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Bone-Patellar Tendon-Bone Graft Superior for Patients with Joint Laxity

Studies show that joint laxity (loose ligaments) in the knee can lead to anterior cruciate ligament (ACL) rupture. In this study, researchers look to see if patients with excessive joint laxity have different results after ACL surgery depending on the type of tendon graft used to repair the rupture.

Two groups of patients were compared. Everyone had an ACL tear and needed reconstructive surgery. The first group had normal joint laxity. The second group had generalized joint laxity (present in all the joints).

Two different types of standard tendon grafts were used in both groups (hamstring graft and bone-patellar tendon-bone graft). It was expected that the patients with joint laxity would have different results depending on which type of graft was used.

One surgeon did all of the operations. The surgical technique was described for both grafts. Everyone had the same postoperative rehab program. X-rays were taken before and after the procedure. The images were uploaded to a special computer program for analysis.

Results were measured based on pain, function, and amount of anterior translation in the knee. Anterior translation refers to the forward sliding motion of the tibia (lower leg bone) under the femur (thighbone). Translation is a measure of knee joint laxity.

There was no difference in results between the two grafts for the normal group. But knee joint laxity was greater in the laxity group when the hamstring graft was used. The authors suspect several reasons for this difference. The first is that the hamstring tendon is smaller in diameter compared to the patellar tendon graft.

Second, the hamstring tendon is folded over on itself and then placed inside a tunnel formed in the bone. This graft is slower to bind to the bone compared to a patellar tendon graft, which uses bone plugs instead of a tunnel. It appears that the hamstring tendon forms a fibrous envelope around itself instead of attaching firmly to the surface of the bone.

The final outcome of this study was to show that the bone-patellar tendon-bone graft is a better choice for ACL repair in patients with generalized joint laxity.

References: Sung-Jae Kim, MD, et al. Anterior Cruciate Ligament Reconstruction in Patients Who Have Excessive Joint Laxity. In The Journal of Bone and Joint Surgery. April 2008. Vol. 90-A. No. 4. Pp. 735-741.

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