Orthopedics · Medical Literature
Safety and feasibility of calcium sulfate/hydroxyapatite with zoledronic acid for the augmentation of helical blades in trochanteric fractures: A randomized pilot study.
Abstract
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). 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. 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. 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.
Clinical relevance
In elderly patients with osteoporotic trochanteric fractures treated with a proximal femoral nail (PFN), does augmentation of the helical blade with a calcium sulfate/hydroxyapatite (CaS/HA) biomaterial, combined with postoperative systemic zoledronic acid (ZA), improve peri-implant bone mineral density, reduce blade migration, and enhance functional outcomes compared to standard PFN fixation with ZA alone? __SNAPSHOT__ {"studyDesign":"Single-center, two-arm, parallel-group, randomized controlled pilot study","setting":"Single center; Aksaray University Faculty of Medicine, Türkiye (lead institution), with collaborating sites at Lund University (Sweden) and Lithuanian University of Health Sciences (Lithuania); December 2023 – January 2025","sampleSize":"n=20 (intervention: n=10, control: n=10); outcome analysis restricted to n=10 (5 per group) due to loss to follow-up and attrition","population":"Adults aged 65–90 years (median 81 years) with osteoporotic trochanteric fractures; 6 male, 14 female; all underwent surgical fixation with a proximal femoral nail","intervention":"PFN with helical blade augmented with CaS/HA biomaterial at the bone-implant interface, plus a single IV infusion of zoledronic acid on postoperative Day 7; infection prophylaxis with cefazoline and doxycycline administered to all patients","comparator":"Standard PFN (no augmentation biomaterial) plus a single IV infusion of zoledronic acid on postoperative Day 7; same infection prophylaxis","primaryOutcome":"Change in peri-implant bone mineral density (BMD) assessed by DXA at predefined regions-of-interest at one week and six months postoperatively","followUp":"Six months","fundingSource":"Not reported"}
Key findings
Of 20 enrolled patients, 19 of 20 received their intended treatment; one patient died within the first week and did not receive zoledronic acid. Complete data for the primary and secondary outcome analyses (peri-implant BMD change, tip-apex distance [TAD], fracture union, and Harris Hip Score [HHS]) were extractable for only five patients in each group (10 of 20 total; 50% attrition/loss to follow-up rate). In the evaluable subset, the intervention group demonstrated a more pronounced increase in peri-implant BMD compared to controls (absolute values, between-group difference, confidence intervals, and p-values: not reported). TAD changed more in the control group than in the intervention group, suggesting less helical blade migration with augmentation (magnitude of difference, confidence intervals, and p-values: not reported). Functional evaluation revealed a slightly greater HHS improvement in the intervention group (magnitude of difference, confidence intervals, and p-values: not reported). No specific adverse events attributable to the CaS/HA augmentation were reported in the abstract. NNT and NNH cannot be calculated from available data.
Practice implications
This pilot RCT provides preliminary, hypothesis-generating evidence that CaS/HA biomaterial augmentation of the PFN helical blade combined with systemic zoledronic acid is technically feasible and appears safe in a small cohort of elderly patients with osteoporotic trochanteric fractures. The directional trends across all three outcomes (peri-implant BMD, TAD, HHS) favor the augmentation approach; however, the study was explicitly designed as a feasibility and safety pilot — it was not powered to detect statistically significant differences in any outcome. The 50% attrition rate in the outcome-evaluable population (only 10 of 20 patients contributed to analysis) severely limits the interpretability of all reported trends. No inferential statistics (p-values, confidence intervals, effect sizes) are reported in the abstract. Accordingly, it cannot be determined from this study whether the observed directional differences are statistically significant, clinically meaningful, or due to chance. The findings do not apply to younger patients, non-osteoporotic fractures, fracture patterns other than trochanteric, or patients with contraindications to bisphosphonates. This study was available only as an abstract at the time of this summary; full-text review is necessary before any practice application. Confirmation in adequately powered trials is required before this combination strategy can be considered for routine clinical use. __LIMITATIONS__ Extremely small sample size (n=20 enrolled, n=10 outcome-evaluable); the study is explicitly a pilot and was not powered for efficacy inference.,Severe attrition: only 50% of enrolled patients (5 per arm) contributed to the primary and secondary outcome analyses, introducing substantial risk of selection bias and rendering all reported directional trends unreliable.,No inferential statistics (p-values, confidence intervals, or effect sizes) are reported in the abstract for any outcome, making it impossible to distinguish signal from noise.,Single-center design at the lead institution limits generalizability across healthcare systems and surgical skill levels.,Short follow-up of six months; long-term outcomes including implant failure, revision surgery rates, secondary fracture, and mortality are unknown.,Both groups received systemic zoledronic acid, making it impossible to isolate the independent contribution of CaS/HA augmentation from that of ZA.,Blinding status of outcome assessors is not reported in the abstract.,The population is predominantly very elderly (median age 81 years, range 65–90) and predominantly female (70%), limiting applicability to younger or male patients with trochanteric fractures.,Funding source is not reported; potential conflicts of interest cannot be assessed.,Abstract-only availability at time of this summary; methodology, randomization procedures, statistical analysis plan, and full adverse event reporting require full-text review. __BOTTOM_LINE_CATEGORY__ promising_but_preliminary __BOTTOM_LINE__ This small randomized pilot study (n=20 enrolled; only n=10 outcome-evaluable) suggests that CaS/HA biomaterial augmentation of the PFN helical blade with adjunct systemic zoledronic acid is technically feasible and appears safe in elderly patients with osteoporotic trochanteric fractures, with directional trends favoring the intervention for peri-implant BMD gain, reduced blade migration, and functional improvement. However, no inferential statistics are reported, attrition was 50%, and the study was not powered for efficacy conclusions; these findings are strictly hypothesis-generating. Practice should not change on the basis of this pilot alone; adequately powered, multicenter RCTs with longer follow-up and hard clinical endpoints (revision surgery, implant failure, mortality) are needed.