Laminar air-flow versus conventional air operating systems: a seven-year patient follow-up.

A 7-year follow-up was conducted on 183 total hip replacements and evaluated for infection. Eighty-seven operations were done in a horizontal laminar air-flow operating room and 89 were done in a conventional operating room without laminar air-flow. In the laminar air-flow group, there were 2 infections (2.2%) and 6 (6.7%) in the conventional operating room. Excluding those patients who had undergone previous operations, there were 3 infections out of 76 (4%) in the conventional operating room group. One infection out of 68 (1%) occurred in the laminar air-flow group. There were no statistical differences in the infection rates. These data are interpreted to suggest that daily uncontrollable variables which may produce infections are minimized by the use of laminar air-flow operating rooms.