After the tendon grafts have been harvested a special jig is used to locate the tunnel in the tibia in the precise position where the old ligament was attached.
Subsequently, through the tibial tunnel, a tunnel is created in the femur in the appropriate position. The location of the tunnels is very important as this determines whether the graft will be under correct tension through the full range of movements of the knee.
Generally the entry point of the tibial tunnel is located 7 mms in front of the most anterior fibres of the posterior cruciate ligament and on the inner face of the medial tibial spine.
The femoral tunnel is located in the intercondylar notch on the inner face of the lateral femoral condyle as far back as possible.
Using a jig and working with the arthroscope, a wire loop is pulled down the femoral tunnel and out through the tibial tunnel.
The prepared tendon graft is then looped through the wire. Pulling on the two ends of the wire now pulls the tendon graft through the tibial tunnel into the femoral tunnel along the path of the original anterior cruciate ligament.
The graft is secured to the femur and the tibia using special screws and staples. Apart from the cut made to harvest the hamstring tendons, all this work is done through two small stab holes on the front of the knee.
The finished operation looks like the diagram below with a transverse screw holding the graft in the femoral tunnel and a n interference screw holding the graft snugly in the tibial tunnel.
After the surgery, the patient can walk with the help of crutches the next day. The crutches can be discarded after three weeks. A intensive course of physiotherapy is begun very soon after surgery to strengthen the muscles and prevent the graft from being overloaded prematurely. The graft needs about 9 months to gain near normal strength and therefore contact sports are prohibited for 6-9 months though normal walking can be resumed in about 6 weeks time.
The advantages of the arthroscopic technique are a quicker recovery time as the knee has not been opened up. The open technique also gives very good results and the important factor in getting good results from this operation are meticulous surgical technique and also a strict adherence to the postoperative exercises prescribed by your physical therapist.
The graft is obviously never better than the GOD given cruciate ligament and an injury sufficient to rupture the original cruciate ligament will almost certainly rupture the reconstructed ligament.
Complications are rare, but can include infection, which may require antibiotics and occasionally stiffness of the knee requiring a further arthroscopic procedure to divide the postoperative adhesions. The lack of the two hamstring tendons in the thigh does not make any difference to the strength of the thigh muscles and the patients do not notice any weakness or difference.