The main goal for this pilot level study is to correlate ultrasound elastography technique
with more standard clinically based outcome measures within the setting of a small sample
sized group of patients affected by moderate-to- severe, chronic (> 6 months) midsubstance
Achilles tendinopathy (AT). Investigators will conduct a 24-week, 2-arm randomized controlled
pilot study to determine whether novel elastography techniques (AE) and shear wave imaging
(SWI), a new quantitative method of ultrasound (US) imaging, correlate with valid clinical
outcome measures (VISA-A and conventional US). Methods will be based on recently published
clinical trials of autologous blood injections for treating AT and will incorporate novel US
outcome measures of Achilles tendon appearance and stiffness, i.e. elasticity. The results of
this multi-disciplinary pilot study will be used to help plan a separate larger scaled study
to evaluate the effects of platelet-rich plasma (PRP) therapy for Achilles tendinopathy in
which elastography will be included as a potential outcome measure and also correlated with
standard clinical outcome surveys.
Pain and function will be evaluated by self-report using a validated clinical outcome
questionnaire (VISA-A). Disease modification will be assessed by novel US-based AE and SWI
methods for stiffness changes (biomechanical) and correlated with morphologic changes using
conventional US. A larger study that will evaluate the effects of PRP in healing AT, while
correlating with elastography assessment, will include a sham injection arm.
Intervention Subjects assigned to the PRP group will then receive the PRP injection under
ultrasound guidance. The injection will take about 15 minutes.
Each subject will undergo a palpatory and ultrasound Achilles tendon exam. Tender areas
associated with the Achilles tendon will be identified. Physical exam will be followed by
Achilles tendon ultrasound which will serve as visual guidance for injection.
At the injection session, the research nurse will perform a single standard antecubital blood
draw (35 mL). The PRP will be obtained from this sample using a two-stage spinning technique:
the 1st separates red blood cells from platelets, and the 2nd concentrates the platelets to
yield approximately 4 mL of concentrated autologous platelet. This layer of platelet rich
plasma will be placed in the syringe by the centrifuge machine.
Platelet counts of subjects' whole blood and PRP processed blood will be analyzed. Platelet
counts in whole blood vary by individual. The optimal quantity of platelets and growth
factors required for tissue healing is not known, but a clinically effective concentration
has been described as being greater than 4 times baseline autologous whole blood platelet
concentrations. Therefore, platelet concentration yield may have important implications in
clinical outcome correlation. In order to validate consistent platelet concentration yields
across subjects, investigators will sample 1 mL of whole blood (approximately one lab
Vacutainer) and an additional 1 mL of platelet rich plasma for lab analysis of platelet
concentration using a standard lab automated analyzer. This extra 1 ml of whole blood will be
drawn at the same time that the 35 ml described above is drawn.
The 3 ml of platelet rich plasma will be injected into the subject's Achilles tendon. The
specimens will not be kept or stored. The blood will be analyzed on the same day as the
procedure is being performed. This will not require storing of the specimen and prevent
erroneous labeling of platelet concentration with a different subject.
After the injections, the subject will rest for 5 minutes. Participants will be given
acetaminophen for "as-needed" analgesia and will be telephoned after 3 days to inquire about
side effects or adverse events. Subjects will be placed in a boot for two weeks with gradual
return to activity. Subjects will also be provided crutches to be non-weight bearing for 24
hours.
Data and Safety Monitoring Plan The data and safety monitoring plan to be implemented in this
study consists, in part, of a monthly staff meeting to discuss subject enrollment, safety,
and retention. These meetings are intended to monitor participant study flow from initial
eligibility assessment to study completion. Standing agenda items for these meetings will be
side effects, adverse events and participant retention.
Unanticipated adverse events and complications will be evaluated and treated if necessary by
the Principal Investigator and the primary Co-Investigator.
In addition, the following processes will help ensure the timely detection, evaluation and
treatment:
1. The Principal Investigator and the primary Co-Investigator will screen subjects for
adverse events prior to treatment with PRP. Standardized forms will be used for
monitoring and reporting of adverse events. The PI will be immediately available to
staff via cell phone in case of a serious adverse event. The PI will immediately report
serious adverse events to the UW Research Subjects Advocate using standardized forms.
Reports will be made using the subject identification number without other identifying
information.
2. Autologous injection of PRP has been found to be safe. The system being used was chosen
for its closed system to prevent contamination and for its ease of use. Although safe,
internal monitoring of PRP injection safety will also be performed. The study
coordinator will assess each PRP injection subject 3 days after treatment with the
following question during a brief telephone interview: "Do you think that you have had
any side effects from the injection you've received?" [If "Yes"] "Please tell me more
about that." Information regarding side effects and adverse events will be made
available to the PI, who will decide if the subject requires further medical care.
Investigators do not expect serious adverse events (SAEs) but are well equipped to manage
them. Investigators have not seen significant adverse events in combined (UW Radiology and
Sports Medicine) clinic use of PRP. Subjects with reactions to acetaminophen or injections
have the option to call study personnel at any time. The PI and the primary Co-Investigator
will share on-call duty for subjects with adverse events through a pager on a 24/7 basis.
Subjects who require significant evaluation and care will be referred to the UW Hospital
Emergency Department.
Adverse events from a diagnostic ultrasound are extremely unlikely because ultrasound is
considered to have non-significant risk by the FDA. All study procedures will be monitored
and documented, and in the unlikely situation where an adverse event occurs, it will be
followed to resolution.
The PI(a Board-Certified radiologist) will assess whether the findings should be reported to
subjects. Findings that would be reported are those considered clinically relevant. Findings
that are considered normal variants (eg. variant anatomy) or clinically insignificant (eg.
simple hepatic cyst) will not be reported. Clinically relevant findings will be reported to
the subject within 24 hours of the scan, and will also be reported to the subject's physician
according to whether the subject has indicated a desire for this in the consent form.
