The prognostic importance of the ossific nucleus in the treatment of congenital dysplasia of the hip

Ischemic necrosis of the femoral head occurring after the treatment of cong enital dysplasia of the hip can negatively affect the long-term prognosis o f the involved hip. Some investigators have suggested that the presence of the ossific nucleus of the femoral head at the time of closed or open reduc tion is associated with a lower rate of ischemic necrosis, This finding, if verified, could lead to a delay in the treatment of a dislocated hip until ossification of the femoral head has begun, which may be well after the ag e when the patient has started to walk. We conducted a computerized search of the medical records at our two tertia ry-care children's hospitals to identify all patients with congenital dyspl asia of the hip who had had a closed or open reduction between January 1, 1 979, and December 31, 1993, One hundred and twenty-four patients (153 hips) who satisfied the criteria for inclusion were identified, The ossific nucl eus was present in ninety hips and absent in sixty-three. Closed reduction was used in 112 hips and open reduction, in forty-one, Ischemic necrosis wa s identified in five hips (3 percent): four (6 percent) of the sixty-three hips that did not have an ossific nucleus and one (1 percent) of the ninety hips that had an ossific nucleus at the time of the reduction. With the nu mbers available for study, we could not detect a difference between these t wo groups. The age at reduction (p > 0.99), the method of reduction (p = 0. 611), previous treatment with a Pavlik harness (p = 0.592), the use of prel iminary traction (p = 0.602), concomitant procedures (p > 0.99), and a fail ure of the primary closed reduction (p = 0.579) were not associated with th e development of ischemic necrosis after reduction, In our analysis of patients who were managed over a fifteen-year period, th e data did not support the hypothesis that the presence of an ossific nucle us at the time of reduction of a congenitally dislocated hip is associated with a lower prevalence of ischemic necrosis of the femoral head. Sound ope rative principles dictate that operative reduction of a congenitally displa ced hip should be performed when the child can be safely placed under anest hesia and without regard to the presence or absence of the ossific nucleus.