Background: During cup implantation,vertical height of the cup center(V-HCC)should be precisely controlled to achieve sufficient bone-cup coverage(BCC).Our study aimed to investigate the acetabular bone stock and the quantitative relationship between V-HCC and BCC in Crowe types Ⅰ to Ⅲ hips.Methods: From November 2013 to March 2016,pelvic models of 51 patients(61 hips)with hip dysplasia were retrospectively reconstructed using a computer software.Acetabular height and doom thickness were measured on the mid-acetabular coronal cross section.V-HCC was defined as the vertical distance of cup rotational center to the interteardrop line(ITL).In the cup implantation simulation,the cup was placed at the initial preset position,with a V-HCC of 15 mm,and moved proximally by 3-mm increments.At each level,the BCC was automatically calculated by computer.Analysis of variance and Kruskal-Wallis test were used to compare the differences between groups.Results: There were no significant between-group differences in maximum thickness of the acetabular doom; however,peak bone stock values were obtained at heights of 41.63±5.14 mm(Crowe type Ⅰ),47.58 ± 4.10 mm(Crowe type Ⅱ),and 55.78 ± 3.64 mm(Crowe type Ⅲ)above the ITL.At 15 mm of V-HCC,median BCC was 78％(75-83％)(Crowe type Ⅰ),74％(66-71％)(Crowe typeⅡ),and 61％(57-68％)(Crowe type Ⅲ).To achieve 80％of the BCC,the median V-HCC was 16.27(15.00-16.93)mm,18.19(15.01-21.53)mm,and 24.13(21.02-28.70)mm for Crowe types Ⅰ,Ⅱ,and Ⅲ hips,respectively.Conclusion: During acetabular reconstruction,slightly superior placement with V-HCC ＜25 mm retained sufficient bone coverage in Crowe Ⅰ to Ⅲ hips.