RADIOFREQUENCY (ELECTROSURGICAL) ABLATION OF ARTICULAR-CARTILAGE - A STUDY IN SHEEP

The objective of this study was to examine the effect of a bipolar abl ation probe on experimentally roughened articular cartilage and compar e it with the traditional mechanical shaving technique using the knee joint of sheep. Twenty-eight skeletally mature ewes were divided rando mly into two groups: one group was treated with a rotating shaving dev ice and another group was treated using the bipolar ablation probe (Bi polar Arthroscopic Probe; Electroscope, Inc, Boulder, CO). Animals wer e killed at 0, 6, 12, and 24 weeks, and histological sections of the e xperimental limbs were compared with sections of the opposite limb usi ng a modified Mankin scale. The following variables were used to deter mine scores: surface (0-6), cells (0-4), hypocellularity (0-3), matrix staining (transitional zone [0-4], radiate zone [0-4], and focal empt y lacunae or hypereosinophilic cells (0-3). Differences in scores for all response variables were calculated as treated limb minus sham limb . Response variables were formed: score >0 recoded as 1 (favorable res ponse treated better than sham), score of 0 recoded as 2 (neutral resp onse no differences), and score <0 recoded as 3 (unfavorable response treated worse than sham). Bipolar ablative probe-treated limbs had 14. 29% favorable responses and 35.71% favorable or neutral responses, whe reas shave-treated limbs had 0% favorable and only 7.14% favorable or neutral responses. For all variables, bipolar ablative probe-treated l imbs had more favorable responses. The less severe histological change in the bipolar ablative probe-treated joints compared with the shave- treated joints suggests that bipolar ablation of articular cartilage m ay be a better treatment for chondromalacia than the usual shaving met hods of debridement. Further, there were no pathological changes in th e subchondral bone.