In vitro mechanical analysis of X-shaped femoroplasty with polymethyl methacrylate boundary a fall on the greater trochanter.

ABSTRACT

To evaluate with mechanical testing (MT) using synthetic femurs, an X-shaped femoroplasty technique with polymethyl methacrylate (PMMA), analyzing the results applied to the prophylaxis of proximal femur (PF) fractures caused by low-energy trauma. MT was performed simulating a fall on the greater trochanter, using fifteen Sawbones™ models. They were divided into three experimental groups (n = 5) control (DP) group, drilled without augmentation (DWA) group, and X-shaped augmentation (DX) group. Maximum load, stiffness, absorbed energy and displacement were analyzed primarily in all groups; and secondarily then, morphology and fracture type were verified in all groups while PMMA volume, temperature and time polymerization were analyzed only in the DX group. The MT results obtained for synthetic models respectively in the DP, DWA, and DX groups were mean maximum load (5562.0 ±â€¯464.8) N, (4798.0 ±â€¯121.2) N, and (7132.0 ±â€¯206.9) N; mean stiffness values (673 ±â€¯64.34) N/mm, (636 ±â€¯8.7) N/mm, and (738 ±â€¯17.13) N/mm, and mean absorbed energy values (36,203 ±â€¯3819) N.mm, (27,617 ±â€¯3011) N.mm, (44,762 ±â€¯3219) N.mm; mean displacement values (13.6 ±â€¯1.45) N, (11.1 ±â€¯0.5) N, and (13.2 ±â€¯0.69) N. The mean volume, temperature reached during filling in the DX group were 9.8 mL, 42.54ºC with 1' 56" of polymerization. The fracture types were similar between the DP and DWA groups, affecting the trochanteric region, as distinctly to those in the DX group, which were restricted to the femoral neck. The values obtained in MT showed statistical significance when analyzed by one-way ANOVA (5%) for maximum load, stiffness, and absorbed energy between groups. In conclusion, X-shaped PMMA augmentation presents a protective biomechanical characteristic against PF fractures generated in synthetic models by boundary a fall on the greater trochanter.