Session IV - Femur

*A Prospective Randomized Trial Comparing Reamed and Unreamed Intramedullary Nailing: An Analysis of Rates of Union

James N. Powell, MD; Russell DeGroote, MD; Hans J. Kreder, MD; Ross K. Leighton, MD; Michael D. McKee, MD; Robert G. McCormack, MD; Robert J. Feibel, MD, Foothills Hospital, Calgary, Alberta, Canada (all authors - a-Synthes, Canadian Orthopaedic Foundation, Calgary General Hospital, Foothills Hospital, Alberta Heritage Foundation, Hip Hip Hooray)

Purpose: The purpose of this study was to compare the rate of union achieved using reamed intramedullary nailing with standard (12mm and greater) diameter intramedullary nails with the rate of union achieved using an unreamed canal preparation and smaller (9-12mm) diameter intramedullary nails. The null hypothesis was that the rate of union would be no different between the two groups.

Methods: The study was a prospective randomized multicentre trial performed in 6 centres. Patients meeting the inclusion criteria for this study were approached for permission to enter them into the study. Those who agreed to be enrolled were then randomized. Patients were determined to be either multiply injured (ISS greater than 18) or to have essentially single limb injury (ISS less than 18). Patients were then assigned to either the reamed or unreamed category.

After the surgical procedure the patients were followed until union had been determined clinically and radiologically or reoperation was undertaken to secure bone union.

Results: To date 224 patients have been entered in the study. One-hundred six patients received a small diameter nail without canal preparation (unreamed technique) and 118 received a standard diameter nail with reamed preparation of the intramedullary canal. The age, sex, and injury severity score were similar in the two groups.

In the unreamed group, 9 of 106 patients developed a nonunion (8.5%). In the reamed group, 2 of 118 patients developed a nonunion (1.7%). The risk of nonunion was 5 times greater in the unreamed group (relative risk=5 with 95% confidence limits 1.1 to 22.7 times). 80% of the nonunions could have been prevented by reaming (relative risk reduction for reaming=.8). This difference was statistically significant. Calculations were performed using SPSS version 11 for PC.

Discussion: This study is in keeping with the emerging literature on unreamed small diameter intramedullary nailing. The rate of union is higher with reamed intramedullary nailing using conventional nail diameters. This study supports continued use of reamed intramedullary nailing as the standard for single-limb injury.

Controversy remains regarding the issue of reamed and unreamed nailing in multiply injured patients. As our previous work has shown no detrimental effect from unreamed nailing with regards to the rate of ARDS, and perhaps a benefit, we plan to continue randomization in multiply injured patients. This study confirms that small diameter, unreamed nailing will be accompanied by a higher rate of nonunion.

Conclusion: We conclude that reamed intramedullary nailing using a conventional diameter nail (12 or greater) is appropriate treatment for isolated femoral shaft fractures.