Artificial Knees at Risk From Dental Surgery

People who have had total knee replacements may be risking infection during dental surgery, Johns Hopkins University researchers report.

Dental procedures that cause considerable bleeding, such as multiple tooth extractions and root canal work, can introduce bacteria into the bloodstream. When the bacteria attack the artificial knee, the area can become seriously infected because the artificial parts lack the body’s normal defenses against infection.

The researchers examined the records of 3,490 knee-replacement patients from 1982 to 1993 and found that 62 developed joint infections six months or more after surgery. An additional 12 similarly infected patients were referred to the study. Researchers examined the source of infection for all 74 patients and discovered that nine cases were linked to dental procedures.

All patients reported knee pain or other problems an average of seven days after the dental visit. The subsequent infections necessitated surgery for all patients an average of 10 days after the visit. If the infections had been left untreated, they could have required amputation, said lead researcher Michael A. Mont.

Mont believes that these patients “may benefit from prophylactic antibiotics, especially if they have other conditions that predispose them to infection, such as diabetes or rheumatoid arthritis.”

The researchers recommend antibiotics before and after dental procedures that might cause significant bleeding. The physicians based their recommendations in part on the fact that antibiotics help reduce infection by 95% when administered to prosthetic heart-valve patients who undergo dental surgery.

The study was published in the Journal of Clinical Orthopedics and Related Research.