This study is conducted to assess whether implanting autologous, culture-expanded, mesenchymal stem cells obtained from the bone marrow of patients with early osteoarthritis, cartilage defects or cartilage and underlying bone and cartilage (osteochondral) defects in joints is effective in the treatment of such conditions and alleviation of patients symptoms.

All procedures are carried out after obtaining informed written consent from patients. Bone marrow is aspirated from the iliac crest (hip bone) of patients with osteochondral defects intraoperatively under complete sterile, aseptic conditions and under proper anaesthesia (general, local). The bone marrow aspirate is placed in tubes and transferred under aseptic conditions to the Tissue Culture Unit in the Biochemistry Department at the Cairo University School of Medicine where it is processed and bone marrow mesenchymal stem cells are isolated and grown in culture for 2-3 weeks. After this time interval, the cells are reprocessed and the cell pellet is obtained. Implantation of the cell pellet into the osteochondral defect of the joint after embedding it on a proper scaffold is performed followed by subsequent defect coverage with an autologous periosteal flap obtained from the proximal tibia to seal the defect and maintain the cell pellet in place. The patients will be assessed clinically with scoring systems preoperatively as well as 6 and 12 months postoperatively to assess relief of symptoms and joint function. Radiological assessment (X-rays and MRIs)of the affected joints will be performed at the same time points aforementioned to assess integrity of the formed cartilage. Second look arthroscopy and biopsy will also be performed to histologically assess the repair tissue and grade it via arthroscopic grading system according to the International Cartilage Repair Society guidelines.

Inclusion Criteria:

• Active patients (15 to 55 years).
• An isolated osteochondral defect (i.e., in a joint with an otherwise healthy articular surface - with cartilage on the opposing surface no more than grade 1 or 2 Outerbridge at the most.
• A defect that is 1 - 4 cm2 or more (up to 16 cm2).

Exclusion Criteria:

• Patients younger than 15 years and older than 55 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.
• Kissing lesions (i.e., on both opposing surfaces of a joint).
• 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.