Importance

We believe that every surgeon performing anterior cruciate ligament reconstruction (ACLR) would benefit by being able to perform at least one of the variants of cortical screw post femoral fixation described here. Although probably not their primary techniques, they are the universal “bail-out” methods for rescuing more exotic and complicated single-incision techniques gone awry on the femoral side. The ability to troubleshoot is arguably the most important skill a surgeon can possess, and these techniques not only troubleshoot all other femoral methods (and all grafts), but they also can be accomplished with materials that are present in every orthopaedic surgical suite.

History

Whipstitch cortical screw post was perhaps the most popular method of soft tissue ACL graft fixation when two-incision methods were commonly used. There are many reports of high stability using this method.^1–6 However, the advent of the Endobutton and then the various cross-pins that did not require a formal second incision relegated the two-incision method to a secondary role. More recently it has become apparent that a second incision for outside-in drilling can facilitate the lower femoral tunnel placement that is now recognized as biomechanically preferable, and more two-incision methods are now being described.

Advantages

We no longer use the femoral screw post through a second incision as a primary method because we have had success using the one-incision Endobutton method. However, we still believe that the two-incision technique has a number of advantages.

The only disadvantage to this technique is that it requires a second incision. However, this disadvantage is usually primarily in the mind of the surgeon. We, and others, have never found the use of a small second incision to be of concern to the patient (see Chapter 49). Furthermore, the incision does not need to be large. Some may dislike the fact that a nonbioabsorbable and nonradiolucent screw remains in the patient. However, we have never seen one of these screws back out, nor have we ever seen one bother the patient² because the screw sits flush on cortical bone under a thick muscular layer. Plus, because they are metadiaphyseal, they are far enough from the joint to not interfere with subsequent magnetic resonance images (MRIs).

Materials

A standard 6.5-mm, two-thirds threaded cortical screw with a smooth washer is usually used. ACL tibial fixation posts can also be used as follows: There are two 4.5-mm screws without washers with which we are familiar, one made by Smith & Nephew (Andover, MA) and one by Arthrex (Naples, FL). If these washerless screws are used, the screw must be slightly angled away from the femoral tunnel to prevent suture or fabric loop slippage. Linvatec (Largo, FL) has a good 6.5-mm screw, which is used with a washer. Arthrex also has a 6.5-mm screw that is used with a washer, but it uses a smaller (2.5-mm) hex screwdriver. In the past we had occasional instances of breakage of the smaller screwdriver when it encountered high torque with the large screw.

Whipstitches should be put in using either standard #5 braided, nonabsorbable polyester sutures such as Ethibond (Ethicon, Somerville, NJ), Tevdek (SybronEndo, Orange, CA), or Mersilene (Ethicon) or one of the newer stronger #2 sutures such as Fiberwire (Arthrex) or Ultrabraid (Smith & Nephew). The surgeon may also pass a 5- or 6-mm Dacron tape through a quadruple graft and tie it around the cortical screw instead of using whipstitches. A 2- or 3-mm tape is not strong enough. The best loop, however, is the fabric loop that is attached to the Endobutton-CL, which comes in 5-mm increments with 15 mm being the smallest.

Incision

The lateral femoral incision should be made with the knee flexed. The posterior border of the lateral femoral condyle should be palpated and the incision made over the middle of the lateral femoral metaphysis at the flare of the condyle. In a lean patient this incision is about 2 cm long. It will need to be larger in larger patients. The iliotibial band is longitudinally split, and the lateral femoral metaphysis is exposed.

Femoral Screw Insertion Technique

The femoral screws should be inserted unicortically as with tibial screw posts for three reasons.

Attaching the Graft to the Femoral Post

There are four methods by which this may be successfully accomplished, all of which we have used. We prefer number four. Numbers one and four require an Endobutton-CL to be available. If it is not available, then method two or three may be used, and both are very satisfactory.