August 28 (HealthDay News) -- The ability to brake suddenly while driving is fully returned six weeks following bunion surgery, researchers say.

A bunion is the bump just below the big toe that can occur when the big toe begins to angle sideways toward the second toe. Bunions can become swollen and painful, sometimes making it hard to walk. In these cases, surgical treatment to realign the bone, ligaments, and tendons may be required.

Six weeks following bunion surgery, most people have low enough pain levels that they are able to drive. But until now, no studies had been done to find out if driving six weeks after bunion surgery is actually safe.

A new study in the August issue of the Journal of Bone and Joint Surgery evaluated motor skills in 28 patients who had undergone bunion surgery on the right foot.

For their study, the researchers used a custom-made driving simulator to compare total brake response time, reaction time, and actual brake time in the bunion surgery patients to a group of 28 control participants matched for age, driving status, and sex.

Two weeks after the surgery, only 25 percent of the patients were able to complete the test. But after six weeks, the patients' reaction, brake, and total brake response times were even better than they had been before the bunion was repaired and were similar to the control group.

"It is probably not advisable to drive before six weeks after bunion surgery on the right foot -- our research shows that the reflexes and the power required to brake suddenly in an emergency is fully returned only at six weeks in the post-operative period," Dr. Graeme Holt, an orthopedic surgeon at Glasgow Royal Infirmary in the United Kingdom and co-author of the study, said in an American Academy of Orthopaedic Surgeons' press release. "However, it is extremely important for all patients to discuss when they can return to driving with their surgeon after having any type of surgery to their foot."

People who drive before six weeks following their surgery are at risk of re-injuring their foot if they have to apply the emergency brake, the researchers said.

SOURCE: American Academy of Orthopaedic Surgeons, news release, Aug. 26, 2008