The object of this study was to determine rate of ability restoration after arthroscopic surgeries in Thoroughbred racehorses. The racehorses that under arthroscopic surgery due to be injured his limbs were studied during exercise or training at Busan Race Park from 2005 to 2010. Rate of arthroscopic surgical treatments was 1.4% (63/4642). The results of arthroscopic surgery for the removal of osteochondral fragments from 70 limbs in 63 horses are reported. Number of patients under arthroscopic surgery were 63 and 58 horses were recovered from the surgeries and 5 horses were in training or resting at the time of publication. Only 52 of 58 horses had previous race experiences before the surgeries. Success horses of returned to the same level of performance were 31 horses (59.6%) and failed horses were 21 horses (40.4%). Average resting periods in success and failed horses were 7 months and 8.8 months, respectively. Resting periods in success horses were shorter than failed horses.