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NCT Number: NCT07489963

Functional Impact at 12 Months Post-op of Posterior Cruciate Ligament Conservation During Robotic-assisted Surgery (MAKO) for Total Knee Replacement.

Studies have been made on the best way to do knee surgery and whether to conserve the posterior cruciate ligament or not during total knee prosthesis insertion is still under debate. However, most of these studies were made before the introduction of robotic knee surgery. It seems timely to do a study comparing these two surgical techniques: preservation versus removal of the posterior cruciate ligament in knee arthroplasty

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Key information

Conditions

Knee Arthroplasty, Total

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Clinique Tivoli-Ducos, Bordeaux, France

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About this study

Knee arthroplasty is a growing surgical discipline and 102,655 prostheses were fitted in France in 2019. The principle of total knee arthroplasty (TKA) is to replace a thickness of bone and cartilage whilst maintaining homogeneous tension of the capsulo-ligamentary envelope. Different designs have been developed over the years to achieve a good compromise between stability and mobility, ligament balancing being one of the major challenges of this procedure. The results of this surgery are good, but remain inferior to those of the total hip prosthesis. Around 1/5 patients operated on are dissatisfied.

The posterior cruciate ligament (PCL) plays a role in the stability of the prosthetic knee, preventing anteroposterior translation and allowing femoral roll-back. It also plays a role in flexion space. However, whether or not the PCL is retained during total prosthetic knee insertion has not been shown to make any difference to clinical or functional outcomes.

The proprioceptive role of mechanoreceptors in the anterior cruciate ligament (ACL) has already been demonstrated in several studies. A similar effect can thus be imagined when the PCL is conserved in TKA. Three prospective randomized studies have attempted to demonstrate this. However, those three studies did not find any significant differences in clinical or functional results. It should be noted, however, that all those studies were carried out without the use of robotics or any other means of assessing PCL preservation.

Robotics have made it possible to obtain better results, as well as greater accuracy and reproducibility of the surgical procedure and better intraoperative laxity control based on the concept of functional alignment.

Mechanical alignment was the first to be used during insertion of the prosthetic knee. It facilitates alignment according to the tibial and femoral mechanical axis, and better implant survival thanks to improved stress distribution. However, the patient's anatomy is not respected, leading to a certain amount of patient dissatisfaction. The concept of kinematic (or anatomic) alignment was designed to achieve greater respect for patient anatomy and ligament balancing. More recently, with the advent of navigation and robotics, the authors have described functional alignment, which optimizes TKA alignment according to residual ligament tension.

Since robotic assistance provides better control of the procedure and, in particular, better preservation of PCL integrity in this surgical variant, we believe it is time to conduct a high-level evidence study comparing these two surgical techniques: preservation versus removal of the posterior cruciate ligament in knee arthroplasty. The investigators hypothesize that preserving the PCL will lead to better functional results, a better quality of life and an earlier return to activity.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Patient scheduled for first-intention robotic-assisted total knee replacement (MAKO).
  • Unilateral replacement, regardless of laterality.
  • Patient able to answer questionnaires.
  • Patient willing to undergo usual 12-month follow-up.
  • Patient has given free and informed consent and has signed the consent form.
  • Patient affiliated with or benefiting from a health insurance scheme.

Exclusion criteria

  • Patient with intraoperative technical impossibility of retaining PCL (flessum > 20°, flexion stiffening < 100°).
  • Previous posterior cruciate ligament surgery.
  • Post-traumatic gonarthrosis.
  • Valgus > 185°.
  • Patient with septic complication.
  • Patient participating in another interventional trial.
  • Patient in an exclusion period determined by another study.
  • Patient under court protection, guardianship or curatorship.
  • Patient unable to give consent.
  • Patients for whom it is impossible to provide informed information.
  • Pregnant women

Treatment and study plan

Total knee arthroplasty

Procedure

Robot-assisted total knee arthroplasty

Primary outcomes

  1. Functional impact at of posterior cruciate ligament preservation in the LCP+group

    Time frame: 12 months post-surgery

    Evaluated according to the FJS-12 (Forgotten Joint Score) self-questionnaire. The FJS-12 is a self-administered questionnaire consisting of 12 items.

    The patient is asked to rate their awareness of their artificial joint for the 12 activities. Each item is then given a score of between 0-4 on a five-point Likert scale in which : 0 - Never,1 - Almost Never, 2 - Seldom, 3 - Sometimes,4 - Mostly.

    The answers are then summed and divided by the number of completed items. The mean value is then multiplied by 25 to obtain the total score of 0-100. The higher scores indicating better outcomes (less awareness of the joint).

  2. Functional impact at of posterior cruciate ligament resection in the LCP-group

    Time frame: 12 months post-surgery

    Evaluated according to the FJS-12 (Forgotten Joint Score) self-questionnaire. The FJS-12 is a self-administered questionnaire consisting of 12 items.

    The patient is asked to rate their awareness of their artificial joint for the 12 activities. Each item is then given a score of between 0-4 on a five-point Likert scale in which : 0 - Never,1 - Almost Never, 2 - Seldom, 3 - Sometimes,4 - Mostly.

    The answers are then summed and divided by the number of completed items. The mean value is then multiplied by 25 to obtain the total score of 0-100. The higher scores indicating better outcomes (less awareness of the joint).

Secondary outcomes

  1. Functional impact at of posterior cruciate ligament preservation in the LCP+group

    Time frame: 4.5 months post-surgery

    Evaluated according to the FJS-12 (Forgotten Joint Score) self-questionnaire. The FJS-12 is a self-administered questionnaire consisting of 12 items.

    The patient is asked to rate their awareness of their artificial joint for the 12 activities. Each item is then given a score of between 0-4 on a five-point Likert scale in which : 0 - Never,1 - Almost Never, 2 - Seldom, 3 - Sometimes,4 - Mostly.

    The answers are then summed and divided by the number of completed items. The mean value is then multiplied by 25 to obtain the total score of 0-100. The higher scores indicating better outcomes (less awareness of the joint).

  2. Functional impact at of posterior cruciate ligament ablation in the LCP-group

    Time frame: 4.5 months post-surgery

    Evaluated according to the FJS-12 (Forgotten Joint Score) self-questionnaire. The FJS-12 is a self-administered questionnaire consisting of 12 items.

    The patient is asked to rate their awareness of their artificial joint for the 12 activities. Each item is then given a score of between 0-4 on a five-point Likert scale in which : 0 - Never,1 - Almost Never, 2 - Seldom, 3 - Sometimes,4 - Mostly.

    The answers are then summed and divided by the number of completed items. The mean value is then multiplied by 25 to obtain the total score of 0-100. The higher scores indicating better outcomes (less awareness of the joint).

  3. Algo-functional OKS (Oxford Knee Score) in the LCP+group

    Time frame: 4.5 months post-surgery

    The OKS is a patient-reported outcome measure that consists of 12 questions about an individual's level of function, activities of daily living and how they have been affected by pain over the preceding four weeks. It uses a scoring system from 0-4 where four is the best outcome and total scores range from 0 (poorest function) to 48 (maximal function).

  4. Algo-functional OKS (Oxford Knee Score) in the LCP+group

    Time frame: 12 months post-surgery

    The OKS is a patient-reported outcome measure that consists of 12 questions about an individual's level of function, activities of daily living and how they have been affected by pain over the preceding four weeks. It uses a scoring system from 0-4 where four is the best outcome and total scores range from 0 (poorest function) to 48 (maximal function).

  5. Algo-functional OKS (Oxford Knee Score) in the LCP-group

    Time frame: 4.5 months post-surgery

    The OKS is a patient-reported outcome measure that consists of 12 questions about an individual's level of function, activities of daily living and how they have been affected by pain over the preceding four weeks. It uses a scoring system from 0-4 where four is the best outcome and total scores range from 0 (poorest function) to 48 (maximal function).

  6. Algo-functional OKS (Oxford Knee Score) in the LCP-group

    Time frame: 12 months post-surgery

    The OKS is a patient-reported outcome measure that consists of 12 questions about an individual's level of function, activities of daily living and how they have been affected by pain over the preceding four weeks. It uses a scoring system from 0-4 where four is the best outcome and total scores range from 0 (poorest function) to 48 (maximal function).

  7. KSS (Knee Society Score) in the LCP+ group

    Time frame: 4.5 months post-surgery

    The KSS questionnaire includes a Knee Score, rating the knee joint itself (pain, range of motion, stability and radiographic alignment), and a Function Score (patient's walking distance, climbing stairs and use of walking aids).The Knee Score allocates a maximum of 100 points to evaluate range of motion (1 point per 5°, maximum 125°), stability (medial/lateral (15 points) and anterior/posterior (10 points)) and pain (50 points) with deductions for extension lag, flexion contracture and malalignment (if leg axis < 5 or > 10° on radiological examination). A maximum score of 100 points is a well-aligned knee with 125° of motion, almost none anteroposterior or mediolateral instability and no pain. The Function Score considers walking distance (50 points) and stair-climbing (50 points) with deduction if a walking aid is used. A patient who walks unlimited and has no trouble climbing stairs gets the maximum Function Score of 100 points.

  8. KSS (Knee Society Score) in the LCP+ group

    Time frame: 12 months post-surgery

    The KSS questionnaire includes a Knee Score, rating the knee joint itself (pain, range of motion, stability and radiographic alignment), and a Function Score (patient's walking distance, climbing stairs and use of walking aids).The Knee Score allocates a maximum of 100 points to evaluate range of motion (1 point per 5°, maximum 125°), stability (medial/lateral (15 points) and anterior/posterior (10 points)) and pain (50 points) with deductions for extension lag, flexion contracture and malalignment (if leg axis < 5 or > 10° on radiological examination). A maximum score of 100 points is a well-aligned knee with 125° of motion, almost none anteroposterior or mediolateral instability and no pain. The Function Score considers walking distance (50 points) and stair-climbing (50 points) with deduction if a walking aid is used. A patient who walks unlimited and has no trouble climbing stairs gets the maximum Function Score of 100 points.

  9. KSS (Knee Society Score) in the LCP- group

    Time frame: 4.5 months post-surgery

    The KSS questionnaire includes a Knee Score, rating the knee joint itself (pain, range of motion, stability and radiographic alignment), and a Function Score (patient's walking distance, climbing stairs and use of walking aids).The Knee Score allocates a maximum of 100 points to evaluate range of motion (1 point per 5°, maximum 125°), stability (medial/lateral (15 points) and anterior/posterior (10 points)) and pain (50 points) with deductions for extension lag, flexion contracture and malalignment (if leg axis < 5 or > 10° on radiological examination). A maximum score of 100 points is a well-aligned knee with 125° of motion, almost none anteroposterior or mediolateral instability and no pain. The Function Score considers walking distance (50 points) and stair-climbing (50 points) with deduction if a walking aid is used. A patient who walks unlimited and has no trouble climbing stairs gets the maximum Function Score of 100 points.

  10. KSS (Knee Society Score) in the LCP- group

    Time frame: 12 months post-surgery

    The KSS questionnaire includes a Knee Score, rating the knee joint itself (pain, range of motion, stability and radiographic alignment), and a Function Score (patient's walking distance, climbing stairs and use of walking aids).The Knee Score allocates a maximum of 100 points to evaluate range of motion (1 point per 5°, maximum 125°), stability (medial/lateral (15 points) and anterior/posterior (10 points)) and pain (50 points) with deductions for extension lag, flexion contracture and malalignment (if leg axis < 5 or > 10° on radiological examination). A maximum score of 100 points is a well-aligned knee with 125° of motion, almost none anteroposterior or mediolateral instability and no pain. The Function Score considers walking distance (50 points) and stair-climbing (50 points) with deduction if a walking aid is used. A patient who walks unlimited and has no trouble climbing stairs gets the maximum Function Score of 100 points.

  11. Radiological posterior laxity in the LCP+ group

    Time frame: 4.5 months post-surgery

    Qualitative. Radiological examination as part of standard treatment.

  12. Radiological posterior laxity in the LCP+ group

    Time frame: 12 months post-surgery

    Qualitative. Radiological examination as part of standard treatment.

  13. Radiological posterior laxity in the LCP- group

    Time frame: 4.5 months post-surgery

    Qualitative. Radiological examination as part of standard treatment.

  14. Radiological posterior laxity in the LCP- group

    Time frame: 12 months post-surgery

    Qualitative. Radiological examination as part of standard treatment.

  15. Cost to the community of the care pathway associated with rehabilitation in the LCP+ group

    Time frame: Up to 12 months after surgery

    Quantitative, in Euros per patient.

  16. Cost to the community of the care pathway associated with rehabilitation in the LCP- group

    Time frame: Up to 12 months after surgery

    Quantitative, in Euros per patient.

  17. Sustainability of the annual planned budget if using the strategy under evaluation, nationwide, from the health insurance's point of view

    Time frame: Up to 12 months after surgery

    Cost to the French health insurance system of adopting the technique of robotic knee arthroplasty with conservation of the posterior cruciate ligament

Study contacts

Contact information is provided by the study sponsor or research team.

Anissa MEGZARI

CONTACT

[email protected]

+33466684236

Rémy COULOMB, Dr

CONTACT

[email protected]

+334.66.68.31.56

Sponsors and collaborators

Lead sponsor

Centre Hospitalier Universitaire de Nīmes

Other

Collaborators

  • Clinique Tivoli Ducos
  • Hôpital de la Croix-Rousse

Registry information

Official study title

Evaluation of the Functional Impact at 12 Months Post-op of Posterior Cruciate Ligament Conservation During Robotic-assisted Surgery (MAKO) for Total Knee Replacement. A Randomized, Single-blind, Multicenter, Controlled Superiority Study.

Acronym: LCPTG

Important dates

Study start
2025
Primary completion
2027
Study completion
2028
First posted
Mar 24, 2026
Registry last updated
Mar 27, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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