OBJECTIVE: To investigate the efficacy of total hip arthroplasty in young and middle-aged (under 50 years old). DATA AND METHODS: Seventy-four cases (77 hips) of artificial total hip replacement patients admitted to our department from December 2000 to February 2010 were retrospectively summarized. There were 49 male cases and 25 female cases, aged 21-49 years old at the time of surgery, with an average of 39 years old. The original disease was femoral head necrosis combined with osteoarthritis in 49 cases, femoral head necrosis in 10 cases, ankylosing spondylitis in 8 cases, femoral head and femoral neck fracture after internal fixation in 7 cases. Preoperative preparation: orthopantomograms of both hips and front and side views of the affected hip including the upper 1/3 of the femur were taken. For patients with femoral head necrosis, CT examination was performed to clarify acetabular changes in order to guide the surgery and help choose the prosthesis type. Patients with systemic diseases such as hypertension and diabetes mellitus should be controlled and stabilized before surgery. During the surgery, the posterior lateral approach was used, the bone cumbers around the acetabulum was removed during the surgery, the acetabulum was grinded to the appropriate type at an angle of 15° of forward tilt and 45° of abduction, and the femoral side was fixed with non-cemented bioprosthesis, the quadriceps function and straight leg raising exercise were carried out on the second day after the operation, and the patients began to walk without weight bearing on the ground with the help of crutches in the first five to seven days after the operation. All patients had preoperative and postoperative Harris scores, and the follow-up intervals were the same, which were reviewed at 1.5, 3, 6, 12, 18, and 30 months after surgery. All 74 cases were evaluated clinically and radiologically. Hip function was scored by the Harris method, and the Harris score ranged from 85 to 96, with a mean of 92. 19 cases were excellent, 4 cases were good, and 1 case was fair, with an excellent rate of 95.83%. There was no infection, no vascular or nerve injury, no loosening or sinking of the prosthesis, and 1 case of hip dislocation. Radiologic follow-up results: acetabular abduction angle 45-54°, average 51°, anterior tilt 15-25°, average 20°, no obvious bone resorption and loosening signs. CONCLUSION: The application of all-ceramic artificial joints in total hip arthroplasty in young and middle-aged people has good stability in the near future, and is a more ideal joint material. OBJECTIVE Hip prosthesis failure is a bottleneck that artificial joints need to overcome urgently. Only by solving the problem of aseptic loosening of the artificial joint can young patients with, for example, ankylosing spondylitis with bilateral hip ankylosis, be benefited and their quality of life improved. The postoperative follow-up of this group of cases showed good early results, stable prosthesis, very low wear rate and good biocompatibility, which attracted a large number of researchers to study its bioabrasion The use of ceramic acetabulas allows patients to get out of bed soon after surgery, which is crucial for young patients, especially those with systemic disorders; ceramic acetabulas theoretically reduce the risk of aseptic loosening in young patients with ankylosing spondylitis and bilateral ankylosis. Compared to conventional acetabular fixation, ceramic acetabulars theoretically reduce the rate of long-term loosening and improve the safety of surgical treatment. The ceramic acetabulum has good near-term stability in middle-aged total hip arthroplasty. Patients can get out of bed and walk with a walker 1 week after surgery, and good stability can be achieved in osteoporotic cases.