Graft Options in ACL Reconstruction

A quick review of all published articles shows that when it comes to research in ACL reconstructions, graft material has the highest amount of research. The comparison between the bone-patella tendon bone (BPTB) graft versus the semitendinosus-gracilis (HS) graft is widely researched and reported .

For the BPTB graft, it is taken from the central third of your patella tendon with adjacent bone blocks from the tibia (shin bone) and femur (thigh bone). It also has been recognized as the gold standard for several years. The graft and bone blocks are about 10mm wide. The bone blocks allow bone to bone fixation and early healing at either end.

The BPTB graft is used beacause of its stiffness, high load to failure , exceptional quality of fixation durability and success at long term follow-up. The BPTB graft also allows for earliest return to high demand activities. The most commonly reported complication from this graft includes front knee pain and pain with kneeling. This functional deficit however is relatively low and especially so in patients whose rehabilitation is immediate and aggressive. Having treated patients with ACL reconstructions for more than 10 years, I've found that those patients who regain full knee extension (straightening) seldom have this problem.

Regardless of whether you choose the BPTB or the HS graft, it is extremely important to regain full extension quickly to reduce anterior knee pain. Don't worry too much about not getting enough knee flexion (bending) early, put more effort in getting full extension.It is much easier to get full knee bending compared to straightening, trust me on this.

In recent times, there is an increased use in the HS graft. HS graft use has evolved from using a single strand to 4-strands now. There is strong evidence that the BPTB graft is superior to the single and 2-strand HS graft, hence the 4-stand HS graft is the standard if you choose this graft.

The semitendinosus-gracilis tendons are harvested near the top of your shin bone. Both tendons are folded in half to make 4 strands which is sewed together at either ends.

Patients who choose to have their surgeons use HS graft will have a slightly smaller incision (or operated area) and theoretically less front knee pain (as the graft site is not there) compared to the BPTB graft.

Disadvantages include concern over hamstring muscle weakness, tendon healing within the drilled tunnel (of your shin and thigh bone) housing the graft and no bony fixation (attachment) as compared to the BPTB graft.

What does all these mean? Both published evidence and my personal observations of the hamstrings graft are that your hamstrings muscle strength are often weaker (in spite of strengthening) up to 5 years after the operation. 

However, this deficit does not seem significant in normal daily activities. (For return to elite sports, it is of course different). 

Whilst there is no published significant difference between the BPTB and 4-strand hamstring graft in terms of range of motion and strength, there seems to be some pain with kneeling in the BPTB group. Most of these studies have a follow-up period of 2 years. Studies that have longer follow-up periods present evidence of increased knee laxity in the hamstring graft.

It is important for our readers to note that for most of the studies reviewed, both grafts often have different fixation methods. This means instead of comparing just the grafts alone, the differences may be due to the hamstring graft having a different attachment compared to BPTB.

Each graft choice has its pros and cons, please speak to your physiotherapist and your surgeon based on your needs to determine which is better for you.