Does the Level and Complexity of Femur Fracture Determine Intramedullary Peak Pressures During Reamed Femoral Nailing? A Prospective Study.

Objectives: To investigate femoral intramedullary (IM) pressures during reamed antegrade nailing and to determine whether fracture level and/or complexity affect peak pressures.

Design: Prospective, nonrandomized observational cohort.

Setting: Single level I trauma center.

Patient Selection Criteria: Patients presenting with femur fractures (OTA/AO 31A3; 32A; 32B; 32C; 33A2; 33A3), requiring antegrade IM nail fixation, were included in this study. Excluded were minors and patients presenting with hemodynamic instability, a reduced level of consciousness and intoxication. Femurs were divided into thirds based on preoperative radiological measurements and allocated to 3 groups based on fracture location: Proximal (A), middle (B), and distal (C) third femur fractures. Fracture complexity was also documented.

Outcome Measures And Comparisons: Peak IM pressures of proximal, middle, and distal third femoral fractures were compared during antegrade femoral IM nail fixation.

Results: Twenty-two fractures in 21 patients were enrolled and treated over a 4-month period with a distribution of fracture locations of group A = 12, group B = 6, and group C = 4. Measured mean resting distal IM pressures were significantly higher ( P < 0.05) in proximal fractures (group A: 52.5 mm Hg) than in middle and distal third fractures (group B: 36.6 mm Hg and group C: 27.5 mm Hg). Greatest peak pressures were generated during the first ream in groups A and B, occurring distal to the fracture in all cases. Group A averaged 363.8 mm Hg (300-420), group B 174.2 mm Hg (160-200), and group C 98.8 mm Hg (90-100). There was a significant difference comparing group A with B and C combined ( P < 0.01) and group A with B ( P < 0.05) and C ( P < 0.05]) individually. Group A consisted of 6 comminuted and 6 simple fracture configurations. Mean peak pressures in these subgroups differed significantly: 329 mm Hg (300-370) versus 398 mm Hg (370-430), respectively ( P < 0.05). Complex fractures in study groups B and C did not have significantly different peak pressures compared with simple fractures ( P > 0.05).

Conclusions: Both the fracture location and comminution affect peak IM pressures during reamed antegrade femoral nailing. Proximal, simple fracture configurations resulted in significantly higher pressures when compared with more distal and comminuted fracture configurations.

Level Of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.