Osteogenic properties of nanohydroxyapatite/polyamide 66-Coated femoral stem prosthesis and its efficacy in total hip replacement combined with staged functional rehabilitation exercises

Abstract

To evaluate the efficacy of nanohydroxyapatite/polyamide 66 (nHA/Pa66)-coated femoral stem prosthesis in total hip arthroplasty (THA) and the advantages of combined post-operative staged rehabilitation functional exercises (SRFE) in restoring hip function, 112 patients with femoral neck fractures were enrolled in the clinical study. Patients were randomized to routine and nHA/Pa66 groups. Patients in the nHA/Pa66 group were treated with nHA/Pa66-coated femoral stem prosthesis and the post-operative SRFE program. We evaluated the physical properties, cytotoxicity, and osteogenic capacity of nHA/Pa66 in an in vitro trial, and the clinical treatment, postoperative improvement in joint function (Barthel score, VAS score, Harris score), imaging performance, and incidence of adverse events were compared between groups. The porosity of nHA/Pa66 was ∼75% and its pore size was in the range of 300–500 μm. Moreover, nHA/Pa66 had good biocompatibility and could improve bone marrow stem cells (BMSCs) activity and enhance the osteogenic function of BMSCs, effectively increasing the levels of COL I, ALP, and OCN. A combination of nHA/Pa66 and SRFE could effectively shorten hospital stay, better restore hip function, and reduce the incidence of complications. Therefore, nHA/Pa66-coated femoral stem prosthesis combined with SRFE showed great potential in THA for femoral neck fractures.