Quick answer: Modern synthetic ACL ligaments (mainly the LARS device) do well in the first one to two years. Patients often recover faster and feel better early. But the long-term evidence (10 years and more) is limited, comes from small studies, and is inconsistent. Several long-term studies report high failure and reoperation rates. Your own tendon (an autograft) is still the gold standard for most patients. A synthetic graft is best kept for a few carefully selected cases.

Why are patients asking about synthetic ACL grafts?

If you have torn your anterior cruciate ligament (ACL), you have probably come across the idea of an "artificial ligament" or a "synthetic ACL". It sounds attractive:

No graft harvest. Nothing is taken from your hamstring, patellar tendon or quadriceps tendon, so there is no donor-site pain or weakness.
Strong from day one. A biological graft weakens for months as it remodels. A synthetic one does not go through that phase.
Faster return to work and sport. This is the main selling point.

The question every patient (and surgeon) should ask is simple: does it last? In this article we look at what the published research actually shows, in the short term and the long term, compared with the autograft.

What is a synthetic ACL graft?

A synthetic ACL graft is a man-made ligament, threaded through bone tunnels in the femur and tibia in the same position as a normal ACL reconstruction. The device most widely used today is the LARS (Ligament Advanced Reinforcement / Augmentation and Reconstruction System). It is made of polyethylene terephthalate (PET), a strong polyester fibre. LARS is a "third-generation" synthetic ligament, designed to avoid the problems that sank earlier designs.

One key difference from an autograft: a synthetic ligament does not become living tissue. A tendon graft slowly turns into ligament-like tissue ("ligamentisation") and is biologically part of your knee. A polyester ligament stays a polyester ligament. It can wear, fray and fatigue over the years, and its fibres can irritate the joint lining.

A history lesson: why surgeons are cautious

Synthetic ACL ligaments are not new. In the 1980s and early 1990s, several devices were widely used: Gore-Tex, Dacron, the Kennedy Ligament Augmentation Device (LAD), Leeds-Keio and Trevira. Gore-Tex was even approved by the US FDA for ACL reconstruction in 1986. Early results looked good, but over time many grafts ruptured and many knees developed reactive synovitis (inflammation of the joint lining caused by wear particles). By the 1990s most of these devices had been abandoned.

The largest systematic review of synthetic cruciate ligament devices (Batty et al., Arthroscopy 2015) gathered 85 studies published between 1985 and 2013:

Device	ACL failure rate (pooled)
Dacron	33.6%
Leeds-Keio (first generation)	16.8%
Kennedy LAD	13.9%
Gore-Tex	12.9%
Trevira	9.8%
LARS	2.6%

Sterile effusion and synovitis ranged from about 0.2% with LARS to over 26% with Gore-Tex.

On paper, LARS looks far better than its predecessors. The authors were careful to call these preliminary results, though. Most of the LARS data were short-term case series, and the studies were too different from one another to be pooled in a formal meta-analysis.

The Leeds-Keio story is a warning about long-term results. At an average of 13.3 years after Leeds-Keio reconstruction, every operated knee showed X-ray signs of degeneration, compared with 39% of the patients' other, uninjured knees (Murray & Macnicol, The Knee 2004).

Short-term results (up to about 2–4 years): synthetic grafts look good

This is where synthetic grafts do best.

Randomised trial – LARS vs patellar tendon (Nau et al., JBJS Br 2002). 53 patients were randomised to LARS or bone–patellar tendon–bone (BPTB) autograft. In the first year, the LARS group scored better on the KOOS questionnaire across all subscales. By 24 months, those differences had disappeared. Laxity was slightly greater in the LARS group throughout, though this was not statistically significant at two years. There was no synovitis and no difference in failure at two years.

LARS vs hamstring autograft (Liu et al., International Orthopaedics 2010). In 60 patients followed for at least four years, LARS knees were slightly more stable on KT-1000 testing (1.2 mm vs 2.4 mm side-to-side difference). Functional scores were similar.

LARS augmentation of hamstring grafts (Indian Journal of Orthopaedics, 2023). This prospective randomised study of 141 patients compared hamstring alone, hamstring augmented with LARS, and hamstring with LARS mesh. Augmented grafts gave better scores at 6 months and a faster return to sport. At 18 months, 3 years and up to 8 years, there were no significant differences between the groups.

Meta-analysis (Jia et al., BMC Musculoskeletal Disorders 2017). Seven studies and 403 patients were pooled. New-generation synthetic ligaments gave results similar to autografts at short- to mid-term follow-up. Early-generation devices did worse and are not recommended.

The short-term takeaway: A synthetic graft can get you moving faster and feeling better in the first months. By one to two years, autograft patients have usually caught up.

Medium-term results: the picture becomes mixed

When the evidence is limited to the strongest study designs, autografts start to pull ahead.

Meta-analysis of randomised trials only (Fan et al., J Orthop Surg Res 2021). Seven RCTs and 504 patients were included. Patellar tendon autograft did better than synthetic grafts on pivot shift, Lachman test, IKDC grade and complication rate. Measured laxity was similar. The authors stressed that their findings do not cover older patients, because none were included. Several of the trials used older-generation devices.
Meta-analysis of autografts vs synthetics (Sun et al., Orthopaedic Surgery 2020). Nine comparative studies of LARS were pooled. The groups differed on instrumented laxity, IKDC, complications and Tegner activity scores, while Lysholm scores and failure risk were similar.
Leeds-Keio vs patellar tendon RCT, 5 years (Ghalayini et al., The Knee 2010). Patellar tendon grafts did better on activity, laxity and hop testing at 2 years. By 5 years, the differences were no longer significant.

Long-term results (8 to 16+ years): this is where the concern lies

You would expect the strongest evidence here, but long-term data on LARS are few, small, mostly retrospective, and contradictory. No large randomised trial has followed LARS against autograft for 10 years or more.

Study	Patients / follow-up	Key finding
Jia et al., Medicine 2017	91 patients, mean ~7.6 years	Failure 4.4%; good outcomes
Bugelli et al. / Parchi group, EJOST 2019	LARS (mostly >40 yrs) vs hamstring, ~8 years	Similar Lysholm and IKDC scores
Parchi et al., Joints 2018	26 patients (mean age 38.5), 11.6 years	15.4% mechanical failure, 3 of 4 after 10 years; no synovitis
Tiefenboeck et al., The Knee 2015	18 patients, ≥10 years	Mediocre scores; authors advise against LARS for primary ACL reconstruction
Tulloch et al., KSSTA 2019	55 patients, median 7.8 years	33% graft rupture (median 3.9 years after surgery); 39% needed further surgery; authors advise against LARS for primary ACL reconstruction
Bone & Joint Journal 2022	41 patients (mean age ~40), median 16.5 years	66% cumulative complications, 24% graft failure, 20% reactive synovitis, 51% reoperation, Lachman positive in 56%
Moretti et al., J Clin Med 2025	53 patients >35 yrs, mid-term	Failure 3.8%; good recovery in middle-aged patients

A few patterns stand out:

Failure rates vary widely, from about 4% to 33%. This depends heavily on the surgeon, patient selection, age and activity level.
Failures continue over time. Synthetic grafts can fail late, sometimes more than 10 years after surgery, because the material fatigues and wears.
Subjective scores can stay good even when the knee is not perfect. In the 16-year study, patients reported good quality of life even though more than half had a positive Lachman test and half had needed further surgery.
Synovitis has not gone away. It is far less common than with Gore-Tex, but second-look arthroscopy studies still find foreign-body reactive synovitis in some LARS knees (Mow/Tulloch et al., KSSTA 2019).
Arthritis. The Leeds-Keio experience (all knees degenerated at 13 years) raises a concern about long-term joint health with synthetics. There are no good long-term arthritis data for LARS specifically. Note that arthritis is also common after any ACL injury and reconstruction, so this needs careful comparison.

Synthetic vs autograft at a glance

	Autograft (hamstring / patellar / quadriceps)	Synthetic (LARS)
Donor-site pain or weakness	Yes, varies by graft	None
Early recovery (0–6 months)	Slower, protected rehab	Faster, often better early scores
Results at 1–2 years	Excellent	Similar to autograft in most studies
Strongest evidence (RCT meta-analysis)	Better stability, IKDC and fewer complications	Inferior to patellar tendon graft in adults
Long-term evidence (10+ years)	Extensive; decades of data	Sparse, small studies; failure 4–33%, reoperation up to 51%
Biological healing	Becomes living, ligament-like tissue	Remains a foreign material; can wear and fatigue
Reactive synovitis	Not an issue	Uncommon but reported
Regulatory status	Standard worldwide	Not licensed for ACL use in the USA; used in Europe, Asia and Australia

So who might benefit from a synthetic ACL graft?

When the evidence is read together, a synthetic ligament is not a routine first choice for a young athlete in pivoting sport. Even studies that favour LARS mostly recommend it for selected groups:

Older patients (typically 35–40+) with a low-to-moderate demand lifestyle who want a quicker return to function.
Patients where a good autograft is not available, for example in multi-ligament knee injuries or some revision situations.
Augmentation of a thin or short hamstring graft. Here the synthetic acts as an "internal splint" while the biological graft heals, rather than replacing it.
Patients with a specific, time-critical need to return who understand and accept the trade-off on long-term durability.

For young, highly active patients, especially in football, kabaddi, basketball, badminton and other cutting and pivoting sports, autograft remains the evidence-based choice.

Questions to ask your surgeon before choosing a synthetic graft

What is your personal failure and revision rate with synthetic ACL grafts, and over how many years?
Why is a synthetic graft better for my knee than an autograft?
If the synthetic graft fails, what does revision surgery involve? (Removing the device and dealing with the bone tunnels can complicate revision.)
Will the faster early recovery change my long-term result, or only how quickly I get there?
How will you monitor for synovitis or late failure?

What's new in 2025–2026?

Newer "bioactive" or grafted synthetic ligaments are being tested. Early comparisons with standard LARS (presented at ISAKOS 2025) show no clear short-term difference, and long-term data do not exist yet.
In July 2026, the US FDA cleared the LARS device for the first time, but only for the shoulder (acromioclavicular joint), not for the ACL. ACL use in the United States still awaits regulatory approval.
The latest reviews (e.g. Acta Medica Lituanica, 2025) continue to conclude that patellar tendon and quadriceps tendon autografts remain the most reliable options. Synthetic grafts may suit selected patients but carry a higher risk of failure and complications.

The bottom line

Short term: Synthetic ACL grafts (LARS) offer a faster, less painful early recovery and comparable results at 1–2 years.
Long term: Evidence is limited and worrying in parts. Some long-term studies show failure rates of a third and reoperation in half of patients, while others report good survival in carefully chosen older patients.
Overall: Autografts remain the gold standard. A synthetic graft is a niche option for selected patients. It should be chosen with honest counselling about long-term durability, not because of the promise of a quick return to sport.

Every knee is different. If you are weighing graft options after an ACL tear, discuss your age, sport, goals and timeline with a sports orthopaedic surgeon who can explain the trade-offs for your knee.

Frequently Asked Questions (FAQ)

Is a synthetic ACL graft better than my own tendon? Not for most patients. Synthetic grafts give a quicker early recovery. High-quality evidence shows autografts, especially the patellar tendon graft, give better long-term stability and fewer complications.

How long does a synthetic ACL ligament last? Nobody can say for certain. Some patients have intact grafts beyond 10 years. In other studies a third of grafts ruptured within about 8 years, and failures can occur more than 10 years after surgery.

Can I return to sport faster with a synthetic ACL? Usually yes, in the first few months. By 1–2 years, autograft patients typically catch up, and the long-term durability of the synthetic graft is less certain.

What is LARS ligament surgery? LARS is a polyester (PET) artificial ligament used to reconstruct the ACL without harvesting a tendon from your own body.

Is a synthetic ACL a good option if I am over 40? It can be considered. Most supportive studies involve patients over 35–40 with moderate activity demands. It is still an individual decision to make with your surgeon.

Does a synthetic ACL cause arthritis? There is no robust long-term arthritis data for LARS. Older synthetic devices (Leeds-Keio) were linked to degenerative change in every knee at 13 years. Arthritis is also common after any ACL injury.

Disclaimer: This article is for patient education and does not replace a personal consultation. Treatment decisions should be made with your orthopedic surgeon.

References

Batty LM, et al. Synthetic devices for reconstructive surgery of the cruciate ligaments: a systematic review. Arthroscopy. 2015;31(5):957–968. doi:10.1016/j.arthro.2014.11.032
Nau T, Lavoie P, Duval N. A new generation of artificial ligaments in reconstruction of the ACL: two-year follow-up of a randomised trial. J Bone Joint Surg Br. 2002;84(3):356–360.
Liu ZT, et al. Four-strand hamstring tendon autograft versus LARS artificial ligament for ACL reconstruction. Int Orthop. 2010;34:45–49.
Jia ZY, et al. Comparison of artificial graft versus autograft in ACL reconstruction: a meta-analysis. BMC Musculoskelet Disord. 2017;18:309.
Sun J, et al. Autografts vs synthetics for cruciate ligament reconstruction: a systematic review and meta-analysis. Orthop Surg. 2020;12(2):378–387.
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Ghalayini SRA, et al. Patellar tendon graft versus Leeds-Keio synthetic graft: five-year follow-up of a prospective RCT. Knee. 2010;17(5):334–339.
Murray AW, Macnicol MF. 10–16 year results of Leeds-Keio ACL reconstruction. Knee. 2004;11(1):9–14.
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Parchi PD, et al. ACL reconstruction with LARS artificial ligament: clinical results after a long-term follow-up. Joints. 2018;6(2):75–79.
Jia Z, et al. Clinical outcomes of ACL reconstruction using LARS artificial graft with an at least 7-year follow-up. Medicine. 2017;96(14):e6568.
Tulloch SJ, et al. Primary ACL reconstruction using the LARS device is associated with a high failure rate at minimum of 6-year follow-up. Knee Surg Sports Traumatol Arthrosc. 2019;27(11):3626–3632.
Long-term outcomes of surgery using the Ligament Advanced Reinforcement System as treatment for ACL rupture. Bone Joint J. 2022;104-B(2). doi:10.1302/0301-620X.104B2.BJJ-2021-0798.R2
Mow C, Norsworthy CJ, Tulloch SJ, Devitt BM. Synovitis following ACL reconstruction using the LARS device. Knee Surg Sports Traumatol Arthrosc. 2019;27(8).
Bugelli G, et al. LARS versus hamstring tendon autograft in ACL reconstruction: 8-year follow-up. Eur J Orthop Surg Traumatol. 2019;29:447–453.
ACL reconstruction using autologous hamstrings augmented with LARS or LARS meshwork vs hamstrings alone: prospective randomised study with 2- to 8-year follow-up. Indian J Orthop. 2023. doi:10.1007/s43465-023-00956-w
Moretti L, et al. ACL reconstruction with LARS synthetic ligament: outcomes and failures. J Clin Med. 2025;14(1):32.
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NICE Medtech Innovation Briefing MIB30: LARS for cruciate ligament reconstruction.

Synthetic ACL Graft vs Autograft: What the Long-Term Evidence Really Shows