Anterior Cruciate Ligament (ACL) Reconstruction with the Gracilis & Semitendinosis


Vincent Chassaing, MD & Jerome Lemoine, MD

Orthopaedic Surgeons)

This operation rest on the principle that the ligament will be reconstructed in the exact anatomic location of the original ligament, using a graft from the patient him (her) self. The new ligament is threaded into the joint via a tunnel in both the tibia and the femur.

The intra-articular portion of the operation is carried out arthroscopically. This avoids opening the knee through large incisions.


The Graft

The gracilis and semitendinosis are similar muscles which, along with the sartorius, make up the "pes anserinus." They run along the inside of the thigh. They feature very long tendons which cross the knee and then insert on the upper inner aspect of the tibia (see figure). It is possible to harvest these tendons with the use of a long instrument called "stripper." These two tendons are folded over in two, and this leads to a four-strand graft. These four strands together are actually stronger than the original ligament.

Harvesting of one of the tendons

The stripper

The four-strand graft


The Bony Tunnels

The tunnels allow the graft to be placed in the exact location of the original ligament. The graft will be threaded through a tunnel in the tibia and in the femur. The graft is then solidly fixed to the bony tunnels.

A special jig placed inside the knee joint allows the initial placement of a guide wire over which a special reamer will be introduced to create the tunnel.

Placement of the tibial jig and guide wire. The reamer creates the tunnel.
A similar procedure is then carried out on the femur.


Passing the Graft

    The new ligament (four strands) passes through the femur in the direction of the tibia, exactly in the position of the original ligament.
The graft is seen within the knee joint


Fixation of the Graft

The graft is fixed within the tibial and femoral bony tunnel. There are a number of ways of fixing the graft.

The interference screw: this is a screw, which is introduced within the bony tunnel in such a way as to wedge the graft tightly against the bone. The screw can be metallic (and is therefore visible on x-rays) or can be absorbable, in which case it will not be visible on x-rays. The screw on the femoral side can be introduced from within the joint or can be introduced "from outside in" via a small incision on the side of the thigh.
Staples: These can squeeze the graft against the bone, as the graft exits the tunnels. These staples can be used alone or in conjunction with screws or sutures.
The "Transfix" system involves a pin and a loop (see figure).


Example of an ACL Reconstruction


Tear of the ACL. The ligament has disappeared and the notch is empty
The course of the original ligament has been drawn in.
The guide wire is introduced into the knee.
The new ligament has been inserted.


Post Operative Care

The degree of bracing and immobilization varies from surgeon to surgeon. Patients can usually bear full weight the day after surgery. In the first three weeks, it is recommended that the patient use crutches or two canes. Physical therapy is usually begun within the first few days or, depending on surgeon preference, at about two to three weeks. The patient need not be an in-patient for his or her physical therapy, though this may occasionally be desirable. Physical activity can be resumed rather rapidly as long as it does not involve twisting of the knee. Swimming and bicycle riding are particularly encouraged. Fast walking and jogging can start around the third or fourth month. No twisting activity is permitted until the sixth through eighth month following surgery. Indeed, it takes time for the graft to mature. The graft actually weakens before maturing towards its final strength.

Note: a number of our illustrations have been inspired by the CD "The Interactive Knee" from Primal Picture.