Choosing the Right Tendon Graft for Elbow Reconstruction

Pain and impaired function of the medial (inside) elbow are common symptoms in the throwing athlete. A tear or rupture of the medial collateral ligament (MCL) along the inside of the elbow can cause these symptoms. Surgery to repair the ligament often uses the palmaris longus tendon as a donor graft.

In this study, male cadaver elbows were used to compare the results using larger grafts. The theory was that larger tendons would resist larger loads on the elbow compared to the currently used palmaris longus docking procedure.

In the docking technique, the graft is held in place by threading it through a tunnel drilled in the bone. This eliminates the need for screws or suture anchors to hold it in place. Previous studies have shown this method requires smaller drill holes, is much stronger, and has less risk of causing fracture of the bone between the drill holes.

The four tendons used as donor grafts included the palmaris longus, gracilis, semitendinosus, and patellar tendon. Each one was subjected to repeated cycles of load until they failed. Other measures used to compare them were stiffness and ability to stretch.

First, the uninjured elbows were tested to find out how much force and load were needed to cause MCL rupture. A digital camera and computer software program were used to measure the distance between markers along the MCL after each set of 10 load cycles. The force of the load was increased after each set of 10 cycles.

The same elbows were repaired using one of the four tendon graft choices. The exact steps used in the docking reconstructive procedure were described. Type, location, and placement of the stitches used to hold the graft in place with the right amount of tension were also discussed.

Analysis of the data showed no difference between the four different types of tendon grafts. The amount of stiffness provided by each one against increasing loads was the same. The normal, healthy tissue was still much stronger than any of the grafts used. Over time and with enough load, the graft tissue stretched out and failed.

The authors concluded there is no added benefit of using a larger graft for MCL repair than the already commonly used palmaris longus tendon. No matter which tendon was used as a donor for the graft, elasticity was the limiting factor in the results of the reconstruction. Graft tendons are too elastic compared with native MCL tissue.

Further research is needed to find a stiffer, stronger graft. The goal is to develop MCL reconstruction with a biomechanical response equal to the native tissue. This would allow a faster, more aggressive rehab program and get the athlete back to competitive throwing sooner.

References: Joe Prud'homme, MD, et al. Biomechanical Analysis of Medial Collateral Ligament Reconstruction Grafts of the Elbow. In The American Journal of Sports Medicine. Vol. 36. No. 4. Pp. 728-732.