Recombined bone xenografts enhance tendon graft osteointegration of anterior cruciate ligament reconstruction

Abstract

The objective of the study was to discover whether recombined bone xenograft (RBX), a porous solid material, could augment healing of the tendon-to-bone interface after anterior cruciate ligament (ACL) reconstruction. ACL reconstruction was performed bilaterally in 25 skeletally mature rabbits using long digital extensor tendon grafts. RBX was implanted into the treated knee, with the contralateral knee serving as control. Three rabbits were killed at postoperative weeks two, six and 12 for routine histology. The remaining 16 rabbits were killed at weeks six and 12, and their femur-graft-tibia complexes were harvested for mechanical testing. The treatment and control groups produced different histological findings at the interface between the tendon and bone. In the treatment group, large areas of chondrocyte-like cells were noted around the tendon-bone interface two weeks after the operation. At six weeks, more abundant bone formation was observed around the tendon. At 12 weeks, an immature neoenthesis structure was seen. In biomechanical evaluation six and 12 weeks after the operation, the ultimate strength of tendon in the bone tunnel was significantly higher in the treatment group than in the control group. RBX can augment the osteointegration of tendon to bone after ACL reconstruction.Résumé L'objectif de cette étude est d'évaluer l'intérêt d'un matériel solide et poreux du type xénogreffe osseuse recombinée. Cette greffe osseuse recombinée (RBX), peutelle augmenter les chances de consolidation au niveau de l'interface tendon-os après reconstruction du ligament croisé antérieur (ACL). Matériel et méthode: une reconstruction du ligament croisé antérieur a été réalisée de façon bilatérale sur 25 lapins « squelettiques » en utilisant une greffe du tendon du long extenseur. RBX a été implanté dans les genoux traités, le genou contro latéral servant de contrôle. Trois lapins ont été sacrifiés à 2,6 et 12 semaines avec un examen histologique de routine, les 16 lapins restant ont été sacrifiés à 6 et 12 semaines, le complexe osseux fémoro tibial ayant été testé mécaniquement. Résultat, le groupe contrôle non traité montre une différ-ence histologique au niveau de l'interface entre le tendon et l'os. Dans le groupe traité par RBX, de larges plages cellulaires de chondrocytes-like ont été repérés autour de l'interface tendon-os 2 semaines après l'opération. 12 semaines après, des formations plus importantes ont été observées autour du tendon de même qu'une néofixation de type immature. L'évaluation bio mécanique a montré que 12 semaines après l'opération l'insertion tendineuse au niveau du tunnel osseux est beaucoup plus solide dans le groupe des lapins traités que dans le groupe contrôle. En conclusion le RBX peut augmenter l'ostéo intégration osseuse de la jonction tendineuse dans les réparations du ligament croisé antérieur. Abbreviations ACLAnterior cruciate ligament RBX Recombined bone xenograft QSTG Quadrupled semitendinosus and gracilis tendons BPTB Bone-patella tendon-bone SEM Scanning electron micr...

Biological enhancement of graft-tunnel healing in anterior cruciate ligament reconstruction

“…However, the slow degradation rate of injectable CPC could block the ingrowth of new bone and might delay the osteointegration process (19). therefore, recombined bone xenograft (RBX), a new type of biosynthetic material which can be directly incorporated into injectable CPC, has been suggested to be more effective in augmenting bone ingrowth in animal models (20). RBX has already been used as a BMP carrier, showing accelerated tendon-bone healing (21).…”

Graft selection in ACL reconstructive surgery

“…16,84,85,89,101 The beneficial effects of the granulocyte colony stimulating factor (GCSF) is related to the production of granulocytes and stem cells in bone marrow, differentiation of neutrophils, angiogenesis, and differentiation and migration of mesenchymal stem cells. 27,70,74,88,90,92,98,104 BMPs are signaling proteins that influence tissue structures in the body, and they have a role in skeletal development. 92 Application of growth factors such as basic fibroblast growth factor (bFGF) and vasculoendothelial growth factor and stem cells merits further investigation but is not immediately clinically applicable.…”

“…It recently has been shown that administration of bFGF resulted in enhanced mesenchymal cell proliferation, collagen preservation, enhanced neovascularization and circulation, improved tissue maturation, which resulted in increased structural and mechanical properties of the injured tendons. 74 The demineralized bone matrix (DBM) is a further source of BMPs, which has been proposed as a mean of enhancing tendon-bone healing and tendon-bone fixation strength by inducing an increase in the growth of fibrocartilage and mineralized fibrocartilage at the tendon bone interface in ovine. 27,70,74,88,90,92,98,104 BMPs are signaling proteins that influence tissue structures in the body, and they have a role in skeletal development.…”

Augmentation of Bone Tunnel Healing in Anterior Cruciate Ligament Grafts: Application of Calcium Phosphates and Other Materials

“…Bone samples can be used as a source of natural BMPs. Pan et al studied the effect of applying recombined bone xenograft within the bone tunnels after ACL replacement [ 43 ]. The xenograft was used to produce BMPs, which were then mixed with cancellous bone and formed into cylinders which were attached to the ends of tendon grafts and implanted in the tibial and femoral bone tunnels in rabbit models.…”