Chondral injury has become one of the most difficult problems to solve in orthopaedics. This pathology is very common: Curl et al. founded an incidence of 63% of chondral lesions (2.7 lesions for knee in 31,156 knee arthroscopies) with a 20% rate of lesions of grade IV of Outerbridge.

During the past few decades many techniques were developed: with these techniques the lesion is just reparied with the formation of fibro-cartilage tissue with biochemical and bioelastic characteristics very different from the hyaline cartilage tissue.

Microfracture technique : This technique, proposed by Steadman et al., utilises hand-drills to create numerous perforations in the subchondral bone at 3–4 mm apart. Indications for this techniques are lesions from 0.5 to 2 cm² with an outlined border in patients with low functional demand. Osteochondral autograft transplantation (OATS, mosaicplasty): Osteochondral autograft transplantation is indicated for isolated lesions from 1 to 3 cm² or in OCD. Outerbridge et al., in a study of 10 patients with 6.5 years of follow-up, achieved good functional results in all pateints treated with this technique. Autologous chondrocyte implant: ACI, reported for the first time by Peterson and colleagues in 1994, is advised for young or middle-aged, active patients with a single painful chondral injury (3–4 grade of Outerbridge scale), starting from more than 2 cm². They. reported good results in the treatment of chondral lesion with a long follow-up (2–10 years). New tissue engeneering techniques with the use of biomaterial derived from hyaluronic acid provides ideal support to the culture and proliferation of chondrocytes, allowing at the same time arthroscopic implant.

Today there are many options in the treatment of chondral lesions, but no one technique can be considered the gold standard. ACI in arthroscopy is a more promising technique in the treatment of the chondral lesions, but the indications are still too restricted.