Inclusion Criteria:

- Active patients (30 to 75 years)

- A localized osteochondral defect of both condyle and/or tibia grade 4 (ICRS
classification)

- with cartilage on the tibial surface no more than grade 3-4, of size < 3-4 cm2, with
3/4 of meniscus present.

- Stable knee ; previous ligament reconstruction, if stable

- A defect that is 1 - 4 cm2 or more, up to 6 cm2, located on the femoral condyle and
/or less of 4 cm2 for tibial plate, and IKS score <75.

- Kissing lesions admitted

- Ability to understand and willingness to sign consent form

Exclusion Criteria:

- Patients younger than 30 years and older than 75 years

- Diffuse and advanced articular cartilage degeneration of the joint

- Axial malalignment, meniscal pathology, and ligamentous instability are relative
contraindications that have to be dealt with primarily either concomitantly or before
the transplantation during 1 of the 2 stages of the procedure. Refusal of the patient
to address these conditions in presence of a cartilage lesion is a criterion for
exclusion from the study, to avoid the impact of these knee pathologies on the final
results

- Existing infection in or around the joint & lesions of infectious or oncologic
etiology.

- Debilitated patients.

- Immunocompromised patients.

- Patients with autoimmune disorders & systemic inflammatory disease.

- Preoperative poor neurological or vascular status of the affected limb.

- Specific contraindications include the use of tobacco and medications that may impair
cell proliferation, such as NSAIDs and immunosuppressive drugs. Patients must be
nicotine-free (stop smoking) prior to the procedure, as studies have shown that the
oxidative effect of smoking impairs cell function and subsequent healing.