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 1001
Topic: Pediatric Hip
A 28-year-old hockey player presents with chronic groin pain exacerbated by hip flexion and internal rotation. Radiographs demonstrate an alpha angle of 70 degrees. This radiographic finding is most consistent with which of the following?
Correct Answer & Explanation
. Acetabular retroversion
Explanation
An alpha angle greater than 50-55 degrees indicates a loss of the normal femoral head-neck offset, characteristic of Cam impingement. Pincer impingement is associated with acetabular overcoverage, such as retroversion or coxa profunda.
Question 1002
Topic: Pediatric Hip
A 13-year-old obese boy undergoes in situ pinning with a single cannulated screw for a stable slipped capital femoral epiphysis (SCFE). Postoperatively, he develops severe, unrelenting hip stiffness and a dramatic loss of joint space on radiographs. Which of the following is the most likely cause of this complication?
Correct Answer & Explanation
. Avascular necrosis of the femoral head
Explanation
Chondrolysis is a devastating complication of SCFE characterized by acute loss of articular cartilage and severe stiffness. It is most strongly associated with unrecognized intra-articular hardware penetration during in situ fixation.
Question 1003
Topic: Pediatric Hip
An obese 13-year-old boy presents with left knee pain and a slight limp for 3 weeks. Examination of the hip reveals obligatory external rotation of the thigh during passive flexion of the hip. What is the most appropriate initial management?
Correct Answer & Explanation
. Non-weight bearing and urgent in situ percutaneous pinning
Explanation
The clinical presentation is classic for a Slipped Capital Femoral Epiphysis (SCFE). Prompt in situ percutaneous pinning with a single screw is the standard of care to prevent further slippage and minimize complications.
Question 1004
Topic: Pediatric Hip
A 45-year-old woman with developmental dysplasia of the hip presents with severe secondary osteoarthritis. Preoperative radiographs reveal that the femoral head is subluxated superiorly by 80% of the height of the normal true acetabulum. According to the Crowe classification, what is her stage?
Correct Answer & Explanation
. Crowe I
Explanation
The Crowe classification stages DDH based on the proximal subluxation of the femoral head relative to the true acetabular height. Crowe I is <50%, Crowe II is 50-74%, Crowe III is 75-100%, and Crowe IV is complete dislocation (>100%).
Question 1005
Topic: Pediatric Hip
A 14-year-old obese male underwent in situ pinning for a severe slipped capital femoral epiphysis (SCFE) 5 years ago. He now presents with groin pain and limited internal rotation. What is the most common long-term biomechanical complication leading to early osteoarthritis in this patient profile?
Correct Answer & Explanation
. Pincer impingement from acetabular retroversion
Explanation
Following in situ pinning of a SCFE, the residual anterior metaphyseal prominence often acts as a cam lesion. This creates femoroacetabular impingement (FAI), which is a leading cause of early osteoarthritis in these patients.
Question 1006
Topic: Pediatric Hip
During an open reduction of a developmental dysplasia of the hip (DDH) via an anterior approach, the surgeon must tenotomize the iliopsoas. What nerve is most at risk of injury just medial to the iliopsoas muscle belly at the level of the pelvic brim?
Correct Answer & Explanation
. Obturator nerve
Explanation
The femoral nerve lies in the groove between the iliacus and the psoas major muscles and is immediately medial to the iliopsoas tendon at the level of the joint capsule. Care must be taken not to injure it during an iliopsoas tenotomy.
Question 1007
Topic: Pediatric Hip
During percutaneous pinning of a slipped capital femoral epiphysis (SCFE), the surgeon must avoid the posterosuperior retinacular vessels to prevent osteonecrosis. These vessels are terminal branches of which artery?
Correct Answer & Explanation
. Lateral femoral circumflex artery
Explanation
The medial femoral circumflex artery (MFCA) provides the primary blood supply to the femoral head via the posterosuperior retinacular vessels. Injury to these vessels during SCFE pinning or femoral neck fracture can lead directly to avascular necrosis.
Question 1008
Topic: Pediatric Hip
A 6-year-old boy presents with a painless limp and restricted hip abduction and internal rotation. Radiographs demonstrate sclerosis and fragmentation of the capital femoral epiphysis, confirming a diagnosis of Legg-Calvé-Perthes disease (LCPD). Which of the following is the most critical prognostic factor for the long-term anatomic outcome of his hip?
Correct Answer & Explanation
. Age of the patient at the time of presentation
Explanation
Age at clinical onset is the single most important prognostic factor in Legg-Calvé-Perthes disease (LCPD). Children who develop the disease before the age of 6 to 8 years generally have a much better prognosis and a higher potential for sphericity and remodeling than older children. The extent of epiphyseal involvement (e.g., the Lateral Pillar or Herring classification) is the second most important prognostic factor.
Question 1009
Topic: Pediatric Hip
A 12-year-old obese boy presents with acute-on-chronic hip pain and an externally rotated lower extremity, consistent with a slipped capital femoral epiphysis (SCFE). In situ pinning is planned. The surgeon must employ careful technique to avoid injury to the primary blood supply of the capital femoral epiphysis, which is a terminal branch derived mainly from the:
Correct Answer & Explanation
. Ligamentum teres artery
Explanation
The medial femoral circumflex artery (MFCA) provides the predominant blood supply to the femoral head and capital femoral epiphysis in children (after age 3-4) and adults. Specifically, the lateral epiphyseal artery, a terminal branch of the deep branch of the MFCA, is the most critical vessel, and injury to it significantly increases the risk of avascular necrosis.
Question 1010
Topic: Pediatric Hip
A 26-year-old professional hockey player presents with chronic groin pain exacerbated by deep hip flexion and internal rotation. A Dunn lateral radiograph is obtained, and the alpha angle is measured to be 68 degrees. This radiographic finding is most consistent with which of the following pathomorphologies?
Correct Answer & Explanation
. Cam impingement due to an abnormal femoral head-neck offset
Explanation
The alpha angle is a radiographic measurement used to quantify the sphericity of the anterior femoral head and the head-neck offset, typically measured on a lateral projection such as the Dunn view. An alpha angle greater than 50-55 degrees (with 68 degrees being clearly pathologic) indicates a loss of the normal concave junction between the anterior femoral head and neck. This morphologic abnormality represents a Cam deformity, which engages and damages the anterosuperior acetabular labrum and articular cartilage during hip flexion and internal rotation (Cam-type Femoroacetabular Impingement).
Question 1011
Topic: Pediatric Hip
A 26-year-old male hockey player presents with chronic groin pain exacerbated by hip flexion and internal rotation. Radiographs show an alpha angle of 65 degrees and a positive crossover sign.
The patient's radiographic findings are most consistent with which of the following?
Correct Answer & Explanation
. Mixed Cam and Pincer impingement.
Explanation
An increased alpha angle (>50-55 degrees) is indicative of a Cam-type morphology (aspherical femoral head-neck junction). The crossover sign indicates focal cranial retroversion of the acetabulum, which is a classic radiographic marker of Pincer-type impingement. The combination of both an elevated alpha angle and a crossover sign indicates mixed femoroacetabular impingement (FAI), which is the most common clinical presentation of FAI.
Question 1012
Topic: Pediatric Hip
A 12-year-old boy with a BMI of 35 presents with a 3-week history of left groin pain and a limp. He is diagnosed with a stable left slipped capital femoral epiphysis (SCFE). Which of the following factors is the strongest indication for prophylactic pinning of the contralateral right hip?
Correct Answer & Explanation
. Concomitant hypothyroidism
Explanation
Prophylactic pinning of the contralateral hip in SCFE is controversial but is generally recommended in patients with endocrine disorders (such as hypothyroidism, renal osteodystrophy, or growth hormone deficiency), previous pelvic radiation, or highly delayed bone age (Modified Oxford bone age score of 16 or less). A score of 22 indicates older bone maturity.
Question 1013
Topic: Pediatric Hip
An 8-year-old boy presents with a 2-month history of a painless limp. Radiographs demonstrate sclerosis and fragmentation of the right capital femoral epiphysis. Which of the following radiographic findings at presentation is the most significant indicator of a poor prognosis in Legg-Calvé-Perthes disease?
Correct Answer & Explanation
. Lateral subluxation of the femoral head
Explanation
Lateral subluxation (extrusion) of the femoral head is one of the 'head-at-risk' signs described by Catterall and is the most significant radiographic indicator of a poor prognosis. It leads to loss of containment, hinge abduction, and severe deformity if not addressed.
Question 1014
Topic: Pediatric Hip
A 4-year-old girl is brought in by her parents for an abnormal gait and limb length discrepancy. She has no prior orthopedic history. Radiographs show a high dislocated left hip with a false acetabulum and severe acetabular dysplasia.
What is the most appropriate surgical management?
Correct Answer & Explanation
. Open reduction with pelvic osteotomy and femoral shortening osteotomy
Explanation
In children older than 3 years with neglected or untreated developmental dysplasia of the hip (DDH), open reduction alone is associated with an unacceptably high rate of avascular necrosis (AVN) and redislocation due to soft tissue contractures and bony deformity. A concomitant femoral shortening osteotomy is necessary to relieve soft tissue tension and decrease the risk of AVN. A pelvic osteotomy (e.g., Dega, Salter, or Pemberton) is required to address the underlying acetabular dysplasia and provide adequate anterolateral coverage for the reduced femoral head.
Question 1015
Topic: Pediatric Hip
A 12-year-old obese boy presents with a left chronic stable slipped capital femoral epiphysis (SCFE) and undergoes uncomplicated in situ pinning. Which of the following is the most significant risk factor indicating the need for prophylactic pinning of the contralateral asymptomatic hip?
Correct Answer & Explanation
. Age less than 10 years or open triradiate cartilage
Explanation
The status of the triradiate cartilage and the modified Oxford bone age are the strongest predictors for the development of a contralateral slip in SCFE. An open triradiate cartilage or a chronologic age of less than 10 years (or less than 12 years in boys) indicates significant remaining growth and a high risk of subsequent contralateral SCFE. In these patients, prophylactic pinning of the contralateral hip is strongly recommended.
Question 1016
Topic: Pediatric Hip
An 8-year-old boy with a chronic limp is diagnosed with Legg-Calvé-Perthes disease. Which of the following radiographic findings is considered a 'head at risk' sign according to Catterall, indicating a poor prognosis and a higher risk of femoral head deformation?
Correct Answer & Explanation
. Gage sign
Explanation
Catterall identified several 'head at risk' signs in Legg-Calvé-Perthes disease that correlate with a poor prognosis and progressive deformity. These include Gage's sign (a V-shaped radiolucency in the lateral portion of the epiphysis and adjacent metaphysis), calcification lateral to the epiphysis, lateral subluxation of the femoral head, a horizontal growth plate, and metaphyseal cysts. The Waldenström sign is widening of the medial joint space, and the crescent sign indicates subchondral fracture, which are standard findings rather than specific Catterall risk factors.
Question 1017
Topic: Pediatric Hip
A 13-year-old boy presents with severe groin pain after a minor fall. He is completely unable to bear weight, even with crutches. Radiographs confirm a severe slipped capital femoral epiphysis (SCFE).
What is the most devastating complication specific to this type of presentation, and what surgical technique is frequently utilized to minimize its risk?
Correct Answer & Explanation
. Avascular necrosis; anterior capsulotomy with gentle or no reduction
Explanation
The patient's inability to bear weight even with crutches defines an unstable SCFE. Unstable SCFE carries a significantly high risk of avascular necrosis (AVN), historically reported to be up to 50%. To minimize this risk, surgeons often employ an anterior capsulotomy (to decompress the intracapsular hematoma and reduce tamponade effect on the epiphyseal vessels) and perform gentle, incidental reduction or fix the slip in situ without forceful manipulation.
Question 1018
Topic: Pediatric Hip
A 6-month-old girl presents for follow-up of a dislocated left hip. She had been treated with a Pavlik harness for 6 weeks starting at 1 month of age, which failed to reduce the hip.
What is the next most appropriate step in management?
Correct Answer & Explanation
. Closed reduction and spica casting
Explanation
In an infant older than 6 months or one who has failed a proper trial of a Pavlik harness, the standard next step in management of developmental dysplasia of the hip (DDH) is closed reduction and spica casting under general anesthesia, typically accompanied by an arthrogram. Open reduction is indicated if a stable, concentric closed reduction cannot be achieved.
Question 1019
Topic: Pediatric Hip
An 8-year-old boy presents with a 2-month history of right hip pain and a limp. Radiographs demonstrate fragmentation of the capital femoral epiphysis with lateral subluxation consistent with Legg-Calvé-Perthes disease. Which of the following is considered the most significant prognostic factor for long-term hip outcome in this patient?
Correct Answer & Explanation
. Age at clinical presentation
Explanation
The most significant prognostic factor in Legg-Calvé-Perthes disease is the age at clinical presentation. Children who present before 6 to 8 years of age have a significantly better prognosis because they have more remaining growth potential, allowing for better remodeling of the femoral head into a spherical shape.
Question 1020
Topic: Pediatric Hip
A 12-year-old boy with a BMI of 32 presents with severe left hip pain and inability to bear weight after a minor fall. Radiographs show an acute-on-chronic slipped capital femoral epiphysis (SCFE). During discussion of treatment, prophylactic pinning of the contralateral hip is considered. In which of the following scenarios is prophylactic pinning of the contralateral hip most strongly indicated?
Correct Answer & Explanation
. SCFE in a 10-year-old girl with primary hypothyroidism
Explanation
Prophylactic pinning of the contralateral hip is strongly indicated in patients with a high risk of developing a bilateral SCFE. Risk factors for bilaterality include endocrine disorders (such as hypothyroidism, panhypopituitarism, or growth hormone deficiency), prior pelvic radiation, and age younger than 10 years.
Test Yourself
Switch to an interactive, timed exam simulation to truly master this topic.
