Prepare for USMLE Step 2 with our QOTD on limited hip abduction, Developmental Dysplasia of the Hip, & Barlow maneuver. Strengthen your exam knowledge!
A 5-month-old girl is brought to the pediatric clinic by her mother for a routine well-child exam. They recently moved to the area and have missed several routine appointments. The patient has been eating, drinking, and sleeping well. Height and weight are in the 90th and 85th percentiles, respectively. Temperature is 37.0°C (98.6°F), blood pressure is 95/58 mmHg, and pulse is 126/min. On physical examination with the patient supine, there is limited hip abduction on the right and there is asymmetry of the gluteal skin folds. With the patient lying supine with flexed hips at 90 degrees and feet flat by the buttocks, the right knee is lower than the left. Which of the following additional findings is most likely to be seen in this patient?
A. Positive Ortolani and Barlow maneuvers
B. Negative Galeazzi test
C. Osteonecrosis
D. Osteomyelitis
E. Hemihyperplasia
Scroll down for the correct answer!
The correct answer to today’s USMLE® Step 2 CK Question is…
A. Positive Ortolani and Barlow maneuvers
Before we get to the Main Explanation, let’s see why the answer wasn’t B, C, D, or E. Skip to the bottom if you want to see the correct answer right away!
Incorrect answer explanations
Today’s incorrect answers are…
B. Negative Galeazzi test
Incorrect: This patient has a positive Galeazzi test. When the patient is lying supine with flexed hips at 90 degrees and feet flat by the buttocks, the right knee is lower than the left.
C. Osteonecrosis
Incorrect: Osteonecrosis occurs from death of bone tissue secondary to compromised blood supply and is most commonly caused by trauma or chronic steroid use. It is not a likely finding in infants with developmental dysplasia of the hip, which this patient most likely has.
D. Osteomyelitis
Incorrect: Osteomyelitis is an infection of the bone and is typically caused by bacteria. Symptoms usually include pain, swelling, warmth and redness at the site of infection. Fever and chills can also be present. This patient more likely has developmental dysplasia of the right hip and will have positive Ortolani and Barlow maneuvers on exam.
E. Hemihyperplasia
Incorrect: Hemihyperplasia refers to asymmetric overgrowth of one or more regions of the body due to irregular cell proliferation (i.e. hyperplasia) and is associated with Beckwith-Wiedemann syndrome (BWS). Other features of BWS include macrosomia, macroglossia, omphalocele, and visceromegaly. None of these features are present in this patient.
Main Explanation
This 5-month-old infant presents with limited hip abduction and thigh-length discrepancy with a positive Galeazzi test on the right, which is strongly suggestive of developmental dysplasia of the hip (DDH). DDH results from misalignment of the femoral head and acetabulum. The Ortolani and Barlow maneuvers should be used to screen all infants less than 6 months of age for DDH, since early identification and intervention can prevent severe complications, such as hip joint osteoarthritis. If either of these tests is positive, bilateral hip ultrasound should be performed to confirm the diagnosis of DDH.
Normally, the femoral head sits within the acetabulum of the hip creating a “ball and socket” joint. However, in cases of DDH, the acetabulum is too shallow, preventing the femoral head from sitting in it. This results in the independent growth of both bony structures, which causes misalignment of the femoral head and acetabulum. Ultimately, this leads to an unstable hip joint.
The Ortolani maneuver is performed with the patient in the supine position. The examiner slowly abducts the hip and then gently presses upwards on the lateral thigh. If the femoral head is dislocated, the Ortolani maneuver will push the femoral head up and into the acetabulum, making a “clunk.” The Barlow maneuver is performed with the patient in the supine position. The examiner slowly adducts the hip and then gently presses down on the knee. If there’s hip joint instability, the femoral head will be pushed down and out of the acetabulum, making a “click.” If either test is positive or if patients are at high risk for DDH, bilateral hip ultrasound should be performed to confirm the diagnosis.
For pediatric patients who are > 6 months of age, the Ortolani and Barlow maneuvers are less sensitive. Examiners should test for decreased abduction, limitations in range of motion, asymmetry, and thigh-length discrepancy on exam. If any of these are present, bilateral hip X-rays should be performed to confirm the diagnosis of DDH. Older children may present with leg-length discrepancy and uneven gait.
Major takeaway
In infants less than 6 months of age, the Ortolani or Barlow maneuvers are used to screen patients for developmental dysplasia of the hip.
References
- (2015). Guidelines for detecting and managing developmental hip dysplasia. JAAOS. https://www.aaos.org/globalassets/quality-and-practice-resources/pddh/ddh-auc_generalist-2022-reissue.pdf
- Mulpuri K, Song KM, Goldberg MJ, Sevarino K. Detection and Nonoperative Management of Pediatric Developmental Dysplasia of the Hip in Infants up to Six Months of Age. J Am Acad Orthop Surg. 2015;23(3):202-205. doi:10.5435/JAAOS-D-15-00006
- Auriemma J, Potisek NM. Developmental Dysplasia of the Hip. Pediatr Rev. 2018;39(11):570-572. doi:10.1542/pir.2017-0239
- Nemeth BA, Narotam V. Developmental dysplasia of the hip. Pediatr Rev. 2012;33(12):553-561. doi:10.1542/pir.33-12-553
- Shaw BA, Segal LS; SECTION ON ORTHOPAEDICS. Evaluation and Referral for Developmental Dysplasia of the Hip in Infants. Pediatrics. 2016;138(6):e20163107. doi:10.1542/peds.2016-3107
Slavotinek, AM. Dysmorphologies. In: Kliegman, RM, St Geme, JW, Blum, eds. Nelson Textbook of Pediatrics. 21st ed. Elsevier; 2020. ––––––––––––
Want more USMLE® Step 2 CK practice questions? Try Osmosis by Elsevier today! Access your free trial and find out why millions of current and future clinicians and caregivers love learning with us.
Leave a Reply