Objective To study the effectiveness and acetabular prosthesis selection of the total hip arthroplasty (THA) for Crowe type IV congenital dysplasia of the hip with dislocation in adults. Methods Between June 2008 and May 2012, 8 adult patients (8 hips) with Crowe type IV congenital dysplasia of the hip with dislocation underwent THA. They were all female, aged 20-35 years with a mean age of 25 years. The left hip was involved in 5 cases and the right hip in 3 cases. The Harris score of involved hip was 53.9 ± 6.6. The shortened length of involved extremity was 4-6 cm (mean, 4.8 cm). The X-ray films showed complete dislocation in all cases. The acetabular prosthesis with diameter of 42-44 mm and S-ROM femoral prosthesis were used in THA. Results The incisions healed by first intention. There was no hip dislocation events and sciatic nerve injury during the follow-up. Femoral nerve injury occurred in 1 case and asymptomatic venous thrombosis of the leg muscle occurred in 2 cases. All the patients were followed up 1-5 years (mean, 3 years). All cases showed obvious improvement of claudication and could restore to work. At 6 months after operation, the mean length difference between affected and contralateral extremities was 0.4 cm (range, — 1.0-0.6 cm); the Harris score was significantly increased to 87.6 ± 0.3 (t=1.77, P=0.00). The X-ray films showed that all cases got bony union at 3-6 months after operation and stable interface between acetabular prosthesis and bone. No revision was involved during the follow-up. Conclusion THA with small acetabular cup and subtrochanteric osteotomy is an effective method in the treatment of Crowe type IV congenital dysplasia of the hip with dislocation in adults. The early effectiveness is satisfactory. The long-term survival rate of prosthesis needs to be followed up.