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NCT Number: NCT06883396

JUPITER 4.0 - Risk Factors for Failure of Isolated Medial Patellofemoral Ligament Reconstruction

The goal of this observational study is to learn about the outcomes of medial patellofemoral ligament (MPFL) reconstruction for the treatment of recurrent patellar instability. The main questions it aims to answer are:

* What are the risk factors for recurrent patellar instability after MPFL reconstruction? * What functional outcomes do patients report after MPFL reconstruction?

Participants undergoing MPFL reconstruction will answer survey questions about their knee and activity level 1 year and 2 years after surgery.

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Key information

Conditions

Patellar Dislocation, Recurrent Disease Attributes Fractures, Bone Joint Diseases Joint Dislocations Knee Fractures Knee Injuries Leg Injuries Musculoskeletal Diseases Patella Fracture Patellar Dislocation Patellar Instability Patellofemoral Dislocation Patellofemoral Disorder Patellofemoral Joint Dislocation Pathologic Processes Pathological Conditions, Signs and Symptoms Recurrence Wounds and Injuries

Age range

10 year–35 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Stanford University, Redwood City, California, United States

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About this study

The JUPITER group consists of high-volume patellofemoral surgeons across the United States, and was organized to facilitate the collection of clinical and radiographic outcomes following surgical and non-surgical treatment of patellar instability. With this study (JUPITER 4.0), the group aims to prospectively enroll a new cohort of consecutive patients with recurrent patellar instability that would undergo isolated MPFL reconstruction regardless of radiographic measurements or anatomic risk factors to address two specific aims - 1) what patient, injury, and surgical factors lead to recurrent instability following isolated MPFL reconstruction and 2) the creation of an instability severity index score, with the long-term objective of identifying preoperatively, patients with a high risk of failure of an isolated MPFL reconstruction who may be better served with concomitant bony procedure.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • 10-35 years old
  • Recurrent patellar instability with at least one episode defined as either (1) a dislocated patella requiring reduction in the emergency department or (2) a convincing history for dislocation, associated with full giving way, and the following physical findings: (a) hemarthrosis or effusion, (b) tenderness along the medial retinaculum, and (c) apprehension when laterally directed force was applied to the patella or (3) MRI-documented dislocation with associated bone bruises

Exclusion criteria

  • Previous ipsilateral knee surgery
  • Obligatory/fixed/habitual patella dislocation or subluxation
  • Unloadable inferior or lateral chondral damage on the patella that would require a tibial tubercle transfer for unloading purposes
  • Pathologic tibiofemoral instability

Treatment and study plan

Medial Patellofemoral Ligament (MPFL) Reconstruction

Procedure

For the purposes of this study, isolated MPFL reconstruction is defined as MPFL reconstruction with a tendon graft, with or without additional soft tissue procedure(s) including lateral retinacular lengthening or release, patellofemoral chondroplasty and/or cartilage restoration. No patient in the study will receive a bony realignment procedure to treat patellar instability.

Primary outcomes

  1. Recurrent patellar instability

    Time frame: Within 24 months post-operatively

    Patient-reported patellar dislocation or subluxation

Secondary outcomes

  1. Patient-Reported Outcome Measures (PROMs): Kujala score

    Time frame: 12 months post-operatively and 24 months post-operatively

    The Kujala score, also known as the Anterior Knee Pain Scale (AKPS), is a 13-item questionnaire that helps assess subjective reactions to activities and symptoms related to patellofemoral pain. It is a 0-to-100 point scale, with higher scores indicating better outcomes and less pain and disability.

  2. Patient-Reported Outcome Measures (PROMs): Pedi-IKDC

    Time frame: 12 months post-operatively and 24 months post-operatively

    The Pedi-IDKC is a modified version of the International Knee Documentation Committee (IDKC) Subjective Knee Form for use in young patients. It is a 15-item knee-specific questionnaire that measures symptoms, function, and sports activity. Scores range from 0-100, with higher scores indicating better outcomes.

  3. Patient-Reported Outcome Measures (PROMs): HSS Pedi-FABS

    Time frame: 12 months post-operatively and 24 months post-operatively

    The Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS) is a validated 8-item questionnaire scored from 0-30, with higher scores indicating higher levels of activity.

  4. Patient-Reported Outcome Measures (PROMs): KOOS-12

    Time frame: Time Frame: 12 months post-operatively and 24 months post-operatively

    The Knee injury and Osteoarthritis Outcome Score-12 (KOOS-12) is a 12-item measure evaluating the difficulties people experience due to problems with their knee. Each question is scored from 0 to 4 points, with 0 representing no knee problems and 4 representing extreme knee problems. Overall, scores range from 0 to 100, where, in contrast to the individual questions, 0 is the worst possible and 100 is the best possible score.

  5. Patient-Reported Outcome Measures (PROMs): BPII 2.0

    Time frame: 12 months post-operatively and 24 months post-operatively

    The BPII 2.0 (Banff Patellofemoral Instability Instrument) is a patient-reported outcome measure assessing quality of life in individuals with patellofemoral instability. The score ranges from 0 to 100, with higher scores indicating greater quality of life.

  6. Patient-Reported Outcome Measures (PROMs): PROMIS-29

    Time frame: 12 months post-operatively and 24 months post-operatively

    PROMIS (Patient-Reported Outcomes Measurement Information System) is a questionnaire that evaluates health-related quality of life across seven key domains: physical function, pain interference, fatigue, sleep disturbance, physical and mental health, and social health. It is scored a T-score metric. High scores mean more of the concept being measured. 10 points on the T-score metric is one standard deviation (SD).

Study contacts

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

Natalie Pahapill

CONTACT

[email protected]

646-714-6738

Simone Gruber

CONTACT

[email protected]

646-797-8947

Sponsors and collaborators

Lead sponsor

Hospital for Special Surgery, New York

Other

Collaborators

  • American Orthopaedic Society for Sports Medicine
  • Children's Hospital Medical Center, Cincinnati
  • Orthopedic Research and Education Foundation

Registry information

Important dates

Study start
2023
Primary completion
2026
Study completion
2027
First posted
Mar 19, 2025
Registry last updated
Feb 13, 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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