A new device for the fixation of anterior cruciate ligament tendon grafts

Anterior cruciate ligament fixation: Is radial force a predictor of the pullout strength of soft-tissue interference devices?

“…Previous studies have suggested the importance of applying sufficient radial force as a means to offer better graft compression and improve the fixation strength of graft-device constructs, specifically by increasing the level of interference in the tunnel [5,23]. Both Martel and Pena et al correlated the fixation strength to an interference parameter that related the cross sectional area taken up by the interference device to the total cross sectional area of the tunnel.…”

“…Both Martel and Pena et al correlated the fixation strength to an interference parameter that related the cross sectional area taken up by the interference device to the total cross sectional area of the tunnel. It was determined that interference devices that have a higher interference parameter (i.e., more radial pressure) exhibit better pullout strength by being able to better grip the tendon against the tunnel [5,24]. In this study, a resultant force (F R ) was used as a representative measure of the amount of radial force being applied by an interference device.…”

“…In high density bone, IntraFix has been shown to exhibit at least 50% more pullout strength in comparison with bioabsorbable [18] and metallic interference screws [25], but its result is not confirmed in low-density bone [9]. Interference screws possess relatively large surface peaks and valleys (threads) that limit the contact area to the graft and bone that is needed to enhance radial force generation [5]. To overcome this limitation, interference screws are often sized larger than the tunnel diameter; however, this practice also induces graft damage and unwanted migration during insertion and thus is not considered an optimal solution [26].…”

“…It offers several advantages over other fixation approaches including a more anatomic placement of the graft in the bone tunnel to promote direct tendon-to-bone healing and reduced intra-tunnel motion and shear stresses that often lead to tunnel enlargement [4]. Interference devices achieve fixation through a press-fit mechanism by which frictional forces are created between the device, graft, and bone preventing the graft from slipping under intra-articular pullout forces [5]. As shown in Fig.…”

Testing of prototype interference screw for ACL reconstruction in porcine femurs

“…In the past two decades many different fi xation method were developed, such as metal and biodegradable interference screws, post fi xations by screws, staples, buttons, sutures and others 9,10,11,12,13 , and several new fi xation methods are under development 14,15,16,17 . Most of these techniques use implants from metallic or absorbable materials 18,19 , which are later surgically removed or are absorbed by the body.…”