Choosing the right graft for your ACL reconstruction
The new ACL that replaces the torn one comes from somewhere — usually a tendon taken from elsewhere in your own body (an autograft). Each graft has its strengths and trade-offs. The right choice depends on your age, sport, body, occupation, and what matters most to you.
Why graft choice matters
Most ACL graft failures happen in the first 12 months after surgery, while the graft is still maturing inside the knee. Choosing the right graft for you reduces the risk of re-injury, supports your rehabilitation, and helps you get back to the activities you care about.
A few things to keep in mind:
- No graft is risk-free. Each option has a small chance of failure and its own pattern of side effects.
- Surgical technique matters as much as graft type. A well-positioned, well-tensioned graft of any type will outperform a poorly placed one.
- Rehabilitation matters more than either. The biggest predictor of a good outcome is consistent, structured physiotherapy through the first 12–24 months.
The point of this page is to help you understand the trade-offs, allowing you to discuss this further with our team if you have questions.
How we make the decision
Our graft recommendation is built around the following factors:
- Age. Younger patients (under 20) are at highest risk of graft failure regardless of graft choice, and benefit from graft and technique decisions that lower that risk.
- Sport and activity level. Pivoting and contact sports (rugby, league, netball, football, basketball, skiing, snowboarding) place different demands on the graft than recreational running or cycling.
- Sex. New Zealand data shows different failure patterns in young women compared with young men, which influences graft choice in some cases (see Patient Archetypes below).
- Occupation. Different graft types cause different levels of kneeling issues long term. If your work involves kneeling, this is taken into consideration.
- Concomitant injuries. A repairable meniscus tear, or other ligament injury, may change the surgical plan and graft selection.
- Previous surgery on the same knee. If this is a revision (your previous ACL has failed), graft availability and tunnel position dictate options.
- Your priorities. What you value most — sprint speed, hamstring strength, the ability to kneel comfortably — affects the recommendation.
We discuss all of these openly. The aim is for you to leave consultation knowing not just what we are recommending, but why.
The graft options
We use the following options in our practice. Each section covers what the graft is, who it suits, failure rates from current literature and registry data, and the trade-offs.
ACL Repair (not a graft — your own ACL)
In selected cases, the torn ACL can be repaired rather than replaced. Recent advances in surgical technique and our understanding of ACL healing have made repair a viable option for specific tear patterns.
- When it’s an option. Tear patterns where the ACL has come away from the femoral attachment, with good tissue quality, and has tried to heal itself.
- What it offers. A more “natural-feeling” knee, faster maturation (around 5 months versus 9 months for a reconstruction), and earlier return to sport.
- What’s the catch? Not every ACL is repairable. The condition of the ligament is assessed at the start of surgery. If a repair is appropriate, it will be offered. If not, we proceed with reconstruction with the most suitable graft.
- Failure rate. Higher in non-selected cases — careful patient selection is the key to good outcomes.
Hamstring tendon — single bundle
The most common ACL graft worldwide. Two of the hamstring tendons (semitendinosus, sometimes with gracilis) are taken from the back of the thigh and used to make the new ACL.
- Failure rate: approximately 10% in the general population. Higher in young, high-demand female athletes.
- Side effects. Some hamstring weakness, cramping, occasional ongoing strain on heavy effort. Kneeling discomfort in about 10%.
- Best for. Low- to medium-demand activities, knees at risk of stiffness, or where some of the native ACL is healing alongside.
- Not ideal for. Young female pivoting-sport athletes (see Archetype 2), or where higher demand and lower failure rate is the priority.
Hamstring tendon — double bundle
Uses the hamstring tendons to recreate both bundles of the native ACL anatomy, rather than the single bundle in standard reconstruction.
- Failure rate: approximately 5%.
- Side effects. Similar to single-bundle hamstring.
- Best for. Medium- to high-demand knees, especially where kneeling discomfort would be a problem — tradies, mechanics, early childhood teachers.
- Trade-off. Can make a knee feel tight, with a higher chance of scar release surgery.
Patellar tendon — bone-tendon-bone (BTB)
The middle third of the patellar tendon with bone plugs at each end is harvested from the front of the knee and used as the graft.
- Failure rate: approximately 5% in the general population.
- Side effects. Kneeling discomfort in approximately 20%, which can be long term.
- Best for. High-demand knees, including professional and competitive athletes; young female pivoting-sport athletes; revision cases.
- Trade-off. Kneeling discomfort is the most common limitation — important to weigh up for tradies, kneelers, and anyone who spends significant time on the floor.
Quadriceps tendon
A strip of the quadriceps tendon is taken from above the kneecap, sometimes with a bone plug from the kneecap as well.
- Failure rate: approximately 7% — comparable to other autografts in current meta-analyses.2
- Side effects. Rehabilitation is more demanding in the first 3 to 6 months because of the quadriceps harvest affecting early quadriceps engagement. There is a small risk of long-term quadriceps weakness if rehabilitation falters.
- Best for. Revision ACL surgery (where hamstring and patellar tendon may already have been used). Selected primary cases where hamstring and patellar tendon graft are unsuitable, or where the patient prefers to avoid kneeling discomfort.
ALL (anterolateral ligament) augmentation
ALL — or lateral extra-articular tenodesis (LET) — is an additional small procedure performed at the time of ACL reconstruction in high-risk knees. A strip of the iliotibial band is used to add a check-rein on the outside of the knee.
- Purpose. Improves rotational stability and reduces graft failure risk in high-risk patients.
- Evidence. In the STABILITY randomised trial of young patients at high risk of failure, adding LET to a hamstring ACL reconstruction reduced graft rupture from 11% to 4% over 2 years.3 Number needed to treat to prevent one graft rupture: 14.
- Best for. Young patients (under 25), pivoting sports, generalised joint laxity, high-grade rotational instability on examination, or revision cases.
- Side effects. The knee can occasionally feel a little tight or stiff in the early weeks.
Patient archetypes — how this looks in practice
These are illustrative examples. They are not personal recommendations — every plan is individualised in consultation.
Archetype 1 — Young male pivoting athlete (rugby, league, football, basketball)
Profile. 16–22 years old, contact or pivoting sport, wants to return to high-level sport, high pivot shift and excessive hyperextension on examination.
Typical recommendation. Hamstring or patellar tendon, with addition of ALL augmentation. If other ligaments are repaired, then ALL augmentation is typically not required.
Archetype 2 — Young female pivoting athlete (netball, football, hockey)
Profile. 15–20 years old, pivoting sport, wants to return to competitive sport.
Typical recommendation. Patellar tendon graft with ALL augmentation. This is the strongest ACL graft combination in the literature, and is our go-to in the highest-risk patients. Kneeling discomfort is a relevant trade-off, particularly for tradeswomen and those whose sport or occupation involves kneeling.
Archetype 3 — Recreational adult skier, runner, or social-sport player
Profile. 35 years and above, returning to recreational pivoting (skiing, social netball, mid-week football), no plans for professional sport.
Typical recommendation. Hamstring single bundle. Lower-demand activity reduces the relative benefit of patellar tendon, while preserving the front of the knee for kneeling comfort.
Archetype 4 — Tradie, gardener, mechanic — kneeling matters
Profile. Any age. Occupation or daily life involves significant time on the knees.
Typical recommendation. Hamstring double bundle graft, avoiding patellar tendon where possible because of the ~20% rate of long-term kneeling discomfort with that graft. Decision is weighted toward functional comfort over the smallest possible failure rate.
Archetype 5 — Revision ACL (previous reconstruction has failed)
Profile. Any age. Previous ACL reconstruction has failed, often because of graft re-rupture, tunnel position issues, or biological failure to incorporate.
Typical recommendation. Quadriceps tendon (if kneeling matters) or patellar tendon, especially where hamstring tendon has been used previously. Revision ACL reconstruction is a major part of our practice. More on the revision ACL page.
What we generally don't use
Allograft (donor tissue). Allograft has a role in some practices internationally, particularly in older patients or complex revisions. We generally do not use allograft for primary ACL reconstruction in younger patients in New Zealand. The data — both from international literature and our local registry — shows higher failure rates in younger pivoting-sport patients compared to autograft.4 For the patient population we typically see, autograft remains the right call.
Synthetic grafts. Despite a long history and continued interest, current evidence does not support the routine use of synthetic ligament grafts for primary ACL reconstruction.
A note on timing
A related question often comes up: should I have surgery soon, or wait?
Recent New Zealand ACL Registry data shows that delaying surgery beyond 6 months increases the rate of medial meniscus tears and cartilage damage, with the highest rates seen when surgery is delayed more than 12 months.4 Each instability episode while waiting can cause further damage to the cartilage and meniscus inside the knee.
This is not a reason to rush an unprepared knee into surgery — prehabilitation is essential (see Stage 5 — Prehab). But it is a reason not to drift.
Frequently asked questions
Can I choose my own graft?
Yes — this is a shared decision. We’ll explain what we recommend and why, but the final choice belongs to you. We will not proceed with a graft you are uncomfortable with.
Which graft has the lowest failure rate?
It depends on who you are. In young women aged 15–20, patellar tendon has a substantially lower failure rate than hamstring based on NZ Registry data.1 In other groups, the differences are smaller and other factors carry more weight.
Does the graft come back to feeling like my own ACL?
The new ligament is not a perfect copy of the original. Most patients say their knee never feels quite the same as before. ACL repair (when appropriate) gives the most “natural” feel because it preserves your own ligament.
Will I be weaker after the graft is taken?
Each donor site recovers differently. Hamstring grafts cause mild hamstring weakness and occasional cramping that usually resolves within 6–12 months. Patellar tendon graft can cause kneeling discomfort in about 20% of patients. Quadriceps tendon graft has more demanding early rehabilitation but recovers well with good physiotherapy.
What if I'm a revision case?
Revision ACL reconstruction often uses a patellar tendon or quadriceps tendon graft, depending on what was used the first time, the position of existing tunnels, and any associated damage. See the revision ACL page for more detail.
How long until you know if my graft will hold?
The first 12 months are the highest-risk window. Most failures happen during this time, while the graft is still maturing. After 12 months, the risk drops substantially — but a structured Return-to-Sport assessment is mandatory before pivoting sport, regardless of how strong the knee feels.
References
The recommendations on this page are grounded in current published evidence, including:
- Tiplady A, Love H, Young SW, Frampton CM. Comparative Study of ACL Reconstruction With Hamstring Versus Patellar Tendon Graft in Young Women: A Cohort Study From the New Zealand ACL Registry. American Journal of Sports Medicine 2023;51(3):627–633. DOI: 10.1177/03635465221146299
- Migliorini F, Eschweiler J, Mansy YE, et al. Quadriceps tendon autograft for primary ACL reconstruction: a Bayesian network meta-analysis. European Journal of Orthopaedic Surgery and Traumatology 2020;30(7):1129–1138. DOI: 10.1007/s00590-020-02680-9
- Getgood AMJ, Bryant DM, Litchfield R, et al. Lateral Extra-articular Tenodesis Reduces Failure of Hamstring Tendon Autograft Anterior Cruciate Ligament Reconstruction: 2-Year Outcomes From the STABILITY Study Randomized Clinical Trial. American Journal of Sports Medicine 2020;48(2):285–297. DOI: 10.1177/0363546519896333
- Rahardja R, Love H, Clatworthy MG, Young SW. Delayed reconstruction is associated with higher rates of medial meniscus and chondral injury following ACL injury: A New Zealand ACL Registry Study. Knee Surgery, Sports Traumatology, Arthroscopy 2025. DOI: 10.1002/ksa.70002
- Sim K, Rahardja R, Zhu M, Young SW. Optimal Graft Choice in Athletic Patients with Anterior Cruciate Ligament Injuries: Review and Clinical Insights. Open Access Journal of Sports Medicine 2022;13:55–67. DOI: 10.2147/OAJSM.S340702
Bring your MRI to your consultation. Most patients are seen within 2 weeks.