[The effects of arthrographically detected femoral head lateralization and soft tissue interposition during closed reduction of developmental dislocation of the hip on mid-term results].

OBJECTIVES

In a prospective, non-randomized evaluation of patients who underwent surgery under general anesthesia for developmental dislocation of the hip (DDH) at or below 18 months of age, we assessed the mid-term effects of arthrographically documented femoral head lateralization and soft tissue interposition under the acetabular labrum during reduction without opening the hip joint capsule.

METHODS

The study included 31 unstable hips of 21 children (mean age 12 months; range 4 to 18 months). After the iliopsoas and adductor longus tendons were sectioned by a medial approach, hip joint arthrography was performed. According to the criteria of Tönnis, all the patients had grade 2 arthrographic reduction and the hip joint capsule was left intact. The mean follow-up was 6.5 years (range 3 to 9.5 years).

RESULTS

Avascular necrosis of the femoral head (AVN), redislocation, and secondary operation were seen in 42%, 19%, and 29%, respectively. The physeal plate was involved in nearly half of the hips with AVN. The occurrence of AVN was less in hips treated at the age of below one year. Complications were more frequent in cases in which more than one intraarticular soft tissue obstacles had been documented by arthrography. Avascular necrosis and redislocation were more commonly encountered in hips in which the medial pool size of contrast material exceeded 7 mm than those with sizes between 3 to 7 mm.

CONCLUSION

Our mid-term complication rates suggest that the hip joint capsule be opened in order to achieve an anatomical reduction through eliminating intraarticular obstacles when arthrography shows lateralization of the femoral head, soft tissue interposition, and medial pooling of the contrast material following closed reduction of DDH.