An interventional study of Off the Shelf Total Knee Replacement and ConforMIS iTotal Knee Replacement in Osteoarthritis, sponsored by Restor3D. Terminated at 8 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-11-21.
Sponsored by Restor3D · Not applicable, Interventional, and Basic science
Patients will be consecutively enrolled by implant. Implant groups will be those who have undergone surgery with either a ConforMIS iTotal® CR TKA or an Off-the- Shelf (OTS) system.
The patient will conduct functional testing and answer questionnaires.
The results will compare the ConforMIS iTotal with an Off the Shelf Knee replacement.
To compare functional and patient reported outcome data for a consecutively enrolled group of subjects who have undergone surgery with either a ConforMIS iTotal® CR TKA or an Off-the- Shelf (OTS) system.The person conducting the functional testing will be blinded to the device implanted. Sites will perform the off-the-shelf total knees conventional instrumentation.
2,974 studies on the registry are indexed under Osteoarthritis; 438 are open to participants now.
This study's enrollment of 215 is above the median of 80 across 2,240 interventional studies indexed under Osteoarthritis.
Browse Osteoarthritis studies →Restor3D is the lead sponsor of 24 studies on the registry; 2 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HbA1c
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
iTotal patient-specific knee replacement system
Device: ConforMIS iTotal Knee Replacement
Off the shelf knee replacement system
Device: Off the Shelf Total Knee Replacement
Off the shelf knee replacement system
Device: Off the Shelf Total Knee Replacement
Off the shelf knee replacement system
Device: Off the Shelf Total Knee Replacement
Off the shelf knee replacement system
Device: Off the Shelf Total Knee Replacement
Off the shelf knee replacement system
Device: Off the Shelf Total Knee Replacement
A knee replacement system by DePuy, Zimmer, Biomet, Smith \& Nephew, or Stryker
A knee replacement performed with patient specific implant and surgical jigs.
Functional Activities Subscale Score Within the Knee Society Score (KSS) Measure
Comparing the functional testing differences between iTotal and off the shelf. "Total Functional Activities Score" - a subscale within the Knee Society Score (KSS) with its individual subscale score. The Total Functional Activities Score subscale interprets the functional knee health of each patient via a series of tests such as walking/standing (30 points), standard activities (30 points), advanced activities (25 points), and sports/recreational activities (15 points). Deductions to score are made for factors that limit a patient's mobility, such as needing to use an ambulatory device. The subscale scoring system ranges from 0-100, with higher scores indicating better knee function.
Time frame: 1 year
Patient Satisfaction Subscale Score Within the Knee Society Score (KSS) Measure
Measuring and comparing the differences between iTotal and off the shelf knees with patient reported outcomes. "Patient Satisfaction", a subscale within the Knee Society Score (KSS), was utilized to capture this metric. The Patient Satisfaction subscale combines scores given for certain responses (very satisfied, satisfied, neutral, somewhat dissatisfied, very dissatisfied) across 5 questions. These questions are designed to determine the level of satisfaction a patient has with their implant across both everyday and active activities. This score ranges from 0-40, with higher scores indicating higher levels of patient satisfaction.
Time frame: 1 year
Incidents of Major Procedure-related and Device Related Complications (Including Revision Rates)
All complications were stratified according to clinicaltrials.gov reporting standards and each site labeled each complication as either device-related, non-device-related, procedure-related, and non-procedure-related.
Time frame: 1 year
While "Biomet Total Knee Replacement" and "Smith and Nephew Total Knee Replacement" Arms/Groups were listed as possible study groups, no included patients utilized these implant systems. This included patients who failed to meet screening criteria, failed to reach the protocol's required follow-up duration, etc. These arms/groups were only established before the study to represent the possible study groups based on available implant systems on the market.
| Milestone | ConforMIS iTotal Knee Replacement | DePuy Total Knee Replacement | Zimmer Total Knee Replacement | Biomet Total Knee Replacement | Smith & Nephew Total Knee Replacement | Stryker Total Knee Replacement |
|---|---|---|---|---|---|---|
| Started | 131 | 38 | 19 | 0 | 0 | 26 |
| Completed | 81 | 28 | 19 | 0 | 0 | 19 |
| Not completed | 50 | 10 | 0 | 0 | 0 | 7 |
Comparing the functional testing differences between iTotal and off the shelf. "Total Functional Activities Score" - a subscale within the Knee Society Score (KSS) with its individual subscale score. The Total Functional Activities Score subscale interprets the functional knee health of each patient via a series of tests such as walking/standing (30 points), standard activities (30 points), advanced activities (25 points), and sports/recreational activities (15 points). Deductions to score are made for factors that limit a patient's mobility, such as needing to use an ambulatory device. The subscale scoring system ranges from 0-100, with higher scores indicating better knee function.
| Score on a subscale | ConforMIS iTotal Knee Replacement | DePuy Total Knee Replacement | Zimmer Total Knee Replacement | Biomet Total Knee Replacement | Smith & Nephew Total Knee Replacement | Stryker Total Knee Replacement |
|---|---|---|---|---|---|---|
| Baseline Score | 42.34 ± 16.31 | 40.38 ± 13.07 | 43.56 ± 12.38 | — | — | 38.87 ± 13.53 |
| 1 Year Score | 77.16 ± 16.47 | 73.65 ± 16.99 | 88.94 ± 6.20 | — | — | 71.20 ± 23.63 |
| Change in Score | 34.82 ± 21.73 | 33.27 ± 18.28 | 45.39 ± 13.18 | — | — | 32.33 ± 19.21 |
Measuring and comparing the differences between iTotal and off the shelf knees with patient reported outcomes. "Patient Satisfaction", a subscale within the Knee Society Score (KSS), was utilized to capture this metric. The Patient Satisfaction subscale combines scores given for certain responses (very satisfied, satisfied, neutral, somewhat dissatisfied, very dissatisfied) across 5 questions. These questions are designed to determine the level of satisfaction a patient has with their implant across both everyday and active activities. This score ranges from 0-40, with higher scores indicating higher levels of patient satisfaction.
| score on a scale | ConforMIS iTotal Knee Replacement | DePuy Total Knee Replacement | Zimmer Total Knee Replacement | Biomet Total Knee Replacement | Smith & Nephew Total Knee Replacement | Stryker Total Knee Replacement |
|---|---|---|---|---|---|---|
| Baseline Score | 12.49 ± 7.09 | 13.62 ± 6.50 | 15.67 ± 7.65 | — | — | 15.50 ± 6.67 |
| 1 Year Score | 33.78 ± 8.28 | 32.00 ± 7.80 | 37.44 ± 3.81 | — | — | 32.93 ± 6.84 |
| Change in Score | 21.29 ± 10.76 | 18.38 ± 9.63 | 21.78 ± 8.08 | — | — | 17.73 ± 8.71 |
All complications were stratified according to clinicaltrials.gov reporting standards and each site labeled each complication as either device-related, non-device-related, procedure-related, and non-procedure-related.
| Patients with Events | ConforMIS iTotal Knee Replacement | DePuy Total Knee Replacement | Zimmer Total Knee Replacement | Biomet Total Knee Replacement | Smith & Nephew Total Knee Replacement | Stryker Total Knee Replacement |
|---|---|---|---|---|---|---|
| Major Procedure Related Complications | 12 | 5 | 1 | — | — | 3 |
| Device Related Complications (including revision) | 1 | 0 | 0 | — | — | 0 |
Collected over 1 year post-operation.. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| ConforMIS iTotal Knee Replacement | 0/81 (0%) | 13/81 (16%) | 26/81 (32.1%) |
| DePuy Total Knee Replacement | 0/28 (0%) | 6/28 (21.4%) | 7/28 (25%) |
| Zimmer Total Knee Replacement | 0/19 (0%) | 2/19 (10.5%) | 1/19 (5.3%) |
| Biomet Total Knee Replacement | — | — | — |
| Smith & Nephew Total Knee Replacement | — | — | — |
| Stryker Total Knee Replacement | 0/19 (0%) | 0/19 (0%) | 7/19 (36.8%) |
| Event | ConforMIS iTotal Knee Replacement | DePuy Total Knee Replacement | Zimmer Total Knee Replacement | Biomet Total Knee Replacement | Smith & Nephew Total Knee Replacement | Stryker Total Knee Replacement |
|---|---|---|---|---|---|---|
| SASGeneral disorders | 13/81 | 6/28 | 2/19 | — | — | 0/19 |
| Event | ConforMIS iTotal Knee Replacement | DePuy Total Knee Replacement | Zimmer Total Knee Replacement | Biomet Total Knee Replacement | Smith & Nephew Total Knee Replacement | Stryker Total Knee Replacement |
|---|---|---|---|---|---|---|
| Procedure Related ComplicationInjury, poisoning and procedural complications | 12/81 | 5/28 | 1/19 | — | — | 3/19 |
| Thrombotic ComplicationsVascular disorders | 0/81 | 0/28 | 0/19 | — | — | 2/19 |
| Pain/Stiffness ComplicationsMusculoskeletal and connective tissue disorders | 4/81 | 2/28 | 0/19 | — | — | 0/19 |
| Infection-related ComplicationInfections and infestations | 5/81 | 0/28 | 0/19 | — | — | 1/19 |
| Wound ComplicationsGeneral disorders | 5/81 | 0/28 | 0/19 | — | — | 1/19 |
Our analysis expected a broader range of off the shelf implants, but no included patients received Biomet or Smith \& Nephew Total Knee Replacements.
| Age, Categorical(Participants) | ConforMIS iTotal Knee Replacement | DePuy Total Knee Replacement | Zimmer Total Knee Replacement | Biomet Total Knee Replacement | Smith & Nephew Total Knee Replacement | Stryker Total Knee Replacement | Total |
|---|---|---|---|---|---|---|---|
| <=18 years | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Between 18 and 65 years | 42 | 10 | 10 | 0 | 0 | 5 | 67 |
| >=65 years | 39 | 18 | 9 | 0 | 0 | 14 | 80 |
| Age, Continuous(years) | ConforMIS iTotal Knee Replacement | DePuy Total Knee Replacement | Zimmer Total Knee Replacement | Biomet Total Knee Replacement | Smith & Nephew Total Knee Replacement | Stryker Total Knee Replacement | Total |
|---|---|---|---|---|---|---|---|
| Mean | 65.728 ± 7.482 | 67.321 ± 6.842 | 63 ± 8.524 | — | — | 68.105 ± 6.590 | 65.986 ± 7.468 |
| Sex: Female, Male(Participants) | ConforMIS iTotal Knee Replacement | DePuy Total Knee Replacement | Zimmer Total Knee Replacement | Biomet Total Knee Replacement | Smith & Nephew Total Knee Replacement | Stryker Total Knee Replacement | Total |
|---|---|---|---|---|---|---|---|
| Female | 45 | 19 | 13 | — | — | 12 | 89 |
| Male | 36 | 9 | 6 | — | — | 7 | 58 |
| Race (NIH/OMB)(Participants) | ConforMIS iTotal Knee Replacement | DePuy Total Knee Replacement | Zimmer Total Knee Replacement | Biomet Total Knee Replacement | Smith & Nephew Total Knee Replacement | Stryker Total Knee Replacement | Total |
|---|---|---|---|---|---|---|---|
| American Indian or Alaska Native | 0 | 0 | 0 | — | — | 0 | 0 |
| Asian | 0 | 2 | 0 | — | — | 0 | 2 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 | — | — | 0 | 0 |
| Black or African American | 12 | 6 | 0 | — | — | 2 | 20 |
| White | 68 | 16 | 19 | — | — | 17 | 120 |
| More than one race | 0 | 0 | 0 | — | — | 0 | 0 |
| Unknown or Not Reported | 1 | 4 | 0 | — | — | 0 | 5 |
| Region of Enrollment(participants) | ConforMIS iTotal Knee Replacement | DePuy Total Knee Replacement | Zimmer Total Knee Replacement | Biomet Total Knee Replacement | Smith & Nephew Total Knee Replacement | Stryker Total Knee Replacement | Total |
|---|---|---|---|---|---|---|---|
| United States | 73 | 27 | 19 | — | — | 10 | 128 |
| Germany | 8 | 1 | 0 | — | — | 9 | 19 |
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No
Ran from Jul 2015 to primary completion in Nov 2022, 88 months.
Results were first posted in Oct 2025, 2 years 10 months after primary completion.
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