Clinical Trial Details
— Status: Enrolling by invitation
Administrative data
NCT number |
NCT04650568 |
Other study ID # |
17082504 |
Secondary ID |
|
Status |
Enrolling by invitation |
Phase |
N/A
|
First received |
|
Last updated |
|
Start date |
November 3, 2017 |
Est. completion date |
December 31, 2025 |
Study information
Verified date |
January 2024 |
Source |
Rush University Medical Center |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Interventional
|
Clinical Trial Summary
This study will evaluate the efficacy of biologic augmentation of ACL reconstruction with
bone marrow derived mesenchymal stem cells as measured by magnetic resonance imaging to
detect graft healing and integration. Secondary endpoints will include validated patient
reported outcome measures, as well as functional outcome using objective examination
findings.
Description:
Introduction
Anterior cruciate ligament (ACL) tears are a common and devastating injury among young
athletes, and re-injury poses significant threats to both successful return to play and long
term outcomes. Graft healing during ACL reconstruction (ACLR) is a slow biologic process,
that involves graft incorporation into bone tunnel sites, as well as intra-articular graft
remodeling . The intra-articular graft remodeling process is known as ligamentization, and
occurs in three phases after ACLR. The first phase of early healing occurs between 0 and
three months, the second phase occurs between 6 months and one year, and the final phase of
maturation occurs after 1 year when the graft appears very similar to the native ACL. The
studies that defined these time points biopsied human bone-patella tendon-bone (BTB) ACL
autografts at different postoperative points, and described changes occurring over time in
regards to vascularization, cellular aspects, and appearance of the extracellular matrix in
comparison to control ACLs . Unlike animal models which display a necrotic stage, grafts in
human models undergo an early vascular invasion, associated with fibroblasts that are
converted to a hyper-cellular matrix with only focalized areas of necrosis . This process
occurs as early as 3 weeks postoperatively, and increases over time as areas similar to the
native patellar tendon with mature collagen and metabolically quiescent cells decrease . This
process is the limiting factor in graft healing for bone-patella tendon-bone (BTB) grafts, as
osteointegration occurs earlier .
The processes of osteointegration and ligamentization are responses to the new intrasynovial
milieu and physical forces that the new graft is exposed to. During these healing and
restructuring processes, failure load and stiffness of grafts decreases by up to 24% at 7
weeks, before strengthening to their potential . This contributes to the long recovery period
for ACLR, and the risk of re-rupture during this period. Advances in biologic adjuncts to
accelerate and improve this healing process would have a significant impact on the management
of ACL injuries.
Recently, biologic preparations of various growth factors have been developed to safely and
effectively treat a variety of musculoskeletal conditions, including tendinopathies and
arthritis . Bone marrow aspirate concentrate (BMAC) consists of undifferentiated mesenchymal
stem cells that are concentrated and applied to the injury site . Previous studies have
demonstrated this treatment to offer the pluripotent potential of the cells to impact
healing, regeneration, biomechanical strength, and reducing bone-tunnel enlargement .
Investigators have demonstrated that mesenchymal stem cell reinforced grafts had a
significantly higher failure load and stiffness as early as 8 week post-operation in a rabbit
model, suggesting an added benefit of advanced healing . Using BMSCs can offer a novel method
to enhance tendon graft osteointegration. While there have been numerous laboratory studies
researching the effect of mesenchymal stem cells, there lacks evidence in translation to the
clinical setting. Silva et al performed a study where they injected bone marrow derived stem
cells (BMSCs) into patellar tendon grafts to examine for increased graft-to-bone tunnel
integration. They did not find a significant difference of tunnel integration on MRI imaging,
but they did not examine the intra-articular portions for the effect on the ligamentization
process, nor did they examine the effect on clinical examination and patient reported
outcomes .
Quantitative MRI is a non-invasive method to interrogate tissue properties and evaluate the
biochemical composition of tissues. The T2* sequence gives information regarding tissue graft
volume, water content, fiber alignment, and tissue density. Median grayscale values (a
measure to determine tissue quality)can also be correlated to maximum failure load, yield
load, and linear stiffness of grafts in a porcine model. Increases in MRI signals in ACL
grafts have been found to be time dependent, becoming well established by three months,
particularly at the distal intra-articular portion near the tibial tunnel . These changes
have not been shown previously to be predictive of graft failure, but Investigators have
recently also confirmed that normalized T2* signal intensity values of ACL grafts have
significant correlation with knee instability related to ligamentization and tunnel healing.
A recent study examined intra-articular graft maturation after platelet-rich plasma gel
(PRPG) application, with MRI at month intervals from 3-12 months postoperatively. The
intra-articular segment was divided in a proximal, middle, and distal segment, on a scale
from 0-3 ranging from completely homogenous to severely heterogeneous. The mean time to
obtain completely homogenous bone-patella tendon-bone (BTB) graft was 109 days for the PRPG
group, and 363 for the control group 8.
We propose using quantitative magnetic resonance (MR) imaging with T2* mapping to investigate
if BMAC treatment at time of ACL reconstruction can accelerate the graft maturation and
healing process. We will perform a randomized controlled trial of patients undergoing ACL
reconstruction with bone-patellar tendon-bone allograft evaluating the T2* weighted MRI
changes of the graft at 3 and 9 months after surgical reconstruction. Additionally, we will
obtain patient-reported outcome measures from this cohort to evaluate if BMAC treatment
imparts a clinically-significant effect on ACL reconstruction.
Study Rationale
This study will evaluate the efficacy of biologic augmentation of ACL reconstruction with
BMSCs as measured by magnetic resonance imaging to detect graft healing and integration.
Secondary endpoints will include validated patient reported outcome measures, as well as
functional outcome using objective examination findings.
Hypothesis
The hypotheses of this study are that there will be improved graft healing and integration at
three and nine months as measured by decreased signal intensity and heterogeneity on T2* MRI
following administration of BMAC during ACL reconstruction compared to the control group.
Additionally, patient reported outcomes and physical examination findings will be
significantly improved at an earlier time in those who receive the BMAC treatment to their
allograft compared to the control group.
Study Plan
This study will be a prospective randomized trial of patients undergoing arthroscopic
reconstruction of full thickness anterior cruciate ligament (ACL) tears. All patients who
sign consent and undergo full thickness ACL reconstruction will be enrolled in the study.
Enrollment will continue until 32 patients, 16 in each group, are enrolled. Follow-up will
take place at 6 weeks, 3 months, 6 months, 9 months, 12 months, and 24 months.