To demonstrate that the deficit in dorsiflexion-tibia-talar joint range of motion can have an effect on the knee operated by arthroplasty by limiting full extension and, in general, the recovery of a full range of motion.

The study is of a prospective, prognostic, observational nature and involves all patients who are candidates for admission to the Rizzoli Orthopaedic Institute for primary knee replacement surgery, recruited in the Orthopaedics department and subsequently followed in the Rehabilitation Medicine department of the DRS. The recruited patients will be subjected to pre-operative measurement of the ankle ROM; if they present a limitation of the same, they will be included in the exposed group, alternatively they will be included in the non-exposed group.

Inclusion Criteria:•

• Patients who are candidates for primary total knee replacement surgery aged 65 to 85 years;
• Patients who have provided informed consent Exclusion Criteria:•
• Patients with known neurological pathologies
• Severe joint deformations such as previous ankle surgery (arthrodesis, ankle prosthesis) congenital malformations (cavus equinus, clubfoot)
• Severe fractures that have compromised the joint
• Traumatic events affecting the lower limb that occurred less than 12 months
• Non-ambulatory patients in the preoperative period

To demonstrate in a Physical Medicine and Rehabilitation department that the deficit in dorsiflexion-tibia-talar joint range of motion can have an effect on the knee operated on with arthroplasty by limiting complete extension and, in general, the recovery of a complete range of motion.