LARS in the Knee Joint Anterior and Posterior Cruciate
Ligaments Operation
LARS ligaments can be
used to reconstruct both the anterior and posterior cruciate
ligaments. LARS also has a special Y ligament to reconstruct
the postero-lateral corner.
The 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 with very good results.
The ACL and PCL both have free fibres in the intra-articular
part of the ligament, which allows for a smaller volume
in the knee, fibroblastic ingrowth and a better resistance
to fatigue in flexion and extension.
The ACL has the intra-articular bundles in clockwise or
anti clockwise orientation; this is to mimic the natural
ligaments in the right or left knee.
The LARS ACL is 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 and 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.
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); and 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.
PTR30s 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 derotate medially the patellar
tendon in case of femoro-patellar pain syndrome due to
hyper external tibial torsion, or to reinforce the medial
patellar retinaculum in case of recurrent patellar instability.
