A retrospective analysis THA results in patients with acetabular bottom protrusion was carried out. Clinical examination, anthropometric analisys and calculation results on a Harris scale were used. The 87 patients with acetabular protrusion hip arthritis were examined, including 56 (64%) women and 31 (36%) men. The number of patients with posttraumatic protrusion hip arthritis was 13 (15%): 9 women and 4 men. A mild degree of protrusion according to Soleo-Garza and Charnley classification was diagnosed in 6 (46.2%) patients, moderate degree - in 3 (23%) and severe degree - in 4 (44.4%) patients. In cases of mild protrusion average time between the trauma and operation was 5 years, in the moderate degree - 7 years and in the severe degree - 13 years. THA for different degrees of protrusion needs for special surgical technics. The need for plastic, as well as the size of the grafts, was determined during THA. In the group of patients with mild and moderate degrees of acetabular protrusion before the THA the average scores on the Harris scale were 35 and 27 points, respectively. After the operation, the indices doubled. One year after the operation, the average points on the Harris scale were 90 and 92. So the patients reached an excellent result. In the group of patients with severe grade before the THA the average score on the Harris scale was 20 points. After the operation, the average score on the Harris scale increased to 48, and one year later was 87 points, which corresponds to a good result. An unilateral protrusion of the acetabulum is a sign of posttraumatic protrusion hip arthritis. Between the beginning of the disease and the THA a period of 5 to 20 years passes. During this time the patient can forget about the fact of injury. Therefore, unilateral protrusion hip arthritis requires a precise analysis of the anamnesis. The screwed cup of the implant makes possible to perform a full grafting of the protrusion acetabular defect. The type of bone frafting of the protrusion defects do not have a significant effect on the restoration of hip joint function in the postoperative period. So obtaining results of THA in cases of posttraumatic protrusion hip arthritis are comparable with the results of routine THA
