On this page
Study tools
Write your answer
Saved on this device. No marking — you are the marker.
Q1: A newborn girl is found to have a positive Ortolani test on the left. Define DDH and explain the underlying pathology. (2 min)
DDH — developmental dysplasia of the hip — is a spectrum of hip joint abnormalities in which the femoral head is not concentrically reduced in the acetabulum, ranging from a lax, dislocatable hip to a frankly dislocated hip with a shallow, dysplastic acetabulum. It was renamed from "congenital dislocation of the hip" because it can develop after birth.
The underlying pathology is failure of concentric reduction: the femoral head normally templates the acetabulum, deepening it (Heuter-Volkmann/Wolff laws). When the head is displaced — even intermittently — a self-perpetuating cycle begins: capsular laxity allows the head to sublux/dislocate posteriorly and superiorly in adduction and extension; the capsule stretches into an hour-glass shape, the iliopsoas and adductors tighten, the labrum inverts (limbus) and a neolimbus forms, the transverse acetabular ligament is pulled up across the socket, and the acetabulum grows shallow and dysplastic. Untreated, this ends in early secondary osteoarthritis by the third to fifth decade.
Q2: How would you examine this infant's hips, and what is the difference between the Barlow and Ortolani tests? (3 min)
Examine on a firm, flat surface with the infant calm and relaxed, both hips exposed and examined together. The dynamic instability tests are done with hips and knees flexed to 90 degrees, the middle finger on the greater trochanter and the thumb on the inner thigh.
- Ortolani (reduction test): abduct the hip while lifting the greater trochanter anteriorly with the middle finger. Positive = a clunk as the dislocated head reduces back into the socket — this is a dislocated but reducible hip, the classic newborn finding.
- Barlow (provocation / dislocation test): adduct the hip and push the flexed knee gently posteriorly. Positive = the femoral head slides out over the posterior rim — a dislocatable hip (still sits in the socket at rest but can be pushed out).
Mnemonic: Barlow = "Ballot out"; Ortolani = "Only in". A clunk is pathological; a soft high-pitched click is benign (often the iliopsoas tendon on the iliopectineal eminence).
In the older infant (over 3 months) Ortolani/Barlow become negative as soft tissues tighten, and the signs shift to limited abduction, asymmetric skin folds, Galeazzi sign (knee lower on the affected side), and the Klisic test. In the walker: painless limp, Trendelenburg gait, and leg-length discrepancy.
Q3: Describe the age-based management ladder and the key parameters of Pavlik harness treatment. (3 min)
The goal is concentric, stable reduction so the acetabulum remodels. Treatment is age-based:
- 0 to 6 months — Pavlik harness: flexion ~100 degrees, abduction 30 to 50 degrees (the human position), worn 23 hours per day. Ultrasound confirmation of reduction within 1 to 3 weeks; abandon if unreduced by 3 to 4 weeks. Success 85 to 95%.
- 6 to 18 months — closed reduction under GA, often with percutaneous adductor longus tenotomy to relax the adductors and reduce AVN risk, an arthrogram to confirm concentric reduction, then a hip spica cast in the human position for ~12 weeks.
- Over 18 months — open reduction (capsulorrhaphy, excision of pulvinar, division of transverse acetabular ligament, release of iliopsoas) ± femoral shortening / derotational osteotomy, in spica.
- Residual acetabular dysplasia (over ~3 to 4 years) — pelvic osteotomy: Salter (redirectional, under 8), Pemberton (reshaping), Dega, Chiari (salvage, medial displacement), or Ganz periacetabular osteotomy in the adolescent/adult.
Q4: What are the complications, and how is the most feared one minimised? (2 min)
Complications: (1) avascular necrosis of the femoral head (most feared — via compromise of the medial circumflex femoral artery, leading to coxa magna, coxa breva, premature physeal closure, LLD, early OA), (2) failure of reduction / redislocation, (3) residual acetabular and femoral dysplasia, (4) leg-length discrepancy, (5) joint stiffness, (6) femoral/pudendal nerve palsy (transient, from hyperflexion or cast compression), (7) early secondary osteoarthritis in untreated or under-treated hips.
AVN is minimised by avoiding forced wide abduction (use the moderate human position), confirming reduction early by ultrasound, performing adductor tenotomy before spica in the older infant, and not delaying treatment past the optimal age window. Overall prognosis is age-at-diagnosis dependent — newborn-treated hips do near-perfectly, late-presenting hips do poorly.