Single tunnel double bundle anterior cruciate ligament reconstruction

The present invention provides a method of performing anterior cruciate ligament replacement. Specifically, a graft tissue is harvested from a patient and single tunnels are prepared in each of the tibia and the femur of the patient. The graft is secured in the femoral tunnel and separated into an anterior cruciate medial bundle and a anterior cruciate posterior lateral bundle. The bundles are inserted through the tibial tunnel. During insertion the posterior lateral bundle is positioned in a posterior lateral position in the tibial tunnel while the anterior cruciate medial bundle is positioned in an anterior cruciate medial position in the tibial tunnel. The anterior cruciate medial bundle is then tensioned while the patient's knee is in approximately 90 degrees of flexion, and the posterior lateral bundle is tensioned while the patient's knee is approximately in full extension. Each of the bundles is then secured in the tibial tunnel.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention provides a method for anterior cruciate ligament reconstruction and, more particularly, a method for single tunnel double bundle anterior cruciate ligament reconstruction.

2. Related Art

Single tunnel single bundle anterior cruciate ligament reconstruction (STSBACLR) has long been established as a method of anterior cruciate ligament (ACL) reconstruction. A variety of graft choices are available to surgeons during ACL reconstruction. These choices include autogenous patellar or quadriceps tendon with bone blocks, or hamstring tendons. In addition, changed here tendon allografts (from donors) may be used. The main portion of the ACL which needs to be reconstructed is the anterolateral bundles. Arthroscopic assisted or open ACL reconstructions involve removing the remaining native ACL and drilling a tunnel at the anatomic attachment site of the anterolateral or posterior medial bundle at the anterolateral wall of the intercondylar notch. This tunnel is drilled in line with the roof of the notch and about 1-3 mm from the posterior articular surface of the lateral femoral condyle. The tibial attachment site is then prepared by identifying the normal attachment site of the ACL at the bottom of the ACL facet. A tibial tunnel is drilled, at approximately a 60 coronal° angle and about 3-6 cm from the joint line, from anterior to posterior. Once the tunnels are drilled, sharp edges and soft tissues around the tunnel exit site are smoothed off with the use of a rasp. The graft is then passed into the joint and fixed in its femoral tunnel (usually with an interference screw). The graft is then tensioned distally while the knee is cycled several times to remove any slack in the graft. The graft is fixed to the tibia, usually with staples, while the knee is flexed 15-30°, distal traction is placed on the graft, and a posterior force is applied to the tibia. After fixation, the anterior cruciate drawer is assessed to verify a return of normal anterior stability to the knee, and the surgical incisions are closed.

Double bundle double tunnel anterior cruciate ligament reconstruction (DBDTACLR) has recently been described as a technique for ACL reconstruction which provides two bundles of tissue in separate tunnels. Recent biomechanical studies have shown that an anatomic double-bundle ACL reconstruction is superior in restoring normal knee laxity compared with the conventional single-bundle isometric reconstruction. One technique uses a double-bundle Y-shaped hamstring tendon graft. A double- or triple-bundle semitendinosus-gracilis tendon graft is utilized and directly fixed with interference screws. In the lateral femoral condyle, two femoral tunnels are created inside-out through a low anterolateral arthroscopic portal. First, in full extension, the double-stranded gracilis graft is fixed with an interference screw inside the lower femoral socket, representing the insertion site of the posterolateral bundle. In 90 degrees of flexion the combined semitendinosus-gracilis graft is pretensioned and fixed inside the upper femoral socket. Alternatively the graft is placed into the a single femoral tunnel and an interference screw simply placed between the grafts without respect for control of rotation and position of the graft to simulate true orientation of the grafts into anteromedial and posteriolateral bundles. The tendon is inserted in the tibial tunnel. Finally, pretension is applied to the bundles in extension and another screw is inserted. Alternatively two separate tibial tunnels are utilized and the separate anteromedial and posterolateral tunnels and fixed with staples or screws. Using this technique, the stronger semitendinosus part of the double-bundle graft, which mimics the anterolateral bundle of the ACL, is fixed in full extension, whereas the smaller gracilis tendon part (posteromedial bundle) is fixed in flexion.

Kinematically the double bundle anterior cruciate ligament reconstruction has shown itself to be more closely related to the actual normal motion of the knee when compared to single bundle anterior cruciate ligament reconstructions. DBDTACLR is technically demanding procedure requiring an extremely high level of surgeon skill. In addition DBDTACLR requires four separate fixation devices to secure the soft tissue bundles in place to recreate a torn anterior cruciate ligament. Each bundle of tissue is separately tensioned in the respective tunnel prior to fixation with orthopedic devices.

SUMMARY OF THE INVENTION

The present invention provides a novel technique in which a double bundle ACL reconstruction is performed through a single tunnel and the separate bundles are independently tensioned. Accordingly, a new type of ACL reconstruction the Single Tunnel Double Bundle Anterior Cruciate Ligament Reconstruction (STBDACLR) is created.

STDBACLR utilizes a standard graft harvest and can be performed using either allograft or autograft tissues such as bone patellar tendon bone, wherein the graft includes a portion of the patellar tendon having a bone plug on each end, or semitendinosus gracilis (hamstring) tendons. Standard tibial and femoral tunnels are prepared using either a trans-tibial or a trans-portal technique. The femoral graft fixation is important because the bundles for the ACL must be oriented in a proper direction to provide separate kinematic bundles created a through a single tunnel. The graft position on the femoral side is held in place through screws and/or other fixation devices used where the graft is prepared and separated into two separate bundles through implant design or through surgeon preparation. When using hamstring grafts, the grafts are positioned on the femoral side to provide for a posterior cruciate bundle that can be independently tensioned after femoral tunnel fixation. When using bone patellar tendon bone grafts, the femoral bone plug is left as one piece when inserted and the graft is prepared to provide for the separate bundles in the tibia.

During graft introduction into the knee two kinematically separate bundles are created. As the graft is pulled into the knee, the surgeon, who has marked the appropriate bundle of tissue which is to be the posterior cruciate lateral bundle, rotates this bundle to the anterior cruciate posterior lateral position in the tibia while rotating the other bundle, the anterior cruciate medial bundle, to the anterior cruciate medial portion of the tibial tunnel, thereby creating the soft tissue required for both the anterior cruciate posterior lateral and anterior cruciate medial bundles. With the separate bundle created in the knee and appropriately oriented, the bundles are tensioned independently. The anterior cruciate medial bundle is tensioned with the knee in 90 degrees of flexion while the anterior cruciate posterior lateral bundle is tensioned with the knee in full extension. An external tensioning device is capable of cycling the separate bundles under tension or this can be accomplished with two separate screws inserted as posts into the tibia. Once the graft is tensioned, tibial fixation is either completed with the screws alone or, using a removable tensioning device, the bundles are secured in the tibial tunnel with a screw type fixation device and the external tensioner is removed. By anatomically creating two separate bundles and kinematically tensioning those separate bundles and fixating them, the surgeon creates a single tunnel double bundle anterior cruciate ligament repair (STDBACLR).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1-7illustrate a method of reconstructing the anterior cruciate ligament (ACL) of the knee11using a single tunnel double bundle technique. Prior to the reconstruction a standard graft harvest is performed using either allograft or autograft tissues such as bone patellar tendon bone or semitendinosus gracilis (hamstring) tendons. Standard tibial and femoral tunnels then are prepared using either a trans-tibial or a trans-portal technique.

As shown inFIG. 1, the graft10is fixed in the femur12using standard fixation techniques. For example, in the exemplary embodiment the graft10is positioned on the femoral side14to provide for an anterior cruciate bundle that can be independently tensioned after femoral tunnel fixation. When using hamstring grafts, the graft is configured to provide separate bundles, as shown inFIG. 8. Alternatively, when using bone patellar tendon bone grafts, the femoral bone plug is left as one piece when inserted and the graft is, prepared to provide for the separate bundles in the tibia as shown inFIGS. 1-2. The graft is fixed in the femoral tunnel16so that the bundles for the ACL are oriented in a proper direction to provide separate kinematic bundles created through a single tunnel. In the exemplary embodiment, the graft10is held in place on the femoral side14using screws and/or other fixation devices17used when the graft is prepared and separated into two separate bundles through implant design or through surgeon preparation.

As shown inFIG. 2, the graft10is separated into two kinematically separate bundles18after the graft10is introduced into the femur12. Each bundle18is marked as either the anterior cruciate posterior lateral bundle20or the anterior cruciate medial bundle22and pulled through a tibial tunnel24formed in the tibia26, as shown inFIG. 3. As shown inFIG. 4, as the graft is pulled through the tibial tunnel24, the surgeon rotates the bundle labeled anterior cruciate posterior lateral bundle20into the posterior cruciate lateral position28, and rotates the bundle labeled anterior cruciate medial bundle22into the anterior cruciate medial position30, thereby creating the soft tissue required for both the anterior cruciate posterior lateral bundle20and anterior cruciate medial bundle22.

With the anterior cruciate posterior lateral bundle20and the anterior cruciate medial bundle22created in the knee and appropriately oriented, the bundles20and22are tensioned independently using a tensioning device32that couples to each bundle20and22. As seen inFIG. 5, the anterior cruciate posterior lateral bundle20is tensioned with the knee11in a first position34of approximately full extension. As will be appreciated by one of skill in the art, the knee is extended to at or near full extension. Specifically, while in this first position34, the tensioning device32applies tension to the anterior cruciate lateral bundle20while the anterior cruciate medial bundle22is left in an untensioned position. As shown inFIG. 6, the knee11is then flexed into a second position36so that there is approximately 90 degrees of flexion between the femur12and the tibia26. As will be appreciated by one of skill in the art, the knee is flexed to at or near 90 degrees. While in this second position36, the tensioning device32applies tension to the anterior cruciate medial bundle22while the anterior cruciate lateral bundle20is left in an untensioned position. In one embodiment, the external tensioning device32cycles the separate bundles20and22under tension as the knee11is moved between the first position34and the second position36. Alternatively, two separate screws are inserted as posts in the tibia26to individually secure the bundles20and22so that tensioning of the bundles20and22is performed without the tensioning device32by moving the knee11between the first position34and the second position36.

FIG. 7illustrates tibial fixation of the anterior cruciate lateral bundle20and the anterior cruciate medial bundle22with a screw38. The fixation is performed after the graft10has been tensioned and before the tensioning device32has been removed. In an alternative embodiment, the tensioning device32is used to secure the bundles20and22with any screw type fixation device. In other embodiments, alternative fixation devices may be used to secure the bundles20and22. After the bundles20and22are secured to the tibia26, the surgical wound is closed using standard techniques.

Accordingly, the above described invention enables the creation of two separate bundles using a single graft that is positioned using a single tunnel. The single tunnel enables a less invasive operation than known methods of replacing an anterior cruciate ligament. Moreover, the present invention enables the kinematic tensioning of separate bundles thereby providing a more effective and successful ligament replacement