Knee Arthroplasty, TotalROCKETSNCT06389435
RObotic-assisted Versus Conventional Knee Endoprosthetic Techniques
A study testing Robot-assisted total knee arthroplasty and Conventional total knee arthroplasty in people with Knee Arthroplasty, Total and Robotic-assisted, run by Danderyd Hospital at 2 sites in Sweden.
Trial summary
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). Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Knee Arthroplasty, Total, Robotic-assisted, Osteoarthritis of the Knee
- What is being tested?
- Robot-assisted total knee arthroplasty and Conventional total knee arthroplasty
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 1,600 participants
- Where
- 2 sitesSweden
- Study dates
- 4 Mar 2024to Dec 2037
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adults aged 18 years and older.
- Eligible for total knee arthroplasty according to local guidelines and routines.
- Willingness to participate in the study.
Who cannot join
- Patients with extreme malalignment necessitating special implants or techniques.
- Patients unfit for surgery due to other medical reasons.
- Patients who, for other reasons such as alcohol or substance abuse, are deemed unsuitable to participate in the study.
- Patients who, for other reasons, cannot fulfil the required patient-reported outcome measures.
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Sweden2 sites, 2 recruiting
- Recruiting
Hässleholm Hospital
Hässleholm, 281 38
- Recruiting
Danderyd Hospital
Stockholm, 182 88
Olof Skoldenberg, MD, PhD, +46 8 123 572 45, olof.skoldenberg@ki.se
Olof Skoldenberg, MD, PhD
About this study
Official title: ROCKETS: RObotic-assisted Versus Conventional Knee Endoprosthetic Techniques in a Randomized, Multicenter, Preference-tolerant Study
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.
Read more
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.
Read the detailed description
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.
- Being tested
- Robot-assisted total knee arthroplasty, Conventional total knee arthroplasty
- Keywords
- Knee arthroplasty, Robotic assisted, Osteoartritis
- Medical subject headings
- Osteoarthritis, Knee
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Robot-assisted total knee arthroplastyProcedure or surgery
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 arthroplastyProcedure or surgery
Conventional total knee arthroplasty using standard manual instrumentation according to local clinical routine.
| Study group | Role | What they receive |
|---|---|---|
| RTKR | Experimental | Robot-assisted total knee arthroplasty (RTKR). Receives: Procedure: Robot-assisted total knee arthroplasty |
| TKR | Active comparator | Conventional total knee arthroplasty (TKR). Receives: Procedure: Conventional total knee arthroplasty |
What is being measured
The primary outcome is the main question the study is designed to answer.
Proportion 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.
Measured: 24 months after surgery
Secondary outcomes (13)
Forgotten Joint Score (FJS), continuous score
FJS is scored from 0 to 100, with higher scores indicating less awareness of the replaced knee.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: Preoperative and approximately 6 weeks after surgery
Surgery time
Duration of the surgical procedure is recorded in minutes.
Measured: During the index operation
Technical and intraoperative surgical outcomes
Technical difficulties and prespecified intraoperative surgical details are recorded.
Measured: During the index operation
Range of motion (ROM)
Knee range of motion is assessed at the 24-month follow-up.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: Up to 24 months; exploratory long-term analyses at 5 and 10 years where data are available
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Apr 2024
- Study start4 Mar 2024
- Primary completionDec 2029 (estimated)
- Study completionDec 2037 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Knee Arthroplasty, TotalStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Two-arm randomized controlled superiority trial with a parallel observational/preference cohort. The primary randomized comparison is between robot-assisted and conventional total knee arthroplasty.
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 1,600 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Danderyd Hospital
- Sponsor type
- University, hospital or other
- Collaborators
- Karolinska Institutet
- Responsible party
- Principal investigator, Olof Skoldenberg, Danderyd Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06389435
- Sponsor's protocol ID
- 2024DS
- Other IDs
- Knee
- Acronym
- ROCKETS
- Status last verified
- Sep 2026
- First submitted
- 4 Apr 2024
- Last updated
- 21 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 21 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- ROCKETS: RObotic-assisted Versus Conventional Knee Endoprosthetic Techniques in a Randomized, Multicenter, Preference-tolerant Study
- ClinicalTrials.gov ID
- NCT06389435
- Acronym / sponsor ID
- ROCKETS / 2024DS
- Keywords
- Knee arthroplasty, Robotic assisted, Osteoartritis
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 1,600 participants (estimated)
- Lead sponsor
- Danderyd HospitalUniversity, hospital or other
- Collaborators
- Karolinska Institutet
- Study start
- 4 Mar 2024 (actual)
- Primary completion
- Dec 2029 (estimated)
- Study completion
- Dec 2037 (estimated)
- First posted
- 29 Apr 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
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 design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
- Model description
- Two-arm randomized controlled superiority trial with a parallel observational/preference cohort. The primary randomized comparison is between robot-assisted and conventional total knee arthroplasty.
| Arm | Type | Receives |
|---|---|---|
| RTKR | Experimental | Procedure: Robot-assisted total knee arthroplastyRobot-assisted total knee arthroplasty (RTKR). |
| TKR | Active comparator | Procedure: Conventional total knee arthroplastyConventional total knee arthroplasty (TKR). |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Adults aged 18 years and older.
- Eligible for total knee arthroplasty according to local guidelines and routines.
- Willingness to participate in the study.
Key exclusion criteria (4 listed)
- Patients with extreme malalignment necessitating special implants or techniques.
- Patients unfit for surgery due to other medical reasons.
- Patients who, for other reasons such as alcohol or substance abuse, are deemed unsuitable to participate in the study.
- Patients who, for other reasons, cannot fulfil the required patient-reported outcome measures.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Robot-assisted total knee arthroplastyRobot-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. | Procedure or surgery | RTKR |
| Conventional total knee arthroplastyConventional total knee arthroplasty using standard manual instrumentation according to local clinical routine. | Procedure or surgery | TKR |
Primary outcome
Proportion of participants achieving a Forgotten Joint Score (FJS) ≥80 points
Time frame: 24 months after surgery
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.
13 secondary outcomes
Forgotten Joint Score (FJS), continuous score
Time frame: Baseline, 6 weeks, 12 months, 24 months, 5 years and 10 years after surgery
Knee injury and Osteoarthritis Outcome Score (KOOS)
Time frame: Baseline, 6 weeks, 12 months, 24 months, 5 years and 10 years after surgery
Self-reported knee instability (ADLS items)
Time frame: Baseline, 6 weeks, 12 months, 24 months, 5 years and 10 years after surgery
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
Time frame: Baseline, 6 weeks, 12 months, 24 months, 5 years and 10 years after surgery
Knee alignment
Time frame: Preoperative and approximately 6 weeks after surgery
Surgery time
Time frame: During the index operation
Technical and intraoperative surgical outcomes
Time frame: During the index operation
Range of motion (ROM)
Time frame: 24 months after surgery
Reoperations and revisions
Time frame: Up to 24 months, with additional follow-up at 5 and 10 years
Adverse events and complications
Time frame: Up to 24 months, with additional long-term assessment at 5 and 10 years
Mortality
Time frame: 90 days, 1 year, 5 years and 10 years after surgery
Health-economic outcomes
Time frame: Up to 24 months; exploratory long-term analyses at 5 and 10 years where data are available
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 21 Sep 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Robot-assisted total knee arthroplasty and Conventional total knee arthroplasty in people with Knee Arthroplasty, Total and Robotic-assisted, run by Danderyd Hospital at 2 sites in Sweden.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 21 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Sweden. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Olof Sköldenberg, MD, PhD (46+700891253, olof.skoldenberg@ki.se), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Proportion of participants achieving a Forgotten Joint Score (FJS) ≥80 points (time frame: 24 months after surgery). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 21 Sep 2026.