Product Application
Acromio Clavicular Dislocation
The LARS range includes two sizes of acromio clavicular ligaments, their use depending on patient weight and sporting activities. The LARS ligament acts as a reinforcement to allow the coracoclavicular ligament to heal and grow into the synthetic fibres. They allow immediate mobilisation with no material through the joint. The fixation is via two bony tunnels and not an «over-the-top» approach, thus reducing clavicular erosions.
The use of loop techniques offers the possibility of an earlier return to work(4) especially in younger, active patients or ones with a high-grade dislocation.
Rotator Cuff
LARS rotator cuff patches are indicated for large defects, forming a strong bridge over the humeral head. The ligament is fixed proximally onto the remnants of the rotator cuff muscles, and distally into tunnels drilled in the top of the humerus in abduction with screws. When the arm is back in adduction the patch pulls the cuff over the top of the humeral head into normal anatomic placement. The ligament comes in two sizes for compatibility with patient weight and activity.
Anterior and Posterior Cruciate Ligaments
LARS ligaments can be used to reconstruct both the anterior and posterior cruciate ligaments and a special Y ligament is available to reconstruct the postero-lateral corner.
LARS ACL and PCL ligaments come in many different sizes so that selection according to weight and activity can be precise. The ACL and PCL synthetic ligaments have both been used extensively for many years with excellent clinical results.
Both ligaments have free fibres in the intra-articular part of the ligament, which allows for a smaller volume in the knee, fibroblastic ingrowth(9) and better resistance to fatigue in flexion and extension (data on file).
The LARS ACL has the intra-articular bundles in clockwise or anticlockwise orientation; this is to mimic the natural ligaments in the right or left knee(10). It can be used in acute injuries or where there is a good ACL stump that is well vascularised. In chronic cases, if the rupture is on the femoral part or the ACL has attached to the PCL, this can be dissected off the PCL and can then be reconstructed like an acute case. In chronic cases where there are no usable ACL remnants, an autogenous reconstruction reinforced by a LARS Actor 8 or 10 is recommended.
With the PCL, reconstruction is ideal in the acute phase. In chronic cases, the Actor 8 or 10 ligaments can also be used with autogenous tissue if required.
A Y shaped ligament is also available to reconstruct the postero lateral corner (PLC), lateral collateral or a double bundle PCL, or a single bundle PCL with PLC.
Actor 8 and 10 Ligaments
These are hollow tubes with an intra-articular free fibre portion. The autograft tissue is placed in the centre of the LARS, the free fibres are aligned in the knee, and fixated in the usual fashion.
The Actor 8 is used as an augmentation for the autogenous tissue and to protect it. The healing process for autogenous tissue may take up to 6-9 months and during that time the transplant undergoes many stages of healing. Excessive loading in the early post-operative rehabilitation period can elongate an autogenous graft. By reinforcing with LARS, the artificial ligament will take some of the stress and protect the fibres of the graft.
Actor 8 is indicated for use with hamstring grafts. Actor 10 is indicated for use with quadriceps grafts.
Medial and Lateral Collateral Ligaments
Reinforcement of the medial collateral ligament is indicated in multiple injuries and after reconstruction of the cruciate ligaments. The synthetic ligament comprises three parts: the cylindrical and knitted part for the femoral tunnel; the medial portion with free fibres that correspond to the MCL itself (these allow fibroblastic ingrowth from the MCL into the LARS Ligament)(9); the flat distal part is for fixation to the tibia.
The lateral collateral ligament is normally reconstructed with a Y ligament. One arm acts as the LCL, wrapping around and then through the fibular head to prevent the fibular head articulating against the tibia, and then through a trans-femoral tunnel. The other arm follows the path of the popliteus tendon and completes the postero-lateral instability repair.
Patellar Tendon
Patellar tendon reconstruction is often a problem after trauma or in revisions (TKR or others). In case of total rupture, the ideal reconstruction involves using two LARS ligaments.
PTR30's are used, one medially and one laterally, to balance the tension and patella tracking. The flat parts are sutured in front of the patella under the fibrous tissues, and the cylindrical parts are anchored with two screws into two tibial tunnels.
The PTR30 can also be used to medially derotate the patellar tendon in cases of femoro-patellar pain syndrome due to excessive tibial torsion, or to reinforce the medial patellar retinaculum in cases of recurrent patellar instability.
Achilles Tendon
These injuries mainly result from sporting activities and are ideally treated acutely.
Rupture of the Achilles tendon is not easy to treat. The length of immobilisation and time off work is costly and the return of ankle mobility and muscular strength is slow. Suturing of the retracted Achilles fibres is complicated and does not always give a satisfactory result.
The LARS Achilles tendon consists of three parts:
- The proximal portion is flat, corresponding to the proximal part of the ruptured tendon and is sutured
- The central portion has open longitudinal fibres which overlay the ruptured tendon, allowing for fibroblastic ingrowth
- The distal portion is cylindrical with a diameter of 5.5mm that corresponds to the distal part of the ruptured ligament and is fixed with an interference screw into the calcaneum
The LARS Achilles tendon can aid a quick return to sporting and normal activities, with active-passive mobilisation of the ankle commencing on day one, partial weight bearing started with caution immediately, returning to full weight bearing on day 35.
Reattachment of Abductor Mechanism in the Hip
A bare trochanter is a lesion similar in pathology to a rotator-cuff tear in the shoulder and is occasionally seen during an anterolateral approach to the hip. Small defects can be repaired by suturing the abductors onto the bare area, but larger defects require a different strategy. Similar defects can be found after posterior approaches to the hip particularly at the time of revision surgery. The broad shaped end of a 30 fibre LARS rotator-cuff ligament (1500 N) is sutured onto the remnants of the gluteus medius tendon in the case of a bare trochanter, or onto the short external rotators in the case of revision posterior approaches . The two limbs of the Y shaped ligament are attached onto the proximal femur through intra-osseous tunnels secured with interference screws. The ends of the ligament are tied onto each other to reinforce the reconstruction. Dynamically reconstructing damaged muscles following hip surgery can be achieved successfully with synthetic ligaments which have inherent strength whilst acting as a scaffold into which native tissue can grow.
Lateral Ankle Instability
These ligaments are mainly indicated for sporting injuries, or where the type of ligament injury does not allow for a solid repair and needs reinforcement, or there is long-term chronic instability.
This implant consists of a special Y-shaped ligament: one arm is passed into the distal fibular tunnel, and the other two are anchored into bony tunnels drilled at the lateral aspect of the calcaneum.
The patient may start passive and active mobilisation from day five. A back splint is applied at 90° to provide protection. A return to sporting activities can be expected at around day 75.
