Radiological Outcomes of Overhead Traction Therapy for Developmental Dysplasia of the Hip in Non-ambulatory Children.

Background: Infants with a dislocated and unstable hip that does not lend itself to stabilisation may be treated using overhead traction to achieve gradual reduction of the hip joint. The aim of this paper was to analyse the radiological outcomes of overhead traction therapy and the effect of duration of traction on the occurrence of complications and final treatment outcomes. Material and methodd. A retrospective analysis of medical records of 26 children (34 affected hips) involved three independent observers assessing radiological parameters before the surgery and at follow-up visits at least two years after the therapy.

Results: Overhead traction was used for an average of 35 days (range: 15-43 days). Twenty six hips were treated solely with reduction and immobilisation in a 'human position' plaster cast. Three hips were qualified for surgery immediately after a preliminary traction period. Five hips showed a suboptimal result following the immobilisation period. A MANOVA model revealed that the following factors had a significant effect on the treatment outcome: superior centring ratio of Smith (with the lowest values recorded in patients with residual hip dysplasia, p = 0.001) and acetabular angle of Sharp (with the lowest values found in patients requiring surgery, p = 0.01). Statistical tests did not show a correlation between the duration of traction and disturbance of proximal femoral metaphysis growth assessed according to Bucholz and Ogden classification. Fifteen hips were classified as type I, eight hips were graded as type II and also eight hips as type III.

Conclusions: The lowest values of acetabular angle of Sharp were recorded in patients requiring surgery and the lowest superior centring ratio of Smith was found in those with residual hip dysplasia. The duration of overhead traction did not directly correlate with the final outcome; it only seemed to be an indicator of the severity of hip dysplasia. Routine use of overhead traction before undertaking closed reduction does not probably decrease the incidence of proximal femoral growth disturbance.