sign)
. Metaphyseal cysts

Correct Answer & Explanation

. Less than 50% maintenance of the lateral pillar height

Explanation

The Herring Lateral Pillar classification is strongly correlated with prognosis in Legg-Calvé-Perthes disease. Group C (less than 50% lateral pillar height maintained) indicates severe involvement and carries the worst prognosis for femoral head sphericity and future joint congruity. Age at onset (>8 years) and Group C classification are the strongest predictors of a poor outcome.

Question 1057

Topic: Pediatric Hip

A 13-year-old boy with a BMI of 35 presents to the emergency department unable to bear weight on his left leg after a minor slip. Radiographs confirm an acute, severe left slipped capital femoral epiphysis (SCFE). He cannot bear weight even with crutches. What is the current consensus regarding surgical treatment for this patient to minimize complications?

. In situ pinning should be delayed for 7 days to allow soft tissues to rest
. Urgent surgical stabilization with capsular decompression reduces the risk of avascular necrosis
. Closed reduction with forceful manipulation followed by spica casting
. Prophylactic pinning of the contralateral hip must be done before addressing the symptomatic hip
. Primary total hip arthroplasty

Correct Answer & Explanation

. Urgent surgical stabilization with capsular decompression reduces the risk of avascular necrosis

Explanation

The patient has an unstable SCFE (defined by the inability to bear weight with or without crutches). Unstable SCFE is associated with a high risk of avascular necrosis (AVN). Current evidence suggests that urgent or emergent surgical stabilization (often within 24 hours), combined with capsular decompression (to reduce intracapsular tamponade), minimizes the risk of AVN. Forceful closed reduction is contraindicated as it increases the risk of AVN.

Question 1058

Topic: Pediatric Hip

A 6-week-old female is being treated with a Pavlik harness for a developmental dysplasia of the hip (DDH) that was dislocated but reducible on exam. At her 1-week follow-up, the parents report she has stopped kicking her left leg. On clinical examination, she holds the left knee in extension and does not actively contract her quadriceps with tickling. Ultrasound confirms the hip is currently reduced. What is the most appropriate next step in management?

. Decrease hip abduction by loosening the posterior straps
. Increase hip flexion by tightening the anterior straps
. Discontinue the harness until active quadriceps function returns
. Transition immediately to a rigid hip abduction orthosis
. Schedule urgent closed reduction and spica casting under anesthesia

Correct Answer & Explanation

. Discontinue the harness until active quadriceps function returns

Explanation

The clinical scenario describes a femoral nerve palsy, a known complication of treating DDH with a Pavlik harness caused by hyperflexion of the hip. Presenting signs include absent active knee extension and loss of quadriceps function. The appropriate initial management is to discontinue the harness to relieve pressure on the femoral nerve and allow for neurologic recovery, which typically occurs over a few days to weeks. Tightening straps or ignoring the palsy risks permanent nerve injury.

Question 1059

Topic: Pediatric Hip

A 13-year-old boy with a BMI in the 99th percentile presents to the emergency department with acute left groin pain. He states he twisted his leg getting out of bed. On examination, he is completely unable to bear weight on the left leg, even with the use of crutches. Radiographs demonstrate a severe posterior and inferior displacement of the left capital femoral epiphysis. According to the Loder classification, his inability to bear weight puts him at highest risk for which of the following complications?

. Chondrolysis
. Contralateral slipped capital femoral epiphysis
. Avascular necrosis (AVN) of the femoral head
. Femoroacetabular impingement (FAI)
. Nonunion of the proximal femoral physis

Correct Answer & Explanation

. Avascular necrosis (AVN) of the femoral head

Explanation

The Loder classification divides Slipped Capital Femoral Epiphysis (SCFE) into stable and unstable based strictly on the ability to bear weight (with or without crutches). An unstable SCFE (inability to bear weight) has a significantly higher rate of avascular necrosis (up to 50%), whereas AVN is exceedingly rare in stable SCFE. Chondrolysis is more commonly associated with unrecognized hardware penetration into the joint space.

Question 1060

Topic: Pediatric Hip
An 8-year-old boy presents with a 4-month history of a painless limp. Radiographs demonstrate fragmentation and sclerosis of the left proximal femoral epiphysis consistent with Legg-Calvé-Perthes disease. The lateral one-third of the femoral head exhibits a 60% loss of height compared to the contralateral normal hip. According to the Herring lateral pillar classification, what is his expected prognosis without surgical intervention?
. Lateral Pillar A, excellent prognosis
. Lateral Pillar B, favorable prognosis
. Lateral Pillar B/C border, variable prognosis
. Lateral Pillar C, poor prognosis
. Lateral Pillar C, excellent prognosis

Correct Answer & Explanation

. Lateral Pillar C, poor prognosis

Explanation

The Herring lateral pillar classification predicts outcome in Perthes disease based on the height of the lateral column of the epiphysis during the fragmentation stage. Group C implies >50% collapse of the lateral pillar. Patients in Group C generally have a poor prognosis with a high likelihood of aspherical congruency and early osteoarthritis, especially in children older than 8 years, regardless of surgical containment.

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