DDH

Question 1

What is DDH?

Answer 1

Developmental dysplasia of the hip is abnormal development of the hip joint. The femoral head is not stable within the acetabulum. DDH can be due to ligamentous laxity, muscular underdevelopment and the abnormal formation of the acetabulum.

Question 2

What causes DDH?

Answer 2

Apparently, when pregnant women secrete hormones to relax their pelvic ligaments, those hormones which help the delivery of the baby can enter the baby’s blood and relax the baby’s ligaments as well. This can therefore cause the ligaments of the baby’s hip to be relaxed.

Question 3

What are the 5 Fs that predispose a child to DDH?

Answer 3

FHx
Female
Frank breech
First born
leFt hip

Question 4

What is the spectrum of conditions that can lead to hip subluxation and dislocation from most “severe” to least?

Answer 4

1. Femoral head is completely dislocated outside the acetabulum
2. Dislocatable femoral head inside the socket
3. Femoral head dislocated outside the socket when provoked
4. Dysplastic acetabulum as it is more shallow and vertical than normal

Question 5

What are the clinical features observed on physical examination in a child with DDH?

Answer 5

Limited abduction of the flexed hip (less than 50-60 degrees)
Shortening of the affected leg which results in asymmetry in skin folds and gluteal muscles with a wide perineum.
Painless (if it is painful dislocation then suspect septic dislocation)

Question 6

How do you make the diagnosis of DDH?

Answer 6

DDH is a largely clinical diagnosis which can be made with physical examination as well as confirmation with U/S in newborns or X-rays in children >18months.

Question 7

What are the two tests on examination that are done to diagnose DDH?

Answer 7

Barlow’s Test (for dislocatable test) – flex hips and knees to 90 degrees and grasp thigh. Adduct the hips fully and then push posteriorly to try and dislocate the hips

Ortalani’s Test (for dislocated hip) – Initial position is same as end of Barlow’s test. Try to reduce the hip as you fully abduct the hips. If the test if positive, you will feel a clunk as the hip is reduced.

Question 8

What investigations are necessary in a patient with DDH?

Answer 8

U/S in the first few months to view cartilage as the bone hasn’t calcified so X-ray at this point is useless. After 3 months though, follow up X-ray.

Question 9

How do you treat a child with DDH between 0-6 months, 6-18 months and after 18 months?

Answer 9

0-6 months: reduce hip using Pavlik harness as a splint to maintain abduction and flexion of the hip
6-18 months: Reduction under GA, hip spica cast for 2-3 months but only if Pavlik harness fails. Spica cast is a plaster cast from the waist down to the knees.
>18months: Open reduction of the hip with strengthening of the surrounding ligaments; pelvic or femoral osteotomy

Question 10

What are the complications of having DDH?

Answer 10

If untreated can develop into a painless limp. Overtime can lead to painful arthritis in the affected hip.
Redislocation, inadequate reduction, stiffness
AVN of the femoral head