FIGURE 1:

In order to minimize donor site morbidity a semi-tendinosis (Fig 1) or Achilles tendon allograft may be used. However, if allograft tissue is not available, autologous tissue may be substituted.

FIGURE 2:

A lateral incision is made through the subcutaneous tissue from the lateral femoral epicondyle to Gerdy's tubercle. The fascia lata is divided longitudinally. Gerdy's tubercle is identified along with the site just posterior to the insertion of the lateral collateral ligament on the femur (Fig 2). Slot-eyed Beath pins are then placed in these positions. Initially, the pins are drilled a short distance into the bone.

FIGURE 3:

Then a suitably strong suture material is then stretched between these two pins (Fig 3). The knee is then put through a full range of motion. Tension changes in the suture so placed should be less than two millimeters. This is a simple but useful approximation of isometry. If the tension in the suture is inadequate or the suture breaks indicating a non-isometric position, the pins are reinserted at a more suitable site until satisfactory isometry is established.

FIGURE 4:

Once this relatively isometric position is established, the femoral pin is drilled through the femoral cortex exiting medially and sufficiently proximal to avoid the femoral tunnel of the previously reconstructed ACL. In order to avoid the tibial tunnel, the tibial pin is advanced distally and medially. Once adequate pin position is achieved a 7 mm cannulated reamer is advanced over the Beath pins and both tunnels are drilled to a depth of 25 mm.

FIGURE 5:

A wire suture is placed at both ends of the graft, which is then advanced into the tunnels with the aid of the slot-eyed Beath pins. With the knee held in 20° of flexion, the graft is tensioned to approximately five kg, and direct tendon to bone fixation is accomplished with 7 mm x 20 mm bioabsorbable interference screws placed over a guide wire (Fig 5). The femoral insertion is fixed first followed by the tibial insertion. Stability is then checked. The pivot-shift phenomenon should be completely eliminated. The wound is then closed with sub-cuticular absorbable sutures.