Analysis of outcomes of one-stage operation for treatment of late-diagnosed developmental dysplasia of hip

Abstract

Objective: To evaluate and identify the middle-term results of one-stage open reduction of patients in late-diagnosed developmental dysplasia of the hip, and to explore the best age group for treatment. Methods: A total number of 311 patients (390 hips) with LDDH in Department of Pediatric Orthopaedic of Anhui Provincial Children's Hospital from June 2006 to December 2010 were retrospectively reviewed. The patients were divided into 3 groups according to age at the start of surgical treatment: 1.5-2.5 years, 2.5-7.0 years and >7.0 years. There were 11 males and 71 females in group of 1.5-2.5 years with average age of (2.1±0.3) years; There were 29 males and 165 females in group of 2.5-7.0 years with average age of (4.4±0.4) years; There were 8 males and 33 females in group >7.0 years with average age of (9.2±1.4) years. The last clinical and radiographic outcomes, complications and avascular necrosis (AVN) of the femoral head were evaluated and compared among the three groups. ANOVA and Pearson's χ(2) statistic were used to analyze data. Results: Among the three groups, there were no statistically differences in gender, acetabular index, different sides and follow-up time(all P>0.05), there was significant difference in Tönnis grade(χ(2)=21.410, P<0.01). There were 77.4% of patients showed an excellent or good result according to McKay's clinical classification and 82.6%(390 hips) according to Severin's radiological classification. A total of 28.5% of all hips had a poor outcome according to the Kalamchi and MacEwen classification (grade Ⅱ to Ⅳ) for AVN. Radiographic(χ(2)=78.860, P<0.01) and AVN(χ(2)=14.756, P=0.001) results (poorest in group of >7.0 years and best in group of 2.5-7.0 years) between three groups had statistically differences. Furthermore, clinical outcomes in group of >7.0 years was significantly lowest than groups of 1.5-2.5 years or 2.5-7.0 years, there was no significant differences between groups of 1.5-2.5 years and 2.5-7.0 years(χ(2)=1.503, P=0.682). The incidence of redislocation and residual acetabular dysplasia in Tönnis grade Ⅱ or Ⅲ hip dislocation(85.0%, 17 hips) was significantly higher (χ(2)=4.440, P=0.035). Conclusion: One-stage treatment of LDDH had good outcome in 1.5 to 7.0 years patients, the best age are 2.5-7.0 years.