Design features and clinical results of anatomic femoral stem in total hip arthroplasty / 中国组织工程研究

ABSTRACT

BACKGROUND:Ribbed anatomic femoral stem meets the biomechanical features of the femur, and has achieved satisfactory clinical efficacy with good initial stability, rapid bone growth and low stress shielding. OBJECTIVE:To evaluate the design features and clinical results of the cementless anatomic Ribbed femoral stem (Ribbed stem) in total hip arthroplasty. METHODWe retrospectively analyzed 52 patients (52 hips) with hip joint disease who were treated with Ribbed stem in total hip arthroplasty between March 2010 and March 2012. There were 20 males and 32 females. The mean age was 59 years (range 22-78 years). The mean fol ow-up was 3.1 years (range 2-4 years). The preoperative and postoperative Harris hip scores, the rate of postoperative thigh pain, the incidence of intraoperative femoral fracture, wound healing, dislocation and revision were recorded. Radiographic evaluation was used to evaluate the rate of stem fil , subsidence of femoral stem, periprosthetic radiolucent line, bone ingrowth, stress shielding, and osteolysis. RESULTS AND CONCLUSION:The incidence of intraoperative femoral fracture was 6%. Al incisions were healed. There were no cases of hip dislocation and revision;the rate of thigh pain was 6%, no patient had thigh pain after 1 year postoperatively. The mean preoperative Harris hip score was 48 points, which improved to a mean of 96 points at the final fol ow-up. Postoperative X-ray showed that al patients had a satisfactory femoral fil in both planes and al of the femoral stems were wel-fixed at the final fol ow-up. The average fil ing rate was 91%, 88%and 86%by normotopia imaging, while 88%, 85%and 81%by lateral imaging, at the metaphysic, middle and distal ends respectively. At the final fol ow-up, 49 hips (92%) showed stable bone ingrowth, 3 hips showed stable fiber ingrowth. No osteolysis around the components at the femur or acetabulum was observed. 5 (10%) hips appeared the subsidence of femoral stems, which were<2 mm. The stress shielding phenomenon occurred in al patients, including first-degree in 31 hips, second-degree in 19 hips, third-degree in 2 hips, and fourth-degree in no case. Experimental findings indicate that, Ribbed stem with a rational design can achieve satisfactory clinical outcomes with good initial stability, rapid bone growth and low stress shielding.