Correlation between the stress shielding and clinical outcome after total hip arthroplasty with extensive porous coated stem

초록

Introduction: There is controversy that the stress shielding of proximal femur may affect the clinical outcome of total hip arthroplasty with extensive porous coated stem. This study investigates the change of bone mineral density of proximal femurs and the correlation between stress shielding and clinical outcomes after total hip arthroplasty with extensive porous coated stems. Materials and Methods : This retrospective study was performed on 51 patients who had had a unilateral primary total hip arthroplasty with use of the extensive porous coated stem. The contralateral normal femur of each patient was used as control. The dual energy x-ray absorptiometry (DEXA) was used to quantify the periprosthetic bone mineral contents for each region of both sides. The clinical outcome was estimated by using Harris hip scores (HHS). Results: Compared to the control side, the bone mineral density (BMD) of the operated side was lower in all seven regions. In region 1 and 2, BMD had decreased more than in other regions. The change of BMD in Gruen zone 7 with time was larger than other zone(r=0.456, p<0.001). However, HHS and pain had no relevance to the change of bone mineral density. Conclusion: Functional outcome and pain had no relevance to the change of bone mineral density after total hip arthroplasty with extended porous coated stems. Therefore, there is no hesitation to use extended porous coated stems for total hip arthroplasty because of the concern for stress shielding of proximal femur.