HAMSTRING V.S PATELLAR TENDON 
AS AUTOGENOUS GRAFT IN A.C.L RECONSTRUCTION.

Dr G. Agar, Dr N. Halperin
Department of Orthopedics 'A, Assaf Harofeh
Medical Center, Zerifin, Israel

Presented at the Biomet spring meetion, Cannes, May 1997.

Damage to the anterior cruciate ligament (ACL) is the most common serious ligamentous injury to the knee (1,2). There is an increased incidence of ACL tears that seems to be at least partly as a result of the increasing participation of individuals of all ages in sports. Choosing the right graft for the right patient. or choosing the right procedure in treating the unstable knee, remains a challenging task for the orthopedic surgeon, in spite of the great progress that gas been made in ACL reconstruction.

The surgeon has to consider the following: A) choosing the right patient (4,5,6);C) finding the 'right' location for the graft (18); D) choosing the best fixation.

Today, the most popular ACS source is the autogenous bone patellar tendon bone. Most authors report 80-95% good to excellent results. This seems to be an excellent technique, however, problems have been reported secondary to disturbing patellofemoral anatomy (eg. Anterior knee pain, patellar fracture, tenditis, and increased incidence of Hoffa syndrome) (10.8).

Patellar fracture can usually be avoided by improved technique. Patellar tendinitis is usually short-lived and after one year, is generally not a problem. Anterior knee pain, however, appears to be more significant with this graft source than with hamstring reconstruction. The use of semitendinosus and gracilis tendon grafts for reconstruction of the anterior cruciate ligament (ACL) has been well established (11,12,13). These tendons may, in fact, offer advantages over other commonly used autografts. When the semitendinosus and gracilis tendons are both used, and both doubled, they provide a large diameter, strong ACL substitute (16, 17). The stiffness characteristics of hamstring tendon grafts mimic the normal ACL more closely than does the stiffer patellar tendon graft. The multiple strands of the hamstring grafts also allow a better opportunity for revascularizatior. Recent studies have demonstrated that when fixed properly, hamstring tendon grafts can have a greater initial pull out strength than patellar grafts fixed with interference fit screws (18). There are also occasions when the use of a patellar tendon autograft is not desirable, either because of its unavailability, or because of extensor mechanism pathology. In these cases, the use of semitendinosus and gracilis tendons becomes a very attractive alternative.

In our department we use both patellar tendon middle third or hamstrings as autografts. We reviewed two different groups of patients who underwent ACL reconstruction. The evaluation of the patients was based on: clinical examination, Lysholm and Terner questioners and arthrometer measurement. The first group of 50 patients underwent ACL reconstruction using semimembranosus gracilis double loop, the proximal anchorage was 2 cm wide strip of llleo tibial tract over which the hamstrings loop was passed thus creating a tenodesis effect. Subjective results at follow-up were excellent and good in 80% of the patients and functional results in 85% of them. However, the results of the objective knee stability tests were excellent and good in 90% of the patients, with a significant post operative improvement in knee stability, as compared to the pre-operative score (p<0.0001).

The other group of 50 patients, patellar tendon middle third was the chosen graft. Subjective results at follow-up were excellent and good in 86% of the patients and functional results in 90% of them. However, the results of the objective knee stability tests were excellent and good in 95% of the patients, with a significant post operative improvement in knee stability, as compared to the pre-operative score (p<0.0001).

These two examples were taken from two presentations we made previously and are presented as examples to show there is no significant difference in the results.

We are engaged now in a prospective study comparing the bone tendon bone Vs hamstrings. We think that both methods are good but there are certain circumstances where one graft is superior to the other.

References.