Is It Possible to Obtain Reliable MPTA and LDFA Values Using Imageless Navigation in Total Knee Arthroplasty? Comparison Between Preoperative CT Scan Measurements and Intraoperative Bone Morphing Before and After Articular Cartilage Removal (CAR-NAV-AL)

May 11, 2026 updated by: Groupe Hospitalier Diaconesses Croix Saint-Simon

Is It Possible to Obtain Reliable MPTA and LDFA Values Using Imageless Navigation in Total Knee Arthroplasty? Comparison Between Preoperative CT Scan Measurements and Intraoperative Bone Morphing Before and After Articular Cartilage Removal.

Title: Evaluation of Image-less Navigation Accuracy in Total Knee Arthroplasty (CARNAVAL)

Summary:

The purpose of this study is to evaluate the accuracy of an imageless navigation system in measuring key anatomical angles (MPTA and LDFA) during Total Knee Arthroplasty (TKA). While preoperative CT scans are currently the gold standard for bone planning, imageless navigation uses a "bone morphing" technique during surgery to create a digital model of the knee.

The study aims to determine if the measurements obtained via bone morphing, both before and after cartilage removal, are consistent with the measurements obtained from preoperative CT scans. The investigators seek to confirm if imageless navigation can provide reliable anatomical data, potentially reducing the need for preoperative radiation and costs associated with CT imaging.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Background:

Accurate alignment is critical for the long-term success of Total Knee Arthroplasty (TKA). Newer robotic and navigated systems rely on bone morphing to define the patient's anatomy per-operatively. However, the impact of cartilage thickness and the intrinsic accuracy of these systems compared to 3D CT-based planning remain subjects of clinical interest.

Objectives:

The primary objective is to compare the Medial Proximal Tibial Angle (MPTA) and the Lateral Distal Femoral Angle (LDFA) measured by:

Preoperative CT scan (Reference standard).

Peroperative image-less navigation (bone morphing) with intact cartilage.

Peroperative image-less navigation (bone morphing) after cartilage removal.

Methodology:

This is a prospective, monocentric, interventional study. All included patients will undergo a standard preoperative 3D CT scan as part of the surgical planning. During the TKA procedure, the surgeon will use the navigation system to perform bone morphing at two specific stages:

Initial stage: On the joint surface with the cartilage still present.

Secondary stage: After the surgical removal of the articular cartilage.

Comparison:

The data collected peroperatively will be compared to the CT scan measurements. The study will evaluate the "fidelity" (accuracy) of the navigation system and analyze whether the presence or absence of cartilage significantly alters the reliability of the digital bone model created by the system.

Expected Outcomes:

The results will help determine the degree of confidence surgeons can place in imageless navigation for achieving precise anatomical alignment without the systematic use of preoperative 3D imaging.

Study Type

Interventional

Enrollment (Actual)

50

Phase

  • 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 Locations

  • France
      • Paris, France, 75020
        • Groupe Hospitalier Diaconesses Croix Saint Simon

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

Patients aged 18 years or older.

Patients with primary or secondary knee osteoarthritis requiring a Total Knee Arthroplasty (TKA).

Patients for whom the surgical planning requires a pre-operative 3D CT scan.

Patients who have been informed about the study and have signed the written informed consent.

Patients affiliated with or beneficiaries of a social security scheme.

Exclusion Criteria:

Revision Total Knee Arthroplasty (re-operation).

Major bone loss or significant bone deformity that prevents reliable anatomical landmarking.

History of prior knee surgery that could interfere with the navigation system trackers (e.g., retained hardware in the femur or tibia).

Pregnant or breastfeeding women.

Persons deprived of liberty or under legal guardianship.

Patients with a known allergy to any component used during the standard surgical procedure.

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: Health Services Research
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Navigation and CT-scan Comparison Group)
All participants undergo Total Knee Arthroplasty (TKA) using an imageless navigation system. Anatomical measurements (MPTA and LDFA) are recorded via bone morphing at two stages: 1) on intact articular cartilage and 2) after cartilage removal.
Procedure: Non-image-based Computer-Assisted Navigation with Bone Morphing
Intraoperative surface morphing of the joint surfaces is performed to obtain LDFA and MPTA values. The procedure compares measurements taken on the residual cartilage versus measurements taken directly on the osseous surface after cartilage debridement. These values are then validated against preoperative 3D CT scan data.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Mean Difference in Medial Proximal Tibial Angle (MPTA) between CT scan and Imageless Navigation.
Time Frame: At the time of surgery (intra-operative).
The mean difference (measured in degrees) between the MPTA calculated from the preoperative 3D CT scan and the MPTA measured intraoperatively via bone morphing after cartilage removal.
At the time of surgery (intra-operative).

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Mean Difference in Lateral Distal Femoral Angle (LDFA) between CT scan and Imageless Navigation.
Time Frame: At the time of surgery (intraoperative)
The mean difference (measured in degrees) between the LDFA calculated from the preoperative 3D CT scan and the LDFA measured intraoperatively via bone morphing after cartilage removal.
At the time of surgery (intraoperative)
Correlation of MPTA and LDFA measurements before and after cartilage removal.
Time Frame: At the time of surgery (intra-operative).
Evaluation of the measurement shift (in degrees) caused by the presence of articular cartilage during the bone morphing process. This assesses the system's ability to extrapolate the subchondral bone surface.
At the time of surgery (intra-operative).

Collaborators and Investigators

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

Sponsor

Groupe Hospitalier Diaconesses Croix Saint-Simon

Investigators

  • Principal Investigator: Antoine MOUTON, Orthopedic surgeon, Diaconesses Croix Saint Simon Hospital Group

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)

July 7, 2025

Primary Completion (Actual)

October 30, 2025

Study Completion (Actual)

October 30, 2025

Study Registration Dates

First Submitted

April 28, 2026

First Submitted That Met QC Criteria

May 5, 2026

First Posted (Actual)

May 8, 2026

Study Record Updates

Last Update Posted (Actual)

May 14, 2026

Last Update Submitted That Met QC Criteria

May 11, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2025-A00825-44

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

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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