LA JOLLA, CALIF. — A 5.5-mm diameter cannulated screw was just as effective as a 4.5-mm diameter screw for fixation of fifth metatarsal Jones fractures, Dr. David Allen Porter reported at the annual meeting of the American Orthopaedic Foot and Ankle Society.
However, it remains unclear whether the wider screw is more effective for this type of fracture, which commonly occurs in competitive athletes.
Dr. Porter, an orthopedic surgeon with Indianapolis-based Methodist Sports Medical Center, and his associates evaluated 20 patients with fifth metatarsal Jones fractures who were treated postoperatively with a 5.5-mm stainless steel cannulated screw. They compared the outcomes with those previously reported by the researchers in a study of similar athletes fixed with a 4.5-mm stainless steel cannulated screw.
The athletes in the current study were rehabilitated in a walking boot with crutches before being transferred to a custom shoe insert. Subjective pain and function were measured in terms of the American Academy of Orthopaedic Surgeons foot and ankle outcomes questionnaire, which includes a 100-point scale for pain and a 100-point scale for function.
All but one athlete, who had an unrelated back injury, returned to sports participation in an average of 9.5 weeks after fixation.
The researchers determined clinical and radiographic evaluations at final follow-up, which was 22.5 months on average. All patients had complete clinical healing. Based on assessment of oblique and lateral images of the foot by an independent radiologist, injuries were healed in 97% of all patients. The mean subjective pain score was 97, and the mean function score was 97.
Dr. Porter said that to date none of the 5.5-mm screws has bent, broken, or had to be removed. One patient had slight penetration of the cortex at surgery, but that healed with no adverse events.
When the researchers compared the findings with those of the previous study, in which patients underwent fixation with the 4.5-mm screw, clinical and radiographic healing rates were similar, as was the time it took to return to competition.
One significant difference between the two groups was screw length. The average length of the 4.5-mm screw was 52.4 mm, compared with 48.2 mm for the 5.5-mm screw.
“There's a higher rate of bending with the 4.5-mm screw and a higher rate of bone penetration with the 5.5-mm screw,” Dr. Porter said.
Fixation with a 5.5-mm cannulated screw resulted in 100% healing at 3 months. Courtesy Dr. David Allen Porter