[Efficiency of conservative treatment by overhead traction in developmental dysplasia of the hip]

Developmental dysplasia of the hip (DDH) is a disorder affecting the development of the acetabulum, proximal femur and joint capsule. The objective of this study was to analyse the results of closed reduction by overhead traction in subluxated and dislocated hips.

In the period from 2002 to 2007, a total of 109 patients (124 hips) were treated by overhead traction. The indication criteria included adductor contracture and misalignment of the hip joint assessed as classes III A, III B or IV according to the Graf ultrasonographic classification. There were 96 (88 %) girls and 13 (12 %) boys. The left side was more frequently affected, at a ratio of 83 to 41, and bilateral DDH was found in 15 patients. Teratologic dislocations were not included in the study. The patients were divided into two groups according to age and the place of primary diagnosis. The children primarily diagnosed at our hospital Na Bulovce where placed in group 1, the patients diagnosed outside our hospital fell in group 2. The average age at the beginning of treatment was 2.2 months in the first group and 6 months in the second group. Our method of overhead traction consists of two phases. Horizontal traction is applied for two weeks in phase 1; the hips are then flexed beyond 90 degrees and gradually abducted for another 4 weeks in phase 2.The outcome of traction is examined by arthrography and a spica cast is applied in the safe zone.We observed the relation between the Graf classification and arthrograpy. The outcome of closed reduction was compared between the groups and the development of avascular necrosis was observed. The hips treated by open reduction were assessed in a different study. RESULTS The efficiency of closed reduction was 84 % in group 1 and 60 % in group 2 in which also two cases of recurrent dislocation were found. No significant differences between the Graf classification and the final arthrographic findings were recorded in either group (p ≥ 0.05). Avascular necrosis as defined by the Salter criteria was not diagnosed.

Early reduction is essential to ensure normal development of the hip joint. Overhead traction therapy for misalignment of the hip joint is a safe method reducing damage to the femoral head. Its principle lies in gradual distraction of the contracted muscles and joint capsule with a concomitant change in traction direction in order to achieve a reduction manoeuvre without placing increased stress on the femoral head.

Overhead traction is the method of choice for management of Graf's class III A, III B and IV hips. For the efficiency of treatment, an early diagnosis and a correct indication are essential. To avoid complications such as avascular necrosis, it is necessary to observe the principle of a safe zone.