title: Anterior cruciate ligament insertion after partial tear: histological changes and chondrocyte turnover.
abstract: OBJECTIVE
  The purpose of this study was to clarify the effects of partial resection on the glycosaminoglycan (GAG) layer thicknesses and chondrocyte turnover (apoptosis and cell proliferation) between uncalcified fibrocartilage (UF) and calcified fibrocartilage (CF) layers in an anterior cruciate ligament (ACL) insertion.
  
  
  METHODS
  Twenty male Japanese white rabbits were evaluated. The anteromedial bundle of the ACL substance was resected in the right knee. The posterolateral bundle was left intact. Five rabbits were evaluated at 1, 2, 4, and 8 weeks after surgery, respectively.
  
  
  RESULTS
  The apoptosis rates in the UF and CF layers were significantly lower in the posterolateral area than those in the anteromedial area at 1 and 2 weeks, respectively. The cell proliferation rates in the UF and CF layers were significantly higher in the posterolateral area than those in the anteromedial area at 2 and 4 weeks, respectively. The GAG layer thicknesses in the UF and CF layers were higher in the posterolateral area than those in the anteromedial area at 1-8 and 2-8 weeks, respectively. The GAG layer thicknesses in the UF and CF layers in the posterolateral area peaked at 2 and 4 weeks, respectively. However, the thicknesses in the two layers in the posterolateral area gradually decreased until 8 weeks.
  
  
  CONCLUSIONS
  The GAG layer thicknesses in the UF and CF layers in the remaining ligament area increased up to 4 weeks and gradually decreased until 8 weeks owing to an imbalance between chondrocyte apoptosis and proliferation. If the reactions in humans are similar to those observed in the rabbits, we consider that augmentation for ligament reconstruction and partial repair should be performed within at least 1 month after injury, before insertion degeneration occurs.
authors: Department of Orthopaedic Surgery, Institute of Clinical Medicine, Graduate School of Comprehensive Human Science, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8575, Japan. sakane-m@md.tsukuba.ac.jp
authors: Masataka
authors: M
authors: Sakane
authors: Hirotaka
authors: H
authors: Mutsuzaki
authors: Hiromi
authors: H
authors: Nakajima
authors: Shinya
authors: S
authors: Hattori
authors: Yoshinori
authors: Y
authors: Shirozu
authors: Yuka
authors: Y
authors: Miyake
authors: Naoyuki
authors: N
authors: Ochiai
references: J Anat. 1998 Nov;193 ( Pt 4):481-94
references: 10029181
references: J Bone Joint Surg Br. 1989 Nov;71(5):825-33
references: 2584255
references: Arthroscopy. 2006 Apr;22(4):463.e1-5
references: 16581465
references: Clin Orthop Relat Res. 1975 Jan-Feb;(106):216-31
references: 1126079
references: Mech Ageing Dev. 1990 Nov;56(2):129-42
references: 2290352
references: Clin Orthop Relat Res. 2004 Nov;(428):272-85
references: 15534553
references: Arthroscopy. 2008 Nov;24(11):1289-98
references: 18971061
references: Knee Surg Sports Traumatol Arthrosc. 2007 May;15(5):602-9
references: 17221277
references: Knee Surg Sports Traumatol Arthrosc. 2010 Sep;18(9):1214-8
references: 20148325
references: J Oral Pathol Med. 2006 Feb;35(2):91-8
references: 16430739
references: Cells Tissues Organs. 2010;192(3):167-76
references: 20395673
references: Am J Physiol Cell Physiol. 2003 Apr;284(4):C934-43
references: 12477665
references: Connect Tissue Res. 2010 Aug;51(4):282-8
references: 20175709
references: J Osteoporos. 2010 Dec 20;2011:786752
references: 21209784
references: Arthroscopy. 2009 Feb;25(2):117-22
references: 19171269
references: J Bone Joint Surg Am. 1970 Jan;52(1):1-20
references: 4189231
references: Sports Med Arthrosc Rehabil Ther Technol. 2009 Dec 10;1(1):27
references: 20003291
references: J Vet Med Sci. 2007 Mar;69(3):253-8
references: 17409640
references: Vet Surg. 2010 Jan;39(1):65-70
references: 20210947
references: J Orthop Res. 1997 Mar;15(2):285-93
references: 9167633
references: J Bone Joint Surg Am. 2009 Jan;91(1):198-208
references: 19122096
references: Biol Chem. 2010 May;391(5):571-9
references: 20180636
references: Knee. 2011 Jan;18(1):47-50
references: 20061154
references: J Anat. 1986 Dec;149:89-100
references: 3693113