The hypothesis of this study is that there are people running following a total knee arthroplasty (TKA).

The objective is (1) to determine if there are people that ran/run following their TKA and (2), in case (1) is true, to identify some general running parameters such as duration, frequency, perceived barriers for running.

Patients with a TKA and a score equal or higher than 9 on the UCLA activity scale at any time between 2 years prior to surgery and at present will be invited to participate in the trial by phone. All these patients will receive the study's information form and questionnaire by post with a pre-stamped envelope to return the documents.The survey was created and piloted internally for this study. There are 21 questions, most of them are "yes or no" and some others open questions to assess parameters such as duration of difficulties faced. The questionnaire is composed of three parts. The first part is interested in the preoperative activity (during the 2 years before surgery), the second part in the postoperative activity (during the 2 years after surgery) and the third part refers to the current practice. For each part, people are asked about specific practice parameters and modalities. Furthermore, we seek to determine whether there was/is a willingness to run following TKA, if patients receive any education/information about it and their personal attitudes towards running with a TKA. The anonymized data will be collected by the main author for subsequent analysis.

Inclusion Criteria:

• TKA and UCLA score = or > 9

Exclusion Criteria:

• Inability to read/write in french language
• Cognitive or neurological impairment

Human adults that underwent a TKA at the investigator's Hospital and with data available on the Institution's Implants Registry