The goal of this clinical trial is to learn whether robotic-assisted total knee replacement improves recovery compared with conventional total knee replacement in adults with knee osteoarthritis when both groups follow the same structured home-based rehabilitation program. Robotic-assisted and conventional (non-robotic) total knee replacement are both widely used as part of routine clinical care. This study will compare recovery during the first six weeks after surgery. The main questions the study aims to answer are: 1. Does robotic-assisted total knee replacement improve knee pain and knee function six weeks after surgery compared with conventional total knee replacement? 2. Does robotic-assisted surgery improve physical function, walking ability, leg strength, quality of life, and participants' experience of rehabilitation? 3. Are there any differences in recovery, length of hospital stay, or safety between the two surgical approaches? Researchers will compare robotic-assisted total knee replacement with conventional total knee replacement. Both groups will complete the same rehabilitation program before and after surgery so that any differences in recovery are more likely to be related to the type of surgery rather than differences in rehabilitation. Participants will: * Be randomly assigned (by chance, similar to flipping a coin) to receive either robotic-assisted or conventional total knee replacement surgery. * Complete a structured rehabilitation program that includes education and exercises during the four weeks before surgery and a home-based exercise program for six weeks after surgery. * Use a study-provided seated exercise bike, receive support from a physiotherapist through telehealth appointments, secure messaging, and home visits where required, and use a digital application to guide the rehabilitation program and record exercise completion and symptoms. * Complete questionnaires about knee pain, knee function, general health, quality of life, and satisfaction with the rehabilitation program. * Attend study assessments before surgery, immediately before surgery after completing the pre-surgery program, and about six weeks after surgery. These assessments include simple physical activities such as standing up from a chair, walking, cycling, and measuring leg strength. * Allow information about their surgery and hospital stay, such as the duration of surgery and the number of nights spent in hospital, to be recorded for the study. The results of this study will help researchers understand whether robotic-assisted total knee replacement provides additional benefits over conventional total knee replacement when both are combined with the same structured home-based rehabilitation program. The findings may help patients, healthcare professionals, and health services make informed decisions about the use of robotic-assisted knee replacement surgery.
Total knee replacement, also known as total knee arthroplasty (TKA) is an effective treatment for people with end-stage knee osteoarthritis who continue to experience pain and functional limitation despite non-surgical management. Advances in enhanced recovery pathways have shortened hospital stays, with much of the recovery process now occurring at home during the first few weeks after surgery. As a result, both surgical technique and postoperative rehabilitation may influence early recovery. Robotic-assisted TKA has been introduced to improve the precision and consistency of implant positioning and alignment. Although robotic systems have demonstrated improvements in surgical accuracy compared with conventional techniques, evidence that these technical advantages translate into clinically meaningful improvements in early patient outcomes remains inconsistent. Previous comparative studies have varied substantially in peri-operative care pathways, rehabilitation protocols, outcome assessment, and follow-up, making it difficult to determine whether differences in recovery are attributable to the surgical technique itself or to differences in postoperative management. This trial has been designed to evaluate robotic-assisted and conventional TKA within an identical, structured peri-operative rehabilitation pathway. By standardising rehabilitation, participant education, postoperative support, and follow-up across both treatment groups, the study aims to minimise variation in postoperative care and provide a clearer assessment of whether robotic assistance offers additional benefit beyond conventional surgical techniques. The study also reflects contemporary models of arthroplasty care that increasingly incorporate virtual rehabilitation, telehealth, remote monitoring, and home-based exercise. Evaluating surgical techniques within a standardised virtual care programme provides evidence that is directly relevant to current clinical practice, where much of early recovery occurs outside the hospital setting. This study is a prospective, single-centre, parallel-group randomised controlled trial conducted at St John of God Murdoch Hospital in Western Australia. Approximately 60 adults undergoing primary TKA for radiographically confirmed knee osteoarthritis will be randomly allocated in a 1:1 ratio to receive either robotic-assisted or conventional surgery performed as part of routine clinical care by experienced orthopaedic surgeons. Participants, outcome assessors, and data analysts will remain blinded to treatment allocation wherever feasible. Because the operating surgeon must perform the allocated procedure, surgeons cannot be blinded. The study focuses on the first six weeks after surgery, corresponding to completion of the structured early rehabilitation programme and the period during which most patients experience the greatest improvements in pain, mobility, and physical function. Analyses will follow the intention-to-treat principle. Participants allocated to either treatment group will undergo the same clinical pathway before and after surgery. Both robotic-assisted and conventional TKA are established procedures routinely used in contemporary orthopaedic practice. Following surgery, all participants will complete the same six-week virtual comprehensive care programme, incorporating pre-operative preparation, structured home-based rehabilitation, physiotherapist supervision, telehealth consultations, digital messaging, remote monitoring, and exercise progression. The rehabilitation programme has been standardised to ensure that postoperative management is equivalent for both treatment groups, allowing any observed differences in recovery to be interpreted in the context of the surgical technique rather than differences in rehabilitation. Recovery will be evaluated using a combination of patient-reported questionnaires, clinical assessments, physical performance tests, and biomechanical measures collected at predefined time points before and after surgery. These assessments are designed to provide a comprehensive evaluation of early recovery by examining symptoms, physical function, strength, walking performance, movement quality during functional tasks, rehabilitation engagement, and patient experience. By combining conventional clinical outcome measures with objective biomechanical assessment, the study aims to provide a detailed understanding of how recovery progresses during the early postoperative period and whether differences between surgical techniques are reflected in both patient-reported outcomes and physical performance. This trial addresses an important evidence gap by evaluating robotic-assisted and conventional TKA within an identical, contemporary rehabilitation programme. By reducing variation in postoperative care, the study is designed to isolate the contribution of surgical technique to early recovery. The findings will improve understanding of the comparative effectiveness of robotic-assisted and conventional TKA during the first six weeks after surgery and may assist patients, clinicians, and health services when making decisions regarding surgical technology and peri-operative care pathways. More broadly, the study will contribute evidence regarding the integration of surgical innovation with structured, digitally supported rehabilitation programmes and may inform future models of patient-centred arthroplasty care.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
60
Primary total knee arthroplasty performed using an approved robotic-assisted surgical system by an experienced orthopaedic surgeon. Robotic assistance is used for pre-operative planning and/or intra-operative execution of bone resections and component positioning in accordance with the manufacturer's instructions for use and the surgeon's standard clinical practice.
Primary total knee arthroplasty performed using conventional manual instrumentation without robotic assistance by an experienced orthopaedic surgeon. Surgical technique follows standard clinical practice.
A standardized hybrid virtually-assisted comprehensive peri-operative care program delivered before and after surgery. The program comprises a 4-week pre-operative preparation phase followed by a 6-week post-operative rehabilitation phase. It includes patient education, home-based cycling and non-cycling exercises, telehealth consultations, tele-messaging support, remote monitoring, limited in-person physiotherapy services, and symptom-contingent, rule-based exercise progression. The program is delivered identically to both study groups using standardized, protocol-defined procedures.
Oxford Knee Score (OKS), a composite patient-reported outcome measure of knee-related pain and functional limitation.
Oxford Knee Score questionnaire (validated 12-item patient-reported outcome measure assessing knee-related pain and functional limitation, combined into a single score ranging from 0 to 48, with higher scores indicating better knee-related health status).
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Adherence to the virtual comprehensive care program
Adherence will be defined as the proportion of prescribed exercise sessions completed over the intervention period, based on session completion logs recorded in the digital rehabilitation platform and study-specific database. Additional data captured by the platform, including cycling metrics (e.g., cadence and power output) and participant-reported pain and perceived exertion, will be used to support physiotherapist monitoring and exercise progression but are not included in the calculation of adherence.
Time frame: Continuously throughout the peri-operative program via the digital platform and summarised weekly (pre-operative weeks 1-4 and post-operative weeks 1-6), with a final cumulative adherence value at 6 weeks post-surgery.
Program completion of the virtual comprehensive care program
Program completion will be determined from records within the digital rehabilitation platform and study-specific database, defined as participation through the full intervention period (4-week pre-operative and 6-week post-operative phases), as documented by session completion logs and physiotherapist records.
Time frame: Assessed at completion of the peri-operative program (6 weeks post-surgery).
Tourniquet time
Provided by the operating surgeon and recorded in the study database using the participant's study identification code.
Time frame: During the total knee arthroplasty procedure.
Hospital length of stay
Hospital length of stay, measured in days from hospital admission to hospital discharge for the index admission for total knee arthroplasty, provided by the operating surgeon and recorded in the study database.
Time frame: From hospital admission until hospital discharge, assessed up to 30 days.
KOOS-JR (Knee Injury and Osteoarthritis Outcome Score - Joint Replacement), a composite patient-reported outcome measure of knee-related symptoms and functional limitation reflecting overall knee-related health status.
KOOS-JR questionnaire (validated patient-reported outcome measure assessing knee-related symptoms and functional limitation, combined into a single score ranging from 0 to 100, with higher scores indicating better knee-related health status).
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Health-related quality of life
EQ-5D-5L questionnaire (validated generic, preference-based measure of health-related quality of life generating a utility index score anchored at 0 \[death\] and 1 \[full health\]).
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Knee pain intensity
Patient-reported pain intensity of the operated knee measured using an 11-point Numeric Rating Scale (NRS), where 0 = no pain and 10 = worst pain imaginable.
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Thigh circumference of the operated limb
Thigh circumference of the operated limb measured using a non-elastic anthropometric tape measure at a standardised distance (10 cm proximal to the superior pole of the patella), with the participant in supine and the knee extended.
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Calf circumference of the operated limb
Calf circumference of the operated limb measured using a non-elastic anthropometric tape measure at the point of maximal calf girth, with the participant in prone and the measurement location standardised relative to the fibular head.
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Active knee flexion end-range angle of the operated limb
Maximum active knee flexion angle of the operated limb with the participant in supine performing a heel slide, measured using a goniometer.
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Active knee extension end-range angle of the operated limb
Maximum active knee extension angle of the operated limb with the participant in supine and the heel supported to allow full knee straightening, measured using a goniometer.
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Passive knee extension end-range angle of the operated limb
Maximum passive knee extension angle of the operated limb with the participant in supine and the heel supported to allow full knee straightening, measured using a goniometer with gentle examiner-applied overpressure.
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Walking speed
10 metre walk test (10MWT), recorded as time to traverse the central 10 m at maximal walking speed using a standardised acceleration and deceleration protocol.
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Step length symmetry during walking
Gait symmetry derived from wearable inertial measurement units during a 10-metre walk test, quantified as the mean symmetry ratio of step length between the operated limb and contralateral limb across all gait cycles of the walk test, with a value of 1 indicating perfect symmetry.
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Peak knee flexion angle during swing phase of walking.
Sagittal plane knee joint kinematics derived from wearable inertial measurement units during a 10-metre walk test, quantified as peak knee flexion angle of the operated knee during the swing phase. Peak knee flexion values are averaged across all steps recorded during the walk test.
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Double support time during walking
Temporal gait characteristics derived from wearable inertial measurement units during a 10-metre walk test, quantified as double support time expressed as a percentage of the gait cycle. Double support time values are averaged across all gait cycles recorded during the walk test.
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Sit-to-stand performance
Five Times Sit-to-Stand Test (5xSTS), recorded as the time (seconds) taken to complete five sit-to-stand repetitions from a standard chair as quickly as possible without use of the upper limbs.
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Sit-to-stand loading symmetry
Measured during the Five Times Sit-to-Stand test using dual force plates, quantified as the mean symmetry ratio of peak vertical ground reaction force between the operated and non-operated limbs across the five sit-to-stand repetitions, with a value of 1 indicating perfect symmetry.
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Sit-to-stand knee extensor moment
Measured during the Five Times Sit-to-Stand test using dual force plates and wearable inertial measurement units, quantified as the peak sagittal-plane knee extension moment of the operated limb during the rising phase, averaged across the five repetitions.
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Isometric knee flexion strength of the operated limb.
Maximum isometric knee flexion torque of the operated limb measured using a fixed force frame.
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Isometric knee extension strength of the operated limb
Maximum isometric knee extension torque of the operated limb measured using a fixed force frame.
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Operated limb muscle power (peak power output, Watts)
Operated limb muscle power will be measured using a standardised cycle ergometer sprint test. Participants perform three 10-second maximal seated sprint efforts on a stationary cycle, with 1-minute recovery between efforts. Power output (Watts) is recorded using a dual-sided crank-based power meter, enabling separate measurement of left and right limb power. Peak power output is defined as the highest power value (Watts) recorded for the operated limb across the three sprint efforts.
Time frame: Baseline (4 weeks pre-operative), pre-surgery (after completion of the pre-operative program), and 6 weeks post-surgery.
Patient satisfaction with care
Patient satisfaction measured using the Net Promoter Score (NPS) questionnaire (0-10 scale, summarised as Net Promoter Score).
Time frame: 6 weeks post-surgery.
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