Assessing the Association Between WBCT PFJ Morphological Metrics and Knee Symptoms

May 1, 2026 updated by: Neil Segal, MD, MS, University of Kansas Medical Center

Patellofemoral joint (PFJ) pain is a common, often chronic, aching pain behind or around the kneecap, frequently called "runner's knee". It occurs when the kneecap does not glide smoothly over the thigh bone, often due to muscle weakness or overuse. It makes sitting for long periods, climbing stairs, or kneeling painful.

Symptomatic knee osteoarthritis (OA) is a common, long-term condition where the protective cartilage in the knee joint wears away, causing the bones to rub together, leading to daily pain and stiffness. In simple terms, it is a "wear-and-tear" disease of the entire joint that makes walking, climbing stairs, or bending the knee difficult.

The PFJ is where the patella (kneecap) meets the femoral trochlea (front part of the lower thigh bone) at the front of the knee. Patellar tracking refers to the movement of the patella that begins to engage in the distal femoral trochlear groove (smooth, U-shaped groove at the bottom of the thigh bone).

By doing this study, we hope to advance clinical knowledge of the PTJ features in a more natural position by using weight-bearing computed tomography (WBCT) images while the leg is straight and slightly bent. Determining links between specific knee symptoms and the PTJ structure on WBCT images could enable providers to effectively target the underlying causes and to develop targeted treatments.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

The patellofemoral joint (PFJ) is the articulation where the patella meets the femoral trochlea at the front of the knee. Patellar tracking refers to the movement of the patella that begins to engage in the distal femoral trochlear groove.

The proposed research will advance clinical knowledge of patellofemoral joint features in a more physiological position by using weight-bearing computed tomography (WBCT) images at 0° and 20° of knee flexion. Determining associations between specific knee symptoms and patellofemoral joint structural metrics on WBCT images could enable providers to effectively target the underlying causes and to develop targeted treatments.

PFJ features have become a significant area of interest, and numerous studies have been conducted to understand morphological characteristics, as it is the most common site associated with many knee symptoms and is a frequent location of early knee osteoarthritis (OA). There is growing evidence indicating that patellofemoral OA contributes to knee pain and functional limitations independent of tibiofemoral OA, and that the etiology and management may differ. A key factor in the risk profile for PFJ dysfunction may be malalignment of the patella with the femoral trochlea and subsequent abnormal tracking in the groove, leading to abnormal loading and wear of PFJ subchondral bone, microtearing of the lateral retinaculum, or irritation of the synovium, one of the most painful structures in the knee.

Quantifying patellofemoral alignment is an important aspect in assessing knee health, particularly in conditions that affect the PFJ, such as patellar instability, OA, or patellofemoral pain syndrome. There is no consensus on PFJ imaging position, knee flexion angle, joint position (e.g. stabilized or free), weight-bearing status, or beam angulation. However, the introduction of weight-bearing CT (WBCT) provides the ability to acquire 3D imaging of the PFJ under functionally loaded conditions. Using WBCT offers a unique advantage in this context because it allows for the evaluation of the knee in a loaded position, closely simulating the conditions under which the joint normally operates during activities like walking, running, and jumping, and under conditions in which the PFJ is symptomatic.

WBCT provides a three-dimensional view of the patellofemoral joint, allowing for the accurate measurement of various alignment parameters. These measurements may include the TT-TG, reTFR, patellar tilt angle, patellar height, and congruence angle. By analyzing these parameters, clinicians can gain insights into the alignment and positioning of the patella relative to the femur and the tibia.

Rationale:

WBCT can give us a better understanding of the patellofemoral joint in a loaded configuration in which the joint normally works during activities like walking, running, and jumping. This three-dimensional view will allow us to measure alignment parameters in a more functional position. This imaging technique is particularly valuable because it demonstrates the influence of factors such as muscle contractions or soft tissue conditions, the lack of which may distort results in non-weight-bearing assessments. Determining the extent to which these parameters are associated with knee symptoms will help to guide treatment decisions and improve clinical outcomes for patients with knee disorders.

Study Type

Observational

Enrollment (Estimated)

36

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 Backup

Study Locations

  • United States
    • Kansas
      • Kansas City, Kansas, United States, 66160
        • Recruiting
        • University of Kansas Medical Center
        • Contact:
        • Contact:
        • Principal Investigator:
          • Neil A Segal, MD, MS
        • Sub-Investigator:
          • Yashaf Zaheer, MD

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

Sampling Method

Non-Probability Sample

Study Population

Voluntary participants who consented to be contacted for research

Description

Inclusion Criteria:

  • Age ≥ 18
  • Knee pain, falling into either of the two groups, i.e., PFJ pain (pain only in the anterior region of the knee) or symptomatic knee OA (pain in any other area of the knee, including the anterior region)

Exclusion Criteria:

  • Bilateral total knee arthroplasty
  • Pregnant
  • Unable to stand safely for 2 minutes with support
  • Any condition that the investigator identifies as inappropriate for participation (e.g., unable to participant in consent process, unsafe to stand on WBCT platform, etc.)

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

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
PFJ pain
Participants experiencing recurrent, atraumatic patella dislocation, knee pain isolated to the anterior region, or PFPS (pain around the patella, exacerbated by prolonged positioning or ascending/descending stairs)
Radiation: WBCT
Images of the knee will be acquired using a WBCT, which provides a three-dimensional view of the patellofemoral joint in a loaded configuration.
Symptomatic knee OA
Participants experiencing pain in any other area of the knee, including the anterior region in combination with other regions
Radiation: WBCT
Images of the knee will be acquired using a WBCT, which provides a three-dimensional view of the patellofemoral joint in a loaded configuration.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
TT-TG
Time Frame: From enrollment to end of study (1 day)
Tibial Tuberosity - Trochlear Grove (TT-TG) will be measured on 3D WBCT knee images acquired at 0° and 20±5° of knee flexion.
From enrollment to end of study (1 day)
reTRF
Time Frame: From enrollment to end of study (1 day)
Relative external tibiofemoral rotation (reTFR) will be measured on 3D WBCT knee images acquired at 0° and 20±5° of knee flexion.
From enrollment to end of study (1 day)
Congruence Angle
Time Frame: From enrollment to end of study (1 day)
Congruence angle will be measured on 3D WBCT knee images acquired at 20±5° of knee flexion.
From enrollment to end of study (1 day)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
PTA
Time Frame: From enrollment to end of study (1 day)
Patellar tilt angle (PTA) will be measured on 3D WBCT knee images acquired at 0° and 20±5° of knee flexion.
From enrollment to end of study (1 day)
Bisect Offset
Time Frame: From enrollment to end of study (1 day)
Bisect offset will be measured on 3D WBCT knee images acquired at 0° of knee flexion.
From enrollment to end of study (1 day)
Patellar Height
Time Frame: From enrollment to end of study (1 day)
Patellar height will be measured on 3D WBCT knee images acquired at 0° and 20±5° of knee flexion.
From enrollment to end of study (1 day)

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Patellar tilt
Time Frame: From enrollment to end of study (1 day)
The angle between the line connecting the most posterior points of femoral condyles and the patella axis through the medial and lateral borders will be measured on WBCT acquired at 0° of knee flexion.
From enrollment to end of study (1 day)

Collaborators and Investigators

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

Sponsor

University of Kansas Medical Center

Investigators

  • Principal Investigator: Neil A Segal, MD, MS, University of Kansas Medical Center

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)

April 29, 2026

Primary Completion (Estimated)

August 1, 2026

Study Completion (Estimated)

August 1, 2026

Study Registration Dates

First Submitted

February 26, 2026

First Submitted That Met QC Criteria

March 11, 2026

First Posted (Actual)

March 16, 2026

Study Record Updates

Last Update Posted (Actual)

May 7, 2026

Last Update Submitted That Met QC Criteria

May 1, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • STUDY00162359

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

Yes

product manufactured in and exported from the U.S.

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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