Objective: To examine the basic biomechanics of locking plate fixation plus calcium phosphate bone cement (CPC) for unstable intertrochanteric fractures.
Methods: A total of 18 Chinese fresh femur specimens without pathological defects, fractures, malformations or neoplasms were collected. In accordance with the Evans classification of IIIA type, the intertrochanteric fracture model was established. There were 18 femoral samples in each group. The experimental group received locking plate (LPFP) fixation plus CPC while the control group had a simple LPFP fixation. The mechanical tests were performed.
Results: Under different load-strain conditions, the results were as follows: 600 kg · m · s(-2) experimental group 98 + 3.6 vs control group 127 + 4.4 µε; 3000 kg · m · s(-2) experimental group 278 + 23 vs control group 457 + 45 µε. And under different load-displacement conditions, 500 kg · m · s(-2) experimental group 0.16 + 0.02 vs control group 0.23 + 0.04 mm; 4000 kg · m · s(-2) experimental group 2.79 ± 0.59 vs control group 5.05 + 0.68 mm. The torsional mechanical 0.1 (°/cm) properties: experimental group 0.14 + 0.01 vs control group 0.23 + 0.04 (kg · m · s(-2) · m); 0.8 (°/cm) experimental group 3.14 + 0.17 vs control group 2.57 (kg · m · s(-2) · m) + 0.08 (kg · m · s(-2) · m) (P < 0.05).
Conclusion: The combined regimen of locking plate fixation and calcium phosphate cement offers remarkable advantages over simple locking plate fixation in its excellent anti-compression and anti-torsion performances in the treatment of unstable intertrochanteric fractures. With a reasonable design, it has a greater stability.