An observational study in Inflammatory Arthritis, Primary Total Knee Arthroplasty Due to Degenerative Joint Disease (Primary Diagnosis of Osteoarthritis) and Post-traumatic Arthritis, sponsored by Smith & Nephew, Inc.. Recruiting at 4 sites in United States. Open to participants aged 18 Years to 80 Years. Per ClinicalTrials.gov, last updated 2026-08-06.
Sponsored by Smith & Nephew, Inc. · Observational
The purpose of this study is to assess the long-term safety and performance of the LEGION Medial Stabilized insert and to generate clinical evidence to support and maintain product registration in global markets.
This is a post market, prospective and retro-prospective, multicentered 10-year observational study. The study is looking at the LEGION Medial Stabilized insert used in primary total knee arthroplasty alongside specific tibia and femur component combinations. There will be 144 knees enrolled across 3 cohorts in the study. All enrolled knees will undergo a primary knee arthroplasty due to degenerative joint disease (primary diagnosis of osteoarthritis), post-traumatic arthritis or inflammatory arthritis. Enrolled subjects will be followed up for 10 years post operation.
2,974 studies on the registry are indexed under Osteoarthritis; 438 are open to participants now.
This study's planned enrollment of 144 is above the median of 100 across 601 observational studies indexed under Osteoarthritis.
Browse Osteoarthritis studies →Smith & Nephew, Inc. is the lead sponsor of 134 studies on the registry; 11 are open to participants now.
Of its 11 completed or terminated interventional studies of FDA-regulated products, 10 (91%) have results posted.
Compared within Osteoarthritis, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Arthritis. The counts are of registry records indexed under each term, refreshed daily. How we classify →
Participants needing primary Total Knee Arthroplasty (TKA) due to degenerative joint disease (primary diagnosis of osteoarthritis), post-traumatic arthritis or inflammatory arthritis.
OR
Participants which have undergone primary TKA using the investigational product in the past 12 months to repair degenerative joint disease, post-traumatic arthritis or inflammatory arthritis and all the following conditions have been met:
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.
A). Prospective Subjects: Subject needing primary Total Knee Arthroplasty (TKA) due to degenerative joint disease (primary diagnosis of osteoarthritis), post-traumatic arthritis or inflammatory arthritis.
OR
B). Retro-prospective Subjects: Subject has undergone primary TKA using the product in the past 12 months to repair degenerative joint disease, post-traumatic arthritis or inflammatory arthritis and all the following conditions have been met:
Exclusion Criteria:
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.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
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.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
LEGION MS with Cemented Tibia (JII) with LEGION CR non-porous (CoCr) Femoral component
Device: Cemented CoCr
LEGION MS with Cemented Tibia (JII) with LEGION CR non-porous (Ox) Femoral component
Device: Cemented Oxinium
LEGION MS with CONCELOC Tibia with LEGION CR porous (without HA) Femoral component
Device: Cementless
Primary TKA performed using the LEGION MS with Cemented Tibia (JII) with LEGION CR non-porous (CoCr) Femoral component
Primary TKA performed using the LEGION MS with Cemented Tibia (JII) with LEGION CR non-porous (Ox) Femoral component
Primary TKA performed using the LEGION MS with CONCELOC Tibia with LEGION CR porous (without HA) Femoral component
Implant Survivorship at 10 Years
Implant survivorship at 10 years post-surgery. Implant survivorship is defined as the cumulative proportion of knee-implanted components without a revision. Survivorship is defined as absence of revision of any, or all, of the tibial / femoral / insert components that were implanted during the primary TKA - not including the patella. (Revision is the removal of some, or all, of the above specified implant components, and replacement with new ones for any reason).
Time frame: 10 years
Implant Survivorship
Implant survivorship at 6 weeks, 1, 2, 3, 5, 7 years post-surgery. Implant survivorship is defined as the cumulative proportion of knee-implanted components without a revision. Survivorship is defined as absence of revision of any, or all, of the tibial / femoral / insert components that were implanted during the primary TKA - not including the patella. (Revision is the removal of some, or all, of the above specified implant components, and replacement with new ones for any reason).
Time frame: 6 weeks, 1 year, 2 years, 3 years, 5 years, and 7 years
Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR)
The Knee injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, JR) is a validated short form of the KOOS that assesses patient stiffness (1 item), pain (4 items), and functions of daily living (2 items). Scores range from 0 to 100 with a score of 0 indicating total knee disability (i.e., worse outcome) and 100 indicating perfect knee health (i.e., better outcome).
Time frame: 6 weeks, 1 year, 2 years, 3 years, 5 years, 7 years, and 10 years
Oxford Knee Score (OKS)
The OKS consists of twelve questions covering function and pain associated with the knee. Scores from the twelve questions are combined to provide an overall score that ranges from 0 to 48, with higher scores indicating better knee function and less pain (i.e., a better outcome)
Time frame: 6 weeks, 1 year, 2 years, 3 years, 5 years, 7 years, and 10 years
Forgotten Joint Score (FJS)
The Forgotten Joint Score (FJS) is a patient reported outcome that focuses on the participant's awareness of a specific joint in everyday life. Joint awareness can be simply defined as any unintended perception of a joint. Scores are on a scale of 1 to 100, with higher scores indicating a better outcome.
Time frame: 6 weeks, 1 year, 2 years, 3 years, 5 years, 7 years, and 10 years
Five-Level EuroQol Five-Dimensional (EQ-5D-5L): Index Score
The EQ-5D-5L score consists of two parts: a descriptive system and a visual analogue scale (VAS). The descriptive system (i.e., index score) is used to describe the participant's health state and consists of five dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Each dimension has 5 levels to choose the most appropriate answer: no problems, slight problems, moderate problems, severe problems and extreme problems. The participant is asked to indicate their health state by marking the most appropriate statement in each of the five areas. The EQ-5D-5L Index Score was based on a scale of 0 to 1, with higher index values indicating better health and lower index values indicating worse health.
Time frame: 6 weeks, 1 year, 2 years, 3 years, 5 years, 7 years, and 10 years
Five-Level EuroQol Five-Dimensional (EQ-5D-5L): Visual Analogue Scale Score
The EQ-5D-5L score consists of two parts: a descriptive system and a visual analogue scale (VAS). The VAS records the participant's self-rated health on a vertical visual analogue scale. The scale ranges from 0 to 100 where 0 indicates 'The worst health you can imagine' and 100 indicates 'The best health you can imagine'.
Time frame: 6 weeks, 1 year, 2 years, 3 years, 5 years, 7 years, and 10 years
Plan to share: No
No publications or documents are linked to this record.
Started Sep 2025 (actual). Primary completion is estimated for Dec 2036, 135 months after the start.
Of 82 industry-sponsored observational studies under Osteoarthritis, half reached primary completion within 93 months of starting (the median), counting those still running; a quarter within 43 and three quarters within 184. This study's planned 135 months is above that.
Counting every sponsor, half of 228 studies reached it within 57 months; a quarter within 21 and three quarters within 141.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.