paediatric
Late-Presenting Developmental Dysplasia of the Hip
advanced
6 min
28 marks
6 questions
Clinical Scenario
An 18-month-old girl presents with a waddling gait noticed since she started walking at 14 months. Her mother is concerned that she "walks funny." She was born at term with no complications. Newborn hip screening was normal. On examination, she has a Trendelenburg gait on the left. The left limb appears shorter. Hip abduction is limited to 40 degrees on the left versus 70 degrees on the right. Galeazzi sign is positive.
AP pelvis radiograph of an 18-month-old showing left hip developmental dysplasia. The acetabular index measures 38 degrees (normal <30 degrees at this age). Shenton's line is disrupted. The femoral head is subluxed with inadequate coverage. The center-edge angle is negative. The sourcil is oblique. There is delayed ossification of the left femoral head ossific nucleus compared to the right. This represents late-presenting DDH requiring surgical intervention.
Source: Measurement of Lateral Acetabular Coverage: CT vs Plain Radiography • PMC4732381 • CC-BY
Questions
Question 1 (4 marks)
Describe the radiographic findings and relevant measurements.
Question 2 (5 marks)
What is the age-based treatment algorithm for late-presenting DDH?
Question 3 (6 marks)
Describe the technique and obstacles encountered in open reduction.
Question 4 (5 marks)
What pelvic osteotomies are available and how do you select between them?
Question 5 (4 marks)
What is the role of femoral osteotomy?
Question 6 (4 marks)
What are the outcomes and complications of late DDH surgery?
Exam Day Cheat Sheet
Must Mention
- •Age-based treatment algorithm
- •Obstacles: iliopsoas, TAL, pulvinar, labrum, lig teres
- •Salter for <6yr, Triple for >6yr
- •Femoral shortening reduces AVN
- •Arthrogram for safe zone
- •Severin classification for outcomes
Common Pitfalls
- •Pavlik for >6 months
- •Missing obstacles
- •Wrong osteotomy for age
- •No femoral shortening
- •Forced abduction
- •Missing AVN risk factors