This is a prospective randomized double-blind controlled clinical trial with parallel arms and 1:1 allocation.

The main objective of the BIOMAT project is to demonstrate, through an RCT, whether the combined approach by knee osteotomy and MAT can provide clinical improvement over knee osteotomy alone for the treatment of patients with monocompartmental knee OA associated with meniscal insufficiency and lower extremity malalignment. Secondary objectives are to demonstrate whether the addition of MAT to knee osteotomy in patients with monocompartmental OA can improve biomechanical parameters and whether this treatment has protective effects on the joint environment and cartilage degeneration.

Patients with single-compartment arthritic pathology of the knee, axial deviation and meniscal deficit, for whom a surgical indication of corrective osteotomy is placed, will be recruited into the study.

Enrollment takes place during hospitalization and is by the physician. All patients will undergo a knee osteotomy to achieve proper alignment of the lower limb and an arthroscopic procedure to macroscopically verify the status of the cartilage and menisci, with associated minor procedures for surgical cleanup when necessary. After intraoperative confirmation of inclusion criteria (complete meniscal deficit and absence of severe articular cartilage impairment) all patients will undergo synovial biopsy and synovial fluid sampling, half of the patients will also undergo arthroscopic homologous meniscus transplantation.

Clinical, biomechanical and biological evaluations will be performed:

Clinical evaluation of the patient will be done through validated questionnaires before surgery and at 1-3-6-12 months. These will document subjective clinical improvement, functional measurements, and imaging using radiographs as per clinical practice and MRI.

Pitch Analysis will be used for biomechanical assessments, and will be performed before surgery and at 12-month follow-up after surgery for all patients enrolled in the two groups.

basal inflammation will be assessed on synovial tissue and synovial fluid samples collected after intraoperative confirmation of patient inclusion criteria (complete meniscal deficit and absence of severe articular cartilage impairment). Serum/plasma and urine samples will be collected before surgical treatment and at 1-3-6-12 months follow-up.

Inclusion Criteria:

1. Male or female patients aged between 20 and 60 years;
2. Single-compartment tibiofemoral osteoarthritis (Kellgren-Lawrence grade ≤ 3);
3. Surgical indication of corrective osteotomy (axial deviation of lower extremities > 5°);
4. Meniscal deficit of the compartment affected by the overload due to malalignment;
5. Ability and consent of patients to actively participate in the rehabilitation protocol and clinical and radiological follow-up (RX and MRI)
6. Signature of informed consent

Exclusion Criteria:

1. Patients who are incapacitated or have neurological disorders that may invalidate the research protocol;
2. Diagnosis of neoplastic diseases;
3. Diagnosis of rheumatoid arthritis, Reiter's syndrome, psoriatic arthritis, gout, ankylosing spondylitis or arthritis resulting from another inflammatory disease; human immunodeficiency virus (HIV) infection, viral hepatitis; chondrocalcinosis;
4. Patients with uncontrolled diabetes mellitus;
5. Patients with uncontrolled thyroid metabolic disorders;
6. Patients abusing alcoholic beverages, drugs or medications;
7. Body Mass Index > 40;
8. Pregnancy or lactation status or intention to become pregnant during the period of study participation;
9. Patients undergoing knee surgery in the previous 12 months.

We will be able to share a subset of aggregated data, wich will not allow for the identification of participants.

Clinical evaluations will be carried out by medical personnel not involved in treatment to ensure double-blinding