Developmental Dysplasia of the Hip (DDH)/Congenital Dislocation of the Hip (CDH)
Developmental dysplasia is preferred term – spectrum of problems that varies from a displacement of femoral head from acetabulum to a radiographic abnormality of acetabulum formation. Dislocation occurs in 1.5 per 1000 births. 1 in 60 at risk. F>M. L>R. 20% bilateral. Usually picked up at birth due to screening. A few may be detected later as a gait problem.
Aetiology unknown (higher risk for breech presentation; flattened acetabulum; females; ligamentous laxity; family history (in up to 30%); higher levels of relaxin during labour; first born; Down syndrome).
• The dislocated hip
• The dislocatable hip
• The subluxatable hip
• The dysplastic hip
Clinical tests (high number of false positive and false negatives):
Barlow’s test: - Test for ligamentous laxity; place infant on back with hips and knees fully flexed; apply thumb pressure in an anterior-posterior direction over the lessor trochanter to dislocate femoral head posteriorly; release thumbs allows head to slip back into socket; if dislocation/relocation occurs unstable hips.
Ortolani Manoeuvre: - Knees flexed, hips flexed to 90 degrees and abducted; during abduction of the hips, a previously dislocated femoral head “clunks” in over the posterior rim of the acetabulum.
Limitation of abduction: - Limitation of 50 degrees or less is a reliable sign
Less significant clinical tests: - Asymmetry of skin fold in thigh and buttocks; telescoping – pushing the leg beyond the usual hip joint articulation; Galeazzi’s sign – apparent shortening of the affected limb when the dislocation is unilateral; Trendelenburg test – when reach weightbearing age; femoral head palpation; bulging of flesh near the femoral head; delayed locomotion.
Radiographic: - definitive. Can also be detected by ultrasound. X-rays will also detect the maldevelopmental problems of the acetabulum (acetabular dysplasia).
Less than one year of age – splinting hip in flexed and abducted position (Pavlik harness)
After one year – traction to force femoral head back into acetabulum
Up to five years – rotational osteotomy of femur usually needed
After seven years – arthroplasty of hip and later a hip prothesis may be needed.
Congenital dislocation of the hip in Adults:
If undiagnosed early may present later with osteoarthritis in a ‘false’ hip joint between subluxed/dislocated femoral head and ilium. Changes may have occurred in spine due to scoliosis.