DEVELOPMENTAL DYSPLASIA OF THE HIP – IS OPEN REDUCTION WITHOUT FEMORAL SHORTENING OBSOLETE?

Abstract

Purpose: To compare the incidence of avascular necrosis, and radiological outcomes between groups treated by closed reduction, open reduction, and open reduction + femoral shortening, under the care of a single surgeon, with open reductions performed through an anterior approach, uninfluenced by the appearance of the ossific nucleus.

Methods: Between Sept 1991 and Dec 2003 we retrospectively studied 66 patients (3 bilateral; 10 males, 53 females) who had undergone reduction under anaesthesia. Of these 34 hips were reduced closed with adductor release (average 0.7 yrs, range 0.2–1.7), 11 reduced open (average age 1.0; 0.4–3.3) and 24 reduced open with femoral shortening (average age 2.4; 0.9–7.8).

Follow up radiographs were graded for the presence of AVN by the Bucholz and Ogden method. Radiological outcome was graded by the Severin score. Average follow up was up to the age of 6.6 years (SD 2.9) for the closed reduction group, open reduction group 8.0 (SD 3.6) and femoral shortening group 9.0 (SD 3.9)

Results:

AVN scores

• Closed Reduction (n=34) : Grade 1 : 5.

• Open Reduction (n= 11) : Grade 1: 2, Grade 2: 1, Grade 3: 1.

• Open, with shortening (n=24): Grade 1: 5, Grade 2: 1. Severin Scores:

• Closed I: 22 II:3 III:8 IV:0

• Open I:6 II:1 III:2 IV:2

• Shortening I: 8 II:8 III:3 IV:2

Conclusions: The group with the highest incidence of AVN & worse Severin grades was the group (average age-1.0) who had open reduction without femoral shortening. The open reduction & shortening group had a higher proportion of good radiological results despite treatment being given at a older age. Concentric closed reduction, where possible, gave the best results.

Significance: Any child presenting with DDH at walking age (over 1) who requires open reduction should also have a femoral shortening. This gives the best chance of avoiding high grade AVN and achieving a good radiological result. Results might improve if open reductions without shortening were discontinued.