Scanning and light microscopic study of irrigated and nonirrigated joints following burr surgery performed through a small incision.

Research was conducted on young, adult male rabbits where osseous burr surgery was performed through a small incision using two methods of joint debris extrusion. Surgical joint debris was found in all specimens at 1 week following surgery. Also, 1 week postoperatively, the surgically untouched chondral and subchondral joint aspects were intact in both irrigated and nonirrigated specimens. There was, however, subchondral bone inflammation in all specimens but the nonirrigated population had a greater inflammatory subchondral infiltrate. The synovium was more inflamed in the nonirrigated group. Bone particles, observed with scanning electron microscopy, generally appeared to be only slightly more evident in the nonirrigated group. Metal particles were observed in several specimens. By 28 weeks, joint debris was practically undetectable. In the irrigated specimens the chondral and subchondral portions presented with occasional degenerative focal loss of the chondral and subchondral layers. In comparison, the nonirrigated group demonstrated not only occasional but moderate-to-frequent focal loss with fissuring in the chondral and subchondral layers in addition to extrinsic repair of the cartilage surface. Subchondral bone inflammation was also more severe in the nonirrigated group. Observations from this project confirm that joint debris is removed through intrinsic joint processes and further suggests that the postoperative course of inflammation is not a totally abrasion-related phenomenon. The findings support the use of intraoperative irrigation as opposed to debris extrusion without irrigation in order to reduce both immediate and chronic postsurgical inflammation.