The Effect of Nonablative Laser Energy on Joint Capsular Properties An In Vitro Histologic and Biochemical Study Using a Rabbit Model

The purpose of this study was to evaluate the effect of laser energy at nonablative levels on joint capsular histologic and biochemical properties in an in vitro rabbit model. The medial and lateral portions of the femoropatellar joint capsule from both stifles of 12 mature New Zealand White rabbits were used. Speci mens were divided into three treatment groups (5 watts, 10 watts, and 15 watts) and one control group using a randomized block design. Specimens were placed in a 37° bath of lactated Ringer's solution and laser energy was applied using a holmium:yttrium-alu minum-garnet laser in four transverse passes across the tissue at a velocity of 2 mm/sec with the handpiece set 1.5 mm from the synovial surface. Histologic anal ysis revealed thermal alteration of collagen (fusion) and fibroblasts (pyknosis) at all energy densities, with higher laser energy causing significantly greater mor phologic changes over a larger area (P < 0.05). Ap plication of laser energy did not significantly alter the biochemi...