Progressive Tendon-loading exercise therapy for patellar tendinopathy in jumping athletes: A randomized controlled clinical trial evaluated with advanced 3D UTE MRI

Patellar tendinopathy is a frequent overuse injury that causes pain and
impaired performance in jumping athletes. Exercise therapy is considered the
best initial treatment option for tendinopathies as clinical improvements in
pain and function have been demonstrated.
Although painful eccentric exercise protocols have been promoted as standard
care based on positive results in early studies, a recent systematic review
demonstrated that these are not associated with improved tendon structure and
are ineffective when applied in-season. Progressive tendon-loading exercise
therapy for patellar tendinopathy constitutes a novel concept in sports
medicine.

A recent study advocates a progressive 4-stage criteria-based exercise protocol
as it results in a less reactive tendon and ability to restore collagen
alignment. This protocol consists of progressive isometric, isotonic,
plyometric, and sport-specific exercises. Isometric exercises have been shown
to reduce pain and decrease motor cortex inhibition of the quadriceps.

This approach would enable jumping athletes to resume sports within the limits
of pain, with improved muscle function, and sufficient tendon structure
re-organization.

The diagnostic imaging work-up of patellar tendinopathy typically consists of
ultrasound, magnetic resonance imaging (MRI), or a combination of both.
Ultrashort echo time (UTE) MRI is an advanced MRI technique, which enables
assessment of tissues with short T2-time, such as tendon, the structure of
which is invisible on regular MRI. UTE has been shown to quantitatively depict
changes in tendon microstructure and therefore allows in-vivo evaluation of
tendon regeneration. It is currently unknown whether quantitative UTE MRI
parameters change after exercise treatment, are related to clinical symptoms of
patellar tendinopathy, have prognostic value for exercise treatment response,
and offer additional value over ultrasound.The ultrasound features that are
typically altered in patients with patellar tendinopathy are Doppler
characteristics (increased blood flow is observed in patients) and shear wave
elastography (SWE) properties (tendon softening is associated with symptoms,
however the exact diagnostic manifestation of patellar tendinopathy compared to
healthy athletes is not well known).

Long term follow-up data of athletes with patellar tendinopathy are currently
scarce. There is a need for more knowledge on the course of this injury in the
long term.

Recently, large language models (LLMs), such as ChatGPT, use artificial
intelligence to engage people with human-like conversation. It is reasonable to
assume that ChatGPT could improve care by learning and producing language to
assist patients in communication with healthcare workers and with each other.
No study has assessed the performance of this LLM to address inquiries related
to patellar tendinopathy care

The primary aim of this research program is to assess whether the 4-stage
exercise protocol is more effective than the usual painful heavy-load eccentric
exercise protocol for the treatment of patellar tendinopathy in jumping
athletes.

Secondary aims are
1) to explore baseline characteristics (personal characteristics, other
questionnaires and results of functional tests) that can aid in predicting the
prognosis for these patients,

2) to validate a novel 3D UTE MRI pulse sequence for quantitative imaging of
the patellar tendon, by determining its responsiveness to exercise treatment,
its correlation with clinical symptoms over time, and its predictive value of
treatment response,

3) to develop novel quantitative 3D UTE MR imaging biomarkers for the
assessment of patellar tendinopathy with the use of advanced image analysis and
machine learning methods and

4) to establish the value of ultrasound parameters (neovascularisation score
and tendon stiffness as measured with SWE) in responsiveness to treatment,
correlation with symptoms, and prediction of symptoms.

The third aim, we will also assess persistence of symptoms, participation in
sports, change in functional test results and ultrasonographic appearance of
the patellar tendon at long term (5 years) follow-up.

Forth aim: We will evaluate the performance of ChatGPT (Chat Generative
Pretrained Transfomer) in answering patient-centered queries related to
patellar tendinopathy care.

Single-blind randomized controlled trial

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The burden of participation consists of completing a total of 3 hospital visits
for inclusion at baseline and follow-up at 12 and 24 weeks.
At inclusion, the patients will be examined by a sports physician and resident
radiology resident (ultrasound, under supervised by a MSK radiologist) for
eligibility, complete questionnaires, perform functional tests, receive
instructions about the exercise therapy and receive the baseline MRI scan.

At the 12 and 24 week follow-up appointments, the patients will complete the
questionnaires, the principal investigator will perform physical examination
and functional tests and the patients will receive the follow-up MRI scan and
ultrasound examination. At 6 and 18 weeks follow-up, an online questionnaire
will be completed. The burden of the healthy volunteers consists of a single
visit to the ultrasound department of the hospital to undergo an ultrasound of
both knees by two trained researchers. There is no follow-up for these healthy
volunteers.

No drugs will be administered in the context of this study, and no adverse
events are to be expected resulting from both exercise regimens under
evaluation. MRI and ultrasound will be performed without contrast agents.

All patients will be screened for contra-indications for MRI, such as metallic
implants, pregnancy, etc.

Both groups are expected to benefit from the exercise therapy as we expect
symptom reduction in both groups.

All potential participants will be examined by an experienced sports physician
and the diagnosis will be confirmed using additional imaging, so we will
provide them with an adequate diagnosis without additional healthcare costs.

Patients will receive one more questionnaire at 5 years follow-up to explore
the long-term outcome of this chronic sports-related injury among athletes.
Completing this questionnaire is estimated to take 15-20 minutes. Additionally,
if these patients are willing to attend the hospital, we will re-test their
physical function and apply ultrasound to monitor their knee structure. This
will take approximately 45 minutes.

10 patients will receive a questionaire to fill out concerning