Influence of Restitution Time in Treatment of Patellar Tendinopathy

Study Overview
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Brief Summary
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The purpose of the present project is to investigate if the restitution time from loading in an exercise-based 12 weeks rehabilitation regime for patellar tendinopathy influences the clinical outcome, tendon structure and function. The investigators hypothesize that greater restitution from loading (1 exercise day per week) will yield a greater positive clinical outcome, and tissue structure and function in patients with patellar tendinopathy compared to less restitution (3 exercise days per week), when impact activities are restricted in both groups.

Detailed Description
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This study is designed as a prospective, randomized, controlled, open label, superiority trial with a two-group parallel design and primary endpoint after 12 weeks. The study has two phases; The first phase includes the main trial in which a 12-week intervention period will be undertaken to test the hypotheses in patients with chronic patellar tendinopathy (symptoms > 3 months). At 12 weeks, a smaller group of patients (responding and not-responding to the 12-week intervention period) will be offered to participate in sub-study 1. In this explorative cross-sectional study, the feasibility of mapping brain structure, function and metabolism using Magnetic resonance imaging (MRI) with Blood Oxygenation Level Dependent (BOLD) imaging technique in chronic patellar tendinopathy patients will be assessed. The second phase in the main study includes the follow-up from 12 week to the secondary endpoint at 52 weeks after baseline. During this period the participants will be monitored via questionnaires for treatment satisfaction and improvements at 4-week intervals. What treatment and the duration of treatment patients will receive in this phase is based on the concept of personalized medicine. We expect the majority of patient to continue in the group with loading-based intervention. A smaller group of the 52 patients from the main study is expected to be included in sub-study two. Sub study two is designed as an observational cohort study. In this sub study, patients reporting no self-evaluated improvement after 12 weeks of loading-based treatment will be asked to be part of a group receiving corticosteroid injection treatment followed by continued exercise-based treatment and avoidance of impact loading. The cohort will further include patients that after week 20, 24, 28, 32, 36 and 40 respond that they have not achieved their Patient Acceptable Symptom State (PASS).

Official Title
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Patellar Tendinopathy - The Role of Restitution Time in Exercise- Based Treatment: A Randomized Controlled Trial (the TEREX Trial)

Conditions
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Patellar Tendinopathy, Jumper's Knee

Intervention / Treatment
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* Other: Resistance training for knee extensors


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Sports active men and women. Age (18-60) years old. BMI (18.5-28) Understand and read Danish Uni- or bilateral patellar tendinopathy Symptom onset >90 days ago Exclusion Criteria: Patellar tendinopathy longer than 24 months Smoking Previous surgery in the knee on the ipsilateral side. Corticosteroid injection in the patellar tendon on the ipsilateral side within the last 6 months. Any confounding diagnosis to the knee joint Known arthritis Known diabetes Inability to follow rehabilitation or complete follow-ups Enrolled in a resistance based-rehabilitation program for the affected patellar tendon within the previous three month Have a work were it is not feasible to avoid pain provoking tasks Extra criteria sub-study one Inclusion criteria: • Five patients from the main study, rating improved and not improved respectively, will be invited to participate in sub-study one. Exclusion criteria: Claustrophobia Pregnancy Breastfeeding Extra criteria sub-study two: Inclusion criteria: Patients from the main study, that rate themselves 'not improved' in symptoms after 12 week. Patients who have not achieved Patient Acceptable Symptom State (PASS) after week 20, 24, 28, 32, 36 and 40, will be invited to participate in sub- study two. Exclusion criteria: Pregnancy Breastfeeding Previously had an allergic reaction for steroid (Depomedrol). Previously had an allergic reaction for local anesthesia treatment.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 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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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Short restitution group (SR)<br>Resistance training for knee extensors three training session per week. | Other: Resistance training for knee extensors<br>* The exercise will be started at 60% of 1 repetition maximum (RM) and progressed to 75% of 1 RM during the first 3 weeks and maintained throughout the intervention period. The exercise will be performed slowly (6 s/ repetition).<br>|
| Experimental: Extended restitution group (ER)<br>Resistance training for knee extensors on training session per week (greater restitution from loading). | Other: Resistance training for knee extensors<br>* The exercise will be started at 60% of 1 repetition maximum (RM) and progressed to 75% of 1 RM during the first 3 weeks and maintained throughout the intervention period. The exercise will be performed slowly (6 s/ repetition).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Patient perception VISA-P | Change in Victorian Institute of Sports Assessment - patella (VISA-P) total score. The VISA-P asses symptoms, function and the ability to participate in sport. It consists of 8 questions, with a maximum score of 100 indicating the person is asymptomatic and fully per-forming and lower scores indicating more symptoms and limitations of function and activity. | Change from baseline at week 12 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Patient perception VISA-P secondary | Change in Victorian Institute of Sports Assessment - patella (VISA-P) total score. The VISA-P asses symptoms, function and the ability to participate in sport. It consists of 8 questions, with a maximum score of 100 indicating the person is asymptomatic and fully per-forming and lower scores indicating more symptoms and limitations of function and activity. | Change from baseline at week 16 and 52 | 
| Patient perception VISA-P truncated | Change in Victorian Institute of Sports Assessment - patella (VISA-P) truncated score. The truncated score only including questions 2-6, with a maximum score of 50. Lower scores indicating more symptoms and limitations of function and activity. | Change from baseline at week 12, 16 and 52 | 
| Self-reported pain (NRS) - Preferred sport | Change in pain rating on an 11 point numeric rating scale (NRS) during preferred sport, with 10 being the worst imaginable pain and 0 denoting no pain. | Change from baseline at week 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52. | 
| Self-reported pain (NRS) - Rest | Change in pain rating on an 11 point numeric rating scale (NRS) during rest, with 10 being the worst imaginable pain and 0 denoting no pain. | Change from baseline at week 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52. | 
| Self-reported pain (NRS) - Daily activities | Change in pain rating on an 11 point numeric rating scale (NRS) during daily activities, with 10 being the worst imaginable pain and 0 denoting no pain. | Change from baseline at week 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52. | 
| Self-reported improvement (GROC) | Self-reported improvement after treatment will be evaluated by the Global Rating of change (GROC) on a 7-point Likert scale ranging from 'much improved' to 'much worse'. | Change from baseline at week 12, 16 and 52. | 
| Sports participation | Number of sports participation hours per week (training and competition). | Week 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52. | 
| Sports types | Typer of sports performed. | Week 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52. | 
| Sports intensity | Intensity of sport performed registred in a self-reported questianaire and categorized as; light, moderate or vigorous. | Week 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52. | 
| Self-reported satisfaction (PASS) | Self-evaluated satisfaction with treatment result will be evaluated by Patient Acceptable Symptom State (PASS) on a 5-point Likert scale ranging from 'very satisfied' to 'very unsaticfied' | Week 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52 | 
| Treatment received | Registration of any additive treatment received from last follow-up measured with self-reported questionnaire. | Week 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52. | 
| Care-seeking behavior | Registration of any additive care-seeking behavior from last follow-up measured with self-reported questionnaire. | Week 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52. | 
| The single-leg decline squat (SLDS) will be used to assess pain during function | Participants performed a decline squat on a 25°decline board and reported pain using an 11 point numeric rating scale (NRS) upon completion, with 10 being the worst imaginable pain and 0 denoting no pain. | Change from baseline at week 12 and 52. | 
| Muscle strength | Maximal muscle strength is obtained during standardized maximal voluntary contractions. | Change from baseline at week 12 and 52. | 
| Ultrasonography - tendon thickness | Grey scale ultrasonography will be used for evaluation of patellar tendon thickness. | Change from baseline at week 12 and 52. | 
| Ultrasonography - tendon neovascularization | Doppler ultrasonography will be used for evaluation of patellar tendon neovascularization. | Change from baseline at week 12 and 52. | 
| Ultrasonography - tendon microvascularisation | B-Flow ultrasonography will be used for evaluation of patellar tendon microvascularisation. | Change from baseline at week 12 and 52. | 
| Counter movement Jump height | Jump height during Counter movement Jump test will be used to assess patellar tendinopathy caused functional deficits. | Change from baseline at week 12 and 52. |