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Alignment More of Issue in Distal Tibial Fracture Union Than Interlocking Screw Application

Fractures of the tibia or femur (shinbone or thighbone) have been fixed using hardware such as screws and plates since 1939, when Gerhard Kuntscher reintroduced a procedure called marrow nailing, insertion of a special nail into the marrow space of the bone. The technique became more refined in the 1950s and now in the 2010s, a narrow, thin nail is used to help hold implants into the bone, when needed.

Kuntscher’s research showed that proper mechanical alignment of the bone was necessary to heal properly and nails would help keep the bone straight at the break, preventing it from angling. While this seems simple enough, there are some types of fractures that would be difficult to treat with this technique, particularly in parts of the bone farthest away from the body, the distal parts. This leads to a question of is it the screws that are used with nail technique affecting the bone healing or is there another issue at hand. The authors of this article looked at the history of 302 tibial and femoral fractures that were treated with nailing to see how interlocking screws worked in the healing process with the nail in helping the bone heal.

Of the 302 patients, researchers found that 107 patients met their critera. They noted how the patients were all treated after surgery and all were fitted with a fracture brace, with progressive weight bearing until they no longer limped. Looking at the surgery records, the researchers noted the number and locations of the screws used, the orientation of the screws, the position of the nail, how the fracture was aligned, and if there was union or not six months after surgery.

The results of the study showed that of 107 fractures, 10 or 9.3 percent, were nonunion, which means they did not heal properly. The average number of screws in these 10 fractures was 3.6, with the screw orientation (degrees from the horizontal axis) was 2.4 and 2.9 in the tibial nonunions. As for nail position, the average for unions was (1.2):(1.4) versus (1.5:1.4) for the nonunions.

When examining the 97 fractures that joined, the unions, the researchers saw that 61 were seen on x-ray to be aligned and 95 had unions on one plane (one surface part of the bone) and “at most, minor malalignment in the second.” The authors wrote that only two of the unions were malaligned in more than one plane and only unions had a major malalignment in a single plane. This compares favorably to the nonunion groups, where none of the 10 had fracture alignment but six did have alignment of the bone on one plane and minor malalignment in the other. The four remaining nonunions had “either nonanatomic alignment in two planes or major malignment in one plane.”

The authors concluded that malalignment of distal tibial and femoral fractures is a problem that surgeons need to be aware of when aligning the bone fragments. This alignment is vital for union of the bone. The use of interlocking screws with the nailing, differing with minor variations according to surgical technique, did not make a difference in bone healing.

Lonnie Douglas, Daniel Benson, and David Seligson. The incidence of nonunion after nailing of distal tibial and femoral fractures. In Current Orthopaedic Practice. January/February 2010. Vol. 21. No. 1. Pp. 49 to 53.

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