FIGURE 1:

The surgical technique asssociated with hamstring tendons is described in this section. The hamstring tendons connect the hamstring muscles, which run down the back of your thigh, to your lower leg. The hamstring muscles allow you to flex (bend) your knee.

Harvesting the hamstring tendons can be difficult. The most frequently encountered and most difficult to correct problem is amptutating the tendon. Most tendon harvestors rely on a single rather sharp, cylindrical knife edge to cut the tendonis insertions from the gastrocnemius muscle. These tendonis bands can be thick and difficult to detach.

FIGURE 2:

Blunt dissection with the fingertip or direct dissection with the scissors are techniques advocated to avoid the problem of tendon amputation. While these techniques are certainly helpful,they are not always adequate and are time consuming.We have approached the problem in a slightly different fashion. A blunt cylinder encased by a sharp outer(recessed) cylinder (Fig 2) solves these problems.

FIGURE 3:

The tendon to be harvested is detached from the boney insertion on the tibia. A "safety" suture is then placed through the tendon to avoid the posibilty of "loosing" the tendon should the grasper lose the grip on the tendon during the harvesting process (Fig 3).

FIGURE 4:

The tendon is then brought through the slots in both cylinders. This is easily done with an arthroscopic grasper. The tendon itself is then grasped with a Kocher or "needle holder" type instrument (Fig 4). Traction is then applied to the tendon while the harvester is advanced in a closed positon.

FIGURE 5:

The inside cylinder has a leading edge which is smooth and dull. The tendon easily slides over the cylinder edge and the smooth edge makes it impossible to cut the tendon itself (Fig 5).

When the tendonis bands or other obstructions to advancement of the harvester are encountered, the handle of the harvester is closed,advancing the sharp outside cylinder. During this process care is taken not to advance the harvester as a whole. The sharp outside cylinder moves forward a distance of approximately 3mm. This is sufficient to cut or begin the process of cutting the tendonis insertions and yet this distance is not enough to cut the tendon itself.

FIGURE 6:

Care must be taken to avoid advancing the tendon harvester as a whole with the handle closed. Obviously, advancing the harvester with the sharp edge exposed could allow the sharp edge to cut the tendon itself. To avoid this potential problem, hold tension on the tendon, advance the harvester until resistance is met,then squeeze the handle, then release the handle and advance the harvester as a whole (Fig 6). When the harvester encounters resistance,the process is repeated until no further resistance is encountered and the harvester advances in the same fashion as other tendon harvesters.

FIGURE 7:

The tendons are prepared on a side table by dissecting muscle and soft tissue from them. Then, using a anchoring cerclage suturing device (Fig 7) designed specifically for this procedure, two #1 anchoring cerclage sutures are placed such that the overall length of the looped tendons coresponds to the intra-articular distance (femoral tunnel to tibial tunnel length) plus additional length (approx 60 mm) to account for the portion of the construct that will be located in the tunnels.

FIGURE 8:

The core of bone, which was obtained from the tibial tunnel, is trimmed to a length of 20mm. It should be noted that the tibial tunnel must be prepared with a coring reamer or similar device in order to obtain the needed bone core. Using a specialized drilling guide two slots are formed lengthwise along the bone core. These slots accommadate the tendon strands in the finished tendon-bone composite graft (Fig 8).

FIGURE 9:

The bone core is then attached to the inner portion of the double tendon loop with the aid of specialized graft table. This table allows the bone to be attached to the tendon under tension (Fig 9). It also contains the drill guide used to slot the core.

FIGURE 10:

The finished bone composite graft is then ready for insertion (Fig 10). The femoral and tibial tunnels are prepared in the same manner as an patellar tendon reconstruction (see ACL with Patellar Tendon). When inserted the graft composite should be oriented such that the end of the graft with the attached bone core is located in the tibial tunnel.

FIGURE 11:

Direct tendon to bone fixation is accomplished on the femoral end using a cannulated bioabsorbable interference screw (Fig 11). Direct tednon to bone fixation provides sturdy fixation which allows for early/aggressive rehabilitation just like the more common bone to bone fixation familiar to those who use patellar tendon grafts. Bone to bone fixation is accomplished in the tibial tunnel in the same manner.