Plates Versus Screws Touted to Repair Jones Fractures
Biloine W. Young • Wed, March 7th, 2018
The fifth metatarsal is the bone in the foot that connects the small toe to the ankle. A break in that bone is called a Jones Fracture. The Jones Fracture has usually been treated by a surgeon by implanting “a screw into the canal of the fifth metatarsal bone to draw the fractured ends back together.”
However, up to 30 percent of Jones fractures repaired with the screw can, in effect, re-fracture says Kevin Varner, M.D., a Houston Methodist foot and ankle orthopedic surgeon.
In his research he has found that a metal plate may provide a more stable repair for Jones fractures.
"Plates are commonly used to help repair fractured bones, but orthopedic surgeons haven't been using plates to repair Jones fractures," Varner said. "After seeing several Jones re-fractures in patients who had been treated with the screw, I wanted to find a better repair method and thought the well-known technique of plating might be that solution."
To test the durability of the screw versus the plate, Varner and a team of researchers divided 12 pairs of foot models into two groups, with one foot from each pair assigned to receive the traditional screw repair and the other receiving the plate repair. After creating a Jones fracture and repairing it with either a screw or a plate, the fifth metatarsal was removed from the foot model, according to a report in News Medical Life Sciences.
Varner and his team then put each bone through a load bearing test in which force was increased every 10 cycles until failure occurred. This process mimicked the stresses placed on the fifth metatarsal during the foot motions of walking and running.
According to Varner, the failures the team observed occurred at the point where the bone connected with the screw implant. They found that the failures were due to either screw pull out or the bone itself had pulled away from the plate. On average, the screw group failed at 37.3 cycles compared to 63.9 cycles for the plate. The plate withstood an average of 35.8 pounds of force, while the screw failed around 21.7 pounds of force.
This new research conducted at Houston Methodist Hospital indicates that a metal plate may become the preferred treatment for this common foot injury seen in athletes and people who work on their feet all day. A paper on this topic—"A Biomechanical Comparison of Fifth Metatarsal Jones Fracture Fixation Methods”– was published online February 21, 2018 by The American Journal of Sports Medicine.