Reconstruction of anterior cruciate ligaments

Abstract

Apparatus for locating an attachment position for a reconstructed anterior cruciate ligament on an attachment surface of a bone comprises locating means 51, 61 arranged to locate at least one reference surface 4 of the bone and guide means 53, 54 arranged to define the attachment position in two dimensions on the attachment surface relative to the reference surface.

1 . Apparatus for locating an attachment position for a reconstructed anterior cruciate ligament on an attachment surface of a bone, the bone having at least one reference surface, the apparatus comprising locating means arranged to locate the at least one reference surface and guide means arranged to define the attachment position in two dimensions on the attachment surface relative to the at least one reference surface. 
     
     
         2 . Apparatus according to  claim 1  wherein the bone has first and second reference surfaces and the locating means is arranged to locate the first and second reference surfaces of the bone to provide location of the attachment position in first and second dimensions. 
     
     
         3 . Apparatus according to  claim 1  wherein the attachment surface is arranged to provide location in a third dimension thereby to define the attachment position in three dimensions. 
     
     
         4 . Apparatus according to any foregoing claim arranged to locate an attachment position on a tibia. 
     
     
         5 . Apparatus according to  claim 4  wherein the tibia has an inter-spinous ridge and the locating means is arranged to locate the inter-spinous ridge. 
     
     
         6 . Apparatus according to  claim 4  wherein the tibia has a spinous process which has lateral and medical aspects and the locating means is arranged to locate one of the aspects. 
     
     
         7 . Apparatus according to  claim 4  wherein the tibia has a posterior tibial trans-condylar axis and the locating means is arranged to locate the posterior tibial trans-condylar axis. 
     
     
         8 . Apparatus according to  claim 4  wherein the tibia has a tibial plateau and the locating means is arranged to locate an edge of the tibial plateau. 
     
     
         9 . Apparatus according to  claim 1  arranged to locate an attachment position on a femur. 
     
     
         10 . Apparatus according to  claim 9  wherein the femur has a femoral intercondylar notch having a posterior edge and transverse ridge at the posterior edge and the locating means is arranged to locate on the transverse ridge. 
     
     
         11 . Apparatus according to  claim 9  wherein the femur has a femoral intercondylar notch having a roof and a side wall and the locating means is arranged to locate on at least one of the roof and the side wall. 
     
     
         12 . Apparatus according to  claim 9  wherein the femur has a femoral condyle having a posterior proximal aspect and the locating means is arranged to locate on the posterior proximal aspect of the femoral lateral condyle. 
     
     
         13 . Apparatus according to  claim 1  wherein the guide means is arranged to define two attachment positions for respective fibre bundles. 
     
     
         14 . Apparatus according to  claim 1  which comprises an instrument wherein the locating means comprises a locating surface arranged to contact the reference surface. 
     
     
         15 . Apparatus according to  claim 14  wherein the bone has two reference surfaces and the locating means comprises two locating surfaces each arranged to locate on a respective one of the reference surfaces. 
     
     
         16 . Apparatus according to  claim 14  wherein the locating surface is formed in two parts angled at from 45° to 60° to each other. 
     
     
         17 . Apparatus according to  claim 14  wherein the instrument comprises a probe including the guide and an alignment means connected to the probe and arranged to aid alignment of the probe. 
     
     
         18 . Apparatus according to  claim 17  wherein the alignment means is arranged to define an alignment axis which is arranged to be aligned with an anatomical feature of the patient when the guide is correctly aligned. 
     
     
         19 . Apparatus according to  claim 18  wherein the alignment member is elongate. 
     
     
         20 . Apparatus according to any of  claim 17  wherein the alignment member is arranged to be aligned with the long axis of a bone of the patient when the guide is correctly aligned. 
     
     
         21 . Apparatus according to  claim 17  wherein the alignment member is connected to the probe by a support that includes an offset portion arranged to extend around an anatomical feature of the patient when the guide is correctly aligned. 
     
     
         22 . Apparatus according to  claim 1  wherein the locating means is arranged to locate the reference surface from data relating to the position of a part of the bone. 
     
     
         23 . Apparatus according to  claim 22  wherein the guide is arranged to define a target position for a guide device and to provide guidance outputs arranged to enable a user to place the guide device in the target position. 
     
     
         24 . A method of locating an attachment position for a reconstructed anterior cruciate ligament on an attachment surface of a bone, the method comprising locating at least one reference surface of the bone and defining the attachment position in two dimensions on the attachment surface relative to the reference surface.