Patellar InstabilityPAPINCT02333825
Pediatric and Adolescent Patellar Instability
A study testing Medial patellofemoral ligament reconstruction surgery and Physical therapy and rehabilitation in people with Patellar Instability, run by Hospital for Special Surgery, New York.
Trial summary
This is a multi-center, randomized controlled clinical trial, the purpose of which is to determine if patients age 25 and younger who undergo medial patellofemoral ligament (MPFL) reconstruction have lower rates of recurrent instability compared to those treated non-operatively. Read more about this study
- Who is it for?
- Ages 8 to 25 years
- Conditions the study is for
- Patellar Instability
- What is being tested?
- Medial patellofemoral ligament reconstruction surgery and Physical therapy and rehabilitation
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 240 participants
- Where
- No sites listed yet
- Study dates
- Dec 2015to Dec 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 8 to 25 years
- All sexes
- No healthy volunteers
- Child, Adult
Who may be able to join
- Patients must be age 25 or younger
- Patients must be first-time dislocators, meaning have had only one episode of patellar instability, during which they dislocated their patella (kneecap)
Who cannot join
- Patients with more than one episode of patellofemoral instability
- Patients who have had prior patellofemoral surgery on the knee of interest
- Patients with large cartilage tears in the knee. These patients will undergo stabilization of the patellofemoral joint (MPFL reconstruction) as per standard of care, and will not be included in the study.
About this study
This is a multi-center, randomized controlled clinical trial, the purpose of which is to determine if patients age 25 and younger who undergo medial patellofemoral ligament (MPFL) reconstruction have lower rates of recurrent instability compared to those treated non-operatively. The MPFL is a ligament that stabilizes the kneecap, and maintains its proper position in the groove on the femur (thighbone). Instability refers to a situation in which the kneecap moves out of place, or dislocates. When instability is recurrent, it occurs more than once in the same knee.
Read the detailed description
A total of 240 patients will be enrolled across participating sites around the country. These sites currently include: The Hospital for Special Surgery, Oregon Health and Science University, Inova Sports Medicine, and Mayo Clinic. Patients are randomly assigned to one of two treatment groups. Patients assigned to the "stabilization" group will undergo surgery to reconstruct the MPFL using either a hamstring tendon that is your own or one obtained from a donor. Patients assigned to the "conservative" group will be treated with physical therapy, and possibly a simple knee arthroscopy if you are found to have a loose fragment on x-ray or MRI. All patients will be required to return for follow-up visits, which will continue over the course of 5 years. During these visits, patients will be examined, asked to answer questions about their surgery and general health, and have imaging (x-ray and MRI) performed on the knee. All patients enrolled in this study will undergo a standardized, intensive rehabilitation protocol. The investigators anticipate that all patients may benefit from extensive rehabilitation, including strengthening and return to sport training. The knowledge gained from this study may benefit others in the future.
- Conditions
- Patellar Instability
- Being tested
- Medial patellofemoral ligament reconstruction surgery, Physical therapy and rehabilitation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Medial patellofemoral ligament reconstruction surgeryProcedure or surgery
Also called CPT code: 27427
Medial patellofemoral ligament reconstruction surgery using hamstring autograft
Physical therapy and rehabilitationOther
A standardized physical therapy and rehabilitation program to be administered and guided by rehab specialists
| Study group | Role | What they receive |
|---|---|---|
| Surgical Intervention | Other | The surgical intervention to be studied in this arm is medial patellofemoral ligament reconstruction surgery using hamstring tendon. The tendon used will generally consist of autograft semitendinosus. If the hamstrings have been previously harvested or injured (i.e. in the setting of anterior cruciate ligament reconstruction or proximal tibial surgery), or if the patient/his or her family prefers to minimize donor site morbidity, allograft may be used. Receives: Procedure: Medial patellofemoral ligament reconstruction surgery |
| Conservative treatment | Other | The intervention to be studied in this arm is a rehabilitation program directed by physical therapists. If patients in this arm are found to have a small loose body, a simple arthroscopy will be performed to remove the loose body, but no stabilization of the patellofemoral joint will be performed. The rehabilitation program will be compiled into a booklet and distributed for use by the physical therapist chosen by the patient. Receives: Other: Physical therapy and rehabilitation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Recurrence of patellar instability
The primary outcome is recurrent episode of patellar instability within 5 years following the primary patellofemoral dislocation event. A preliminary analysis will be performed at 2 years to examine for any early results of the study. Patellar instability will be defined as any patient-reported episode of subluxation or dislocation following the index event. Subluxation or dislocation will be defined as a feeling of dissociation of the patella from its trochlear groove. Subluxation will be noted if the patella spontaneously reduces into the groove, and dislocation will be noted if the patella requires any change in position or force (i.e. extending the knee or exerting a medially-directed force on the patella) in order to reduce into its trochlear groove. (Apprehension will not be classified as subluxation unless the patient specifically notes a sensation of departure of the patella from its trochlear groove at some point during the experience.)
Measured: 5 years
Secondary outcomes (5)
Kujala Scoring Questionnaire
The Kujala Scoring Questionnaire is a validated patient reported outcome measure
Measured: Preoperatively and at 1 year, 2 years, 3 years, 4 years, and 5 years after treatment.
Knee Injury and Osteoarthritis Outcome Score (KOOS)
The KOOS is a validated patient reported outcome measure
Measured: Preoperatively and at 1 year, 2 years, 3 years, 4 years, and 5 years after treatment.
International Knee Documentation Committee (IKDC) Subjective Knee Evaluation
The IKDC Subjective Knee Evaluation is a validated patient reported outcome measure
Measured: Preoperatively and at 1 year, 2 years, 3 years, 4 years, and 5 years after treatment.
Hospital for Special Surgery Pediatric Functional Activity Brief Scale
The Hospital for Special Surgery Pediatric Functional Activity Brief Scale is a validated patient reported outcome measure
Measured: Preoperatively and at 1 year, 2 years, 3 years, 4 years, and 5 years after treatment.
Outerbridge grade of any cartilage lesions
Outerbridge grade will be used to describe the severity of articular cartilage lesions at initial presentation and for surgical patients, 1 and 5 years after treatment as well
Measured: MRI taken at initial exam, and for patients randomized to surgery only at 1 year and 5 years after surgery as well
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 Jan 2015 (estimated)
- Study startDec 2015
- Primary completionDec 2026 (estimated)
- Study completionDec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Patellar InstabilityStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Enrolment
- 240 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Hospital for Special Surgery, New York
- Sponsor type
- University, hospital or other
- Collaborators
- Mayo Clinic, Oregon Health and Science University, Inova Medical Group
- Responsible party
- Sponsor
- Investigators
- Beth E Shubin Stein, MD, Principal investigator, Hospital for Special Surgery, New YorkJacqueline Munch, MD, Study chair, Oregon Health and Science University HospitalDiane Dahm, MD, Study chair, Mayo ClinicRobin V West, MD, Study chair, Inova Sports Medicine
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02333825
- Sponsor's protocol ID
- 2014-087
- Acronym
- PAPI
- Status last verified
- Feb 2024
- First submitted
- 12 Dec 2014
- Last updated
- 13 Feb 2026
- Results posted
- No
- Data monitoring committee
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 13 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Pediatric and Adolescent Patellar Instability
- ClinicalTrials.gov ID
- NCT02333825
- Acronym / sponsor ID
- PAPI / 2014-087
- Conditions
- Patellar Instability
- Study type
- Interventional
- Recruitment status
- Enrolling by invitation
- Enrolment
- 240 participants (estimated)
- Lead sponsor
- Hospital for Special Surgery, New YorkUniversity, hospital or other
- Collaborators
- Mayo Clinic, Oregon Health and Science University, Inova Medical Group
- Study start
- Dec 2015
- Primary completion
- Dec 2026 (estimated)
- Study completion
- Dec 2026 (estimated)
- First posted
- 7 Jan 2015 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This is a multi-center, randomized controlled clinical trial, the purpose of which is to determine if patients age 25 and younger who undergo medial patellofemoral ligament (MPFL) reconstruction have lower rates of recurrent instability compared to those treated non-operatively. The MPFL is a ligament that stabilizes the kneecap, and maintains its proper position in the groove on the femur (thighbone). Instability refers to a situation in which the kneecap moves out of place, or dislocates. When instability is recurrent, it occurs more than once in the same knee.
Detailed description
A total of 240 patients will be enrolled across participating sites around the country. These sites currently include: The Hospital for Special Surgery, Oregon Health and Science University, Inova Sports Medicine, and Mayo Clinic. Patients are randomly assigned to one of two treatment groups. Patients assigned to the "stabilization" group will undergo surgery to reconstruct the MPFL using either a hamstring tendon that is your own or one obtained from a donor. Patients assigned to the "conservative" group will be treated with physical therapy, and possibly a simple knee arthroscopy if you are found to have a loose fragment on x-ray or MRI. All patients will be required to return for follow-up visits, which will continue over the course of 5 years. During these visits, patients will be examined, asked to answer questions about their surgery and general health, and have imaging (x-ray and MRI) performed on the knee. All patients enrolled in this study will undergo a standardized, intensive rehabilitation protocol. The investigators anticipate that all patients may benefit from extensive rehabilitation, including strengthening and return to sport training. The knowledge gained from this study may benefit others in the future.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Surgical Intervention | Other | Procedure: Medial patellofemoral ligament reconstruction surgeryThe surgical intervention to be studied in this arm is medial patellofemoral ligament reconstruction surgery using hamstring tendon. The tendon used will generally consist of autograft semitendinosus. If the hamstrings have been previously harvested or injured (i.e. in the setting of anterior cruciate ligament reconstruction or proximal tibial surgery), or if the patient/his or her family prefers to minimize donor site morbidity, allograft may be used. |
| Conservative treatment | Other | Other: Physical therapy and rehabilitationThe intervention to be studied in this arm is a rehabilitation program directed by physical therapists. If patients in this arm are found to have a small loose body, a simple arthroscopy will be performed to remove the loose body, but no stabilization of the patellofemoral joint will be performed. The rehabilitation program will be compiled into a booklet and distributed for use by the physical therapist chosen by the patient. |
Who may qualify
- Ages
- 8 to 25 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
Key inclusion criteria (2 listed)
- Patients must be age 25 or younger
- Patients must be first-time dislocators, meaning have had only one episode of patellar instability, during which they dislocated their patella (kneecap)
Key exclusion criteria (3 listed)
- Patients with more than one episode of patellofemoral instability
- Patients who have had prior patellofemoral surgery on the knee of interest
- Patients with large cartilage tears in the knee. These patients will undergo stabilization of the patellofemoral joint (MPFL reconstruction) as per standard of care, and will not be included in the study.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Medial patellofemoral ligament reconstruction surgeryAlso: CPT code: 27427Medial patellofemoral ligament reconstruction surgery using hamstring autograft | Procedure or surgery | Surgical Intervention |
| Physical therapy and rehabilitationA standardized physical therapy and rehabilitation program to be administered and guided by rehab specialists | Other | Conservative treatment |
Primary outcome
Recurrence of patellar instability
Time frame: 5 years
The primary outcome is recurrent episode of patellar instability within 5 years following the primary patellofemoral dislocation event. A preliminary analysis will be performed at 2 years to examine for any early results of the study. Patellar instability will be defined as any patient-reported episode of subluxation or dislocation following the index event. Subluxation or dislocation will be defined as a feeling of dissociation of the patella from its trochlear groove. Subluxation will be noted if the patella spontaneously reduces into the groove, and dislocation will be noted if the patella requires any change in position or force (i.e. extending the knee or exerting a medially-directed force on the patella) in order to reduce into its trochlear groove. (Apprehension will not be classified as subluxation unless the patient specifically notes a sensation of departure of the patella from its trochlear groove at some point during the experience.)
5 secondary outcomes
Kujala Scoring Questionnaire
Time frame: Preoperatively and at 1 year, 2 years, 3 years, 4 years, and 5 years after treatment.
Knee Injury and Osteoarthritis Outcome Score (KOOS)
Time frame: Preoperatively and at 1 year, 2 years, 3 years, 4 years, and 5 years after treatment.
International Knee Documentation Committee (IKDC) Subjective Knee Evaluation
Time frame: Preoperatively and at 1 year, 2 years, 3 years, 4 years, and 5 years after treatment.
Hospital for Special Surgery Pediatric Functional Activity Brief Scale
Time frame: Preoperatively and at 1 year, 2 years, 3 years, 4 years, and 5 years after treatment.
Outerbridge grade of any cartilage lesions
Time frame: MRI taken at initial exam, and for patients randomized to surgery only at 1 year and 5 years after surgery as well
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Feb 2026.
- Principle Investigator: Beth Shubin Stein, MDLink provided by the sponsor.
Related trials for Patellar Instability
RecruitingObservational study
JUPITER 4.0 - Risk Factors for Failure of Isolated Medial Patellofemoral Ligament Reconstruction
Patellar Dislocation, Recurrent, Patellar Dislocation
Recruiting
Comparison of Dynamic and Static Medial Patellofemoral Ligament Operation Technique for Recurrent Patellar Dislocation
Patellar Instability
Active, not recruitingObservational study
French Version of the Banff Patellar Instability Instrument 2.0
Patellar Instability
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Beth E Shubin Stein, MD principal investigator
Hospital for Special Surgery, New York
Jacqueline Munch, MD study chair
Oregon Health and Science University Hospital
Diane Dahm, MD study chair
Mayo Clinic
Questions about this trial
What is this clinical trial studying?
A study testing Medial patellofemoral ligament reconstruction surgery and Physical therapy and rehabilitation in people with Patellar Instability, run by Hospital for Special Surgery, New York.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 13 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Recurrence of patellar instability (time frame: 5 years). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 13 Feb 2026; AzTrials last refreshed its copy on 30 Oct 2026.