Kinematic and Mechanical Alignment Randomized Trial

NCT ID: NCT06787417

Last Updated: 2025-05-08

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: PHASE4
• Total Enrollment: 260 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-02-20
• Study Completion Date: 2029-02-28

Brief Summary

Knee replacement surgery is the second most common surgery in Canada. People who have very painful knee arthritis usually receive a knee replacement where the surgeon aims to make everyone's knee as straight as possible (called mechanical alignment). Mechanical alignment focuses on making the implant last as long as possible. However, everybody's knee shape is different and we think that it is important to take individual differences into account. A newer technique that is more personalized is called restricted kinematic alignment. This technique customizes the placement of the new knee to reproduce each patient's unique knee shape, which may not be perfectly straight. We think this newer technique may feel more natural, be more stable, and lead to better knee function. Restricted kinematic alignment might last as long or longer than mechanical alignment, but the research that has been conducted to date is not clear. We are conducting this study to help surgeons better understand which technique is better. One of the reasons the existing research is not clear is because new developments in robotic technology now allow surgeons to place knee implants very precisely, which was not done in most previous research. In this study everyone will receive a robot-assisted knee surgery so we can be sure the implants are placed as precisely as possible.

The purpose of this trial is to determine whether there are differences in patient outcomes using restricted kinematic alignment rather than the traditionally used mechanical alignment for total knee replacements.

Participants who are having total knee replacements will be randomized to receive either a robot-assisted total knee replacement using mechanical alignment, or a robot-assisted total knee replacement using restricted kinematic alignment . We will ask participants to walk in a markerless motion capture system which will measure walking characteristics at pre-op, 6 months postop and 12 months postop. Participants will also complete a series of standardized questionnaires at preop and 6 months, 12 months, and 24 month postop.

Detailed Description

Total Knee Arthroplasty (TKA) is recognized as a highly effective procedure for alleviating pain and restoring function in patients with knee arthritis. Despite its high success rate, approximately 20% of patients remain dissatisfied with the outcomes, primarily due to loss of functional outcomes, persistent pain, and reduced knee range of motion. This has sparked a debate on the optimal surgical alignment technique in TKA-whether mechanical alignment (MA), or personalized alignment philosophies such as kinematic alignment (KA) or restricted kinematic alignment (rKA) provides superior patient outcomes.

MA traditionally targets a neutral 180-degree hip-knee-ankle (HKA) axis, as it was taught traditionally that this approach focuses on the longevity and stability of the implant. However, this one-size-fits-all philosophy overlooks individual anatomical differences. Personalized alignments such as KA customize the placement of prosthetic components to replicate each patient's unique knee geometry and ligament tensions. Personalized alignment philosophies aim to achieve a more natural knee motion, which may enhance patient satisfaction. The precision provided by robotic-assisted surgery has increasingly facilitated the implementation of personalized alignment philosophies in TKA. Recent evidence suggests that while MA and KA yield comparable outcomes in terms of knee functionality and motion, KA may improve satisfaction and the natural feel of the knee in certain groups, particularly those without severe preoperative deformities. There is also the emerging approach of restricted kinematic alignment (rKA) which aims to provide a compromise by aligning the prosthesis within safe anatomical limits, thus avoiding the extremes of anatomical variation. This approach tailors the surgery more closely to the individual's anatomy without the risks associated with the broader variances permitted in pure KA. Hypothetically, KA and rKA techniques should more closely replicate natural knee biomechanics and improve waking gait. There are advantages and disadvantages to these alignment philosophies which should be addressed with high-quality research. While there have been several previous randomized trials on MA vs KA and its variations, the evidence is still unclear with meta-analyses having conflicting findings.

Patients will be randomly assigned to either mechanical alignment or restricted kinematic alignment. All participants will receive robot-assisted TKA using the Stryker Mako surgical robot and Stryker implants. Perioperative care, postoperative pain medications, and rehabilitation will be standardized according to local standard care.

Conditions

Total Knee Arthroplasty; Osteoarthritis

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: DOUBLE

Study Groups

Mechanical Alignment

Group Type: ACTIVE_COMPARATOR

Mechanically-Aligned Arthroplasty

Intervention Type: PROCEDURE

Robot Assisted with Mechanically Aligned TKA.

Restricted Kinematic Alignment

Group Type: EXPERIMENTAL

Restricted Kinematically-aligned Arthroplasty

Intervention Type: PROCEDURE

Robot Assisted with Restricted Kinematically-Aligned TKA.

Interventions

Restricted Kinematically-aligned Arthroplasty

Robot Assisted with Restricted Kinematically-Aligned TKA.

Intervention Type: PROCEDURE

Mechanically-Aligned Arthroplasty

Robot Assisted with Mechanically Aligned TKA.

Intervention Type: PROCEDURE

Eligibility Criteria

Inclusion Criteria

• Adult aged 18 years or older
• Knee osteoarthritis requiring total knee arthroplasty
• Provide informed consent

Exclusion Criteria

• Inability to provide informed consent (e.g. cognitive disability, language barrier)
• Revision knee surgery
• Simultaneous bilateral knee surgery
• Recent lower extremity surgery or trauma interfering with gait assessment
• A CT scan cannot be obtained prior to surgery
• Inability or unwillingness to comply with the study protocol

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Research Institute of St. Joseph's Hamilton

UNKNOWN

Sponsor Role: collaborator

Canadian Orthopaedic Foundation (funding)

UNKNOWN

Sponsor Role: collaborator

McMaster University

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Locations

St. Joseph's Healthcare

Hamilton, Ontario, Canada

Site Status: RECRUITING

Countries

Canada

Central Contacts

Kim Madden, PhD

Role: CONTACT

maddenk@mcmaster.ca

289-237-7380

Facility Contacts

Kim Madden, PhD

Role: primary

maddenk@mcmaster.ca

289-237-7380

Other Identifiers

KMART

Identifier Type: -

Identifier Source: org_study_id