The effects of periacetabular osteotomy in the treatment of borderline developmental dysplasia of the hip / 中华骨科杂志

ABSTRACT

Objective:To investigate the effects of periacetabular osteotomy (PAO) in treating borderline developmental dysplasia of the hip (DDH).Methods:The patients with borderline DDH [lateral center-edge angle (LCEA) 18°-25°) who received PAO with follow-up duration for more than 2 years from January 2011 to January 2018 in our hospital were retrospectively analyzed. The patients in the control group were matched on a 1∶2 ratio based on gender, age, body mass index (BMI) and follow-up duration. There were 66 patients in the 0°≤LCEA<10° group and 66 patients in the 10°≤LCEA<18° group. The LCEA, anterior center-edge angle (ACEA), T?nnis angle, femoral head extrusion index, femoro-epiphyseal acetabular roof (FEAR) index, femoral anteversion angle, West Ontario and McMaster University (WOMAC) index and International Hip Outcome Tool (iHOT-12) were compared among the three groups before operation and the last follow-up.Results:In the preoperative 18°≤LCEA<25° group, three of 33 patients (9.1%) had LCEA, because the only imaging feature suggested acetabular dysplasia, while other parameters were evaluated within the normal range. There were 17 patients with ACEA <20° (51.5%), 24 patients (72.7%) with T?nnis angle >10°, 12 patients (36.4%) with ACEA <20° and T?nnis angle >10°. The positive rate of posterior wall signs in the 18°≤LCEA<25° group (72.7%) was lower than that in the 10°≤LCEA<18° group (77.3%) and the 0°≤LCEA<10° group (90.9%) with statistically significant difference (χ 2=6.417, P=0.040) at preoperation. The positive rate of cross sign (27.3%) and ischial spine sign (48.5%) in the 18°≤LCEA<25° group were higher than those in the 10°≤LCEA<18° group (10.6% and 18.2%, respectively, χ 2=7.002, P=0.030) and the 0°≤LCEA<10° groups (9.1% and 13.6%, respectively, χ 2=16.497, P<0.001). The FEAR index in the 18°≤LCEA<25° group (3.7±8.0) lower than that in the 10°≤LCEA<18° group (4.3±7.9) and the 0°≤LCEA<10° group (11.0±8.8) with significant difference ( F=12.703, P<0.001). In the 18°≤LCEA<25° group, postoperative LCEA increased from 20.4°±1.8° to 37.8°±7.1°, ACEA increased from 18.3°±7.8° to 36.3°±6.3°. T?nnis angle decreased from 12.7°±6.2° to -5.6°±9.2°, the femoral head extrusion index decreased from 22.9%±6.7% to 10.7%±12.2%, the WOMAC index decreased from 20.1±13.4 to 6.0±6.3, and the iHOT-12 score increased from 50.2±19.9 to 90.0±13.7. The above difference before and after surgery was statistically significant ( P<0.05). At the last follow-up, the WOMAC score in the 18°≤LCEA<25° group was 6.0±6.3, wich was less than 10°≤LCEA<18° group (9.3±9.6) and 0°≤LCEA<10° group (12.0±16.0) ( F=6.515, P=0.002). The iHOT-12 score in the 18°≤LCEA<25° group was 90.0±13.7, which was greater than 10°≤LCEA<18° group (77.7±17.3) and 0°≤LCEA<10° group (78.1±20.5) ( F=15.833, P<0.001). Conclusion:After 2 years follow-up, PAO significantly improved bone coverage of femoral head and hip function in patients with borderline DDH. Before surgery, we should pay attention to the comprehensive evaluation of different radiological parameters of the acetabulum, to make better preoperative planning.