title: Alterations in subchondral bone plate, trabecular bone and articular cartilage properties of rabbit femoral condyles at 4 weeks after anterior cruciate ligament transection.
abstract: OBJECTIVE
  To quantify early osteoarthritic-like changes in the structure and volume of subchondral bone plate and trabecular bone and properties of articular cartilage in a rabbit model of osteoarthritis (OA) induced by anterior cruciate ligament transection (ACLT).
  
  
  METHODS
  Left knee joints from eight skeletally mature New Zealand white rabbits underwent ACLT surgery, while the contralateral (CTRL) right knee joints were left unoperated. Femoral condyles were harvested 4 weeks after ACLT. Micro-computed tomography imaging was applied to evaluate the structural properties of subchondral bone plate and trabecular bone. Additionally, biomechanical properties, structure and composition of articular cartilage were assessed.
  
  
  RESULTS
  As a result of ACLT, significant thinning of the subchondral bone plate (P < 0.05) was accompanied by significantly reduced trabecular bone volume fraction and trabecular thickness in the medial femoral condyle compartment (P < 0.05), while no changes were observed in the lateral compartment. In both lateral and medial femoral condyles, the equilibrium modulus and superficial zone proteoglycan (PG) content were significantly lower in ACLT than CTRL joint cartilage (P < 0.05). Significant alterations in the collagen orientation angle extended substantially deeper into cartilage from the ACLT joints in the lateral femoral condyle relative to the medial condyle compartment (P < 0.05).
  
  
  CONCLUSIONS
  In this model of early OA, significant changes in volume and microstructure of subchondral bone plate and trabecular bone were detected only in the femoral medial condyle, while alterations in articular cartilage properties were more severe in the lateral compartment. The former finding may be associated with reduced joint loading in the medial compartment due to ACLT, while the latter finding reflects early osteoarthritic changes in the lateral compartment.
authors.affiliation: Department of Applied Physics, University of Eastern Finland, POB 1627, FI-70211 Kuopio, Finland; Department of Mechatronics, "Politehnica" University of Timişoara, Mechanical Engineering Faculty, Bd. Mihai Viteazul 1, RO-300222 Timişoara, Romania. Electronic address: cristina.florea@uef.fi.
authors.forename: C
authors.initials: C
authors.lastname: Florea
authors.affiliation: Department of Applied Physics, University of Eastern Finland, POB 1627, FI-70211 Kuopio, Finland. Electronic address: markus.malo@uef.fi.
authors.forename: M K H
authors.initials: MK
authors.lastname: Malo
authors.affiliation: Department of Applied Physics, University of Eastern Finland, POB 1627, FI-70211 Kuopio, Finland; Department of Radiology, University of Oulu, POB 5000, FI-90014 Oulu, Finland; Medical Research Center Oulu, University of Oulu, POB 5000, FI-90014 Oulu, Finland. Electronic address: jari.rautiainen@uef.fi.
authors.forename: J
authors.initials: J
authors.lastname: Rautiainen
authors.affiliation: Department of Applied Physics, University of Eastern Finland, POB 1627, FI-70211 Kuopio, Finland. Electronic address: janne.makela@uef.fi.
authors.forename: J T A
authors.initials: JT
authors.lastname: Mäkelä
authors.affiliation: Department of Applied Physics, University of Eastern Finland, POB 1627, FI-70211 Kuopio, Finland. Electronic address: jfickbiomaterials@yahoo.com.
authors.forename: J M
authors.initials: JM
authors.lastname: Fick
authors.affiliation: Department of Radiology, University of Oulu, POB 5000, FI-90014 Oulu, Finland; Department of Diagnostic Radiology, Oulu University Hospital, POB 50, FI-90029 Oulu, Finland. Electronic address: miika.nieminen@oulu.fi.
authors.forename: M T
authors.initials: MT
authors.lastname: Nieminen
authors.affiliation: Department of Applied Physics, University of Eastern Finland, POB 1627, FI-70211 Kuopio, Finland. Electronic address: jukka.jurvelin@uef.fi.
authors.forename: J S
authors.initials: JS
authors.lastname: Jurvelin
authors.affiliation: Department of Mechatronics, "Politehnica" University of Timişoara, Mechanical Engineering Faculty, Bd. Mihai Viteazul 1, RO-300222 Timişoara, Romania. Electronic address: arjana.davidescu@upt.ro.
authors.forename: A
authors.initials: A
authors.lastname: Davidescu
authors.affiliation: Department of Applied Physics, University of Eastern Finland, POB 1627, FI-70211 Kuopio, Finland. Electronic address: rami.korhonen@uef.fi.
authors.forename: R K
authors.initials: RK
authors.lastname: Korhonen
mesh_terms: D000818:Animals; D000070598:Anterior Cruciate Ligament Injuries; D002358:Cartilage, Articular / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D004195:Disease Models, Animal; D018450:Disease Progression; D005269:Femur / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D021621:Imaging, Three-Dimensional; D007718:Knee Injuries / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D011509:Proteoglycans / Q000378:metabolism; D011817:Rabbits; D055114:X-Ray Microtomography
chemical_list: D011509:Proteoglycans
keywords: Anterior cruciate ligament transection; Articular cartilage; Micro-computed tomography; Osteoarthritis; Subchondral bone plate; Trabecular bone