Retard the collapse. We conducted a two-year prospective, randomized, open-label, multicenter study to determine whether zoledronate prevents the collapse and reduces the need for total hip arthroplasty. Methods: We randomly assigned patients who had Steinberg stage-I or II nontraumatic osteonecrosis of the femoral head with a necrotic area of ≥30% to either the zoledronate group or the control group. Patients in the zoledronate group received 5 mg of zoledronate intravenously per year for two years, while patients in the control group did not receive this medication. The primary efficacy outcome was the survival rate in terms of the occurrence of collapse (≥2 mm). The patients were observed for a minimum of two years after enrollment. Results: A total of 110 patients (110 hips) underwent randomization; fifty-five patients were assigned to the zoledronate group and fifty-five, to the control group. During the two-year follow-up, twenty-nine femoral heads in the zoledronate group and twenty-two in the control group collapsed (p > 0.05). Nineteen hips in the zoledronate group and twenty in the control group underwent total hip arthroplasty (p > 0.05). Conclusions: Zoledronate for Steinberg stage-I or II osteonecrosis of the femoral head, with a medium to large necrotic area, did not prevent the collapse of the femoral head or reduce the need for total hip arthroplasty. Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence....

Ji HM, et al. Clin Orthop Surg. 2016 Jun;8(2):194-202. http://dx.doi.org/10.4055/cios.2016.8.2.194

The choice of implant is one of the most easily controllable factors affecting the outcome of intertrochanteric fractures. While most of the caput-collum-diaphysis (CCD) angles of the femur are within the range of 125° and 130°, there is a shortage of data on whether 125° or 130° implants are preferable. Thus, the present finite element analysis (FEA) aimed to compare the biomechanical effects on the fracture surface when using implants with different CCD angles where the anatomical CCD angle of the femur was between 125° and 130°. After establishing a finite element model of an unstable intertrochanteric fracture from the femur with a native CCD angle of 127.3°, proximal femoral nail antirotation (PFNA) models with CCD angles of 125° and 130° were virtually implanted to have the same position of screw tip, respectively. In the one-leg stance during walking, when the implant with 130º CCD angle was used, the magnitude of compressive stress (1.61 and 2.12 MPa in the 130° and 125° model, respectively) was lower and the area of the fracture surface under tensile stress (55% and 5% in 130° and 125° model, respectively), the interfragmentary movements (40.9% more movement in 130° model), and the magnitude of bone deformation (23.5% more deformation in 130° model) were more than those of the 125° model. The intertrochanteric fracture fixed with PFNA with a 125º CCD angle revealed less interfragmentary movement on the fracture surface when the native CCD was an in-between angle in the FEA.