Inclusion Criteria:  Informed Consent signed by the subject Aged between 40 to 80 years Early to mid-stage (KL 1 - 3) OA of the medial compartment of the knee based on X-ray and MRI images Plano-valgus foot deformity based on clinical assessment Availability of conventional radiographs, long-leg films, and a knee-MRI no older than 1 year at time of inclusion Ability to walk without walking aid for more than 15min  Exclusion Criteria:  Contraindications and limitations of the MD as described in the instructions for use. Inability to follow the procedures of the investigation, e.g. due to language problems, psychological disorders, dementia, etc. of the subject, Enrolment of the PI, his/her family members, employees and other dependent persons Relevant OA (Kellgren-Lawrence-Score >2) of the lateral compartment of the knee based on X-ray and MRI images BMI higher than 40 kg/m Fix varus deformities over 20 degrees Neurological or rheumatoid diseases of any kind History of high tibial osteotomy, other realignment surgery of the knee or foot Foot or ankle problems that contraindicated the use of footwear load-modifying interventions Relevant ligamentous instability