Rationale for conducting the study: The ROCKET study evaluates the clinical and economic outcomes of robot-assisted total knee arthroplasty (RTKR) compared with conventional total knee arthroplasty (TKR). The primary endpoint is the proportion of randomized participants achieving a Forgotten Joint Score (FJS) of ≥80 points at 24 months after surgery. Secondary outcomes include patient-reported knee function, health-related quality of life, self-reported instability, physical activity, radiographic alignment, surgical and technical outcomes, complications, reoperations, revisions, and health-economic outcomes. Study design: International multicentre, preference-tolerant, randomized, controlled superiority trial with two treatment arms comparing RTKR with conventional TKR. Participants in the randomized part are allocated 1:1. At selected centres where feasible, an optional participant-blinded randomized component may be implemented. Eligible patients who do not undergo randomization may participate in a parallel observational/preference cohort, which is analysed separately from the primary randomized comparison. Study population: Adults aged 18 years and older who are eligible for total knee arthroplasty according to local guidelines and who provide informed consent. Number of patients: Up to 1,600 randomized participants. Eligible non-randomized participants may additionally be included in the observational/preference cohort. Primary outcome: Proportion of randomized participants achieving FJS ≥80 points at 24 months after surgery. Long-term follow-up: Patient-reported and registry-based outcomes are planned at 5 and 10 years after surgery where feasible.
The ROCKET study is an international multicentre, prospective, preference-tolerant randomized controlled superiority trial comparing robot-assisted total knee arthroplasty with conventional total knee arthroplasty. Participants in the randomized component are allocated 1:1 to robot-assisted or conventional total knee arthroplasty. Randomization is stratified by participating centre and sex. At selected centres where practical and approved, participants may remain blinded to treatment allocation until completion of the 24-month follow-up unless earlier unblinding is clinically required or requested by the participant. Surgeons and operating-room personnel cannot be blinded. Outcome assessment is performed blinded to treatment allocation whenever feasible. Eligible patients who are unwilling to undergo randomization, or for whom treatment equipoise cannot be achieved, may enter a parallel observational/preference cohort. Treatment in this cohort follows patient and surgeon preference. The observational/preference cohort is analysed separately from the primary randomized comparison. The primary endpoint is the proportion of randomized participants achieving a Forgotten Joint Score (FJS) of ≥80 points at 24 months after surgery. Follow-up includes patient-reported outcomes, activity, radiographic alignment, surgical and technical variables, complications, reoperations, revisions and health-economic outcomes. Long-term follow-up is planned at 5 and 10 years after surgery, including PROMs where available and registry-based outcomes such as reoperations, revisions, complications and mortality.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
1,600
Robot-assisted total knee arthroplasty using an approved robotic surgical system to assist intraoperative planning, bone preparation, implant positioning and balancing according to the participating centre's approved technique.
Conventional total knee arthroplasty using standard manual instrumentation according to local clinical routine.
Hässleholm Hospital
Hässleholm, Sweden
RECRUITINGDanderyd Hospital
Stockholm, Sweden
RECRUITINGProportion of participants achieving a Forgotten Joint Score (FJS) ≥80 points
The primary endpoint is the proportion of randomized participants achieving an FJS of ≥80 points at 24 months after surgery. The FJS ranges from 0 to 100, with higher scores indicating less awareness of the replaced knee during everyday activities.
Time frame: 24 months after surgery
Forgotten Joint Score (FJS), continuous score
FJS is scored from 0 to 100, with higher scores indicating less awareness of the replaced knee.
Time frame: Baseline, 6 weeks, 12 months, 24 months, 5 years and 10 years after surgery
Knee injury and Osteoarthritis Outcome Score (KOOS)
KOOS assesses knee-related pain, symptoms, activities of daily living, sport/recreation and knee-related quality of life. Each subscale ranges from 0 to 100, with higher scores indicating better outcome.
Time frame: Baseline, 6 weeks, 12 months, 24 months, 5 years and 10 years after surgery
Self-reported knee instability (ADLS items)
Self-reported slipping/partial giving way and buckling/full giving way are assessed using items from the Activities of Daily Living Scale of the Knee Outcome Survey.
Time frame: Baseline, 6 weeks, 12 months, 24 months, 5 years and 10 years after surgery
EQ-5D and EQ VAS
Health-related quality of life is assessed using EQ-5D and EQ VAS.
Time frame: Baseline, 6 weeks, 12 months, 24 months, 5 years and 10 years after surgery
Patient activity and walking distance
Patient activity and walking distance are assessed during follow-up using the study's prespecified activity measurements.
Time frame: Baseline, 6 weeks, 12 months, 24 months, 5 years and 10 years after surgery
Knee alignment
Coronal knee alignment is assessed using long-standing radiographs, including Hip-Knee-Ankle alignment and Coronal Plane Alignment of the Knee (CPAK) classification.
Time frame: Preoperative and approximately 6 weeks after surgery
Surgery time
Duration of the surgical procedure is recorded in minutes.
Time frame: During the index operation
Technical and intraoperative surgical outcomes
Technical difficulties and prespecified intraoperative surgical details are recorded.
Time frame: During the index operation
Range of motion (ROM)
Knee range of motion is assessed at the 24-month follow-up.
Time frame: 24 months after surgery
Reoperations and revisions
Reoperations and revisions of the index knee are recorded during the primary study period and assessed during long-term follow-up where data are available.
Time frame: Up to 24 months, with additional follow-up at 5 and 10 years
Adverse events and complications
Adverse events and complications related to the index knee arthroplasty are recorded. Long-term complications may additionally be assessed using approved registry or other data sources.
Time frame: Up to 24 months, with additional long-term assessment at 5 and 10 years
Mortality
Mortality is assessed using available approved registry or other data sources.
Time frame: 90 days, 1 year, 5 years and 10 years after surgery
Health-economic outcomes
Health-economic analyses include direct and indirect costs and cost-effectiveness using health-related quality-of-life data.
Time frame: Up to 24 months; exploratory long-term analyses at 5 and 10 years where data are available
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