Such devices are described in W094/22395 as being manufactured by securing a plurality of tows of biocompatible material (e. g. polyester) side-by-side in a flat elongate array, as by light braiding, looping the tows back at one end (or both ends) of the device to form an eye (or an eye at both ends), and applying lashing around the base of the eye (or eyes), which is available for attachment of a pulling cord or wire and/or for secure fixing of that end of the device by fitting the eye round an anchor member secured to a bone.

W094/22395 also describes the lengths of flat elongate array being secured side-by-side by stitching, and also applying whipping around grouped tows around the eye.

Such a device having an eye at one end can have its stitched-together side-by-side lengths of flat elongate array wrapped round one end of an autologous graft, with the mating edges stitched together to form a sleeve over that end of the graft and stitched thereto, whereby the device can serve as a delivery device for the graft. The other end of the autologous graft may be similarly treated.

In recent years, hamstring grafts have been advocated for ACL reconstruction due mainly to the reduced morbidity associated with the harvesting procedure. In laboratory testing, a quadrupled hamstring graft was shown to have equal or greater strength than a bone-patellar tendon-bone graft. A problem, however, is that all previous fixation techniques have been less effective. A major disadvantage is the excessive distance between the fixation points on the tibia

and the femur. This distance leads to low initial graft stiffness and allows micromotion of the graft in the bone tunnels in the femur and tibia, called the"bungee"effect, which could potentially cause adverse healing and/or failure of the graft.

An object of the present invention is to alleviate this problem.

According to the present invention, therefore, an artificial ligament device comprises a plurality of tows of biocompatible material secured side-by-side in a flat elongate array, looped back at both ends to form an eye at both ends, with lashing around the bases of the eyes, characterized in that the lengths of flat elongate array are secured side-by-side at intervals, thus forming"button-holes".

In use for ACL reconstruction, the end portions of an autologous graft are fed through "button-holes"towards each end of the device and then sutured to the device, and a mid-section of the device is cut out to leave purely autologous tissue to serve as the replacement ACL.

However, use of the device alone as an artificial ligament per se is not precluded.

The device is preferably made of polyester as it attracts vigorous tissue ingrowth, which provides further strengthening of the fixation with time, compared with largely inert mechanical fixation devices currently in clinical use, and allows unobstructed X-ray and MRI images.

The device is preferably available in different lengths to suit the requirements of individual patients.

The free ends of the flat elongate array preferably meet at the middle of a mid-section of the device and are stitched to each other, and the mid-section of the device may be defined by a length in which the lengths of flat elongate array are not secured to each other over a length appreciably longer than the length of a"button-hole".

The securing together of the lengths of flat elongate array may be effected by stitching extending all the way across both lengths.

The tows may be grouped around each eye and whipping may be applied around the grouped tows; however, it may suffice to simply fold the flat elongate array over to form the eyes, and then twist one of the lengths through 180° adjacent to the eyes to bring that length into the same plane as and alongside the other length.

An embodiment of the invention and its manner of use will now be described, by of example only, with reference to the accompanying drawings, in which:- Figure 1 is an elevation of the device; Figure 2 is a view of the device as seen from the left hand side of Figure 1; Figure 3 corresponds generally to Figure 2 but shows an autologous graft fed through "button-holes"towards each end of the device; and Figure 4 corresponds to Figure 3 but also shows the graft after it has ben sutured to the device and a mid-section of the device has been cut out.

In Figures 1 and 2 an artificial ligament device 10 comprises a plurality of tows 11 of biocompatible material, such as polyester, secured side-by-side in a flat elongate array, as by braiding 12, the array being looped back at both ends to form an eye 13 at both ends, with lashing 14 around the bases of the eyes, and with the free ends 15 of the flat elongate array meeting at the middle of the device and being stitched to each other. The flat elongate array is simply folded over to form the eyes 13 and then one of the lengths 16,17 twisted through 180o to bring that length into the same plane as and alongside the other length.

In accordance with the present invention, the lengths 16,17 (the latter of which includes the stitched-together ends 15) are secured side-by-side, as by stitching 18 extending all the way across both lengths, at intervals, thus forming"button-holes"19 towards each end, a mid-section 20 of the device being defined by a length in which the lengths 16,17 of flat elongate array are not secured to each other over a length appreciably longer than the length of a"button-hole".

In Figure 4 end portions 21 of an autologous graft 22 are fed through"button-holes"19 towards respective ends of the device 10 and then sutured to the device as indicated at 23 in Figure 4, after which the mid-section 20 of the device is cut out to leave purely autologous tissue to serve as, for example, a replacement ACL; however, use of the device 10 above as an artificial ligament per se is not precluded.

The eyes 13 are available for fitting round anchor members at fixation points on, for example, the tibia and the femur, and one of the eyes may be provided with a pulling cord or tape or a wire (not shown) for threading one end of the device and graft through a bone tunnel..