Safety and feasibility of calcium sulfate/hydroxyapatite with zoledronic acid for the augmentation of helical blades in trochanteric fractures: A randomized pilot study.

Abstract

Objectives: This study aims to evaluate the feasibility, safety, and peri-implant bone formation of augmenting a proximal femoral nail (PFN) helical blade with a calcium sulfate/hydroxyapatite (CaS/HA) biomaterial combined with systemic zoledronic acid (ZA).

Patients and methods: This single-center, two-arm, parallel-group, randomized-controlled pilot study included a total of 20 patients with osteoporotic trochanteric fractures (TFs) between December 2023 and January 2025. The patients were randomized into a control group receiving standard PFN or an intervention group receiving PFN augmented with CaS/HA biomaterial. All patients received cefazoline and doxycycline for infection prophylaxis. On postoperative Day 7, both groups received a single intravenous infusion of ZA. The primary outcome was the change in bone mineral density (BMD) defined by previously published peri-implant regions-of-interest at one week and six months postoperatively. Secondary outcomes included tip-apex distance (TAD) for assessing blade migration and the Harris Hip Score (HHS) for functional evaluation.

Results: Of a total of 20 patients included in the study, 6 were male and 14 were female with a median age of 81 (range, 65 to 90) years. Regarding intervention delivery, all 10 randomly assigned patients received their intended treatment. While 19 of the 20 randomly assigned patients received the intended treatment; one patient died within the first week and did not receive ZA. The required data for clinical analysis (change in peri-implant BMD, TAD, fracture union, and HHS) could only be extracted for five patients in the control group and five patients in the intervention group. There were no intraoperative complications, and no adverse effects related to the CaS/HA biomaterial were reported. Ten patients were included for the outcome analysis. The intervention group demonstrated a more pronounced increase in peri-implant BMD compared to controls. Additionally, TAD changed more in the control group. Functional evaluation revealed that the intervention group demonstrated a slightly greater HHS improvement.

Conclusion: Our study results suggest that augmentation using the CaS/HA and ZA is a feasible and safe procedure for patients with osteoporotic TF. Preliminary findings indicate a potential trend toward enhanced peri-implant bone formation in the intervention group.