10-year Follow-up After Tibial Tubercle Transposition

Study Overview
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Brief Summary
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Patellofemoral pain is a common complaint especially in young adults. It can be caused by patellar maltracking. Part of this is a patella alta. When patellar maltracking is the cause of the problem and conservative therapy fails, surgery, a tibial tuberosity transposition, may be considered. Most research has been done in patients with recurrent patella luxation. However, in patients without luxation, research is scarce. It is known that patients with patella alta have an increased risk of developing patellofemoral chondropathy due to increased pressure. With this study, we aim to investigate whether and how a tibial tuberosity transposition in patients with patella alta and no instability affects the degree of patellofemoral chondropathy and patient satisfaction after 10 years. This will allow us to educate patients regarding long-term outcomes better.

Detailed Description
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Anterior knee pain is a common complaint, especially in younger and active adults. An obvious source for anterior knee pain is patellar maltracking, which is often associated with patella alta (a high-riding patella). Due to maltracking, the cartilage of the patella can face a greater amount of pressure, which can cause cartilage damage. When conservative treatment fails, a surgical intervention can be considered. One of the surgical options is performing a tibial tubercle transfer (TTT), where the patella is being distalized and medialized. As a result, the improvement in patellar tracking will reduce the pressure on the retropatellar cartilage. The TTT has been proven effective in patients with patellar instability but less is known about patients without instability. Specifically, whether these patients face a higher risk of developing retropatellar cartilage damage ('retropatellar chondropathy') due to this intervention is currently unknown. The primary aim of this study is to determine the incidence and the degree of retropatellar chondropathy 10 years after a TTT in patients with anterior knee pain without patellar instability. The secondary aim is to evaluate the long-term patient reported outcomes (PROMs) 10 years after a TTT in patients with anterior knee pain without patellar instability.

Official Title
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Long-term Outcomes and Development of Retropatellar Chondropathy After Tibial Tubercle Distomedialisation for Patellar Maltracking and Patella Alta Without Instability: 10 Year Follow-up of a Prospective Cohort

Conditions
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Anterior Knee Pain Syndrome

Intervention / Treatment
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* Diagnostic Test: MRI, radiological assessment


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age between 18 and 80 years Participated in an earlier cohort study Underwent a tibial tubercle transposition between 2012 and 2015 Preoperative MRI available Exclusion Criteria: No preoperative MRI is available Patellar-related surgery after the initial surgery Female patients that are (expecting to be) pregnant

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Diagnostic Test: MRI, radiological assessment|MRI and radiological assessment of the involved knee|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Modified Outerbridge Classification | Degree of retropatellar cartilage damage | 10-year follow-up assessment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Patellar height | Patellar height measured by radiological assessment lateral view | 10-year follow-up assessment | 
| Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire | KOOS consists of 5 subscales; Pain, other Symptoms, Function in daily living (ADL), Function in sport and recreation (Sport/Rec) and knee related Quality of life (QOL). The previous week is the time period considered when answering the questions. Standardized answer options are given (5 Likert boxes) and each question is assigned a score from 0 to 4. A normalized score (100 indicating no symptoms and 0 indicating extreme symptoms) is calculated for each subscale. | 10-year follow-up assessment | 
| Kujala Anterior Knee Pain Score (AKPS) questionnaire | The Kujala AKPS is a 13-item screening instrument designed to assess patellofemoral pain in adolescents and young adults, with a variable ordinal response format (e.g., no pain (5) to constant pain (0)). Total scores range from 0 to 100, with a higher score indicating less symptoms. | One measurement | 
| Visual Analogue Scale (VAS) for pain | The pain VAS is a unidimensional measure of pain intensity, scored from 0 (no pain) to 100 (highest possible pain intensity). | 10-year follow-up assessment | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Tibial tubercle transfer, Long-term follow-up