The effect of skeletal maturity on functional healing of the anterior cruciate ligament.
BACKGROUND
The effects of skeletal maturity on functional ligament healing are unknown. Prior studies have suggested that ligament injuries in skeletally mature animals heal with improved mechanical properties. In this study, we hypothesized that skeletally immature animals have improved functional healing compared with skeletally mature animals.


METHODS
Twenty-one Yucatan minipigs (eight juvenile, eight adolescent, and five adult animals) underwent bilateral anterior cruciate ligament transection. On one side, the ligament injury was left untreated to determine the intrinsic healing response as a function of age. On the contralateral side, an enhanced suture repair incorporating a collagen-platelet composite was performed. Biomechanical properties of the repairs were measured after fifteen weeks of healing, and histologic analysis was performed.


RESULTS
Anterior cruciate ligaments from skeletally immature animals had significantly improved structural properties over those of adult animals at three months after transection in both the untreated and repair groups. Use of the enhanced suture technique provided the most improvement in the adolescent group, in which an increase of 85% in maximum load was noted with repair. The repair tissue in the adult tissue had the highest degree of hypercellularity at the fifteen-week time point.


CONCLUSIONS
Functional ligament healing depends on the level of skeletal maturity of the animal, with immature animals having a more productive healing response than mature animals.
Murray
Martha M
MM
Department of Orthopaedic Surgery, Children's Hospital Boston, Hunnewell 2, 300 Longwood Avenue, Boston, MA 02115, USA. martha.murray@childrens.harvard.edu
Magarian
Elise M
EM
Harrison
Sophia L
SL
Mastrangelo
Ashley N
AN
Zurakowski
David
D
Fleming
Braden C
BC
D000367:Age Factors; D000818:Animals; D016118:Anterior Cruciate Ligament / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D001696:Biomechanical Phenomena; D001846:Bone Development; D004195:Disease Models, Animal; D019651:Plastic Surgery Procedures; D013552:Swine; D013556:Swine, Miniature; D014945:Wound Healing
Am J Sports Med. 2009 Aug;37(8):1554-63
19336614
J Orthop Res. 2010 Aug;28(8):1100-6
20127960
Clin Orthop Relat Res. 2008 Mar;466(3):622-33
18264850
J Orthop Res. 2010 May;28(5):644-51
19890988
Ann Rheum Dis. 2004 Mar;63(3):269-73
14962961
J Orthop Res. 2006 Apr;24(4):820-30
16555312
J Orthop Res. 2008 Nov;26(11):1500-5
18528857
Am J Sports Med. 2009 Dec;37(12):2401-10
19940313
Calcif Tissue Int. 1989 Nov;45(5):292-7
2509018
J Bone Joint Surg Am. 1991 Mar;73(3):373-83
2002075
J Orthop Res. 2001 Sep;19(5):841-4
11562130
J Orthop Res. 2010 Jun;28(6):703-9
20058276
J Orthop Res. 2010 Aug;28(8):1107-12
20186834
J Bone Joint Surg Am. 2000 Oct;82(10):1387-97
11057466
J Orthop Res. 2005 Mar;23(2):287-93
15734238
J Orthop Res. 2007 Aug;25(8):1007-17
17415785
Am J Sports Med. 1991 May-Jun;19(3):217-25
1867330
J Orthop Res. 2009 May;27(5):639-45
18991345
J Athl Train. 2004 Dec;39(4):352-364
15592608
Arthroscopy. 2010 Sep;26(9 Suppl):S49-57
20810092
Acta Orthop Scand. 1988 Dec;59(6):704-7
3213461
J Orthop Res. 2007 Jan;25(1):81-91
17031861
J Orthop Res. 2002 Nov;20(6):1345-51
12472251
J Orthop Res. 2009 May;27(5):631-8
19009602