Effect of Dynamic Changes in Anterior Cruciate Ligament In Situ Graft Force on the Biological Healing Response of the Graft-Tunnel Interface.
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Publisher DOI
PubMed ID
29298079
Description
BACKGROUND
Anterior cruciate ligament (ACL) grafts that are placed for reconstruction are subject to complex forces. Current "anatomic" ACL reconstruction techniques may result in greater in situ graft forces. The biological effect of changing magnitudes of ACL graft force on graft-tunnel osseointegration is not well understood.
PURPOSE
The research objective is to determine how mechanical force on the ACL graft during knee motion affects tendon healing in the tunnel.
STUDY DESIGN
Controlled laboratory study.
METHODS
Male rats (N = 120) underwent unilateral ACL reconstruction with a soft tissue flexor tendon autograft. ACL graft force was modulated by different femoral tunnel positions at the time of surgery to create different graft force patterns with knee motion. External fixators were used to eliminate graft load during cage activity. A custom knee flexion device was used to deliver graft load through controlled daily knee motion. Graft-tunnel healing was then assessed via biomechanical, micro-computed tomography, and histological analyses.
RESULTS
ACL graft-tunnel healing was sensitive to dynamic changes in graft forces with postoperative knee motion. High ACL graft force with joint motion resulted in early inferior ACL graft load to failure as compared with knees that had low-force ACL grafts and joint motion and knees that were immobilized (mean ± SD: 5.50 ± 2.30 N vs 9.91 ± 3.54 N [ P = .013] and 10.90 ± 2.8 N [ P = .001], respectively). Greater femoral bone volume fraction was seen in immobilized knees and knees with low-force ACL grafts when compared with high-force ACL grafts at 3 and 6 weeks.
CONCLUSION
The authors were able to demonstrate that ACL graft-tunnel incorporation is sensitive to dynamic changes in ACL graft force with joint motion. Early high forces on the ACL graft appear to impair graft-tunnel osseointegration.
CLINICAL RELEVANCE
Current "anatomic" techniques of ACL reconstruction may result in greater graft excursion and force with knee motion. Our results suggest that the postoperative rehabilitation regimen may need to be modified during the early phase of healing to protect the reconstruction.
Anterior cruciate ligament (ACL) grafts that are placed for reconstruction are subject to complex forces. Current "anatomic" ACL reconstruction techniques may result in greater in situ graft forces. The biological effect of changing magnitudes of ACL graft force on graft-tunnel osseointegration is not well understood.
PURPOSE
The research objective is to determine how mechanical force on the ACL graft during knee motion affects tendon healing in the tunnel.
STUDY DESIGN
Controlled laboratory study.
METHODS
Male rats (N = 120) underwent unilateral ACL reconstruction with a soft tissue flexor tendon autograft. ACL graft force was modulated by different femoral tunnel positions at the time of surgery to create different graft force patterns with knee motion. External fixators were used to eliminate graft load during cage activity. A custom knee flexion device was used to deliver graft load through controlled daily knee motion. Graft-tunnel healing was then assessed via biomechanical, micro-computed tomography, and histological analyses.
RESULTS
ACL graft-tunnel healing was sensitive to dynamic changes in graft forces with postoperative knee motion. High ACL graft force with joint motion resulted in early inferior ACL graft load to failure as compared with knees that had low-force ACL grafts and joint motion and knees that were immobilized (mean ± SD: 5.50 ± 2.30 N vs 9.91 ± 3.54 N [ P = .013] and 10.90 ± 2.8 N [ P = .001], respectively). Greater femoral bone volume fraction was seen in immobilized knees and knees with low-force ACL grafts when compared with high-force ACL grafts at 3 and 6 weeks.
CONCLUSION
The authors were able to demonstrate that ACL graft-tunnel incorporation is sensitive to dynamic changes in ACL graft force with joint motion. Early high forces on the ACL graft appear to impair graft-tunnel osseointegration.
CLINICAL RELEVANCE
Current "anatomic" techniques of ACL reconstruction may result in greater graft excursion and force with knee motion. Our results suggest that the postoperative rehabilitation regimen may need to be modified during the early phase of healing to protect the reconstruction.
Date of Publication
2018-03
Publication Type
Article
Subject(s)
Keyword(s)
ACL animal model anterior cruciate ligament healing graft healing graft isometry
Language(s)
en
Contributor(s)
Ma, Richard | |
Chen, Tina | |
Sisto, Marco | |
Nguyen, Joseph | |
Voigt, Clifford | |
Deng, Xiang-Hua | |
Rodeo, Scott A |
Additional Credits
Series
The American journal of sports medicine
Publisher
Sage
ISSN
1552-3365
Access(Rights)
metadata.only