This briefing describes the regulated use of the technology for the indication specified, in the setting described, and with any other specific equipment referred to. It is the responsibility of healthcare professionals to check the regulatory status of any intended use of the technology in other indications and settings.
The Ligament Augmentation and Reconstruction System (LARS) is a synthetically‑produced ligament scaffold that is constructed from polyethylene terephthalate (PET) fibres. The LARS is manufactured by the LARS Company and distributed in the UK by the Corin Group.
Occasionally LARS is referred to as Ligament Advanced Reinforcement System, although this name is less common.
The LARS is available in different forms for use in soft‑tissue reconstruction applications for the knee, shoulder, foot and ankle, hip joint and in reconstructive surgery following treatment for soft‑tissue tumours. This briefing focuses on the LARS as a scaffold for treating damaged anterior cruciate ligaments (ACLs) and posterior cruciate ligaments (PCLs). Other applications for the LARS are beyond the scope of this briefing.
The LARS was first CE‑marked to the LARS Company as a Class IIb medical device in August 1997. The certificate was extended in August 2014, and is valid until August 2017. This certificate includes all ligament types, as well as auxiliary clips and screws. A coterminous certificate applies to instrument kits that include ligament pins, a drill bit, a drill bit guide, a cannulated drill bit and a K‑wire.
The LARS is formed from an intra‑ and an extra‑articular section. The intra‑articular section of the LARS is placed within the knee joint and is made of parallel longitudinal fibres that are twisted into a spiral. The fibres of the extra‑articular section are also arranged longitudinally, and are additionally knitted together by a transverse structure made of the same polyethylene terephthalate (PET) fibres (Mascarenhas and MacDonald 2008). This design aims to mimic the natural anatomy of cruciate ligaments and overcome fibre breakdown, which was a problem in the early generations of artificial ligaments. Fibre breakdown can result in accumulation of synthetic material in the knee, causing inflammation of the joint — known as synovitis. High rates of synovitis were associated with older‑generation artificial ligaments (Machotka et al. 2010). Depending on the severity of the synovitis, this can cause some people to need revision surgery (Batty et al. 2015).
The LARS is intended to act as scaffolding to the damaged ligament. Its main role is to allow tissue ingrowth and provide structural support to the repairing ligament, which can be an autograft, allograft or the native ligament, if sufficient tissue remains. It also protects the repairing ligament during healing (Newman et al. 2013). The LARS remains in the joint once the ligament has repaired.
LARS scaffolds are sold individually, and are available in different sizes based on the total number of fibres in the scaffold. Cruciate ligament procedures use LARS with between 80 and 160 fibres. The surgeon chooses the size of the ligament, depending on various factors including: joint size; quality of the bone for ligament attachment; type of lesion; and the volume and vascularisation status of remaining tissue (Dericks 1995).
In most cruciate ligament procedures, 2 screws fix the LARS in place and sometimes staples may also be needed. Pins may be used to create bone tunnels for effective fixation of the LARS. All of the components needed to fix the LARS must be bought separately from Corin Group, or in exceptional circumstances from other manufacturers.
Reusable instrument kits are also available from Corin Group. These kits are procedure‑specific and so separate ACL and PCL kits are available. Each kit contains the equipment needed for a LARS procedure, including the appropriate drills and drill guides. For hospitals performing infrequent LARS procedures the instrument kits can be loaned from Corin Group. In these cases Corin Group send an implant kit that contains a range of components used to fix the LARS in place.
The LARS can be used for orthopaedic procedures involving the reconstruction of missing or damaged ligaments. Uses beyond the reconstruction of knee ligaments are outside of the scope of this briefing.
The LARS should only be used in cruciate ligament procedures after non‑synthetic alternatives (autograft and allografts) have been considered as possible treatment options by the clinician and the patient. The success of the LARS procedure in ACL and PCL reconstruction depends on various factors. These include the experience of the surgeon, especially their ability to correctly place the bone tunnels and fix LARS in place, and the quality of the post‑operative rehabilitation.
The LARS is intended for use in secondary or tertiary care for non‑emergency patients. Depending on the nature of the reconstruction, the procedure may be carried out in a day‑case, inpatient or outpatient setting. The procedure should be done by surgeons who have experience of cruciate ligament reconstruction and who have had relevant training in the LARS procedure.
There are currently 2 treatment options for cruciate ligament injuries available on the NHS. The first line of therapy is conservative treatment, which focuses on physiotherapy to restore motion in the knee joint and strength in the muscle. However, conservative treatment does not always restore complete function of the injured knee, and this can result in persistent joint pain. The second‑line option is surgical reconstruction. This option is particularly common for people with active lifestyles (NOC 2015).
Surgical reconstruction is usually done arthroscopically and uses a graft to reconstruct the ruptured ligament. Autograft procedures are most commonly used for ligament reconstruction, with allografts also an option in certain circumstances, such as when there are concerns regarding morbidity associated with autograft harvest (Robertson et al. 2006). Treatment decisions are made through discussions between the surgeon and the patient. Following surgical reconstruction, patients have a structured rehabilitation programme that includes physiotherapy appointments and recovery exercises (NHS Choices 2015).
Surgeons and patients involved in ACL reconstruction procedures can also register their reconstruction surgeries on the UK National Ligament Registry (NLR). The NLR aims to improve the management of, and outcomes from, ACL surgery.
NICE is aware of the following CE marked devices that appear to fulfil a similar function to LARS:
The cost, excluding VAT, of the LARS and associated consumables are:
the LARS scaffold: £1391
the LARS screw (4.7×15 mm, 5.2×15 mm, 5.2×20 mm or 5.2×30 mm): each £153
staple (8×20 mm): £171
pin (2x250 mm): £30
ligament screw (6×30 mm, 7×25 mm, 7×30 mm, 8×25 mm, 8×30 mm, 9×25 mm, 9×30 mm): each £171.
All consumables are single‑use and can be purchased individually in sterile packaging from the distributor, Corin Group.
The distributor sells reusable instrument kits to hospitals that frequently do LARS procedures. Alternatively, the distributor will loan the instrument kits on a short‑term basis to hospitals where procedures are carried out infrequently. When the instrument kits are loaned, an implant kit, containing a range of fixings, is provided. The surgeon is charged for the fixings used (according to the prices listed above), and the remaining fixings in the kit are returned to Corin Group:
purchase cost of instrument kit for ACL procedure: £3600
purchase cost of instrument kit for PCL procedure: £5500
loan cost of instrument kit (ACL or PCL procedures): £450.
The surgical procedure for ligament reconstruction using the LARS is different from autograft or allograft reconstruction without the LARS. Therefore, surgeons must complete training for this procedure. Training can be in the form of a 1‑hour online session run by experienced surgeons or a workshop at the surgeon's own hospital. Surgeons with no experience of doing LARS procedures may also observe an experienced surgeon. All training is organised by Corin Group, the distributor, and provided free‑of‑charge.
The costs of autograft and allograft procedures were not available from the NHS Reference Costs database.
Following cruciate ligament surgery, patients have a structured rehabilitation programme that is coordinated by the surgeon and/or a physiotherapist. This programme includes exercises to strengthen the joint and surrounding muscles. A full recovery can be expected within 6 months of the procedure (NHS Choices, 2015). The use of the LARS is unlikely to impact on the pre‑operative care pathway, and it is unclear whether it will impact on the post‑surgical care pathway.
All 3 specialist commentators felt that the main role of the LARS could be to provide an alternative treatment, where there are barriers to using autografts. The possible roles include allograft revision surgery procedures, multi‑ligament reconstructions, or where there is not enough material for an autograft procedure. One commentator noted that there is an unmet need for surgical procedures when there is no native ligament tissue available, such as in revision surgery.
One specialist commentator observed there was no long‑term evidence, such as 10‑year follow‑up data, to support the use of the LARS in cruciate ligament indications. This commentator noted that, in their experience, none of the synthetic ligament scaffolds worked in the long term. They added that there was no evidence that any PET synthetic ligament scaffold has been associated with intra‑articular ingrowth in the knee. Another commentator noted that the LARS has not demonstrated superiority over the well‑established autograft surgery for ligament reconstruction.
All 3 specialist commentators remarked that there is no evidence to support the claims that the LARS can lead to faster rehabilitation or allow people to return to sport sooner. One of the commentators reflected that a more important factor for the post‑surgical recovery time is the use of appropriate surgical technique. A second commentator agreed that the success of the surgery was more likely to relate to the surgical procedure, noting that the positioning of bone tunnels, tensioning of the ligament scaffold and adequacy of its fixation were important factors.
One commentator stated that there is a general opinion that using synthetic ligament augmentation devices, such as the LARS and other synthetic scaffolds, shields the repairing native ligament or autograft ligament from physical stress. This stress on the ligament is thought to be needed to allow the ligament to re‑grow normally and for the collagen to be correctly orientated. As a consequence, the use of synthetic scaffolds could cause the ligament to have sub‑optimal mechanical characteristics. They felt that the LARS might be more useful in the reconstruction of lateral collateral ligaments, medial collateral ligaments and medial patellofemoral ligaments.
NICE is committed to promoting equality and eliminating unlawful discrimination. We aim to comply fully with all legal obligations to:
promote race and disability equality and equality of opportunity between men and women
eliminate unlawful discrimination on grounds of race, disability, age, sex, gender reassignment, pregnancy and maternity (including women post‑delivery), sexual orientation, and religion or belief, in the way we produce our guidance (these are protected characteristics under the Equality Act 2010).
Most intra‑articular ligament reconstruction procedures in England are performed on men, with a mean age of 30 years, indicating that younger men in particular could benefit from the LARS scaffold. Sex and age are protected characteristics under the 2010 Equality Act.