Risk of acetabular protrusion is low in rheumatoid arthritis patients treated with bipolar hemiarthroplasty for displaced femoral neck fractures without rheumatoid change in hip joints.

Objectives: The aim of this study was to analyze the radiological outcomes of bipolar hemiarthroplasty after displaced femoral neck fractures of non-arthritic hip joints in rheumatoid arthritis patients. Methods: We retrospectively investigated 25 hip joints in 23 rheumatoid arthritis patients who underwent bipolar hemiarthroplasty for displaced femoral neck fracture of non-arthritic hip joints. All patients were female with an average age of 69.8 years (range 51-83 years). Mean follow-up duration was 8.4 years (range 5-12 years). Radiographs taken immediately, 1 year after surgery and most recently, were collected for each case. Radiographic measurement of the migration distance of the outer-head prosthesis in the direction of vertical, horizontal and medial to Köhler's line was undertaken at 1 year after surgery and most recently. Results: No patients had hip-related pain after surgery. No case indicated apparent central migration and >3-mm migration of the hemisphere in each direction. There was no significant change in migration distance between evaluation at 1 year after surgery and most recently. Conclusions: We conclude that risk of acetabular protrusion appears to be low in patients of rheumatoid arthritis treated with bipolar hemiarthroplasty for displaced femoral neck fractures of non-arthritic hip joints in the medium term. [ABSTRACT FROM AUTHOR]