This study evaluates the feasibility of a short-term, digitally supported prehabilitation program for patients scheduled for elective total knee replacement (TKR). Osteoarthritis is a leading cause of disability, and recovery following TKR remains heterogeneous, with a substantial proportion of patients experiencing delayed functional recovery. Prehabilitation may improve perioperative outcomes, but its implementation is often limited by short preoperative time windows. The Prehab2Rehab-KneeTEP trial is a single-center, two-arm, randomized controlled feasibility study conducted in Austria. Patients will be randomized (1:1) to either a multimodal video-supported prehabilitation program or usual care. The intervention consists of a 10 to 14-day preoperative exercise program including strength, endurance, coordination, and gait training, supported by a digital application, and is complemented by a digitally supported transition phase after hospital discharge until the start of inpatient rehabilitation. The primary objective is to assess feasibility in terms of recruitment, retention, adherence, fidelity, acceptability, and safety. Secondary exploratory outcomes include clinical recovery indicators, functional performance, and patient-reported outcomes assessed across the perioperative pathway.
Total knee replacement (TKR) is an effective treatment for advanced knee osteoarthritis, yet postoperative recovery remains heterogeneous, with a substantial proportion of patients experiencing persistent functional limitations. Prehabilitation has the potential to optimize patients' physical and psychological readiness before surgery. However, in clinical practice, prehabilitation is often constrained by limited time between surgical indication and procedure. Digitally supported interventions may offer a feasible solution to deliver structured programs within short timeframes while supporting continuity of care across the perioperative pathway. The Prehab2Rehab-KneeTEP trial is a single-center, randomized, two-arm feasibility study conducted at the Medizinisches Zentrum Bad Vigaun, Austria. The study aims to evaluate the feasibility, acceptability, and safety of a short-term, digitally supported prehabilitation intervention in patients scheduled for elective TKR. Eligible patients with advanced knee osteoarthritis will be randomized in a 1:1 ratio following baseline assessment (PRE1) to either (i) a multimodal video-supported prehabilitation intervention with an additional digitally supported transition phase or (ii) usual care. Randomization will be performed using computer-generated permuted blocks with stratification for sex and baseline functional capacity assessed by the 6-minute walk test. The intervention consists of a 10 to 14-day prehabilitation phase prior to surgery, including endurance, resistance, coordination, and gait training. The program is delivered through a combination of in-person instruction and home-based training supported by a digital application (aktivplan), which provides structured exercise guidance and enables documentation of adherence. A teleconsultation via a secure video platform (CAATS) is conducted to ensure exercise safety, provide feedback, and support progression. Sensor-based systems may be used for documentation and research-related measurements but are not used for clinical decision-making. Following surgery and hospital discharge, participants in the intervention group enter a digitally supported transition phase lasting approximately 10 to 14 days until the start of inpatient rehabilitation (REH1). During this period, patients receive low-threshold exercise guidance and educational content via the digital application to support early recovery, maintain mobility, and promote self-efficacy. Participants in both groups receive standard surgical care and standardized inpatient rehabilitation according to institutional and national guidelines. The total study participation duration is approximately 47 to 61 days, covering prehabilitation, hospital stay, transition, and rehabilitation phases. Outcomes are assessed at predefined time points along the perioperative pathway, including baseline (PRE1), end of prehabilitation (PRE2), hospital discharge, start of rehabilitation (REH1), and end of rehabilitation (REH2). The primary objective is to assess feasibility across multiple domains, including recruitment, retention, adherence, fidelity, acceptability, usability of digital tools, and safety. Feasibility outcomes will be evaluated descriptively across process, resource, management, and participant engagement domains. Secondary objectives are exploratory and include the assessment of clinical recovery indicators such as length of hospital stay, complication rate, and readmission rate, as well as patient-reported outcomes, anthropometric and body composition parameters, and functional performance measures. Given the feasibility nature of the trial, analyses will be descriptive and hypothesis-generating, without confirmatory statistical testing. The findings of this study will inform the design and implementation of a future adequately powered randomized controlled trial evaluating the effectiveness of digitally supported prehabilitation in patients undergoing total knee replacement
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
60
A short-term multimodal, video-supported prehabilitation program delivered over 10 to 14 days before surgery, including endurance, resistance, coordination, and gait training with crutches. The intervention is introduced during an in-person session and subsequently performed at home using a digital application to provide structured exercise guidance and support adherence. A single teleconsultation is conducted to ensure safety, provide feedback, and allow individualized progression. In addition, digital support is extended into the early post-discharge transition phase, providing low-threshold exercise guidance and educational content to support mobility, self-efficacy, and continuity of care until the start of inpatient rehabilitation.
Participants allocated to the usual care group will receive the standard perioperative treatment provided at the study site. This includes preoperative consultation, elective total knee replacement surgery according to institutional standards, and routine postoperative care. After hospital discharge, participants return home until the start of standardized inpatient rehabilitation (Phase II), including interdisciplinary care such as physiotherapy, occupational therapy, medical supervision, and health education. No structured prehabilitation or digitally supported intervention will be provided.
Medizinisches Zentrum Bad Vigaun GmbH & Co. KG
Hallein, State of Salzburg, Austria
Recruitment rate
The recruitment rate will be calculated as the percentage of eligible patients who consent to participate in the study. The reported value will be: (number of enrolled participants / number of eligible patients) × 100%.
Time frame: Continuous throughout the recruitment period (12 months recruitment period)
Retention Rate
Retention will be measured as the percentage of enrolled participants who complete all required study procedures. The reported value will be: (number of participants completing the study / number of enrolled participants) × 100%.
Time frame: Continuous throughout the data collection period (14 months data collection period)
Adherence to the Intervention
Adherence will be defined as the proportion of prescribed prehabilitation sessions that participants complete. The reported value will be: (number of completed sessions / number of prescribed sessions) × 100%.
Time frame: During the intervention period (typically 2-4 weeks prior to surgery).
Completeness of Outcome Data
Completeness of data will be assessed as the percentage of planned outcome assessments that are successfully completed and available for analysis. The reported value will be: (number of completed assessments / number of planned assessments) × 100%.
Time frame: Continuous throughout data collection period (14 months)
Acceptability of the Intervention
Acceptability and usability of the digital intervention will be assessed using the mHealth App Usability Questionnaire (MAUQ). The MAUQ evaluates usability, satisfaction, ease of use, and perceived usefulness of mobile health applications. Items are rated on a 7-point Likert scale, ranging from 1 = strongly disagree to 7 = strongly agree. The outcome will be reported as the mean MAUQ score across completed questionnaires, with higher scores indicating greater perceived usability and acceptability.
Time frame: At discharge from inpatient rehabilitation (REH2, approximately 6 to 8 weeks after surgery)
Health Assessment Questionnaire (HAQ)
Patient-reported outcome assessing functional ability in activities of daily living using the HAQ score. The instrument captures disability across multiple domains including dressing, arising, eating, walking, hygiene, reach, grip, and common daily activities. Total HAQ scores range from 0 to 3, with higher scores indicating greater functional impairment and lower functional status. The HAQ is used to evaluate changes in patient-reported functional status across the perioperative pathway.
Time frame: Baseline, prehabilitation discharge (10-14 days after baseline, before surgery), rehabilitation admission (3-4 weeks after surgery), rehabilitation discharge (6-8 weeks after surgery).
Barthel-Index (BI)
Observer-based outcome assessing functional independence in activities of daily living using the Barthel Index (BI). The instrument evaluates performance in domains including feeding, bathing, grooming, dressing, bowel and bladder control, toilet use, transfers, mobility, and stair use. Total BI scores range from 0 to 100, with higher scores indicating greater functional independence and lower dependency. The BI is used to evaluate changes in functional independence across the perioperative pathway.
Time frame: Baseline (prior to intervention), admission to inpatient rehabilitation (3-4 weeks post-surgery), discharge from inpatient rehabilitation (6-8 weeks post-surgery)
Oxford Knee Score (OKS)
Patient-reported outcome assessing knee-specific pain and functional status using the OKS score. The instrument captures difficulties in activities such as walking, standing, and rising from a seated position. Scores are calculated according to standard OKS procedures, with higher values indicating better knee function and lower symptom burden. The OKS is used to evaluate changes in knee-related symptoms and function across the perioperative pathway.
Time frame: Baseline (prior to intervention) and discharge from inpatient rehabilitation (6-8 weeks post-surgery)
Patient Health Questionnaire-4 (PHQ-4)
Patient-reported outcome assessing symptoms of anxiety and depression (PHQ-4). Total score ranges from 0 to 12, with higher values indicating greater psychological distress. Used to monitor changes in psychological well-being across the perioperative pathway.
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Time frame: Baseline (prior to intervention), after completion of prehabilitation (10-14 days after baseline, prior to surgery), admission to inpatient rehabilitation (3-4 weeks post-surgery), discharge from inpatient rehabilitation (6-8 weeks post-surgery)
Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)
Patient-reported outcome assessing knee pain, stiffness, and physical function (WOMAC). Higher scores indicate worse symptoms and functional limitations. Used to evaluate changes across the perioperative rehabilitation pathway.
Time frame: Baseline (prior to intervention), admission to inpatient rehabilitation (3-4 weeks post-surgery), discharge from inpatient rehabilitation (6-8 weeks post-surgery).
EuroQol-5 Dimensions-5 Levels (EQ- 5D-5L)
The EuroQol-5 Dimensions-5 Levels (EQ-5D-5L) is a standardized, patient-reported outcome measure assessing health-related quality of life across five dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Each dimension is rated on five levels of severity. Responses are converted into a health utility index score, with higher values indicating better health status. The instrument also includes a visual analogue scale (EQ-VAS), ranging from 0 to 100, with higher scores indicating better self-rated health.
Time frame: Baseline (prior to intervention), after prehab intervention (10-14 days post-baseline)), discharge (6-12 days post-surgery), admission to inpatient rehabilitation (3-4 weeks post-surgery), discharge from inpatient rehabilitation (6-8 weeks post-surgery).
Rapid Assessment of Physical Activity (RAPA)
Self-reported questionnaire assessing level of physical activity (RAPA). Scores reflect engagement in aerobic and strength-based physical activity, with higher scores indicating higher activity levels. Used to evaluate changes in physical activity behavior across the perioperative pathway.
Time frame: Baseline (prior to intervention), and discharge from inpatient rehabilitation (6-8 weeks post-surgery).
Exercise Self-Efficacy Scale (ESES)
Exercise Self-Efficacy Scale (ESES). Self-reported measure assessing confidence in the ability to perform and maintain physical activity. Total scores range from 10 to 40, with higher scores indicating greater exercise self-efficacy and therefore a better outcome. Used to evaluate changes in exercise-related confidence across the perioperative pathway.
Time frame: Baseline (prior to intervention), after prehab intervention (10-14 days post-baseline), discharge (6-12 days post-surgery), discharge from inpatient rehabilitation (6-8 weeks post-surgery).
Body Fat Mass
Body fat mass measured using bioelectrical impedance analysis (BIA). Body fat mass represents the total amount of body fat and will be reported in kilograms (kg).
Time frame: Baseline (prior to intervention) and discharge from inpatient rehabilitation (6-8 weeks post-surgery).
Body Lean Mass
Body Lean Mass measured using bioelectrical impedance analysis (BIA). Body Lean Mass represents the total amount of non-fat body tissue and will be reported in kilograms (kg).
Time frame: Baseline (prior to intervention) and discharge from inpatient rehabilitation (6-8 weeks post-surgery).
Phase Angle
Phase angle measured using bioelectrical impedance analysis (BIA). Phase angle is a marker of cellular integrity and body cell mass and will be reported in degrees (°).
Time frame: Baseline (prior to intervention) and discharge from inpatient rehabilitation (6-8 weeks post-surgery).
6-Minute Walk Test (6MWT)
The 6-Minute Walk Test (6MWT) is used to assess functional exercise capacity. Participants are instructed to walk as far as possible for six minutes along a standardized corridor, with distance covered recorded in meters. Standardized instructions and encouragement are provided according to established guidelines.
Time frame: Baseline (prior to intervention), admission to inpatient rehabilitation (3-4 weeks post-surgery), discharge from inpatient rehabilitation (6-8 weeks post-surgery).
Timed Up and Go Test (TUG)
The Timed Up and Go Test (TUG) assesses functional mobility. Participants are instructed to stand up from a seated position, walk a short distance, turn, return, and sit down, with the total time recorded in seconds under standardized conditions.
Time frame: Baseline (prior to intervention), after prehab intervention (10-14 days post-baseline), admission to inpatient rehabilitation (3-4 weeks post-surgery), discharge from inpatient rehabilitation (6-8 weeks post-surgery).
Single-Leg Stance (SLS)
The Single-Leg Stance (SLS) test assesses static balance. Participants are instructed to stand on one leg for as long as possible under standardized conditions, with time recorded in seconds.
Time frame: Baseline (prior to intervention), after prehab intervention (10-14 days after baseline), admission to inpatient rehabilitation (3-4 weeks post-surgery), discharge from inpatient rehabilitation (6-8 weeks post-surgery).
Fifteen-meter Gait Analysis with crutches (15-mGA+)
The Fifteen-meter Gait Analysis with crutches (15-mGA+) assesses gait performance under assisted walking conditions. Participants walk a standardized distance of 15 meters using crutches, with performance recorded under standardized conditions.
Time frame: Baseline (prior to intervention), after prehab intervention (10-14 days post-baseline), admission to inpatient rehabilitation (3-4 weeks post-surgery).
Ten-meter Walk Test without crutches (10-mWT)
The Ten-meter Walk Test without crutches (10-mWT) assesses gait speed. Participants are instructed to walk a standardized distance of 10 meters without assistive devices, with time recorded under standardized conditions.
Time frame: Baseline (prior to intervention), after prehab intervention (10-14 days after baseline), discharge from inpatient rehabilitation (6-8 weeks post-surgery).
Knee Range of Motion (ROM)
Knee Range of Motion (ROM) assesses joint mobility. Range of motion of the knee joint is measured in degrees under standardized conditions.
Time frame: Baseline (prior to intervention), discharge (6-12 days post-surgery), admission to inpatient rehabilitation (3-4 weeks post-surgery), discharge from inpatient rehabilitation (6-8 weeks post-surgery).
Lower limb strength (LLS)
Lower limb strength (LLS) assesses muscular strength of the lower extremities. Strength is measured using an isokinetic dynamometer (Biodex) under standardized conditions.
Time frame: Baseline (prior to intervention), after prehab intervention (10-14 days after baseline), admission to inpatient rehabilitation (3-4 weeks post-surgery), discharge from inpatient rehabilitation (6-8 weeks post-surgery).
Handgrip strength (HG)
Handgrip strength (HG) assesses upper limb muscle strength using a handheld dynamometer under standardized conditions.
Time frame: Baseline (prior to intervention) and discharge from inpatient rehabilitation (6-8 weeks post-surgery).