Does the level and type of femur fracture determine intra-medullary peak pressures during reamed femoral nailing? A Prospective study

Abstract

OBJECTIVES: Investigation of femoral intra-medullary pressures during reamed antegrade nailing and to determine whether fracture level and/or complexity affect peak pressures METHODS: Design: Prospective, non-randomized observational cohort Setting: Single level I trauma centre Patient selection criteria: Included were patients presenting with femur fractures (OTA/AO 31A3; 32A; 32B; 32C; 33A2; 33A3), requiring antegrade intra-medullary nail fixation. Excluded were minors and patients presenting with haemodynamic instability; a reduced level of consciousness and intoxication. Femurs were divided into thirds based on pre-operative 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 intra-medullary pressures of proximal, middle and distal third femoral fractures were compared during antegrade femoral IM nail fixation. RESULTS: Twenty-two fractures in twenty-one 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 mmHg) than in middle and distal third fractures (Group B: 36.6 mmHg and Group C: 27.5 mmHg). 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 mmHg (300-420); Group B 174.2 mmHg (160-200) and Group C 98.8 mmHg (90-100). There was a significant difference comparing group A with B and C combined [p <0.01] as well as 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: 329mmHg (300-370) vs 398mmHg (370-430) respectively [p <0.05]. Complex fractures in study groups B and C did not have significantly different peak pressures compared to simple fractures [p >0.05]. CONCLUSIONS: Both the fracture location and comminution affect peak intra-medullary pressures during reamed antegrade femoral nailing. Proximal, simple fracture configurations resulted in significantly higher pressures when compared to more distal and comminuted fracture configurations. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.