Autologous chondrocyte implant (ACI) is a very effective technique in the treatment of chondral lesions in order to restore normal hyaline cartilage. This technique, reported for the first time by Peterson 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. New tissue engineering techniques with the use of biomaterial derived from hyaluronic acid (HYAFF matrix) provide ideal support for the culture and proliferation of chondrocytes, allowing at the same time arthroscopic implant. There are many advantages of arthroscopic techniques: easy implant and less pain post-operatively; however, the indications for arthroscopic technique are still restricted: single chondral inury, 2–6 cm² in size and localisation at the femoral condyles.

At the Department of Orthopaedic Surgery of the University “ Federico II ” of Naples starting from January 1996 to the present, 29 patients were treated with ACI. Eight patients (six men and two women) had an arthroscopic implant. Median age was 18; in seven patients an OCD of the medial femoral condyle was present and just one patient had a post-traumatic injury of the medial femoral condyle. Hyalograft was used in all cases. All patients underwent CPM starting from the second post-operative day and full charge was allowed after 2 months. All patients were evaluated by clinical examination with IKDC score and functional score (Tegner) at 3, 6 and 12 months after surgery and with a MNR at 6 and 12 months after surgery and then every year.

Good results were found subjectively in 88% of the patients, with a complete lack of pain in 70% cases. Using the IKDC score good results were found in 85% of the cases (average score 90). With the Tegner score we reported an improvement in the level of activity in 60% of the cases.

The MNR images, performed with standard sequences, fat-suppressed and in the last cases with dGEMRIC, showed the presence of regeneration tissue inside the chondral defects, with a signal very similar to that of the cartilage tissue, sometimes slightly deeper.

Our experience shows that ACI is an effective way of treating chondral lesions with excellent results. We think that progress in the field of biomaterials will extend the indications for arthroscopic techniques, also allowing implants in larger lesions and at other sites.

Neglected rupture of quadriceps tendon is an infrequently occurring lesion resulting from sport, but it is very interesting as regards the physiological and functional repercussions. The lesion is common in football players. The pathogenesis is a flexion trauma of knee. Many authors point out the importance of a pre-existent degeneration due to exogenous and endogenous factors. Pain, inextensible knee, ecchymosis, axe hit are a common presentation in acute events, difficult knee extension and pain in chronic. X-ray study shows calcification at the tendon-bone junction.

The treatment of neglected rupture of quadriceps tendon is surgical. If a defect of 5 cm or more is present between the ends of tendon the fascia lata can be used to correct the gap. When the ends can be apposed an end-to-end repair is possible. We treated a neglected rupture of quadriceps femoris muscle tendon in a bodybuilder with a particular technique: we stripped and harvested the semitendinosus and gracilis tendon and sutured them together. Then we made a transverse hole in the mid-portion of the patella; the tendons were passed through the transverse hole in the patella and sutured with the lateral, medial and intermendial vastus, and with the rectum femoral. At 6-month follow-up the patient has no pain and stability is improved, a practical range of knee motion regained. Full forceful extension is not completely restored.