Watchful waiting for the undisplaced hip dysplasia when undergoing contralateral hip reconstruction

Patients undergoing surgical reduction of the dislocated hip secondary to developmental dysplasia may have a contralateral undisplaced dysplastic hip. This study aimed to compare the observation of the contralateral undisplaced dysplastic hip with the treatment by acetabuloplasty in terms of persistent dysplasia to determine the need for bilateral surgery.

Acetabular dysplasia was defined by an acetabular index (AI) of more than 30 degrees plus a center edge angle (CEA) of less than 20 degrees. A surgical database was queried retrospectively for a cohort between 2008 and 2016. Inclusion criteria were aged between 1 and 6 years, unilateral developmental dysplasia (international hip dysplasia institute grade 1) with contralateral dislocation, no previous treatment and a minimum follow-up of 1 year.

Fifty-seven patients were included, 40 in the observation group and 17 in the acetabuloplasty group. The mean age (interquartile range) was 20 (17-23) months, and the mean follow-up was 42 (22-62) months. The baseline values were similar for both groups. At the final follow-up, no hip had dysplasia, as specified a priori in either group, but the final AI and CEA were corrected more in the acetabuloplasty group (p < 0.001). Based on the adjusted analysis, both acetabuloplasty and follow-up without treatment were associated with improved acetabular coverage.

Watchful expectancy of undisplaced hip dysplasia presenting in patients undergoing contralateral hip reconstruction during years of acetabular growth is safe as the risk of persistent dysplasia and additional surgery is low.

III.