Objective To compare the effectiveness of arthroscopic osteochondral autologous transplantation (OAT) in the treatment of young and middle-aged patients with the articular cartilage injury. MethodsA clinical data of 43 patients (43 knees) with articular cartilage injury, who underwent OAT between January 2008 and August 2016, was retrospectively analyzed. There were 23 patients aged 20-40 years (young group) and 20 patients aged 40-60 years (middle-aged group). The difference in age between the two groups was significant (t=14.120, P=0.001). There was no significant difference in gender, body mass index, complications, affected side, lesion site, lesion area, and the International Cartilage Repair Society (ICRS) grade of cartilage injury between the two groups (P>0.05). The function of knee joint was evaluated by Lysholm score and International Knee Documentation Committee (IKDC) score during the follow-up. MRI examination was performed to observe the repair of both receiving and the donor sites. ResultsAll the incisions in the two groups were healed by first intention. All patients in the two groups were followed up with an average of 3.6 years (range, 2-8 years). At 2 years after operation, the Lysholm and IKDC scores were significantly improved in the two groups when compared with the preoperative scores (P<0.05). The Lysholm and IKDC scores in the young group were significantly better than those in the middle-aged group before operation and at 2 years after operation (P<0.05). However, there was no significant difference in the differences of the Lysholm and IKDC scores between pre- and post-operation between the two groups (P>0.05). The MRI examination at 2 years after operation showed that both receiving and the donor sites healed well in the two groups. ConclusionAccording to the texture, thickness, elasticity, and lesion area of the cartilage, arthroscopic OAT might be the first choice for the articular cartilage injury in middle-aged patients and can obtain the satisfactory short-term effectiveness.