The study proposes to compare performances and safety of intra-articular injections of aMAT with those of a control group (PRP injections) for the treatment of symptomatic OA of the knee. The end-points will be determined evaluating the performances of the treatment group in terms of improvement of the symptomatology, functional recovery and radiological appearance.

The clinical trial is a prospective, randomized, controlled, two-arm, single-blind study, involving 118 patients affected by symptomatic OA of the knee joint. Eligible subjects will be randomly allocated to one of the two treatment groups, with a 1:1 randomization ratio. Respectively, 59 patients treated with a single intra-articular injection of aMAT, and 59 patients treated with a single intra-articular injection of PRP.

The patients enrolled in the study will be treated according to the study protocol and followed after treatment with periodic visits and diagnostic imaging examinations, as Magnetic Resonance Imaging at twelve and twenty-four months follow-up and X-Ray, at three, six, twelve, and twenty-four months of follow-up.

Inclusion Criteria

1. Patients provided written informed consent;
2. Patients aged between 18 and 75 years;
3. Knee symptomatic OA (Kellgren-Lawrence grade 1-4)
4. Failure of conservative treatment for at least 3 months;
5. Patients agreed to actively participate in the rehabilitation protocol and follow-up program;
6. Male or female patients;
7. Women of childbearing age had to use a proven method to prevent pregnancy, before the surgical treatment.

Exclusion Criteria

1. Patients incapable to understanding and will;
2. Patients participating in previous, concurrent or not, trials (ongoing or completed within three months);
3. Patients surgically treated for the same defect within one year;
4. Patients affected by malignancy;
5. Patients affected by metabolic or thyroid disorders;
6. Patients used to alcohol or drug (medication) abuse;
7. Patients affected by synovitis;
8. Varus or valgus misalignment exceeding 15°;
9. Body Mass Index > 40;
10. Patients with trauma within 6 months pre-operative.