Fig. 2

A 54-year-old female patient was diagnosed with bilateral acetabular protrusion secondary to RA. (1) Preoperative anteroposterior x-ray of the pelvis showing bilateral femoral heads protruding inward beyond the Kohler’s line. The patient was classified as type II according to Sotello-Garza and Charnley criterion. (2) Cementless THA accompanied by acetabular reconstruction using impacted bone grafting. Immediate postoperativexX-rays revealed that the acetabular prosthesis had a good position and initial stability, and the rotational center of the hip joint had returned to the normal anatomical location. (3) The 5-year follow-up after right hip replacement, there was no obvious loosening of the prosthesis, invagination of the acetabular cup, complete bone graft healing, and no bone resorption. Anteroposterior x-ray of the pelvis showed that left femoral head protruding inward beyond the Kohler’s line, which was classified as type II. (4) postoperative x-rays revealed that bilateral acetabular prosthesis had a good position and stability, and the left hip center had returned to the normal anatomical location; (5) The 2-year follow-up after left hip replacement, there was no obvious loosening of the prosthesis, and invagination of the acetabular cup