This is an article of two homogenic groups treatment comparison, with 25 patients in each. Between 1998 and 2001 twenty-five patients underwent osteochondral or chondral fragment excision with Pridie tunelisations and 25 patients (controls)--osteochondral/chondral fragment excision alone (O-CFE). Average follow-up was 12.4 (range 10-14 months) and 23.6 months (range 22-25 months). All patients were younger than 30 years of age. Patients were evaluated through ICRS and modified HSS scales, arthroscopically, histologically and with x-rays. A blinded research assistant performed all follow-up evaluations. Sixteen of 25 (64%) tunelised (Pridie) results were good and 9 (36%)--fair at the time of last follow-up. Twelve of 25 (48%) in O-CFE group results were good and 12 (48%)--fair 23.6 months post operations. Final modified HSS evaluation showed statistically significantly better results in the Pridie group at the 12.4 and 23.6 months (p = 0.005). Last follow-up showed deterioration in both groups (p < 0.05). At an average 23.6 months follow-up x-rays showed initial osteoarthritis signs in the knees. Consequently, we recommend Pridie tunelisation procedure until final indications of cartilage grafting techniques will be established.