Radiologic Changes After 10 Years Postreduction in Developmental Dysplasia of the Hip Treated With Different Reduction Methods and Risk Factors for Osteoarthritis

Abstract

Background: This study examined how radiologic indices at 10 years postreduction change over time and influence the final outcome through a comparative study of 3 reduction methods for developmental dysplasia of the hip, including the Pavlik harness, closed reduction, and open reduction (OR). Methods: Patients treated from 1990 to 2000 for dysplasia of the hip and followed up for >20 years were included in this study. Radiologic indices at 10 years postreduction and final follow-up (average 24 years postreduction) were measured in the 3 groups. The relative joint space of <66% compared with the healthy side was defined as positive osteoarthritis (OA) at the final follow-up. The relationship between OA and factors such as age, sex, method of reduction, radiologic indices, and Severin and Kalamchi classifications at 10 years postreduction were examined. Clinical evaluation was performed using the modified Harris Hip Score; a score of ≥80 was defined as good performance at the final follow-up. Results: Sixty-five patients (totaling 74 hips) were included. There were no significant differences in radiologic indices between the 10-year postreduction time and final follow-up. Excluding 9 bilateral patients, based on the relative joint space, 21% of the patients (13/56 hips), were positive for OA. Univariate analysis showed that the incidence of positive OA was significantly associated with OR and Kalamchi grade 4 at 10 years postreduction. The modified Harris Hip Score was 80 or higher in 90% of the cases at the final follow-up. Conclusions: No significant changes in hip morphology were observed at 10 years postreduction. The Kalamchi classification at 10 years postreduction and OR were significantly associated with the incidence of OA at the final follow-up. Therefore, patients who undergo OR and/or display Kalamchi grade 4 have a high risk of developing OA and would require individual instructions for their daily lives to prevent further progression of OA and longer follow-up. Level of Evidence: Level Ⅲ—case-control study.