Influence of Restitution Time in Treatment of Patellar Tendinopathy (TEREX)

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

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.

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).

Resistance training for knee extensors on training session per week (greater restitution from loading).

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).

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 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 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 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 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 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.

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'.

Intensity of sport performed registred in a self-reported questianaire and categorized as; light, moderate or vigorous.

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'

Registration of any additive treatment received from last follow-up measured with self-reported questionnaire.

Registration of any additive care-seeking behavior from last follow-up measured with self-reported questionnaire.

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.

Jump height during Counter movement Jump test will be used to assess patellar tendinopathy caused functional deficits.

Magnetic resonance imaging (MRI) with Blood Oxygenation Level Dependent (BOLD) imaging technique - Brain structure mapping.

It will be testet If it is feasible to map brain structure changes in patient with chronic patellar tendinopathy using MRI BOLD imaging technique. The outcome will only be used for participants included in sub-study one.

Magnetic resonance imaging (MRI) with Blood Oxygenation Level Dependent (BOLD) imaging technique - Brain function mapping.

It will be testet If it is feasible to map brain function changes in patient with chronic patellar tendinopathy using MRI BOLD imaging technique. The outcome will only be used for participants included in sub-study one.

Magnetic resonance imaging (MRI) with Blood Oxygenation Level Dependent (BOLD) imaging technique - Brain metabolism mapping.

It will be testet If it is feasible to map brain metabolism changes in patient with chronic patellar tendinopathy using MRI BOLD imaging technique. The outcome will only be used for participants included in sub-study one.

Patient self-reported satisfaction will be assessed by Patient Acceptable Symptom State (PASS) and brain structure by Magnetic resonance imaging (MRI) with Blood Oxygenation Level Dependent (BOLD) imaging technique. The outcome will only be used for participants included in sub-study one.

Patient self-reported satisfaction will be assessed by Patient Acceptable Symptom State (PASS) and brain function by Magnetic resonance imaging (MRI) with Blood Oxygenation Level Dependent (BOLD) imaging technique. The outcome will only be used for participants included in sub-study one.

Patient self-reported satisfaction will be assessed by Patient Acceptable Symptom State (PASS) and brain metabolism by Magnetic resonance imaging (MRI) with Blood Oxygenation Level Dependent (BOLD) imaging technique. The outcome will only be used for participants included in sub-study one.

Grey scale ultrasonography will be used for evaluation of patellar tendon thickness. Only for patients participating in sub-study two.

Doppler ultrasonography will be used for evaluation of patellar tendon neovascularization. Only for patients participating in sub-study two.

B-Flow ultrasonography will be used for evaluation of patellar tendon microvascularisation. Only for patients participating in sub-study two.

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'Symptom State (PASS) scale.

Pain rating will be evaluated on an 11 point numeric rating scale (NRS) during injection, with 10 being the worst imaginable pain and 0 denoting no pain. Only for patients participating in sub-study two.

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.