The Hospital for Special Surgery (HSS) Knee Surgery Expectations Survey is a 17 item questionnaire. The survey is comprised of five different categories of expectations: pain, walking, psychological state, essential activities and non-essential activities. The responses range from ''very important'' (score: 1) to ''this does not imply to me'' (score: 5). The total summed raw score ranges from 0 to 76 and the transformed score [ = (raw score/76)×100] ranges from 0 to 100. Higher scores indicate expecting more improvement for more items.

Information on pain is collected by the so called "painDETECT" questionnaire, a self-reported screening tool for the identification of neuropathic pain. The questionnaire contains seven weighted sensory descriptors, one item relating to spatial pain characteristics and one item relating to temporal characteristics. A total score ranging from -1 to 38 can be calculated. The total score is divided into three categories (unlikely neuropathic pain (<13), unclear (13-18), likely neuropathic pain (>18)).

Based on a single question 9 months after surgery patients are asked to grade their level of satisfaction with the methodology and rehabilitation procedure. They can choose between "very dissatisfied", "dissatisfied", "satisfied" or "very satisfied".

The Net Promoter Score (NPS) is an index ranging from -100 to 100 that measures the willingness of patients to recommend the treatment to others. It is used as a proxy for gauging the patient's overall satisfaction with a treatment. Patients are surveyed on one single question. They are asked to rate on an 11-point scale the likelihood of recommending the treatment to a friend or colleague. "On a scale of 0 to 10, how likely are you to recommend the same treatment to a friend or a colleague?" Based on their rating, customers are then classified in 3 categories: detractors, passives and promoters. 'Detractors' gave a score lower or equal to 6. 'Passives' gave a score of 7 or 8. 'Promoters' answered 9 or 10. The NPS is determined by subtracting the percentage of customers who are detractors from the percentage who are promoters.

The Depression, Anxiety and Stress Scale - 21 Items (DASS-21) is a set of three self-report scales designed to measure the emotional states of depression, anxiety and stress. Each of the three DASS-21 scales contains 7 items with a four point rating scale (ranging 0 - 3 points) for each item. The depression scale assesses dysphoria, hopelessness, devaluation of life, self-deprecation, lack of interest / involvement, anhedonia and inertia. The anxiety scale assesses autonomic arousal, skeletal muscle effects, situational anxiety, and subjective experience of anxious affect. The stress scale assesses difficulty relaxing, nervous arousal, and being easily upset / agitated, irritable / over-reactive and impatient. The total score is calculated by summing the scores for the relevant items, the minimum score is 0 points, the maximum score for each section is 21. A lower score represents less depression, anxiety and stress.

The active Range of Motion (ROM) is measured with the BPMpathway sensor and application 3 times per day for the entire duration of usage of the sensor. In general, the sensor is used for pre- and postoperative training. Patients are expected to use the sensor from pre-op consultation up to 3 month after surgery.