The objective of this clinical trial is provide in vivo data thus to model the ligament biomechanical behavior within the physiologically healthy joint and to use the implemented model to predict risk and success rates focusing on knee joint Anterior Cruciate Ligament (ACL) reconstruction. Current ACL surgery offers 3 alternatives: autografts, allografts and bioengineered grafts; the choice of the implant and its characteristics still remains a critical point. The knowledge of patient-specific joint and graft biomechanics is fundamental to reduce surgical revision rate and low functional outcome. This clinical trial will provide data coming from patient-specific biomechanics into a prognostic computational model, able to provide information on both the optimal customized reconstruction and graft status during the early rehabilitation phase. This patient-specific approach will lead to quicker return to sports activity, reducing also the possibility of early osteoarthritis.

Inclusion Criteria:

• Primary ACL lesion
• Ability to read and sign the informed consent.
• Age between 16 and 50 years old

Exclusion Criteria:

• Prior surgeries at the same knee
• Grade II or higher lesions at the collateral ligaments
• Posterior Cruciate Ligament lesion
• Inflammatory arthritis or other forms systemic inflammatory diseases
• Local or systemic infections
• Any injury or condition that adversely affects the ability to walk or to participate to I/II level activities
• Previous or concomitant lesions at the contralateral knee
• Skeletal immaturity
• Other potential risk factors for the development of osteoarthritis

Patients with primary lesion of the anterior cruciate ligament (ACL), assessed by clinical manouvers and confirmed by means of MRI.