An Analysis of Healthy Caucasian Knees (PC-CT KNEE)

An Analysis of Healthy Caucasian Knees: Variability in Threedimensional Anatomy, Mediolateral Ligamentous Balance, Lower Limb Alignment and Trabecular Micro-structure.

In current literature, databases of healthy knee anatomy and function are confined to small sample sizes or singular imaging modalities. In this study, the investigator propose constructing a unique and large-scale database of healthy Caucasian knee anatomy and function by utilizing a combination of ultra-high resolution capabilities from photon-counting CT, lower limb weightbearing orthogonal imaging (EOS) of full leg, and non-invasive ultrasound-based functional testing of the knee. This study is a collaborative effort between the orthopaedics, radiology and biomechanical engineering departments in which the same prospectively acquired database will be used for multiple independent research questions.

Study Overview

• Status: Recruiting
• Conditions: Healthy Volunteers
• Intervention / Treatment: Radiation: CT scan images of the knee; Radiation: EOS scan of full leg; Diagnostic test: Ultrasound-based gap analysis

Detailed Description

Total knee arthroplasty (TKA) is the mainstay of treatment of end-stage osteoarthritis. Despite recent robotic advancements in TKA surgical technique, satisfaction rates remain low compared to the golden standard of hip arthroplasty surgery. Personalization in TKA, i.e. accurate recreation of individual anatomy and biomechanical properties of the knee joint, is increasingly recognized as an important variable in achieving satisfaction after TKA. Therefore, this study aims to gain foundational knowledge necessary for further research in anatomical and biomechanical personalization in TKA.

Anatomical personalization in TKA aims at recreating the pre-arthritic anatomy of each patient. The combination of native knee joint-line anatomy as well as native overall lower limb alignment anatomy can be referred to as the concept of 'constitutional anatomy'.

Historically, anatomical personalization in TKA focused primarily on variable tibiofemoral anatomy in the coronal plane. This led to the groundbreaking work, introducing the concept of coronal plane alignment of the knee (CPAK) phenotyping. This classification categorized knees into nine coronal morphologies based on limb alignment and knee joint line obliquity.

Another facet of personalization lies in biomechanical components, particularly the variable native mediolateral ligamentous balance of the knee (referred to as 'constitutional balance'). Presently, personalized ligamentous balancing in TKA remains largely unexplored, with surgeons aiming for a standardized balancing target regardless of patient-specific variations. This systematic approach towards knee balancing is a result of difficulty in predicting constitutional balance in arthritic knees, as progressive osteoarthritis alters the native ligamentous balance due to osteophyte formation, ligamentous wear and contractures. Given that joint biomechanics result (in part) from threedimensional joint line anatomy, it is plausible that variable constitutional balance might directly relate to variable constitutional anatomy. This assumption will be further evaluated in this study and, if confirmed, would imply the clinical possibility of determining constitutional balance by determining constitutional anatomical phenotype.

This study aims to identify phenotypes of constitutional anatomy and balance and correlate both by analysis of a prospectively acquired database of Caucasian volunteers with 'healthy knees' (see inclusion criteria for definition of a 'healthy knee').

For the anatomical analysis, a combination of photon-counting CT (PC-CT) and EOS full leg imaging will be used. The combination of these novel imaging modalities allows for a highly detailed evaluation of knee joint line anatomy combined with analysis of weight-bearing lower limb alignment in all three anatomic planes, whilst ensuring minimal exposure levels to ionizing radiation.

For the analysis of constitutional balance, this study will use an ultrasound-based technique. Ultrasound-based gap analysis is a non-invasive and previously validated method of determining medio-lateral laxity of the knee joint.

• Study Type: Interventional
• Enrollment (Estimated): 200
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Anna Tarasiuk; Phone Number: +32 16 33 88 18; Email: orthopedie.research@uzleuven.be
• Study Contact Backup: Name: Lennart Scheys, Prof. Ir.; Phone Number: +32 16 33 88 18; Email: lennart.scheys@uzleuven.be

Study Locations

• Belgium
  • Vlaams-Brabant
    • Leuven, Vlaams-Brabant, Belgium, 3000
      • Recruiting
      • Universitaire Ziekenhuizen KU Leuven
      • Contact: Anna Tarasiuk; Phone Number: +32 16 33 88 18; Email: orthopedie.research@uzleuven.be
      • Contact: Lennart Scheys, Prof. Ir.; Phone Number: +32 16 33 88 18; Email: lennart.scheys@uzleuven.be
      • Principal Investigator: Lennart Scheys, Prof. Ir.

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Aged 20-35 years old.

• 'Caucasian':

  1. Self-identification as Caucasian or of European descent.
  2. Self-identification as having 'fair' skin tone.
  3. Both parents and all grandparents are of Caucasian or European descent.

• Healthy knee and lower limb:

  1. No bony orthopaedic or trauma history in the lower limb (pelvis - foot).
  2. No ligamentary or soft tissue trauma history in the knee.
  3. No ligamentary or soft tissue trauma in the lower limb requiring cast immobilization.

Exclusion Criteria:

• Individuals identifying with a race or ethnicity other than Caucasian or European descent.
• Participants with known mixed racial or ethnic backgrounds that include non-Caucasian ancestry.
• Participant uncertainty of pregnancy status.
• Open wounds over the knee joint.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Other: Healthy Caucasian knees; Healthy Caucasian volunteers aged from 20 till 35 years old

Radiation: CT scan images of the knee; CT scan images of the knee allow for detailed anatomical analysis of joint shape through the means of statistical shape modelling.; Radiation: EOS scan of full leg; Software-based reconstruction of orthogonal images provided by EOS imaging allows for a comprehensive three-dimensional analysis of lower limb alignment without the need for a full leg CT scan, minimizing exposure to ionizing radiation in the pelvic region.; Diagnostic test: Ultrasound-based gap analysis; For the analysis of constitutional balance, this study will use an ultrasound-based technique. This is a non-invasive and previously validated method of determining medio-lateral laxity of the knee joint.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
CT scan	CT scan images of the knee allow for detailed anatomical analysis of joint shape through the means of statistical shape modelling (SSM).	Day 1
EOS scan	EOS imaging of the full leg	Day 1
Ultrasound	Ultrasound-based gap analysis is a non-invasive and previously validated method of determining medio-lateral laxity of the knee joint.	Day 1

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
International Physical Activity Questionnaire	The questionnaire is used to estimate physical activity level. The questionnaire consists of 31 questions divided into 5 sub-areas. A higher score corresponds to a more physically strenuous activity.	Day 1

Collaborators and Investigators

• Sponsor: Universitaire Ziekenhuizen KU Leuven
• Investigators: Principal Investigator: Lennart Scheys, Prof. Ir., Universitaire Ziekenhuizen KU Leuven

Study record dates

Study Major Dates

• Study Start (Actual): August 8, 2025
• Primary Completion (Estimated): January 1, 2027
• Study Completion (Estimated): January 1, 2027

Study Registration Dates

• First Submitted: April 17, 2025
• First Submitted That Met QC Criteria: March 12, 2026
• First Posted (Actual): March 13, 2026

Study Record Updates

• Last Update Posted (Actual): March 13, 2026
• Last Update Submitted That Met QC Criteria: March 12, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Healthy Caucasian knees
• Other Study ID Numbers: S68929

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