THREE-POINT BENDING PERFORMANCE OF 6.5-MM CANNULATED VS SOLID CANCELLOUS SCREWS: AN IN VITRO BIOMECHANICAL STUDY
İzmir Eğitim ve Araştırma Hastanesi Tıp Dergisi, cilt.30, sa.2, ss.125-130, 2026 (TRDizin)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 30 Sayı: 2
- Basım Tarihi: 2026
- Dergi Adı: İzmir Eğitim ve Araştırma Hastanesi Tıp Dergisi
- Derginin Tarandığı İndeksler: TR DİZİN (ULAKBİM)
- Sayfa Sayıları: ss.125-130
- Dokuz Eylül Üniversitesi Adresli: Evet
Özet
Introduction: Cannulated cancellous screws are commonly used for minimally invasive femoral neck fixation; however, cannulation may reduce bending resistance compared with solid-core designs. This study compared three-point bending behavior of 6.5-mm cannulated and non-cannulated (solid-core) cancellous screws made of titanium and stainless steel. Material and Methods: Forty screws were tested (n = 10/group): titanium cannulated, titanium non-cannulated, stainless-steel cannulated, and stainless-steel non-cannulated. A standardized three-point bending test with a 50- mm support span was performed at 1 mm/min after a 100-N preload and terminated at 2 mm displacement. Outcomes were yield load (primary), stiffness, deformation at 1000 N, and deformation at yield. Results: Non-cannulated screws showed higher yield load than cannulated screws in both materials: titanium 1173.4 ± 42 vs 964.3 ± 99 N (p = 0.002) and stainless steel 1289 ± 45 vs 926.1 ± 16 N (p = 0.008). Titanium non-cannulated screws had higher stiffness than cannulated screws (821.5 ± 12 vs 717.6 ± 28 N/mm; p = 0.004), whereas stainlesssteel stiffness did not differ (p = 0.080). Deformation at 1000 N was lower in non-cannulated screws for titanium (1.38 ± 0.05 vs 1.64 ± 0.05 mm; p = 0.001) and stainless steel (1.00 ± 0.10 vs 1.62 ± 0.04 mm; p = 0.001). Conclusion: In a standardized three-point bending test, central cannulation significantly reduced yield load and increased deflection under a given load in 6.5-mm cancellous screws. These findings suggest a reduced bendingrelated mechanical safety margin for cannulated designs and support considering implant selection and construct strategy when bending robustness is a priority.