ACL graft options — which is best for me?

Why graft choice matters

When a patient has an ACL reconstruction, the torn ligament is not repaired — it is replaced. The new ligament is constructed from a graft: tissue taken either from the patient themselves (an autograft) or from a donor (an allograft). The graft choice is one of the most important decisions in ACL surgery, and there is no single right answer that applies to every patient.

Different grafts have different mechanical properties, different harvest sites, different rehabilitation implications, and different evidence bases. Understanding what is available — and what the evidence says — helps patients engage meaningfully in the decision about their own surgery.

Hamstring tendon autograft

The hamstring autograft — most commonly using the semitendinosus tendon, sometimes combined with the gracilis — has been the most widely used graft in Australia for primary ACL reconstruction over the past two decades. The graft is harvested through a small incision below the knee joint and folded to create a multi-strand construct.

Hamstring grafts have a well-established track record. They produce a reliable, strong reconstruction with relatively low donor site morbidity — most patients regain near-normal hamstring strength within 12–18 months, and the harvest site heals uneventfully in the vast majority of cases. The graft is flexible, adapts well to the bone tunnels, and has good long-term outcome data from large studies.

The main consideration with hamstring grafts is graft size. The diameter of the harvested tendon varies between individuals, and smaller grafts (under about 8mm) have been associated with higher re-rupture rates in the literature. For patients with smaller tendons — particularly some female athletes — this may influence the decision toward an alternative graft.

Patellar tendon autograft (bone-patellar tendon-bone)

The patellar tendon graft — also called a bone-patellar tendon-bone graft because bone plugs are harvested from the patella and tibia along with the central third of the patellar tendon — was the gold standard for ACL reconstruction for many years, particularly in high-level athletes.

Its main advantage is the bone-to-bone healing at each end of the graft, which is faster and more reliable than soft tissue healing into a bone tunnel. This means the graft can be loaded earlier in rehabilitation, and many elite sports programs have favoured it for this reason.

The trade-offs are a more significant harvest site, with donor site pain at the front of the knee that can take several months to fully resolve. Kneeling discomfort and, less commonly, patellar fracture or tendon rupture are known complications. There is also a slightly higher risk of anterior knee pain compared to hamstring grafts. For patients whose work or activity involves kneeling, or for those with pre-existing anterior knee pain, these considerations are relevant.

Quadriceps tendon autograft

The quadriceps tendon graft has grown significantly in popularity over the past several years, and for good reason. Harvested from the thick tendon that runs from the quadriceps muscle to the patella, it produces a large, strong graft with good tissue quality — typically larger in diameter than a hamstring graft from the same patient.

Early concerns about donor site morbidity (strength deficit in the quadriceps) have not been well-supported by recent evidence. Studies show that quadriceps strength recovers well, and the harvest site is generally well-tolerated. The graft can be taken with or without a bone block from the patella, offering flexibility in fixation technique.

Quadriceps tendon graft is now a preferred option for many surgeons for primary ACL reconstruction, particularly in cases where graft size is a concern or where a bone-in construct is desired without the anterior knee pain risk of the patellar tendon approach.

There is no universally “best” ACL graft. The right choice depends on the patient’s anatomy, activity level, sport, and the specific demands being placed on the reconstruction. The conversation about graft selection is an important part of surgical planning.

Allograft (donor tissue)

An allograft is tissue sourced from a deceased donor and processed for surgical use. Various tissues can be used — patellar tendon, Achilles tendon, tibialis anterior — and allografts avoid any donor site morbidity for the patient.

The evidence for allograft ACL reconstruction, however, is less favourable than for autograft, particularly in younger and more active patients. Multiple studies, including randomised controlled trials, have shown higher re-rupture rates with allograft compared to autograft in patients under 40 returning to pivoting sport. The biological integration of donor tissue is slower and less reliable than autograft.

Allograft has a role in revision ACL reconstruction — where the original graft has failed and autograft options may be limited — and in lower-demand patients for whom the re-rupture risk difference is less relevant. For primary reconstruction in an active young patient, autograft is strongly preferred on the current evidence.

How graft choice is decided in practice

At consultation, the discussion around graft choice takes into account several factors: the patient’s age, sex, body habitus, the sport or activity they are returning to, the presence of any other knee pathology (such as a meniscal tear or cartilage damage that also needs addressing), and patient preference.

In most primary ACL reconstructions in active patients, the choice is between hamstring, patellar tendon, and quadriceps tendon autograft. The addition of a lateral extra-articular tenodesis (LET) — a supplementary procedure performed alongside the ACL graft — is considered in patients at higher risk of re-rupture, including young athletes returning to pivoting sport. LET is discussed in detail in a separate article.

The goal is to match the reconstruction to the patient — their anatomy, their goals, and the demands they will place on the knee — rather than applying a one-size-fits-all approach.