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 361
Topic: Pediatric Hip
A 4-year-old child with developmental dysplasia of the hip (DDH) is scheduled for a Pemberton osteotomy. Which of the following best describes the biomechanical effect and structure of this specific pelvic osteotomy?
Correct Answer & Explanation
. A complete osteotomy redirecting the entire acetabulum to improve anterior coverage
Explanation
The Pemberton osteotomy is an incomplete pericapsular osteotomy that hinges on the flexible triradiate cartilage. It changes the shape of the acetabular roof, effectively reducing acetabular volume and improving anterolateral coverage.
Question 362
Topic: Pediatric Hip
A 13-year-old obese male presents with an unstable slipped capital femoral epiphysis (SCFE). He undergoes in-situ percutaneous pinning. Postoperatively, he develops severe hip pain and restricted range of motion. Radiographs show profound uniform joint space narrowing but no collapse of the femoral head. What is the most likely diagnosis?
Correct Answer & Explanation
. Avascular necrosis of the femoral head
Explanation
Chondrolysis is a severe complication of SCFE, notably associated with unstable slips and unrecognized hardware penetration into the joint. It is characterized by acute, uniform joint space narrowing, severe stiffness, and pain, differentiating it from the segmental collapse seen in avascular necrosis.
Question 363
Topic: Pediatric Hip
Which of the following clinical profiles serves as the strongest absolute indication for prophylactic in situ pinning of the contralateral, asymptomatic hip in a child presenting with a unilateral slipped capital femoral epiphysis (SCFE)?
Correct Answer & Explanation
. Age greater than 14 years at initial presentation
Explanation
Endocrinopathies (such as hypothyroidism or panhypopituitarism) are a strong indication for prophylactic pinning of the contralateral hip due to an extremely high risk of bilateral involvement. Other indications include age under 10 years or inability to follow up reliably.
Question 364
Topic: Pediatric Hip
Figure A is a pelvic radiograph of a healthy 20-month old girl with a limb leg discrepancy. A hip arthrogram under general anesthesia reveals concentric reduction of the left hip ONLY when the hip is positioned in 70 to 80 degrees of abduction. The next best step in treatment would be: Review Topic
Correct Answer & Explanation
. Observation
Explanation
Figure A shows left hip subluxation consistent with late presenting developmental hip dysplasia (DDH). The most appropriate treatment at this stage would be open hipcapsulorrhaphy, +/- femoral osteotomy +/- pelvic osteotomyIn children older than 18 months, open reduction is the preferred treatment for hip dysplasia. Open reduction is also considered when concentric closed reduction cannot be achieved or when excessive abduction (>60 degrees) is required to maintain reduction (due to increasing risk of avascular necrosis). The goal of open reduction is to remove the blocks to reduction and to increase stability by preforming soft-tissue or bone procedures.Wenger et al. reviewed the surgical treatment of DDH. They say that the impediment to congruent reduction are the iliopsoas muscle, joint capsule, ligamentum teres, pulvinar, labrum, and transverse acetabular ligament. The most commonly used approaches are anterior and medial/anteromedial to the hip.Gholve et al. reviewed DDH and the factors that contribute to secondary procedures. In their study, neither age nor unilateral vs bilateral dislocation had a direct influence on the outcome or the need for secondary procedures. The variable that significantly influenced the need for a secondary procedure was the concomitant use of a femoral osteotomy during initial surgical treatment. Of the 27 patients who did not have concurrent femoral osteotomy at index surgery, 19/27 (73%) required a secondary procedure (P<0.001).Figure A shows an AP pelvic radiograph of an infant. Focusing on the left hip, there is lateral and superior subluxation of the femoral head, with the femoral head lateral to Perkin's line. The medial joint space is increased. The acetabular index is increased>30 degrees. Shenton's line is disrupted. These are all features of DDH.Incorrect Answers:
Question 365
Topic: Pediatric Hip
A 7-year-old patient has had a painless limp for several months. Examination reveals pain and spasm with internal rotation, and abduction is limited to 10° on the involved side. Management consists of 1 week of bed rest and traction, followed by an arthrogram. A maximum abduction/internal rotation view is shown in Figure 40a, and abduction and adduction views are shown in Figures 40b and 40c. The studies are most consistent with
Correct Answer & Explanation
. Catterall II involvement.
Explanation
DISCUSSION: The radiographs show classic hinge abduction. The diagnostic feature is the failure of the lateral epiphysis to slide under the acetabular edge with abduction, and the abduction view shows medial dye pooling because of distraction of the hip joint. Persistent hinge abduction has been shown to prevent femoral head remodeling by the acetabulum. Radiographic changes are characteristic of severe involvement with Legg-Calve-Perthes disease. The Catterall classification cannot be well applied without a lateral radiograph, but this degree of involvement would likely be considered a grade III or IV. Because the lateral pillar is involved, this condition would be classified as type C using the Herring lateral pillar classification scheme.REFERENCE: Reinker KA: Early diagnosis and treatment of hinge abduction in Legg-Perthes disease. J Pediatr Orthop 1996;16:3-9.
Question 366
Topic: Pediatric Hip
A 53-year-old man with a history of severe left hip pain has a significant limp that is the result of a 5-cm limb-length discrepancy. An AP radiograph is shown in Figure 48. The underlying etiology is most likely related to a history of
Correct Answer & Explanation
. Legg-Calve-Perthes disease.
Explanation
DISCUSSION: Radiographic abnormalities such as coxa magna, coxa breva secondary to growth arrest, and coxa plana and acetabular deformities are associated with healed Legg-Calve-Perthes disease. Femoral heads that were flat yet congruent with the acetabulum are at risk for disabling arthritis in the sixth decade of life in 50% of these untreated patients. As the normal ball-and-socket joint deforms to a flattened cylinder, the hip loses abduction and rotation capability, while retaining flexion and extension potential. If the femoral head is flat and is not concentric with the acetabulum, early severe arthritis occurs. Hinge abduction and anterior impingement are known sequelae of a flat, incongruent femoral head.REFERENCE: Beaty JH (ed): Orthopaedic Knowledge Update 6. Rosemont, IL, American Academy of Orthopedic Surgeons, 1999, pp 3-23.
Question 367
Topic: Pediatric Hip
An otherwise healthy adolescent girl was treated for left slipped capital femoral epiphysis. The contralateral hip had not slipped, but was stabilized prophylactically with a single cannulated screw. The implants were removed after 1 year. The pelvic radiographs (Figures 215a and 215b) and the MRI scans of the hip that had not originally slipped (Figures 215c through 215e) were obtained 10 months after screw removal (22 months after the original fixation). Which findings are shown in these studies?
Correct Answer & Explanation
. Both hips are normal and no further assessments will be needed.
Explanation
Question 368
Topic: Pediatric Hip
A 12-year-old child falls from his bicycle and injures his right knee. Evaluation in the emergency department reveals knee effusion and pain with extremes of range of motion. Radiographs are shown in Figures 13a and 13b. Attempts at closed reduction are made and he is placed in a long leg cast with the knee flexed at 10 to 20 degrees. At follow-up, repeat radiographs continue to show anterior displacement of the fracture. What structure is most likely entrapped under the fragment?
Correct Answer & Explanation
. Anterior fat pad
Explanation
DISCUSSION: Avulsion fractures of the tibial spine are a relatively rare injury in children. Historically, the most common cause of this fracture was falls from bicycles, but with the increased participation in competitive sports, the etiology is changing. Most fractures occur in children ages 8 to 14 years, and they typically present with a painful hemarthrosis and refusal to bear weight. The Meyers and McKeever classification is based on degree of displacement, where type I is minimally displaced, type II is anteriorly displaced with an intact posterior hinge, and type III is completely displaced. The Ilia and Illb modifications have been added to account for fragment comminution and rotation, respectively. Long leg casting is advocated for type I fractures, though there is debate whether the knee should be maintained in full extension or in 10 to 20 degrees of flexion. Management of type II and III fractures is much more controversial. Type II fractures can be treated closed if adequate reduction can be achieved, but if not, surgical management is indicated. Surgery is also indicated for type III fractures, and results of open versus arthroscopic procedures are similar long term. Kocher and associates examined 80 consecutive skeletally immature patients with type II or III tibial eminence fractures that were treated surgically. They found that the anterior hom of the medial meniscus was entrapped beneath the displaced fracture fragment in 36 of 80 cases, whereas the lateral meniscus was only entrapped in 1 of 80 cases. This is not to be confused with the datafrom Lowe and associates in JBJS 2002 where they found the lateral meniscus to be involved in blocking reduction. This was not thought due to entrapment of the lateral meniscus. Rather, with the anterior cruciateligament and lateral meniscus still being attached to the avulsed fracture fragment, they felt the two structures were pulling in opposite directions and therefore blocking reduction of the fragment.REFERENCES: Falstie-Jensen S, Sondergard-Petersen PE: Incarceration of the meniscus in fractures of the intercondylar eminence of the tibia in children. Injury 1984;15:236-238.Kocher MS, Micheli LJ, Gerbino P, et al: Tibial eminence fractures in children: Prevalence of meniscal entrapment. Am J Sports Med 2003;31:404-407.Accousti WK, Willis RB: Tibial eminence fractures. Orthop Clin North Am 2003;34:365-375.Lowe J, Chaimsky G, Freedman A, et al: The anatomy of tibial eminence fractures: arthroscopic observations following failed closed reduction. J Bone Joint Surg Am 2002;84:1933-1938.Figure 14a Figure 14b Figure 14c Question 14A 14-year-old boy underwent in situ screw fixation for a left slipped capital femoral epiphysis 8 months ago. Henoted 3 months of intermittent right hip pain but is presently asymptomatic. The last episode of pain was 2 days prior to this office visit. He reports that he has pain approximately once a week over the past 3 months. Examination of the right hip is normal, and includes pain-free internal rotation. Radiographs and an MRI scan are shown in Figures 14a through 14c. Treatment should consist of which of the following?In situ screw fixation of the right hipPhysical therapyLimitation of activities and return to the clinic if pain persistsBiopsy of the femoral neck lesionIrrigation and debridement of the right hip PREFERRED RESPONSE: 1DISCUSSION: The patient history is concerning for a pre-slip slipped capital femoral epiphysis (SCFE) of the right hip. In one study, nearly 40% of patients with SCFE had bilateral involvement, and of that 40%, half presented initially with a unilateral SCFE but had a subsequent SCFE on the contralateral limb. Radiographs are normal, but the MRI scan shows increased signal about the proximal femoral physis. Treatment should include prophylactic screw fixation of the right hip.REFERENCES: Aronsson DD, Loder RT, Breur GJ, et al: Slipped capital femoral epiphysis: Current concepts. J Am Acad Orthop Surg 2006;14:666-679.Loder RT, Aronson DD, Greenfield ML: The epidemiology of bilateral slipped capital femoral epiphysis: A study of children in Michigan. J Bone Joint Surg Am 1993;75:1141-1147.Loder RT: Controversies in slipped capital femoral epiphysis. Orthop Clin North Am 2006;37:211-221, vii.Figure 15a Figure 15b
Question 369
Topic: Pediatric Hip
03 Figure 72 shows the radiograph of a 4 y/o girl who has a painless right Trendelenburg limp. Management should consist of
Correct Answer & Explanation
. – open reduction with femoral shortening and pelvic osteotomy
Explanation
Many high dislocations in children with DDH may remain mobile and pain free for decades despite an inefficient gait. Unilateral dislocations usually create difficulties with limb-length discrepancies and spinal malalignment(unlike their bilateral counterparts which generally do not need to be reduced). Open reduction is used to obtain absolute concentric reduction. In the dislocated hip reduced at age 15 mths or older, there is usually enough associated bony deformity, either femoral, acetabular, or both to require stabilizing osteotomy to maintain the concentric reduction. Femoral shortening is often necessary to relax soft tissues before a perfect reduction is possible in children > 2 y/o.back to this question next question
Question 370
Topic: Pediatric Hip
Figures 43a and 43b show the radiographs of an 8-year-old boy who was referred by his gym teacher because of an awkward running pattern. The patient denies any pain in his hips. Examination reveals a mild Trendelenberg gait and decreased internal rotation of the left hip to 25 degrees compared to 40 degrees on the right. What is the most likely diagnosis?
Correct Answer & Explanation
. SCFE
Explanation
The referenced article is a current concept review on the treatment of Legg-Calve-Perthes Disease and does not specifically mention diagnosis. Self limited non-inflammatory deformity of the weight-bearing portion of the femur, likely due to osteonecrosis. Usually seen in 4-8 year old males with delayed skeletal maturity. Family history, low birth weight, and abnormal birth presentation.Symptoms include-pain, effusion (from synovitis), and a limp, decreased ROM especially Abduction internal rotation. Trendelenburg stance is common.The key in this question is the age, decreased ROM, Trendelenburg gait. The prognosis is directly related to the age at presentation, after 8 years old the prognosis is poor. SCFE(Slipped Capital Femoral Epiphysis)-Usually seen in obese adolescent boys with a family history. African American more common. Often related to endocrine abnormalities, presenting with externally rotated gait, decreased internal rotation, thigh atrophy, with hip or knee pain, symptoms vary with the acuteness of the slip.Hypothyroidism is often a finding with patients presenting with SCFE and chondrolysis is a known complication of SCFE.
Question 371
Topic: Pediatric Hip
A 9-year-old girl reports the immediate onset of severe groin pain and the inability to walk after tripping on a curb. Examination reveals marked hip pain with passive range of motion. A radiograph is shown in Figure 21. Regardless of treatment, what is the most common complication following this injury?
Correct Answer & Explanation
. Osteonecrosis of the femoral head
Explanation
DISCUSSION: The patient has an unstable slipped capital femoral epiphysis (SCFE). According to the classification system based on physeal stability, an unstable SCFE is one in which the patient is unable to walk, even with crutches. Ischemic necrosis, or osteonecrosis, of the femoral head is the most devastating complication of SCFE. One study found a 47% incidence of ischemic necrosis following unstable slips. This complication is most likely the result of vascular injury associated with initial femoral head displacement rather than the result of either tamponade from joint effusion or gentle repositioning prior to stabilization. Chondrolysis is a relatively uncommon complication following treatment of SCFE. This complication has been associated with persistent penetration of the hip joint with screws or pins used to stabilize the femoral head or with spica cast immobilization. There are no reports to suggest that osteochondritis dissecans, nonunion, or coxa magna follows treatment of SCFE. REFERENCES: Loder RT, Richards BS, Shapiro PS, et al: Acute slipped capital epiphysis: The importance of physeal stability. J Bone Joint Surg Am 1993;75:1134-1140. Rhoad RC, Davidson RS, Heyman S, et al: Pretreatment bone scan in SCFE: A predictor of ischemia and avascular necrosis. J Pediatr Orthop 1999;19:164-168.
Question 372
Topic: Pediatric Hip
An obese 10-year-old boy has had left groin pain and a limp for the past 2 months. Examination reveals decreased abduction and internal rotation. Laboratory studies show normal renal function and an elevated thyroid-stimulating hormone (TSH) level. AP and frog lateral radiographs of the pelvis are shown in Figures 30a and 30b. What is the best course of action?
Correct Answer & Explanation
. In situ pinning of both hips
Explanation
The radiographs show a grade I slipped capital femoral epiphysis (SCFE) that is classified as stable because the child is able to bear weight. The elevated TSH level indicates possible hypothyroidism. SCFE usually occurs in boys age 12 to 14 years. Because of the patient’s young age and hypothyroidism, he is at increased risk for slippage of the contralateral hip; therefore, prophylactic pinning of the uninvolved side also should be considered. Because of the risk of slip progression, crutch treatment and nonsteroidal anti-inflammatory drugs are not indicated. Realignment osteotomy is not indicated for grade I SCFE. Traction to reduce the slip, followed by pinning, has been advocated for unstable slips but is not indicated here.
Question 373
Topic: Pediatric Hip
Figure 46 shows the radiograph of an obese 12-year-old boy who has had left hip pain for the past 3 months. What is the best course of action?
Correct Answer & Explanation
. Left hip pinning in situ
Explanation
The patient has an obvious slipped capital femoral epiphysis of the left hip for which the recommended treatment is percutaneous pinning in situ. Development of a contralateral slip is less likely at this age; therefore, observation of the right hip is indicated because there is no general agreement regarding prophylactic fixation. Typically, there is no role for spica casting. Physical therapy is not indicated as a primary treatment, and reduction is contraindicated, as it has been associated with osteonecrosis.
Question 374
Topic: Pediatric Hip
A 40-year-old man has had hip pain with increased activity over the past year. Examination reveals restriction of motion and tenderness with combined hip flexion, adduction, and internal rotation. An AP radiograph is shown in Figure 34. What is the most likely diagnosis? Review Topic
Correct Answer & Explanation
. Developmental dysplasia of the hip
Explanation
Femoral acetabular impingement (FAI) is a pathologic entity leading to pain, reduced range of motion in flexion and internal rotation, and development of secondary arthritis of the hip. There are two types of FAI: cam impingement and pincher impingement. Cam impingement is seen when a nonspherical femoral head produces a cam effect when the prominent portion to the femoral head rotates into the joint. This mechanism produces shear forces that damage articular cartilage. Radiographs reveal early joint degeneration and flattening of the head neck junction (the so-called “pistol grip deformity”) as seen in this image. The pincher type of impingement involves abnormal contact between the femoral head neck junction and the acetabulum, in the presence of a spherical femoral head.
Question 375
Topic: Pediatric Hip
During total hip arthroplasty for a patient with Crowe Type IV developmental dysplasia of the hip (DDH), a subtrochanteric shortening osteotomy is planned. Which of the following is the most critical reason for performing the shortening osteotomy in this specific patient population?
Correct Answer & Explanation
. To correct excessive femoral anteversion inherent to the dysplastic femur
Explanation
In Crowe Type IV DDH, the femoral head is completely dislocated and migrated proximally. Bringing the femoral head down to the true acetabulum (which is biomechanically optimal) requires significant lengthening of the limb. Lengthening the leg by more than 4 cm poses a very high risk of stretch injury to the sciatic nerve. A subtrochanteric shortening osteotomy allows the component to be seated in the true acetabulum while protecting the sciatic nerve from excessive tension.
Question 376
Topic: Pediatric Hip
A radiograph of a 12-year-old boy who has had an insidious onset of pain in the right hip for the past 6 weeks shows diffuse narrowing of the joint space. Examination reveals that he is afrebile, and the range of motion of the hip is less than 50% of normal in all planes. Laboratory studies show an erythrocyte sedimentation rate of 21 mm/hr and a WBC of 11,000/mm3. What is the most likely diagnosis?
Correct Answer & Explanation
. Sickle cell crisis
Explanation
First, sickle cell crisis is a localized area of bone marrow infarction with excruciating pain. Swelling of the extremity and limitation of motion are usually mild. Temperature elevation is usually mild but is >39 degrees celsius in 29% of patients. It is also limited to 3-5 days in duration.This patient has no history of hemophilia given. Hemophilic arthropathy begins with a hemarthrosis.In osteoid osteoma the pain is typically unrelenting, sharp, boring, worse at night, and relieved with aspirin. It is not associated with joint space narrowing.The most common age for Legg-Calve-Perthes disease is 4-8 years. It causes AVN of the femoral head and widening of the medial joint space is an early radiographic finding.In Bleck’s report on Idiopathic Chondrolysis JBJS 1983 nine cases were seen at the reporting institution between 1973 and 1978. The average age was 11.5 years. All the patients were otherwise healthy and had no history of systemic illness of previous trauma. All the patients reported the insidious onset of pain in the anterior part of the hip. All had a decreased passive ROM. Radiographic examination showed regional osteoporosis, premature closure of the femoral capital physis, narrowing of the joint space, and lateral overgrowth of the femoral head on the neck. All laboratory examinations were negative for evidence of infection or rheumatoid arthritis. Treatment consists of administration of aspirin, active non-loading exercise of the hip, and protected weight-bearing with crutches.
Question 377
Topic: Pediatric Hip
A 13-year-old boy who has a history of a pituitary adenoma has an unstable unilateral slipped capital femoral epiphysis. What is the indication for prophylactic pinning of the contralateral, unslipped side? Review Topic
Correct Answer & Explanation
. Patient gender
Explanation
Endocrine disorders post the highest risk for bilateral involvement, and prophylactic pinning of the uninvolved side is most often recommended. Risk of contralateral slippage is highest in the youngest patients. In a study by Riad and associates, all girls younger than age 10 and all boys younger than age 12 presenting with a unilateral slipped capital femoral epiphysis subsequently developed a contralateral slip. Initial presentation of an unstable slip has not been shown to be an independent risk factor for later contralateral slippage.
Question 378
Topic: Pediatric Hip
The rate of complications after in situ pinning of a chronic slipped capital femoral epiphysis is highest with placement of the screw in what quadrant of the femoral head?
Correct Answer & Explanation
. Anterior superior
Explanation
The rate of complications increases as the pin moves farther from the ideal position, which is the center of the head. This is the strongest argument for the use of a single pin. The highest rate of complications, primarily osteonecrosis and pin penetration, is associated with pin placement in the anterior superior quadrant.
Question 379
Topic: Pediatric Hip
A 12-year-old boy reports limping and chronic knee pain that is now inhibiting his ability to participate in sports. Clinical examination and radiographs of the knee are normal. Additional evaluation should include Review Topic
Correct Answer & Explanation
. mechanical alignment radiographs.
Explanation
While all of the answers may be appropriate, radiating pain from hip pathology must be excluded. At this age, a slipped capital femoral epiphysis is likely. Therefore, the hip must be examined.
Question 380
Topic: Pediatric Hip
Figure 42 shows the radiograph of a 12-year-old boy who has a limp and pain in the left hip with athletic activity. Examination reveals decreased abduction and internal rotation of the left hip, with pain at the extremes of motion and a 1-cm limb-length discrepancy. Management should consist of
Correct Answer & Explanation
. valgus osteotomy of the proximal femur.
Explanation
DISCUSSION: The radiograph shows changes that are most consistent with Legg-Calvé-Perthes disease. Valgus extension osteotomy is the salvage procedure of choice in patients with late symptomatic Perthes disease with severe joint incongruity. Prerequisites for valgus extension osteotomy include an adequate range of hip adduction and proof of improved congruity in the new position. Total hip arthroplasty is not a good alternative in the young patient. Varus osteotomy would further shorten the extremity and place a flattened portion of the femoral head in the acetabulum. A prerequisite of the innominate osteotomy is a congruent reduction.
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