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 341
Topic: Pediatric Hip
A 2-week-old neonate presents with asymmetric gluteal folds and pseudoparalysis of the right lower extremity. The infant is afebrile with normal inflammatory markers. Ultrasound demonstrates a right hip effusion. What is the most appropriate next step?
Correct Answer & Explanation
. Urgent hip aspiration and surgical drainage
Explanation
Neonates with septic arthritis often lack systemic signs like fever or elevated inflammatory markers. Pseudoparalysis and an effusion demand urgent aspiration and drainage to prevent devastating joint destruction.
Question 342
Topic: Pediatric Hip
A 28-year-old patient with a history of trauma presents with a complex multi-planar deformity of the distal tibia. Preoperative planning reveals a Mechanical Lateral Distal Femoral Angle (mLDFA) of 88°, a Medial Proximal Tibial Angle (MPTA) of 86°, and a Lateral Distal Tibial Angle (LDTA) of 75°. The Joint Line Convergence Angle (JLCA) is 0°. Based on these measurements, where is the primary anatomical location of the angular deformity?
Correct Answer & Explanation
. Distal tibia (valgus deformity)
Explanation
Correct Answer: DTo determine the primary anatomical location of the angular deformity, we compare the patient's measured joint orientation angles to their normal ranges:mLDFA (Mechanical Lateral Distal Femoral Angle):Patient's is 88°. Normal range is 85° to 90°. This is within the normal range, indicating no significant distal femoral deformity.MPTA (Medial Proximal Tibial Angle):Patient's is 86°. Normal range is 85° to 90°. This is within the normal range, indicating no significant proximal tibial deformity.LDTA (Lateral Distal Tibial Angle):Patient's is 75°. Normal range is 86° to 92° (average 89°). A value of 75° is significantly less than the normal range. An LDTA less than 86° indicates a distal tibial valgus deformity.JLCA (Joint Line Convergence Angle):Patient's is 0°. Normal range is 0° to 2°. This is normal, ruling out significant intra-articular pathology as the primary angular deformity source.Therefore, the primary anatomical location of the angular deformity is the distal tibia, specifically a valgus deformity.
Question 343
Topic: Pediatric Hip
A 28-year-old female presents with a Trendelenburg gait and chronic hip pain. Radiographs reveal a femoral neck-shaft angle of 115°. Based on Paley's principles, what is the most likely diagnosis and its direct biomechanical consequence?
Correct Answer & Explanation
. D. Coxa vara, leading to a shortened limb and abductor weakness.
Explanation
Correct Answer: DThe correct answer is D. The normal Neck-Shaft Angle (NSA) ranges from 124° to 136° (average ~130°). An NSA of 115° is significantly less than the normal range. The case defines an NSA less than 120° as coxa vara. The clinical implication of coxa vara is that it 'shortens the limb and can lead to a Trendelenburg gait due to abductor weakness' because the abductor muscles lose their mechanical advantage (moment arm) due to the altered femoral neck geometry.Option Ais incorrect because coxa valga is an NSA greater than 135°, and while it affects the abductor moment arm, it typically increases it, not decreases it in the context of a Trendelenburg gait.Option Bis incorrect because coxa vara leads to adecreasedabductor moment arm, resulting in weakness, not an increased one.Option Cis incorrect because coxa valga (NSA > 135°) would lead to a relatively longer limb, and the patient has coxa vara.Option Eis incorrect because an NSA of 115° is clearly outside the normal range (124-136°), indicating a significant deformity.
Question 344
Topic: Pediatric Hip
A 50-year-old patient with a history of hip trauma presents with a Trendelenburg gait and reports difficulty with abductor strength. Radiographs show a high-riding greater trochanter relative to the femoral head. Which of the following angles, as defined by Paley's principles, would be most directly affected by this anatomical finding and explain the patient's abductor weakness?
Correct Answer & Explanation
. B. Mechanical Lateral Proximal Femoral Angle (mLPFA)
Explanation
Correct Answer: BThe correct answer is B, the mechanical Lateral Proximal Femoral Angle (mLPFA). The case defines the mLPFA as the angle formed when a line from the proximal tip of the greater trochanter to the center of the femoral head intersects the mechanical axis of the femur. A normal mLPFA ranges from 85° to 95° (average ~90°). The clinical implication section for mLPFA explicitly states: 'The mLPFA is a brilliant measure of the articulotrochanteric distance (ATD). If the tip of the greater trochanter rides too high (e.g., due to a collapsed femoral neck or coxa vara), the mLPFA decreases. A high-riding trochanter creates functional abductor weakness because the gluteus medius loses its tension and resting length.' This directly explains the patient's high-riding trochanter and abductor weakness.Option A (NSA)is the Neck-Shaft Angle. While coxa vara (a low NSA) can lead to a high-riding trochanter, the mLPFA is thedirectmeasure of the articulotrochanteric distance and its impact on abductor mechanics, as described in the text.Option C (mLDFA)assesses distal femoral frontal plane alignment and is unrelated to hip abductor mechanics.Option D (MPTA)assesses proximal tibial frontal plane alignment and is unrelated to hip abductor mechanics.Option E (PDFA)assesses distal femoral sagittal plane alignment and is unrelated to hip abductor mechanics.
Question 345
Topic: Pediatric Hip
During extensive femoral lengthening (e.g., >5 cm), which of the following hip complications is most commonly encountered if prophylactic measures are not taken?
Correct Answer & Explanation
. Subluxation or dislocation of the hip joint
Explanation
Extensive femoral lengthening significantly increases tension on the soft tissues crossing the hip joint, particularly the iliotibial band and hip abductors. This elevated tension can lead to progressive hip subluxation or dislocation, often necessitating prophylactic IT band release.
Question 346
Topic: Pediatric Hip
A 50-year-old female presents with a severe valgus knee deformity. Preoperative full-length weight-bearing radiographs show a Mechanical Axis Deviation (MAD) of 25mm lateral to the center of the knee. Which of the following joint orientation angle measurements would be most consistent with a primary distal femoral deformity contributing to this valgus malalignment?
Correct Answer & Explanation
. mLDFA of 80°
Explanation
Correct Answer: BThe case content defines the Mechanical Lateral Distal Femoral Angle (mLDFA) as defining the relationship between the femoral mechanical axis and the distal femoral joint line. It states that anmLDFA < 85° indicates distal femoral valgus. A valgus knee deformity with a lateral MAD is consistent with distal femoral valgus. Therefore, an mLDFA of 80° (which is less than 85°) directly points to a primary distal femoral deformity as a significant contributor to the overall valgus malalignment.Option A (MPTA of 88°)is incorrect. The Medial Proximal Tibial Angle (MPTA) defines the relationship between the tibial mechanical axis and the proximal tibial joint line. A normal range is 85° to 90°. An MPTA of 88° is within the normal range, indicating no significant proximal tibial varus or valgus deformity.Option C (JLCA of 3°)is incorrect. The Joint Line Convergence Angle (JLCA) measures the angle between the distal femoral and proximal tibial joint lines. An increased JLCA (> 2°) suggests gapping due to ligamentous laxity or severe cartilage loss, not a primary bony deformity contributing to valgus.Option D (LDTA of 89°)is incorrect. The Lateral Distal Tibial Angle (LDTA) assesses ankle joint orientation. A normal range is 86° to 92°. An LDTA of 89° is within the normal range, indicating no significant distal tibial deformity.Option E (mLPFA of 92°)is incorrect. The Mechanical Lateral Proximal Femoral Angle (mLPFA) evaluates proximal femoral geometry. A normal range is 85° to 95°. An mLPFA of 92° is within the normal range, indicating no significant proximal femoral deformity (like coxa vara or coxa valga).
Question 347
Topic: Pediatric Hip
A 48-year-old patient presents with knee pain and a radiograph is obtained for deformity analysis. The image below shows a full-length standing radiograph of the lower extremity. The mechanical axis of the femur is drawn, and the angle formed between this axis and the distal femoral articular surface is measured. If this angle, the Mechanical Lateral Distal Femoral Angle (mLDFA), is measured at 95 degrees, what is the most likely clinical implication based on the provided normal values?
Correct Answer & Explanation
. C. The patient has genu varum.
Explanation
Correct Answer: CThe text states that the average normal value for the Mechanical Lateral Distal Femoral Angle (mLDFA) is 88 degrees, with a normal range of 85-90 degrees. It further specifies that 'Abnormal values indicate genu varum (>90°) or genu valgum (<85°).' A measured mLDFA of 95 degrees is greater than 90 degrees, indicating genu varum. The image provided visually supports a varus deformity.Incorrect Options:A. The patient has a normal distal femoral alignment:A 95-degree mLDFA is outside the normal range of 85-90 degrees, indicating an abnormal alignment.B. The patient has genu valgum:Genu valgum is indicated by an mLDFA less than 85 degrees, not greater than 90 degrees.D. The patient has coxa vara:Coxa vara is indicated by an abnormal Mechanical Lateral Proximal Femoral Angle (mLPFA) less than 85 degrees, which relates to the proximal femur, not the distal femur.E. The patient has coxa valga:Coxa valga is indicated by an abnormal mLPFA greater than 95 degrees, also relating to the proximal femur.
Question 348
Topic: Pediatric Hip
A 65-year-old female presents with hip pain and a full-length standing radiograph is obtained. The image below shows a close-up of the proximal femur. The angle formed between the mechanical axis of the femur and the femoral neck axis (or the articular surface of the femoral head) is measured. If this angle, the Mechanical Lateral Proximal Femoral Angle (mLPFA), is measured at 80 degrees, what is the most appropriate diagnosis based on the provided normal values?
Correct Answer & Explanation
. D. Coxa vara.
Explanation
Correct Answer: DThe text states that the average normal value for the Mechanical Lateral Proximal Femoral Angle (mLPFA) is 90 degrees, with a normal range of 85-95 degrees. It further specifies that 'Abnormal values indicate coxa vara (<85°) or coxa valga (>95°).' A measured mLPFA of 80 degrees is less than 85 degrees, which indicates coxa vara. The image provided visually supports a coxa vara deformity.Incorrect Options:A. Normal proximal femoral alignment:An mLPFA of 80 degrees is outside the normal range of 85-95 degrees, indicating an abnormal alignment.B. Genu varum:Genu varum is indicated by an abnormal Mechanical Lateral Distal Femoral Angle (mLDFA) greater than 90 degrees, relating to the distal femur, not the proximal femur.C. Genu valgum:Genu valgum is indicated by an abnormal mLDFA less than 85 degrees, also relating to the distal femur.E. Coxa valga:Coxa valga is indicated by an mLPFA greater than 95 degrees, not less than 85 degrees.
Question 349
Topic: Pediatric Hip
A patient with a history of pediatric hip pathology presents with a compensatory genu varum. Radiographic evaluation is performed, and the surgeon is assessing the proximal femoral mechanical angle (PFMA).
Correct Answer & Explanation
. 87-89 degrees; coxa vara.
Explanation
Correct Answer: BThe proximal femoral mechanical angle (PFMA), specifically the Mechanical Lateral Proximal Femoral Angle (MLPFA) in Paley's system, is the lateral angle formed by the femoral mechanical axis and a line perpendicular to the femoral head articular surface. The normal range for the MLPFA is approximately 87 +/- 3 degrees (i.e., 84-90 degrees). A decreased MLPFA (less than 84 degrees) indicates a coxa vara deformity, where the femoral neck-shaft angle is reduced, causing the femoral head to be more varus relative to the mechanical axis. An increased MLPFA (greater than 90 degrees) would indicate coxa valga. Therefore, 87-89 degrees is within the normal range, and a decreased angle suggests coxa vara.
Question 350
Topic: Pediatric Hip
A 55-year-old patient presents with a proximal femoral varus deformity (coxa vara) requiring correction. The CORA is identified in the subtrochanteric region, and a closing wedge osteotomy is being considered.
Correct Answer & Explanation
. Lateral closing wedge, to increase the valgus angle.
Explanation
Correct Answer: BA proximal femoral varus deformity (coxa vara) means the femoral neck-shaft angle is decreased, causing the femoral head to be more varus relative to the mechanical axis. To correct this, the proximal femur needs to be brought into more valgus alignment (i.e., increase the neck-shaft angle). A lateral closing wedge osteotomy involves removing a wedge of bone from the lateral side of the femur. When this wedge is closed, the distal fragment is shifted laterally, effectively increasing the valgus angle of the proximal femur and correcting the coxa vara. Option A would worsen the varus. Option C is incorrect as a medial closing wedge would increase valgus. Option D is incorrect as it describes decreasing valgus. Option E addresses a different plane of deformity.
Question 351
Topic: Pediatric Hip
A 28-year-old patient with a history of Slipped Capital Femoral Epiphysis (SCFE) requires a precise assessment of proximal femoral deformity for surgical planning. The surgeon needs a true lateral view of the femoral neck, perpendicular to its axis. Which of the following radiographic techniques, as described in Paley's principles, is the gold standard for this evaluation?
Correct Answer & Explanation
. The Sugioka view, with the hip flexed 90 degrees and abducted approximately 45 degrees.
Explanation
Correct Answer: CThe text explicitly states that 'The Sugioka view is an elegant, highly effective technique designed to achieve this true lateral projection' of the femoral neck. It describes the technique as placing the patient supine, flexing the affected hip to exactly 90 degrees, and then abducting approximately 45 degrees, followed by a standard AP radiograph. This maneuver places the femoral neck in a perfectly horizontal position relative to the x-ray beam, providing a crystal-clear Sugioka view, making it the gold standard for evaluating conditions like SCFE.Option A is incorrectbecause the text states that a standard 'frog-leg' lateral is 'highly variable and inadequate for precise, mathematical surgical planning' for proximal femoral deformities.Option B is incorrectbecause a full-length standing AP radiograph is for global lower limb alignment in the frontal plane, not for a true lateral view of the proximal femur.Option D is incorrectbecause a cross-table lateral is typically used for trauma or when the patient cannot move, and while it provides a lateral view, it does not achieve the precise perpendicularity to the femoral neck axis that the Sugioka view does for deformity analysis.Option E is incorrectbecause while CT scans can provide excellent 3D information, the question asks for the radiographic technique described in Paley's principles for a true lateral view of the femoral neck, which is the Sugioka view. The text focuses on radiographic methods.
Question 352
Topic: Pediatric Hip
A 14-year-old male presents with a chronic, stable Slipped Capital Femoral Epiphysis (SCFE) and a measured Neck Shaft Angle (NSA) of 120 degrees on his initial AP hip radiograph (indicating coxa vara). The orthopedic surgeon plans to obtain a Sugioka view for precise preoperative planning. To achieve a true lateral projection of the femoral neck, what adjustment to the standard Sugioka positioning is required for this patient?
Correct Answer & Explanation
. The hip should be flexed to 90 degrees and abducted approximately 60 degrees.
Explanation
Correct Answer: CThe text provides specific guidance for adjusting the Sugioka view based on the Neck Shaft Angle (NSA). It states: 'The degree of abduction must be dynamically adjusted based on the patient's specific Neck Shaft Angle (NSA) measured on the initial AP view: Normal NSA (135°): Requires 45° of abduction. Coxa Valga (e.g., NSA 150°): Requires less abduction (e.g., 30°). Coxa Vara (e.g., NSA 120°): Requires more abduction (e.g., 60°).' Since the patient has a Coxa Vara with an NSA of 120 degrees, the hip should be flexed to 90 degrees and abducted approximately 60 degrees to achieve the true lateral projection of the femoral neck.Option A is incorrectas 30 degrees of abduction is indicated for coxa valga (e.g., NSA 150°), not coxa vara.Option B is incorrectas 45 degrees of abduction is indicated for a normal NSA of 135 degrees.Options D and E are incorrectbecause the Sugioka view requires the hip to be flexed to exactly 90 degrees, not 45 degrees or 0 degrees extension, to move the femoral neck's orientation into the transverse plane.
Question 353
Topic: Pediatric Hip
A 14-year-old male presents with a suspected slipped capital femoral epiphysis (SCFE). To accurately assess the deformity between the femoral head and neck, a true lateral view of the femoral neck is crucial. The surgeon decides to use the Sugioka method for this specific radiographic projection, as depicted in the image. Which of the following describes the correct patient positioning for obtaining this view?
Correct Answer & Explanation
. The hip is flexed 90° and abducted 45°.
Explanation
Correct Answer: CThe text explicitly describes the Sugioka method: 'The other method with which to obtain a true LAT view of the femoral neck is to flex the hip 90° and abduct the thigh 45°. This positions the femoral neck in the frontal plane. An AP view radiograph obtained with the patient in this position provides the true LAT view of the femoral neck, known as the Sugioka method (1978).' The image also visually represents this position.Option A is incorrectbecause the hip should be flexed, not extended.Option B is incorrectbecause the hip should be abducted, not adducted.Option D is incorrectbecause this describes an alternative method for obtaining a true lateral view of the femoral neck (with the tube inclined), not the Sugioka method, which involves specific patient positioning.Option E is incorrectbecause internally rotating the hip to neutralize version and obtaining an AP view provides a true AP view of the femoral neck and head, not a true lateral view.
Question 354
Topic: Pediatric Hip
Studies have shown that the parents and grandparents of people with developmental dysplasia of the hip (DDH)
Correct Answer & Explanation
. were more likely to receive a hip arthritis diagnosis and undergo total hip arthroplasty (THA) than the general population.
Explanation
DISCUSSIONThe hip arthritis RR is significantly increased in patients with DDH (RR = 82.4; P < 2e-16), their parents (RR = 2.22; P = 0.0003), and their grandparents (RR = 1.33; P = 0.011). The THA RR also is significantly increased for patients with DDH (RR = 1168; P < 3e-08) and their grandparents (RR = 2.06; P = 0.01). First-degree and second-degree relatives were not at higher risk for knee arthritis or knee arthroplasty. The RR for DDH was significantly increased for first-degree relatives (RR = 12.1; P < 0.000001) and siblings (RR = 11.9; P < 0.000001).
Question 355
Topic: Pediatric Hip
The familial occurrence of Legg-Calvé-Perthes disease may, in some cases, be attributed to:
Correct Answer & Explanation
. deficiency of protein S and protein C
Explanation
One of the suggested causes of Perthes disease is a hypercoagulable state in a child. This would lead to thrombotic venous occlusion in the proximal femur resulting in venous hypertension and osteonecrosis of the femoral head. Therefore, look for an answer that would result in a hypercoagulable state. There is no link between hypophosphatemia or high dietary cholesterol intake and a hypercoagulable state. Elevated levels of antithrombin III would result in bleeding, not coagulation. The referenced paper demonstrated a familial occurrence in protein S and protein C deficiency and elevated levels of lipoprotein A. Protein C and S are antithrombotic factors and lipoprotein A is a thrombogenic, atherogenic lipoprotein associated with osteonecrosis in adults.
Question 356
Topic: Pediatric Hip
A 5-year-old boy has had right hip pain and a limp for the past 3 months. Examination of the right hip reveals irritability and restricted abduction and internal rotation. AP and lateral radiographs of the hips are shown in Figures 31a and 31b. Initial management should consist of
Correct Answer & Explanation
. symptomatic treatment, including traction, activity modification, and nonsteroidal anti-inflammatory drugs.
Explanation
DISCUSSION: A favorable prognosis can be expected in up to 70% of children with Legg-Calve-Perthes disease who are younger than age 6 years. Containment treatment has not been shown to alter the outcome in this age group. The goals of treatment in this patient are to reduce pain (synovitis), restore motion, and improve function. Symptomatic treatment modalities include bed rest, traction, crutches, activity modification, and nonsteroidal anti-inflammatory drugs. REFERENCES: Herring JA: The treatment of Legg-Calve-Perthes disease: A critical review of the literature. J Bone Joint Surg Am 1994;76:448-458. Richards BS (ed): Orthopaedic Knowledge Update: Pediatrics. Rosemont, Ill, American Academy of Orthopaedic Surgeons, 1996, pp 161-166.
Question 357
Topic: Pediatric Hip
Figure 54 shows the preoperative radiograph of a 45-year-old woman who is considering total hip arthroplasty with her orthopaedic surgeon. What femoral characteristic is a typical concern in this patient?
Correct Answer & Explanation
. Excessive anteversion
Explanation
Developmental dysplasia of the hip (DDH) leads to early arthritis of the hip as seen in this patient. Although DDH is believed to mostly affect the acetabulum, most patients with DDH also have anatomic aberrations of the femur. Using three-dimensional computer models generated by reconstruction of CT scans, dysplastic femurs were shown to have shorter necks and smaller, straighter canals than the controls. The shape of the canal became more abnormal with increasing subluxation. The studies also have shown that the primary deformity of the dysplastic femur is rotational, with an increase in anteversion of 5 degrees to 16 degrees, depending on the degree of subluxation of the hip. The rotational deformity of the dysplastic femur arises within the diaphysis between the lesser trochanter and the isthmus and is not attributable to a torsional deformity of the metaphysis. Osteopenia is not a concern in a patient with an excellent cortical index (thick cortices and narrow canal). Femoral varus or bowing of the femur is not a typical finding in patients with DDH.
Question 358
Topic: Pediatric Hip
Figure 26 shows the radiograph of an otherwise healthy Caucasian 5-year-old boy who has a painless limp. What is the best treatment option?
Correct Answer & Explanation
. Physical therapy and range-of-motion exercises
Explanation
The prognosis of Legg-Calve-Perthes disease in children younger than age 6 years is good. There is no indication that surgical treatment will improve the outcome. Range-of-motion exercises to prevent contracture may be helpful.
Question 359
Topic: Pediatric Hip
Which of the following pelvic osteotomies used in the treatment of developmental dysplasia of the hip (DDH) involves a complete cut through the innominate bone without entering the true pelvis, relying on the pubic symphysis as a hinge to provide anterolateral acetabular coverage?
Correct Answer & Explanation
. Salter osteotomy
Explanation
The Salter innominate osteotomy is a complete, single transiliac cut extending from the sciatic notch to the AIIS. It uses the pubic symphysis as an intrinsic hinge, allowing the entire acetabulum to be rotated anterolaterally to improve coverage in DDH. In contrast, Pemberton and Dega osteotomies are incomplete pericapsular cuts that hinge on the triradiate cartilage.
Question 360
Topic: Pediatric Hip
A 12-year-old obese male is diagnosed with an unstable slipped capital femoral epiphysis (SCFE). Current evidence suggests that which of the following surgical intra-operative interventions during fixation is most directly targeted at reducing the risk of avascular necrosis (AVN)?
Correct Answer & Explanation
. Routine anterior capsulotomy for hematoma decompression
Explanation
Unstable SCFE has a high rate of avascular necrosis (AVN) due to kinking or tamponade of the retinacular vessels. Performing a routine anterior capsulotomy decompresses the intracapsular hematoma, significantly reducing intracapsular pressure and thereby restoring blood flow and minimizing the risk of AVN. Over-reduction forcefully stretches the vessels and actively increases AVN risk.
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