This eagerly awaited post will discuss the evidence behind the LARS surgical procedure for ACL reconstruction (http://physiosolutions.blogspot.com/2011/01/lars-for-acl-reconstruction.html). This is a follow up to our original current trends in ACL reconstruction management which first started on March 19 2009 (http://physiosolutions.blogspot.com/2009/03/current-trends-in-anterior-cruciate.html).
In all the papers reviewed, knee laxity was objectively measured from injured to non-injured side using the KT-1000. Most of the papers reported that laxity was within normal range but did not give the exact measurements so it is difficult to compare.
In one of the papers, a significant difference was found in knee stability between the 4-strand hamstring graft group (4SHS) showing 2.4mm difference from side-to-side compared with 1.2mm difference in the
LARS group (Liu et al. 2009). However, laxity scores were found to be significantly greater in the LARS group at 6 months compared with the bone-patella tendon bone (BPTB) group and remained greater throughout the follow-up but although it was not statistically significant (Nau et al. 2002).
At 24 months the BPTB group had 2.38mm laxity and the
LARS group 4.86mm (Nau et al. 2002). There was a fair range of measurements shown in each study, although measurements were taken over differing time periods which may account for this.
It is interesting to note that the BPTB group had greater stability compared to the
LARS group, where the 4SHS did not.
Well, the results of studies have shown that
LARS is comparable to the use of autologous surgery (of BPTB & 4SHS) in short-term studies. With similar findings in knee laxity post-surgery and return to functional activities. There also appears to be a low risk of complications including synovitis which was the main concern for the previous use of artificial ligaments. Patient satisfaction appears to be higher which may be due to the possibility of a quicker rehabilitation time period.
The implications for patients (and that means you) include the need for a faster rehabilitation program and the need to adapt exercises for a shorter recovery period. There appears to be a lack of current protocol for therapy following the
LARS surgery as evidenced by the differing time periods to weight-bear and return to previous levels of activity.
The evidence found is positive for the future that the
LARS may be used for elite athletes or manual labourers who need to return to previous injury levels quickly. However, further comparative research is required to draw a more accurate conclusion. Longer term studies are also required to look at any further potential complications.
Looking at all the evidence, the biggest "positive" is not harvesting a patient's patella or hamstring and thereby causing pain/ weakness potentially in that area. If the LARS ruptures again though, it would end up much more complicated and it will have to be redone in 2 different procedures.
Gao K, Chen S et al (2010)Anterior Cruciate Ligament Reconstruction with LARS Artificial Ligament: A Multicenter Study With 3 – 5 Year Follow-up. Arthroscopy: The Journal of Arthroscopic and Related Surgery, vol. 26(4), pp. 515-523.
Legani C et al (2010). Anterior cruciate ligament reconstruction with synthetics grafts. A Review of Literature.’International Orthopaedics (SICOT), vol. 34, pp. 465-471.
Liu Z, Zhang X, Jiang Y et al (2009). Four-strand hamstring tendon autograft versus LARS artificial ligament for anterior cruciate ligament reconstruction. International Orthopaedics (SICOT), pp. 1-5.
Nau T, Duval, N et al (2002). A new generation of artificial ligaments in reconstruction of the anterior cruciate ligament: Two-year follow-up of a randomised controlled trial. JBJS vol. 84, pp. 356-360.
*Picture from Herald Sun.