Osteoarthritis develops in the operated joint of an ovine model following ACL reconstruction with immediate anatomic reattachment of the native ACL

Abstract

We tested the hypothesis that immediate reattachment of the native anterior cruciate ligament (ACL) can prevent kinematic changes and the development of osteoarthritis (OA). Five sheep underwent anatomic unilateral ACL reconstruction (ACL-R). Animals from a previous study served as sham (n ¼ 7) or non-operated (n ¼ 17) controls. At 4 points of walking gait, 6 degrees of freedom stifle joint kinematics of ACL-R animals were compared with sham controls at 4 and 20 weeks post-surgery. Gross cartilage, bone, and meniscal changes were graded at euthanasia; paired and differential scores were compared. Inter-animal differences were noted in all groups. Of 48 points of gait comparison between ACL-R and sham operated groups, 42 points showed no difference (p > 0.05). Of the six significant differences (p < 0.05), internal rotation in ACL-R animals accounted for three. At 20 weeks, differential scores showed that sham operated joints were morphologically indistinguishable from non-operated controls (p ! 0.129) while ACL-R joints had significantly higher combined cartilage and osteophyte scores than those controls (p 0.003). This method of ACL reconstruction in sheep did not restore normal walking gait kinematics completely and allowed some OA to develop in operated joints. OA may result from relatively subtle mechanical abnormalities, apparently more so in some individuals than others. The premature development of osteoarthritis (OA) following anterior cruciate ligament (ACL) reconstruction remains a common clinical problem. 1 Much clinical evidence exists that normal joint stability may not be fully restored after all ACL reconstructions, 2 which could explain some of the incidence of OA. 2 Technical refinements, in particular the use of double bundle techniques, have been designed to improve post-operative joint kinematics and therefore reduce the occurrence of OA. However, it has yet to be demonstrated that these newer approaches to more anatomic replacement of the ACL actually achieve that goal. 1 Animal models provide a method of isolating and defining the causes of OA and any potential role(s) of mechanical abnormalities in OA development. Ovine stifle joints develop OA following isolated ACL injury 3 and are large enough to enable quantification of joint kinematics. 4 For example, in a combined ACL/medial collateral ligament injury (ACL/MCL Tx) model, we showed a potential correlation between changes in the medial/lateral degree of freedom and gross bone and cartilage changes. 5 To investigate the potential mechanisms of OA following ACL injury and reconstruction more specifically, here we have created a model of ACL reconstruction in which the native ACL is cored out at one end and immediately replaced as anatomically as possible. 6 This model simulates a number of features of human ACL reconstructive surgery, including bone drilling and graft reattachment. The model eliminates some confounding factors such as variation in graft attachment site and the use of non-ligamentous graft material that may have...

Osteoarthritis in the Knee Joints of Göttingen Minipigs after Resection of the Anterior Cruciate Ligament? Missing Correlation of MRI, Gene and Protein Expression with Histological Scoring

“…Neither Calvo et al [93] nor McDevitt et al [96] could find significant differences between the non operated controls and the sham operated knees in their animal models with rabbits and dogs respectively. This was also confirmed later for a large animal model with sheep by O’Brien et al [97]. Therefore the inclusion of a control group of animals without surgical treatment seemed not to be justified when the study protocol was performed also in terms of animal welfare (http://eur-lex.europa.eu, European directives on the protection of animals used for scientific purposes, DIRECTIVE 2010/63/EU, visited July 25th 2016 and [98]).…”

“…Thus it seems unlikely, that the sham–operation itself may be the cause of the higher degrees of change in the articular cartilage. Further studies [93,94,95,96,97] were able to show that the cartilage of sham operated animals was not distinguishable from non operated controls in terms of degenerative changes. Neither Calvo et al [93] nor McDevitt et al [96] could find significant differences between the non operated controls and the sham operated knees in their animal models with rabbits and dogs respectively.…”

Fresh and Frozen Tissue-Engineered Three-Dimensional Bone–Ligament–Bone Constructs for Sheep Anterior Cruciate Ligament Repair Following a 2-Year Implantation

“…The sham control group in this study underwent an identical surgical procedure, but without detachment of ACL, showing osteophyte formations after 20 weeks of recovery similar to the experimental repair group. 14 Future work will need to be done to delineate the degenerative changes associated with the surgical procedure from the graft repair, and whether these changes are alleviated with implementation of postoperative rehabilitation programs.…”

Alterations in Hoffa’s fat pad induced by an inflammatory response following idealized anterior cruciate ligament surgery

“…Following ACL-R surgery, an inflammatory response develops that impacts the integrity of the IPFP tissue and could potentially contribute to the associated degenerative events that compromise the integrity of the knee joint over time [25]. We evaluated the IPFP subsequent to an In previous publications, we reported that early intraarticular inflammation in the synovium of the knee joint correlates to the gross morphological score of the joint following ACL-R surgery [8].…”