Purpose: This study was accomplished to evaluate the clinical & radiological results of cementless total hip arthroplasty using a fully hydroxyapatite-coated femoral stem after follow up of at least, 2 years.
Materials and Methods: Thirty one hips in 28 patients, who underwent primary total hip arthroplasty using a fully hydroxyapatite-coated femoral stem between september 2007 and May 2009, were followed up for more than 2 years after surgery. The average age of patients was 67 years old, and the average duration of follow up was 35 months. Preoperative diagnosis was 17 cases of osteonecrosis and 10 cases of femoral neck fracture. Clinical evaluation was done by Harris hip score (HHS). Radiological evaluation was done in terms of stability of components, subsidence of femoral stem and occurrence of osteolysis.
Results: The average of HHS improved from 34.3 preoperatively to 82.6 at final follow-up. Radiologically, fixation by bony ingrowth was 23 cases(74%) and fibrous ingrowth was 8 cases(26%). Subsidence was within 2-4 mm and occurred within 6 weeks in all 5 cases. There were 4 cases of intra-operative femoral fracture, 1 case of superficial infection.
Conclusion: Short-term clinical and radiological results of cementless total hip arthroplasty using a fully hydroxyapatite-coated femoral stem were not good enough. Radiologically, bony ingrowth were no more than 74%. Therefore, longer-term follow up would be necessary.

Keywords: Hip, Total hip arthroplasty, Femoral stem, Hydroxyapatite