EXPERIMENTAL-STUDY ON HOLMIUM - YAG-LASER SYNOVECTOMY VERSUS MECHANICAL ABRASION TREATMENT

The goal of this study was to evaluate tissue reactions in rabbit knee s following laser synovectomy using a holmium:YAG laser (wavelength: 2 .1 mum) and to compare these results with those found after convention al mechanical abrasion treatment. Chronic arthritis was immunologicall y induced in one knee joint each of 48 rabbits. Twelve served as contr ols, 12 were sham-operated, 12 were exposed to laser radiation, and 12 others were treated according to conventional methods. In the laser g roup, a pulse length of 1 ms at a repetition rate of 3 Hz resulted in a pulse energy of 600 mJ. After periods of 1 day, 1 week and 1, and 3 months, respectively, three animals from each group were sacrificed an d the synovialis was examined macroscopically and histologically using light and electron microscopy. Edema, acute inflammation, and coagula tion necrosis occurred immediately following laser therapy. After 1 we ek, the synovial layer showed slight fibrosis, which was comparable to that found in the controls. One month later the surface appeared to b e smooth. The mechanical abrasion caused hemorrhage and necrosis. Fibr osis was pronounced in all capsular layers, and after 3 months the sur face appeared coarse and villous in this group. Based on these prelimi nary findings, holmium-laser synovectomy may offer an alternative to e xisting therapeutic techniques in the treatment of rheumatoid arthriti s. The arthroscopic approach could prevent additional capsular fibrosi s associated with mechanical irritation.