Knee OsteoarthritisNCT06617871
Mechanical Alignment vs Kalipered Kinematic Alignment Total Knee Arthroplasty
A study testing Mechanical Alignment (MA) and Kinematic Alignment (KA) Interventions: in people with Knee Osteoarthritis and Knee Arthropathy, run by Northwestern University at 1 site in United States.
Trial summary
Knee replacement surgery can be performed in one of two ways. Traditionally the goal was for the new joint to be in a neutral position with respect to the femur (thigh bone). This is called Mechanical Alignment (MA). Read more about this study
- Who is it for?
- Ages 21 to 79 years
- Conditions the study is for
- Knee Osteoarthritis, Knee Arthropathy
- What is being tested?
- Mechanical Alignment (MA) and Kinematic Alignment (KA) Interventions:
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 95 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Aug 2024to Dec 2028
- 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 21 to 79 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patient undergoing primary TKA with a medially-stabilized SpheriKA knee system
- Able to read and understand consent form and PRO instruments and willing to return for follow up visits
Who cannot join
- Varus or Valgus malalignment >15 degrees to mechanical axis
- Flexion contracture >15 degrees or flexion <90 degrees
- BMI >40
- Revision TKA or other prior knee surgery other than arthroscopy or arthroscopic-assisted ligament reconstruction
- Diagnosis or history of any of the following
- inflammatory arthritis
Show all 14Show fewer
- infection in study knee
- chronic pain
- chronic opioid use
- metabolic musculoskeletal disorder other than osteopenia/osteoporosis
- Patients receiving workers' compensation for study condition
- Patients who cannot complete questionnaires in English
- Patients with comorbidities preventing surgery
- Patients who are not able to provide informed consent
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Northwestern Medicine
Chicago, Illinois, 60611
Melissa Shauver, MPH, 312-472-6024, melissa.shauver@northwestern.edu
Megan VanDyke, BSN, 312-472-3445, megan.vandyke@nm.org
About this study
Official title: A Prospective, Randomized, Single-blinded Clinical Trial Comparing Mechanical Alignment vs Kalipered Kinematic Alignment Total Knee Arthroplasty Using Medacta Spherika
Knee replacement surgery can be performed in one of two ways. Traditionally the goal was for the new joint to be in a neutral position with respect to the femur (thigh bone). This is called Mechanical Alignment (MA). The neutral position is different than the human knee's natural position, so MA often requires the surgeon to make additional cuts to the ligaments and other soft tissue around the knee. More recently surgeons have started to place the new joint in a position that more closely replicates the natural alignment of the human knee. This is called Kinemetic Alignment (KA). KA can be done without additional soft tissue dissection but the procedure requires a higher level of precision that can be difficult to achieve in every case.
Some studies have found no difference in outcomes between MA and KA, whereas others have found KA to be superior. But these were small studies or studies that did not consider patient-rated outcomes.
Read the detailed description
Up to 20% of patients that report dissatisfaction and chronic pain following Total knee arthroplasty (TKA). Prior research has identified patient demographic, comorbidity, and expectations as factors that are associated with dissatisfaction. Emerging literature has also suggested that surgical factors including component alignment, soft tissue balance, and kinematics may play a role in patient satisfaction, and that modifications to alignment may result in better function than performing soft tissue releases. Personalized alignment strategies have been proposed that aim to more closely recreate native knee morphology and kinematics. Kinematic alignment (KA) describes a technique that aims to restore the pre-arthritic joint surfaces and alignment of the femur and tibia by removing the bone and cartilage thickness that will be replaced by the implant, taking into account cartilage wear. KA can therefore be conceptualized as a resurfacing procedure, wherein native joint surfaces are replaced by prosthetic surfaces but the position and alignment of the joint surfaces are not changed. This contrasts with mechanical alignment (MA), in which implants are positioned perpendicular to the mechanical axes of the femur and tibia in a manner independent of the pre-arthritic joint surfaces, and soft tissue releases are performed to bring limb alignment into mechanical neutral.
There have been prior randomized trials comparing kinematic and mechanical alignment, and these have had mixed results regarding the superiority of one approach over the other. The majority of these trials did not use the same operative modality for both groups (manual vs computer-assisted techniques) or did not include relevant patient reported outcomes (PROs). There is a need for a prospective, randomized trial comparing outcomes following kinematic vs mechanical alignment TKA, with the same operative modality used in both groups with inclusion of relevant PROs.
- Conditions
- Knee Osteoarthritis, Knee Arthropathy
- Being tested
- Mechanical Alignment (MA), Kinematic Alignment (KA) Interventions:
- Keywords
- randomized trial, knee arthroplasty
- Medical subject headings
- Osteoarthritis, Knee
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Mechanical Alignment (MA)Procedure or surgery
Primary TKA with the Medacta SpheriKA, utilizing either MA methodology.
Kinematic Alignment (KA) Interventions:Procedure or surgery
Primary TKA with the Medacta SpheriKA, utilizing either KA methodology.
| Study group | Role | What they receive |
|---|---|---|
| Mechanical Alignment (MA) | Active comparator | Primary TKA with the Medacta SpheriKA, utilizing either MA methodology. Receives: Procedure: Mechanical Alignment (MA) |
| Kinematic Alignment (KA) | Active comparator | Primary TKA with the Medacta SpheriKA, utilizing either KA methodology. Receives: Procedure: Kinematic Alignment (KA) Interventions: |
What is being measured
The primary outcome is the main question the study is designed to answer.
6-week Knee Injury and Osteoarthritis - Joint Replacement Score (KOOS-JR)
The Knee Injury and Osteoarthritis Score - Joint Replacement (KOOS-JR) score; range: 0 (worst knee health) - 100 (perfect knee health)
Measured: 6 weeks postoperative
Secondary outcomes (1)
Forgotten Joint Score (FJS)
Forgotten Joint Score (FJS) questionnaire score; range: 0 (worst outcome) - 100 (best outcome)
Measured: 1 year postoperative
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Oct 2024
- Study start1 Aug 2024
- Primary completionJul 2028 (estimated)
- Study completionDec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Knee OsteoarthritisStudies of the same condition, open and under way.
- More trials run by Northwestern UniversityThe sponsor's other registered studies.
- 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
- 1:1
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 95 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Northwestern University
- Sponsor type
- University, hospital or other
- Collaborators
- Medacta International SA
- Responsible party
- Principal investigator, Adam Edelstein, Northwestern University
- Investigators
- Adam Edelstein, MD, Principal investigator, Assistant Professor of Orthopaedic Surgery
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06617871
- Sponsor's protocol ID
- STU00219231
- Status last verified
- Mar 2026
- First submitted
- 25 Sep 2024
- Last updated
- 24 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Aggregate data will be shared via ClinicalTrials.gov
Study at a glance
From the registry record, last updated by the sponsor on 24 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Prospective, Randomized, Single-blinded Clinical Trial Comparing Mechanical Alignment vs Kalipered Kinematic Alignment Total Knee Arthroplasty Using Medacta Spherika
- ClinicalTrials.gov ID
- NCT06617871
- Acronym / sponsor ID
- STU00219231
- Conditions
- Knee Osteoarthritis, Knee Arthropathy
- Keywords
- randomized trial, knee arthroplasty
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 95 participants (estimated)
- Lead sponsor
- Northwestern UniversityUniversity, hospital or other
- Collaborators
- Medacta International SA
- Study start
- 1 Aug 2024 (actual)
- Primary completion
- Jul 2028 (estimated)
- Study completion
- Dec 2028 (estimated)
- First posted
- 1 Oct 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.
Knee replacement surgery can be performed in one of two ways. Traditionally the goal was for the new joint to be in a neutral position with respect to the femur (thigh bone). This is called Mechanical Alignment (MA). The neutral position is different than the human knee's natural position, so MA often requires the surgeon to make additional cuts to the ligaments and other soft tissue around the knee. More recently surgeons have started to place the new joint in a position that more closely replicates the natural alignment of the human knee. This is called Kinemetic Alignment (KA). KA can be done without additional soft tissue dissection but the procedure requires a higher level of precision that can be difficult to achieve in every case.
Some studies have found no difference in outcomes between MA and KA, whereas others have found KA to be superior. But these were small studies or studies that did not consider patient-rated outcomes.
Detailed description
Up to 20% of patients that report dissatisfaction and chronic pain following Total knee arthroplasty (TKA). Prior research has identified patient demographic, comorbidity, and expectations as factors that are associated with dissatisfaction. Emerging literature has also suggested that surgical factors including component alignment, soft tissue balance, and kinematics may play a role in patient satisfaction, and that modifications to alignment may result in better function than performing soft tissue releases. Personalized alignment strategies have been proposed that aim to more closely recreate native knee morphology and kinematics. Kinematic alignment (KA) describes a technique that aims to restore the pre-arthritic joint surfaces and alignment of the femur and tibia by removing the bone and cartilage thickness that will be replaced by the implant, taking into account cartilage wear. KA can therefore be conceptualized as a resurfacing procedure, wherein native joint surfaces are replaced by prosthetic surfaces but the position and alignment of the joint surfaces are not changed. This contrasts with mechanical alignment (MA), in which implants are positioned perpendicular to the mechanical axes of the femur and tibia in a manner independent of the pre-arthritic joint surfaces, and soft tissue releases are performed to bring limb alignment into mechanical neutral.
There have been prior randomized trials comparing kinematic and mechanical alignment, and these have had mixed results regarding the superiority of one approach over the other. The majority of these trials did not use the same operative modality for both groups (manual vs computer-assisted techniques) or did not include relevant patient reported outcomes (PROs). There is a need for a prospective, randomized trial comparing outcomes following kinematic vs mechanical alignment TKA, with the same operative modality used in both groups with inclusion of relevant PROs.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
- Model description
- 1:1
| Arm | Type | Receives |
|---|---|---|
| Mechanical Alignment (MA) | Active comparator | Procedure: Mechanical Alignment (MA)Primary TKA with the Medacta SpheriKA, utilizing either MA methodology. |
| Kinematic Alignment (KA) | Active comparator | Procedure: Kinematic Alignment (KA) Interventions:Primary TKA with the Medacta SpheriKA, utilizing either KA methodology. |
Who may qualify
- Ages
- 21 to 79 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Patient undergoing primary TKA with a medially-stabilized SpheriKA knee system
- Able to read and understand consent form and PRO instruments and willing to return for follow up visits
Key exclusion criteria (14 listed)
- Varus or Valgus malalignment >15 degrees to mechanical axis
- Flexion contracture >15 degrees or flexion <90 degrees
- BMI >40
- Revision TKA or other prior knee surgery other than arthroscopy or arthroscopic-assisted ligament reconstruction
- Diagnosis or history of any of the following
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 |
|---|---|---|
| Mechanical Alignment (MA)Primary TKA with the Medacta SpheriKA, utilizing either MA methodology. | Procedure or surgery | Mechanical Alignment (MA) |
| Kinematic Alignment (KA) Interventions:Primary TKA with the Medacta SpheriKA, utilizing either KA methodology. | Procedure or surgery | Kinematic Alignment (KA) |
Primary outcome
6-week Knee Injury and Osteoarthritis - Joint Replacement Score (KOOS-JR)
Time frame: 6 weeks postoperative
The Knee Injury and Osteoarthritis Score - Joint Replacement (KOOS-JR) score; range: 0 (worst knee health) - 100 (perfect knee health)
1 secondary outcome
Forgotten Joint Score (FJS)
Time frame: 1 year postoperative
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 24 Mar 2026.
- Individual participant dataSharing planned: Yes. Aggregate data will be shared via ClinicalTrials.gov
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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.
Adam Edelstein, MD principal investigator
Assistant Professor of Orthopaedic Surgery
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Mechanical Alignment (MA) and Kinematic Alignment (KA) Interventions: in people with Knee Osteoarthritis and Knee Arthropathy, run by Northwestern University at 1 site in United States.
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 2 inclusion and 14 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 24 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. 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 Melissa Shauver, MPH (312-472-6024, melissa.shauver@northwestern.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
6-week Knee Injury and Osteoarthritis - Joint Replacement Score (KOOS-JR) (time frame: 6 weeks postoperative). 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 24 Mar 2026; AzTrials last refreshed its copy on 26 Oct 2026.