Osteoarthritis is the most common affection of joints worldwide. Multiple international guidelines on the approach and treatment of knee osteoarthritis are available. Nevertheless there seems to be a gap between usual care and the preferred one.

A vigorous set of evidence-based quality indicators on osteoarthritis diagnosis and therapy was developed by a multidisciplinary expert team. This project aims to map usual care and to explore the gaps between usual care and international guidelines in a second stage. This will enable us to develop a tightly targeted quality improvement intervention later on.

Inclusion Criteria:

• Diagnosis of knee osteoarthritis

Exclusion Criteria:

• Knee replacement surgery
• Acute trauma (recruitment by orthopedic surgeons)

General Practice: Based on the electronic patient files of general practiotioners of the MEDIDOC users-group (an electronic software package) a list will be generated of patients diagnosed with knee osteoarthritis. A random sample of these patients will be addressed to take part into the study by a questionnaire.

Orthopedic Surgery: Patients, consulting orthopedic surgeons for knee osteoarthritis will receive a patient questionnaire.

Physiotherapy: Patients, recruited by general practitioners and orthopedic surgeons will be asked about the care they received by their physiotherapist. Moreover physiotherapists will be recruited by the national association of physiotherapists to complete a questionnaire about the care they usually deliver.