Surgical Alignments for Knee Arthritis

Overseen By Megan VanDyke, BSN

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Northwestern University

Must not be taking: Opioids

Disqualifiers: Inflammatory arthritis, Chronic pain, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 2

Duration: 1 week

95 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests two methods of knee replacement surgery for individuals with arthritis. Mechanical Alignment (MA) positions the new knee straight, potentially requiring extra cutting. Kinematic Alignment (KA) seeks to match the knee's natural bend with less cutting but demands greater precision. The trial includes participants undergoing knee replacement with specific equipment and who can attend follow-up visits and complete forms. As an unphased trial, it offers patients the chance to contribute to innovative surgical techniques that could enhance future knee replacement outcomes.

Will I have to stop taking my current medications?

The trial protocol does not specify whether you need to stop taking your current medications. However, if you are using chronic opioids, you may not be eligible to participate.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research shows that both Kinematic Alignment (KA) and Mechanical Alignment (MA) are generally safe methods for knee replacement surgery. Studies have found no major differences in results between these techniques, indicating that patients tolerate both well.

For Kinematic Alignment, one study reported good patient outcomes and stable knee function over five years, suggesting that the procedure remains safe and effective over time. Another review found that KA often results in better knee pain relief and flexibility.

Mechanical Alignment is also considered safe. Research comparing MA and KA found no major differences in patient outcomes or walking ability, demonstrating that MA is also well-tolerated.

In summary, both KA and MA are safe choices for knee surgery. They are widely used and have been studied for their effectiveness and safety, showing good results in patients without major safety concerns. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about kinematic and mechanical alignment techniques for knee arthritis because they offer a new approach to knee replacement surgery. Unlike traditional methods, which focus on a one-size-fits-all alignment, kinematic alignment customizes the alignment to mirror the patient's natural knee anatomy. This personalization aims to improve joint function and patient satisfaction. Mechanical alignment, on the other hand, emphasizes a precise, standardized alignment across patients, which could enhance the stability and longevity of the knee implant. These methods may offer better outcomes than current standard practices, potentially leading to faster recovery and improved long-term joint performance.

What evidence suggests that this trial's treatments could be effective for knee arthritis?

This trial will compare two surgical alignment methods for knee arthritis: Kinematic Alignment (KA) and Mechanical Alignment (MA). Research has shown that KA in knee replacement surgery often leads to better results than MA. KA typically results in higher patient satisfaction and improved knee function. Studies have found that patients receiving KA experience greater pain relief and more natural movement. For instance, one study found that KA patients scored better on tests measuring knee function, such as the WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) and KSS (Knee Society Score), compared to those with MA. However, some research has found no significant difference in outcomes between the two methods. Overall, while KA may offer some benefits, both approaches can be effective for knee replacement surgery. ^{2 4 5 6 7}

Who Is on the Research Team?

Adam Edelstein, MD

Principal Investigator

Assistant Professor of Orthopaedic Surgery

Are You a Good Fit for This Trial?

This trial is for individuals with knee osteoarthritis needing replacement surgery. It's comparing two surgical methods: traditional Mechanical Alignment (MA) and the newer Kinematic Alignment (KA). Suitable participants should not have conditions that may interfere with the surgery or recovery.

Inclusion Criteria

I am having a knee replacement with a specific type of knee system.

Able to read and understand consent form and PRO instruments and willing to return for follow up visits

Exclusion Criteria

Patients receiving workers' compensation for study condition

I am unable to understand or sign the consent form.

Diagnosis or history of chronic opioid use

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants undergo Total Knee Arthroplasty (TKA) using either Mechanical Alignment (MA) or Kinematic Alignment (KA) methodology

1 week

1 visit (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment, including assessment of KOOS-JR score

6 weeks

1 visit (in-person)

Long-term Follow-up

Participants are assessed for long-term outcomes, including the Forgotten Joint Score (FJS)

1 year

What Are the Treatments Tested in This Trial?

Interventions

• Kinematic Alignment
• Mechanical Alignment

Trial Overview The study tests whether aligning the new knee joint to mimic natural anatomy (KA) has better outcomes than aligning it in a neutral position (MA). The focus is on patient-rated results, addressing gaps in previous research.

How Is the Trial Designed?

Group I: Mechanical Alignment (MA) Active Control 1 Intervention

Primary TKA with the Medacta SpheriKA, utilizing either MA methodology.

Group II: Kinematic Alignment (KA) Active Control 1 Intervention

Primary TKA with the Medacta SpheriKA, utilizing either KA methodology.

Kinematic Alignment is already approved in European Union, United States, Canada, Japan, China, Switzerland for the following indications:

Approved in European Union as Kinematic Alignment for:

• Total Knee Arthroplasty
• Knee Replacement Surgery

Approved in United States as Kinematic Alignment for:

• Total Knee Arthroplasty
• Knee Replacement Surgery

Approved in Canada as Kinematic Alignment for:

• Total Knee Arthroplasty
• Knee Replacement Surgery

Approved in Japan as Kinematic Alignment for:

• Total Knee Arthroplasty
• Knee Replacement Surgery

Approved in China as Kinematic Alignment for:

• Total Knee Arthroplasty
• Knee Replacement Surgery

Approved in Switzerland as Kinematic Alignment for:

• Total Knee Arthroplasty
• Knee Replacement Surgery

Who Is Running the Clinical Trial?

Northwestern University

Lead Sponsor

Trials

1,674

Recruited

989,000+

Medacta International SA

Industry Sponsor

Trials

51

Recruited

9,100+

Founded

1999

Headquarters

Castel San Pietro, Switzerland

Known For

Orthopedic innovations

Top Products

AMIS Hip Platform, MyKA Knee Platform, NextAR Spine Platform

Published Research Related to This Trial

Kinematic alignment in total knee arthroplasty resulted in better knee joint function scores and improved flexion angles compared to mechanical alignment, based on a meta-analysis of 19 studies involving 1845 total knee arthroplasties.

Despite the differences in functional outcomes, both kinematic and mechanical alignments showed similar overall clinical outcomes and complication rates, suggesting that kinematic alignment can be a safe and effective option for knee surgery.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Kinematic and mechanical alignments in total knee arthroplasty: A meta-analysis with ≥1-year follow-up. Wang, G., Chen, L., Xu, J.[2023]

In a meta-analysis of 458 total knee arthroplasty patients, functional outcomes (measured by WOMAC and KSS scores) were similar between those who underwent kinematic alignment (KA) and those who had traditional mechanical alignment (MA), indicating that KA may not provide significant advantages in overall function post-surgery.

A slight improvement in pain scores was observed in the KA group, but no specific patient subgroups were identified that benefited more from the KA technique, suggesting that the choice of alignment method may not significantly impact long-term outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Outcome of kinematic alignment using patient-specific instrumentation versus mechanical alignment in TKA: a meta-analysis and subgroup analysis of randomised trials. Woon, JTK., Zeng, ISL., Calliess, T., et al.[2018]

In a meta-analysis of 1112 participants, kinematic alignment (KA) in total knee arthroplasty showed significantly better functional outcomes, including improved Knee Society Scores and greater knee flexion range compared to mechanical alignment (MA).

Patients who underwent KA also had a longer walking distance before discharge, indicating enhanced recovery, while other outcomes such as complication rates remained similar between the two alignment techniques.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Kinematic alignment versus mechanical alignment in primary total knee arthroplasty: an updated meta-analysis of randomized controlled trials. Liu, B., Feng, C., Tu, C.[2022]

A study analyzing 4884 knee CT scans found that using a restricted kinematic alignment (KA) protocol for total knee arthroplasty (TKA) resulted in significantly less modification of knee anatomy compared to the standard mechanical alignment (MA) technique, with mean corrections of only 0.5° for the medial proximal tibial angle (MPTA) and 0.3° for the lateral distal femoral angle (LDFA).

The restricted KA protocol allowed 51% of knees to undergo surgery without any adjustments, and 83% required only minor corrections, suggesting that this approach can better preserve the patient's native knee anatomy while still achieving effective surgical outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The Impact of Mechanical and Restricted Kinematic Alignment on Knee Anatomy in Total Knee Arthroplasty. Almaawi, AM., Hutt, JRB., Masse, V., et al.[2018]

The kinematic alignment (KA) technique in total knee replacement surgery led to significant improvements in clinical, psychological, and functional outcomes for 12 patients, as measured by various tests before and after surgery.

Patients experienced a fast postoperative recovery, with notable enhancements in their scores from the day after surgery to 14 days post-operation, indicating the potential effectiveness of KA in treating knee osteoarthritis.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Analysis of Short-Term Clinical and Functional Outcomes in Patients Undergoing Total Knee Arthroplasty with Kinematic Alignment Technique. Giorgino, R., Nannini, A., Scuttari, E., et al.[2023]

Kinematic alignment is emerging as a viable alternative to mechanical alignment in total knee arthroplasty (TKA), with a significant increase in research from 11 to 91 studies in the past 5 years.

This review aims to summarize the growing body of literature comparing the outcomes of kinematic alignment versus mechanical alignment, highlighting the evolving understanding of their impact on implant survival and clinical results.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Current evidence base for kinematic alignment. Tuecking, LR., Savov, P., Windhagen, H., et al.[2021]

In a study of 99 total knee arthroplasties, there was no significant difference in 2-year patient-reported outcome scores between kinematic alignment (KA) and mechanical alignment (MA) techniques, suggesting that KA may not provide the expected benefits in pain and function.

While the KA technique resulted in different component alignments (more varus tibial and valgus femoral positioning), these changes did not translate into improved clinical outcomes, raising concerns about the long-term implications of these alignment differences.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The Chitranjan S. Ranawat Award : No Difference in 2-year Functional Outcomes Using Kinematic versus Mechanical Alignment in TKA: A Randomized Controlled Clinical Trial. Young, SW., Walker, ML., Bayan, A., et al.[2022]

In a study of 126 patients undergoing total knee arthroplasty, those who received kinematic alignment (KA-TKA) showed significantly better clinical outcomes, including higher knee joint clinical scores and functional scores, compared to those who received mechanical alignment (MA-TKA) at both 3 months and 2 years post-surgery.

Both KA-TKA and MA-TKA resulted in similar lower limb alignment after surgery, indicating that while KA-TKA may enhance clinical performance and patient satisfaction, it does not compromise alignment outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

An early clinical comparative study on total knee arthroplasty with kinematic alignment using specific instruments versus mechanical alignment in varus knees. Wen, L., Wang, Z., Ma, D., et al.[2023]

This study will evaluate the effectiveness of robot-assisted surgery (RAS) and kinematic alignment (KA) in total knee arthroplasty (TKA) compared to traditional methods, involving 300 patients and assessing outcomes over 2 years using the Knee injury and Osteoarthritis Outcome Score (KOOS-12).

The research aims to determine not only the clinical and functional benefits of RAS and KA but also their impact on radiographic precision and long-term prosthetic survivorship, providing a comprehensive analysis of these modern surgical techniques.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Robotic-assisted surgery and kinematic alignment in total knee arthroplasty (RASKAL study): a protocol of a national registry-nested, multicentre, 2×2 factorial randomised trial assessing clinical, intraoperative, functional, radiographic and survivorship outcomes. MacDessi, SJ., Wernecke, GC., Bastiras, D., et al.[2022]

Kinematic alignment (KA) in knee replacement surgery resulted in more internal rotation of the tibia and a larger medial rotation point compared to mechanical alignment (MA), suggesting improved knee joint mechanics.

The study, which tested eight fresh frozen human knee specimens during active flexion, indicates that KA combined with a medial stabilized implant may better replicate natural knee movement during bending.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Influence of kinematic alignment on femorotibial kinematics in medial stabilized TKA design compared to mechanical alignment. Bauer, L., Woiczinski, M., Thorwächter, C., et al.[2023]

In a study of 296 patients who underwent total knee arthroplasty, both kinematic alignment (KA) and mechanical alignment (MA) techniques showed similar clinical outcomes in terms of range of motion and knee society score after one year.

Patients with a body mass index (BMI) over 30 kg/m² had better outcomes with MA, while those with severe varus deformities (HKA angle over 10 degrees) benefited more from the KA technique, suggesting tailored approaches based on individual patient characteristics.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

How to choose kinematic or mechanical alignment individually according to preoperative characteristics of patients? Luan, C., Xu, DT., Chen, NJ., et al.[2021]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10826793/

Effectiveness of Kinematic Alignment-Total Knee Arthroplasty ... The study findings showcased that KA-TKA efficiently relieved pain and restored function in patients with valgus alignment. While patients with ...

2. orthopedicreviews.openmedicalpublishing.org orthopedicreviews.openmedicalpublishing.org/article/122318-systematic-review-and-meta-analysis-of-long-term-outcomes-and-innovations-in-total-knee-arthroplasty-kinematic-personalized-knee-vs-conventional

Systematic review and meta-analysis of long term ... 2. kinematic alignment showed better clinical outcome scores and better mean flexion with higher odds for pain free knee. WOMAC and KSS scores ...

3. bmcmusculoskeletdisord.biomedcentral.com bmcmusculoskeletdisord.biomedcentral.com/articles/10.1186/s12891-025-08868-6

Clinical outcomes of restricted kinematic alignment versus ... This study suggests that rKA provides better functional outcomes in TKA compared to MA, particularly in terms of WOMAC score and KSS.

4. cureus.com cureus.com/articles/424876-functional-outcomes-and-patient-satisfaction-in-kinematic-vs-mechanical-alignment-total-knee-arthroplasty-a-systematic-review

Functional Outcomes and Patient Satisfaction in Kinematic ... KA in TKA appears to provide meaningful short- to mid-term advantages over MA, particularly in terms of functional outcomes, joint awareness, ...

5. boneandjoint.org.uk boneandjoint.org.uk/Article/10.1302/2633-1462.38.BJO-2021-0214.R1

Kinematic alignment in total knee arthroplasty: a five-year ... Kinematic alignment produces good patient outcomes and stable ligament laxity at five years for a wide range of hip-knee-ankle angles and joint line ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC12231638/

Clinical outcomes of restricted kinematic alignment versus ... Restricted Kinematic Alignment (rKA) is a well-established technique for total knee arthroplasty (TKA) that aims to approximate natural knee ...

7. trials.arthritis.org trials.arthritis.org/trials/NCT06617871

Mechanical Alignment Vs Kalipered Kinematic Alignment ... 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 ...