The basis for deficiencies of the anterior cruciate ligament ("ACL") and various techniques of repair or replacement have been known for many years. See, The Anterior Cruciate Ligament Deficient Knee, Clinical Orthopaedics and Related Research, No. 172 (January-February 1983) (J. Feagin, Jr., M. D., Guest Ed.). The great variety of techniques and the non-uniform acceptance of any single technique may have contributed to the lack of specialized instrumentation for performing replacement or repair of the ACL. Instrumentation which has become somewhat specialized in this area is drill guides for locating holes in the tibia and femur. Hewson, Drill Guides for Improving Accuracy in Anterior Cruciate Ligament Repair and Reconstruction, Clin. Orth. Rel. Res. 172: 119-124 (January-February 1983) presents a survey of various drill guides. However, none of the drill guides available are without its particular disadvantages.
One technique for the replacement of the ACL, which has gained in popularity in recent years, is the use of a graft taken from the patellar tendon and inserted into tunnels reamed in the femur and tibia. This technique is described in Lambert, Vascularized Patellar Tendon Graft with Rigid Internal Fixation for Anterior Cruciate Ligament Insufficiency, Clin. Orth. Rel. Res. 172: 85-89 (January-February 1983). In this the portion of the patellar tendon used is separated from the tibia and patella with a scalpel and osteotome. The osteotome is used to separate the graft with small pieces of bone (to serve as bone plugs) naturally attached at each end of the tendon. One problem associated with this procedure is that the osteotome creates V-shaped defects or recesses where the small bone pieces are removed. The V-shape of the defects can create high stress concentration at those points.
Tunnels or holes are drilled in the tibia and femur, both opening to the intercondylar region. Lambert teaches that the most accurate placement of the holes is achieved by drilling both holes from the outside of the bone towards the inside. Lambert also recommends the use of a Hewson intercondylar drill guide for accurate placement of the holes.
Once the holes have been formed in the tibia and femur, the graft is twisted 180.degree. and pulled through the bone holes by sutures placed through the bone plugs. The twisting of the graft is important to maintain the isometric function of the graft. The ligament graft is secured in place by interference fit of bone screws between the bone hole wall and the bone plug attached to the tendon ends. The procedure as described by Lambert is not arthroscopic.
Rosenberg, Technique for Endoscopic Method of ACL Reconstruction (Acufex Brochure 1989), describes a modification of the Lambert technique. The Rosenberg technique is arthroscopic and utilizes a femoral tunnel drilled from below the femur. Rosenberg illustrates the difficulty in locating the center of the femoral tunnel. A method for testing the location to ensure that it will provide proper isometric function of the ligament graft is disclosed, but the location must still be selected without the use of a guide to ensure placement relative to the bone mass in which the tunnel is formed. The location thus depends to a large extent on the skill of the surgeon. While specialized instrumentation is described, it is related only to the method of testing the location for isometric positioning.
Although procedures for repair of the ACL have become relatively common, without special instrumentation, such as guides and reamers, the success of these procedures depends to a greater extent upon the specialized skills of a particular surgeon, more so than if such specialized instrumentation were available. Thus, there has existed a need in the art for a surgical procedure with a range of associated specialized instrumentation to facilitate repair or replacement of the ACL.
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