Impact of presence of ossific nucleus on results of closed reduction in treatment of developmental dysplasia of the hip (302 hips)

Abstract

Closed reduction is an effective treatment method for developmental dysplasia of the hip (DDH). Still, there are certain controversial issues regarding the timing of the treatment. In this study, we investigated the results of closed reduction and Outcomes of 302 hips of 218 patients treated with closed reduction have been analyzed retrospectively. One hundred fifty-two hips that had ossific nucleus [ossific nucleus (+)] during reduction have been compared with 150 hips that had no ossific nucleus [ossific nucleus (-)] during reduction. Also, the patients have been divided into two groups, the patients treated with closed reduction before the sixth month and the patients treated with closed reduction after the sixth month. Groups have been compared between themselves in terms of avascular necrosis (AVN) and redislocation. Seventy-seven of the 112 hips treated with closed reduction in the first six months were ossific nucleus (-), and AVN has been noted in 5 (6%) patients. However, although no AVN has been seen in any of the 35 ossific nucleus (+) hips, no statistically significant difference has been found between two groups. Seventy-three of the 190 hips treated with closed reduction after the sixth month were ossific nucleus (-), and AVN has been seen in 13 (17%) of these hips. AVN has been seen in 9 (7%) of the 117 ossific nucleus (+) hips. The AVN ratio was found significantly lower in the ossific nucleus (+) hips (P < 0.034). Although the presence of ossific nucleus does not provide extra protection against AVN in before the sixth month, the presence of ossific nucleus is protective against AVN after the sixth month.