Bone marrow nails created by percutaneous osteoplasty for long bone fracture: comparisons among acrylic cement alone, acrylic-cement-filled bare metallic stent, and acrylic-cement-filled covered metallic stent.

Purpose: This study was designed to compare the strength among bone marrow nails created to treat long bone fractures using interventional procedures.

Methods: Twelve resected intact tibiae of healthy swine were used. A circumferential bone fracture was made in nine tibiae and restored with the following created bone marrow nails: acrylic cement alone (ACA) (n=3), acrylic-cement-filled bare metallic stent (AC-FBMS) (n=3), and acrylic-cement-filled covered metallic (AC-FCMS) stent (n=3). The remaining intact tibiae (n=3) were used as controls.

Results: A bone marrow nail was successfully achieved within 30 min in all swine. The maximum injection volume of acrylic cement for creating ACA, AC-FBMS, and AC-FCMS was 1.7±0.3, 3.2±0.4, and 2.9±0.4 mL, respectively. The thickness of bone marrow nail created in the ACA, AC-FBMS, and AC-FCMS groups was 3.6±1.0, 10.3±0.26, and 9.6±0.32 mm, respectively (AC-FBMS group versus AC-FCMS group, p=0.038), probably because of leakage of acrylic cement surrounding the interstices. The maximum bending power (kilonewton) and bending strength (newton/mm2) in the normal long bone, ACA, AC-FBMS, and AC-FCMS groups were: 1.70±0.25 and 79.2±16.1; 0.21±0.11 and 8.8±2.8; 0.46±0.06 and 18.2±1.6; and 0.18±0.04 and 7.8±2.7, respectively.

Conclusions: Although the maximum bending power and bending strength of AC-FBMS were not satisfactory, it was the most robust of the three marrow nails for restoring fractured long bone.