Fracture Neck Femur in Adults Managed with Three Cannulated Cancellous Screws Put in Biplane Double Supported Fixation (BDSF) vs Conventional Inverted Triangle Configuration: A Comparative Randomised Control Study of the Functional Outcome

Abstract

Background and Rationale: Fracture neck of femur in the adult population constitutes a formidable orthopaedic challenge, with fixation configuration critically determining biomechanical stability and functional recovery. The Biplane Double-Supported Screw Fixation (BDSF) technique — by distributing three cannulated cancellous screws (CCS) across two anatomical planes — offers a theoretically superior load- sharing construct compared to the conventional inverted triangle arrangement. However, comparative clinical evidence in the adult age group remains limited.Aims and Objectives: To prospectively compare the intraoperative feasibility and post-operative functional outcome of BDSF versus conventional inverted triangle CCS fixation in adult femoral neck fractures using the Harris Hip Score and complication profile.Methods: In this prospective, interventional, single-centre RCT conducted at UPUMS Saifai over 18 months (June 2023–December 2024), 60 adult patients aged 18–60 years with femoral neck fractures (Pauwels I–III; closed/Gustillo Grade I) were randomized by random block technique into two equal groups: Group A (Conventional Inverted Triangle, n=30) and Group B (BDSF, n=30). Primary outcome was Harris Hip Score at 6 months. Secondary outcomes included intraoperative parameters (operative time, blood loss, fluoroscopy exposure), rehabilitation milestones, and complications (AVN, non-union, implant failure, femoral neck shortening, surgical site infection). Baseline equivalence was confirmed across all demographic and clinical variables (p>0.05).Results: Both groups were statistically comparable at baseline in age (45.33±8.21 vs. 44.87±7.92 years; p=0.826), gender, fracture laterality, mechanism of injury, Pauwels classification, and injury-to- surgery interval. Intraoperatively, fluoroscopy exposure time was significantly lower in Group B (28.07±4.36 sec vs. 35.17±5.68 sec; p<0.0001), with a trend toward shorter operative duration (50.81±9.37 vs. 55.23±10.11 min; p=0.084). Complication rates consistently favoured BDSF: non-union 0% vs. 6.67%, implant failure 6.67% vs. 16.67%, femoral neck shortening >1 cm 6.67% vs. 13.33%, AVN 3.33% vs. 6.67%, surgical site infection 3.33% vs. 10.00%, and hip stiffness 3.33% vs. 10.00%. Harris Hip Score at 6 months was excellent (90–100) in 80% of Group B vs. 60% of Group A, with treatment failure (HHS <60) entirely absent in Group B versus 6.67% in Group A.Conclusion:The BDSF technique demonstrates clear superiority over the conventional inverted triangle configuration across intraoperative efficiency, complication profile, rehabilitation parameters, and functional recovery. With a significantly reduced fluoroscopic burden, zero non-union, and superior Harris Hip Scores, BDSF is recommended as the preferred fixation strategy for femoral neck fractures in adult patients. Multicentre validation with extended follow-up is warranted to consolidate these findings.