OTA 2006 Posters

Scientific Poster #68 Basic Science

Is There a Difference Between Locked Intramedullary Nails and Locked Plates for Distal Metaphyseal Tibia and Tibia-Fibula Fractures? A Laboratory Evaluation
Eric J. Strauss, MD (n); Daniel Alfonso, MD (n),
Kenneth Egol, MD (n); Nirmal Tejwani MD (n);
Department of Orthopaedic Surgery, NYU-Hospital for Joint Diseases,
New York, New York, USA

Purpose: Our objective was to compare the biomechanical properties and fixation stability of intramedullary nails to locked plates for the management of distal metaphyseal tibia and tibia-fibula fractures.

Methods: A simulated, distal metaphyseal tibia fracture was created in eight pairs of cadaveric tibia-fibula specimens. One of each pair was treated using an intramedullary nail and the other was treated with a locked plate. Each specimen was vertically loaded to 250 N in central, anterior, posterior, medial, and lateral locations; in cantilever bending; and in torsion. Each specimen was then cyclically loaded. Fracture displacements were measured and stiffnesses remeasured. A fibular osteotomy was then created at the same level as the tibia fracture to simulate a concurrent tibia-fibular fracture and specimens retested.

Results: The locked plate construct fixation was stiffer than the intramedullary nail fixation for central, anterior, and posterior loading (P <0.005, <0.03, and <0.02 respectively). The intramedullary nail fixation produced a stiffer construct than the locked plate for both anterior-posterior and posterior-anterior cantilever bending (P< 0.03 and <0.02 respectively). There was no significant difference between treatment groups with respect to fracture displacements after cyclic, vertical loading. After fibular osteotomy, fracture displacements after 1000 and 10,000 cycles significantly increased and torsional stiffness significantly decreased for both treatment groups. In the tibia-fibular fracture pattern, locked plate fixation resulted in less fracture displacement after cyclic loading of 1000 and 10,000 (P <0.001 and <0.0001 respectively) and was stiffer in torsional loading compared to specimens treated with intramedullary nail fixation (P <0.05).

Conclusion/Significance: This study demonstrated that in the treatment of distal metaphyseal tibia fractures, locked plates showed generally increased fixation stability compared to intramedullary nails. Locked plates appear to be superior for distal tibia-fibula fracture patterns in which the fibula cannot be effectively stabilized.

If noted, the author indicates something of value received. The codes are identified as a-research or institutional support; b-miscellaneous funding; c-royalties; d-stock options; e-consultant or employee; n-no conflicts disclosed, and *disclosure not available at time of printing.
· The FDA has not cleared this drug and/or medical device for the use described in this presentation (i.e., the drug or medical device is being discussed for an "off label" use). · · FDA information not available at time of printing.