Mako Functionally Aligned Total Knee Arthroplasty vs Mako Mechanically Aligned Total Knee Arthroplasty

July 7, 2025 updated by: University College, London

A Prospective Randomised Control Trial Comparing Mako Robotic-arm Assisted Functionally Aligned Total Knee Arthroplasty Versus Mako Robotic-arm Assisted Mechanically Aligned Total Knee Arthroplasty

This study evaluates outcomes of robotic-arm assisted mechanically aligned total knee arthroplasty [MA TKA] versus robotic-arm assisted functionally aligned total knee arthroplasty [FA TKA]. Half the study will receive MA TKA and half will receive FA TKA.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Total knee arthroplasty [TKA] is an estabilshed treatment for symptomatic end-stage knee osteoarthritis, but there is a higher disatisfaction rate when compared to total hip arthroplasty. The exact aetiology of this is not clear but recent studies have shown one possible reason to be conventional TKA with mechanical alignment [MA] may force the knee into an unnatural position. This may lead to altered knee anatomy and kinematics that may compromise patient satisfaction.

Total knee arthroplasty using functional alignment [FA] aims to restore the patient's prearthritic knee anatomy and native joint kinematics. Early clinical and functional outcome studies have reported promising outcomes in TKA with FA but results of longer term studies have not yet been published.

There are very few prospective studies exploring clinical and radiological outcomes in MA versus FA for TKA. It is possible to improve on previous studies by recording a more comprehensive range of clinical and functional outcome measures, blinding patients and observers recording outcomes of interest, and using longer follow-up times.

Robotic-arm assistance can be used to improve the accuracy of implant positioning. Clinical and functional outcomes should also be correlated to longer-term outcomes to better establish the "safe zone" for functional alignment. The findings of this study will enable an improved understanding of the clinical and functional benefits of FA compared to MA. These outcomes will improve our understanding of the optimal TKA alignment with possible improved outcomes; improved cost-effectiveness by reduced revisions and better patient satisfaction and function; and improved long-term implant survival.

100 patients will be enrolled in a 1:1 ratio between the two treatment groups. Trial patient will be allocated to either the MA TKA ['Control group'] or to the FA TKA ['Investigation group']. Outcomes will be recorded at specific milestones.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
100

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United Kingdom
      • London, United Kingdom, NW1 2PG
        • University College London Hospital NHS Foundation Trust

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 80 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Patient has symptomatic knee osteoarthritis requiring primary TKA
  • Patient and surgeon are in agreement that TKA is the most appropriate treatment
  • Patient is fit for surgical intervention following review by surgeon and anaesthetist
  • Patient is between 18-80 years of age at time of surgery
  • Gender: male and female
  • Patient must be capable of giving informed consent and agree to comply with the postoperative review program
  • Patient must be a permanent resident in an area accessible to the study site
  • Patient must have sufficient postoperative mobility to attend follow-up clinics and allow for radiographs to be taken

Exclusion Criteria:

  • Patient is not suitable for routine primary TKA e.g. patient has ligament deficiency that requires a constrained prosthesis
  • Patient has bone loss that requires augmentation
  • Patient is not medically fit for surgical intervention
  • Patient requires revision surgery following previously failed correctional osteotomy or ipsilateral TKA
  • Patient is immobile or has another neurological condition affecting musculoskeletal function
  • Patient is less than 18 years of age or greater than 80 years of age
  • Patient is already enrolled on another concurrent clinical trial
  • Patient is unable or unwilling to sign the informed consent form specific to this study
  • Patient is unable to attend the follow-up programme
  • Patient is non-resident in local area or expected to leave the catchment area postoperatively

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Mechanically aligned
Neutral limb alignment irrespective of the patient's native knee anatomy and joint mechanics
Device: Total knee arthroplasy
Surgical implantation of prosthetic knee using robotic-arm assist
Experimental: Functionally aligned
Restore the patient's own pre-arthritic knee anatomy
Device: Total knee arthroplasy
Surgical implantation of prosthetic knee using robotic-arm assist

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Western Ontario and Mcmaster Universities Arthritis Index (WOMAC)
Time Frame: 2 years post-intervention
Patient recorded outcome questionnaire evaluating pain, stiffness and disability in affected joint
2 years post-intervention

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
European Quality of Life questionnaire with 5 dimensions for adults (EQ-5D)
Time Frame: Pre-op; 6 weeks post-op; 6 months post-op; 1 year post-op; 2 years post-op
Patient recorded outcome measure with 5 domains; score -1 to 1, with 1 being best score
Pre-op; 6 weeks post-op; 6 months post-op; 1 year post-op; 2 years post-op
Lower limb alignment
Time Frame: pre op and 6 weeks post op
Assessed using Computerised Tomography (CT) scanogram. Measurements of the hip-knee-angle (HKA), medial proximal tibial angle (MPTA), lateral distal femoral angle (LDFA), femoral flexion angle, and posterior tibial slope will be recorded preoperatively and postoperatively
pre op and 6 weeks post op
Operating time
Time Frame: interoperative
Operating time [minutes]
interoperative
Time to discharge
Time Frame: Documented when participant leaves hospital, an average of 72 -96 hours
Time to discharge from admission until documented discharge from hospital (hours)
Documented when participant leaves hospital, an average of 72 -96 hours
Forgotten Joint Score (FJS)
Time Frame: Pre-op; 6 weeks post-op; 6 months post-op; 1 year post-op; 2 years post-op
Patient recorded outcome measure via questionnaire. Score cumulative with -100 being best score and 0 being worst score
Pre-op; 6 weeks post-op; 6 months post-op; 1 year post-op; 2 years post-op
Oxford Knee Score (OKS)
Time Frame: Pre-op; 6 weeks post-op; 6 months post-op; 1 year post-op; 2 years post-op
Patient recorded outcome measure via questionnaire. 48 is best score and 0 worst score
Pre-op; 6 weeks post-op; 6 months post-op; 1 year post-op; 2 years post-op
Short form health survey of 12 items (SF-12),
Time Frame: Pre-op; 6 weeks post-op; 6 months post-op; 1 year post-op; 2 years post-op
Patient recorded outcome measure. Questions concerning attitudes to physical and mental heath with 12 questions combined to give overall norm-based values; higher score better, lower score worse.
Pre-op; 6 weeks post-op; 6 months post-op; 1 year post-op; 2 years post-op
Knee injury and osteoarthritis outcome score (KOOS)
Time Frame: Pre-op; 6 weeks post-op; 6 months post-op; 1 year post-op; 2 years post-op
Patient recorded outcome measure via questionnaire. 6 separate domains including pain, stiffness, quality of life, symptoms, and function; each domain creates percentage with overall cumulative percentage achieved; best score 100%
Pre-op; 6 weeks post-op; 6 months post-op; 1 year post-op; 2 years post-op
University of California at Los Angeles knee (UCLA)
Time Frame: Pre-op; 6 weeks post-op; 6 months post-op; 1 year post-op; 2 years post-op
Patient recorded outcome measure via questionnaire. Patient records current level of activity; 10 best possible score, 0 worst possible score
Pre-op; 6 weeks post-op; 6 months post-op; 1 year post-op; 2 years post-op
Use of mobility aids
Time Frame: during inpatient admission and postoperatively at 6- weeks, 6 months, 1 year and 2 years
description of any mobility aids used to assist with ambulation; can describe wheelchair, walker, crutches, sticks or no need for any mobility aid
during inpatient admission and postoperatively at 6- weeks, 6 months, 1 year and 2 years
Mobilisation distance
Time Frame: during inpatient admission and postoperatively at 6- weeks, 6 months, 1 year and 2 years
Mobilisation distance (metres)
during inpatient admission and postoperatively at 6- weeks, 6 months, 1 year and 2 years
Range of movement
Time Frame: inpatient admission and postoperatively at 6 weeks, 6 months, 1 year and 2 years
Range of movement (degrees) in knee joint
inpatient admission and postoperatively at 6 weeks, 6 months, 1 year and 2 years
radiosteriometric analysis (RSA)
Time Frame: postoperatively at 2 weeks, 6 weeks, 6 months, 1 year, and 2 years
Femoral and tibial implant early migration as assessed using RSA
postoperatively at 2 weeks, 6 weeks, 6 months, 1 year, and 2 years
Gait analysis
Time Frame: performed postoperatively at 6 months and 1 year postoperatively
Walking on an instrumented treadmill with force plates
performed postoperatively at 6 months and 1 year postoperatively
Complications
Time Frame: during inpatient admission and postoperatively at 6- weeks, 6 months, 1 year and 2 years
Complications relating to surgery
during inpatient admission and postoperatively at 6- weeks, 6 months, 1 year and 2 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University College, London

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Stryker Orthopaedics

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Chair: Fares S Haddad, UCLH

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 28, 2018

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
February 6, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
February 6, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 13, 2019

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 16, 2019

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 17, 2019

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 9, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 7, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 17/0721

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

No plan

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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