Compositional mapping of the mature anterior cruciate ligament-to-bone insertion.
The anterior cruciate ligament (ACL)-to-bone interface constitutes a complex, multi-tissue structure comprised of contiguous ligament, non-mineralized fibrocartilage, mineralized fibrocartilage, and bone regions. This composite structure enables load transfer between structurally and functionally dissimilar tissues and is critical for ligament homeostasis and joint stability. Presently, there is a lack of quantitative understanding of the matrix composition and organization across this junction, especially after the onset of skeletal maturity. The objective of this study is to characterize the adult bovine ACL-to-bone interface using Fourier transform infrared spectroscopic imaging (FTIRI), testing the hypothesis that regional changes in collagen, proteoglycan, and mineral distribution, as well as matrix organization, persist at the mature insertion. It was observed that while collagen content increases continuously across the adult interface, collagen alignment decreases between ligament and bone. Proteoglycans were primarily localized to the fibrocartilage region and an exponential increase in mineral content was observed between the non-mineralized and mineralized regions. These observations reveal significant changes in collagen distribution and alignment with maturity, and these trends underscore the role of physiologic loading in postnatal matrix remodeling. Findings from this study provide new insights into interface organization and serve as benchmark design criteria for interface regeneration and integrative soft tissue repair. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2513-2523, 2017.
Biomaterials and Interface Tissue Engineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, New York 10027.
Dovina
D
Qu
Biomaterials and Interface Tissue Engineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, New York 10027.
Siddarth D
SD
Subramony
Musculoskeletal Integrity Program, Hospital for Special Surgery, New York, New York 10021.
Adele L
AL
Boskey
Tissue Imaging and Spectroscopy Laboratory, Department of Bioengineering, Temple University, Philadelphia, Pennsylvania 19122.
Nancy
N
Pleshko
Analytical Microscopy Laboratory, Hospital for Special Surgery, New York, New York 10021.
Stephen B
SB
Doty
Biomaterials and Interface Tissue Engineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, New York 10027.|Department of Biomedical Engineering, Columbia University, 1210 Amsterdam Avenue, 351 Engineering Terrace, MC 8904, New York, New York 10027.
Helen H
HH
Lu
D000818:Animals; D016118:Anterior Cruciate Ligament / Q000737:chemistry*; D002417:Cattle; D003094:Collagen / Q000032:analysis; D005260:Female; D007719:Knee Joint / Q000737:chemistry*; D008903:Minerals / Q000032:analysis; D011509:Proteoglycans / Q000032:analysis; D017550:Spectroscopy, Fourier Transform Infrared
D008903:Minerals; D011509:Proteoglycans; D003094:Collagen
aging; fibrocartilage; insertion; interface; ligament