Content uploaded by Peter Annear
All content in this area was uploaded by Peter Annear on Oct 16, 2018
Content may be subject to copyright.
TITLE: Anterior cruciate ligament reconstruction with single bundle hamstrings versus
hamstrings augmented with synthetic LARS: An early comparison of patient outcomes.
Background: A high rate of re-tear exists after primary anterior cruciate ligament
reconstruction (ACLR), and lower limb strength and functional symmetry is considered
imperative in minimizing the risk of re-tear. Of course, the primary goal of ACLR patient is
to return to sport (RTS) as soon as possible, so addressing these strength and functional
deficits before that time is important.
Purpose: The purpose of this study was to compare the early strength and functional
outcomes between patients undergoing ACLR combined with a standard hamstrings autograft
(HAMS), versus a hamstrings autograft augmented with synthetic LARS (H-AUG).
Methods: A total of 160 patients were included in this analysis of two prospectively recruited
patient groups. The HAMS group (n=97) had a mean age of 26.6y (range 15-57) and body
mass index of 25.1 (range 17.8-34.5), and 64 patients (65.9%) were male. The H-AUG group
had a mean age of 27.5y (range 14-55) and body mass index of 25.0 (range 18.1-35.6), and
38 patients (60.3%) were male. Patients were clinically evaluated at 1 and 2 years post-
surgery, via patient-reported outcome measures (PROMs), knee range of motion, maximal
isokinetic knee extensor and flexor strength assessment, and a 4-hop test battery. Knee laxity
(KT-1000 measurements of anterior drawer in mm) was only undertaken in the H-AUG
cohort. Limb Symmetry Indices (LSIs) were calculated to ascertain the strength/function of
the operated limb as a percentage of the non-operated limb, and LSIs above 90% for the
aforementioned measures are considered satisfactory.
Results: No differences existed between groups (p>0.05) in descriptive variables. Over the 2
year collection period, 2 patients (2.1%) in the HAMS group suffered a re-tear, compared
with 1 patient (1.6%) in the H-AUG group. Of the entire cohort at 12 months, 37 patients
(34.1%) in the HAMS group were ≥90% LSI in quadriceps strength, with 59 (60.8%) ≥90%
LSI in the single hop for distance. For the H-AUG group, 39 patients (61.9%) were ≥90%
LSI in quadriceps strength, with 47 (74.6%) ≥90% LSI in the single hop for distance. In total,
34 patients (35.1%) in the HAMS group and 61 patients (62.9%) in the H-AUG group had
returned to Noyes Level 1 (participation 4-7 days/week) or Level 2 (participation 1-3 days
per week) activities that included jumping, hard pivoting, cutting, running, twisting and/or
turning sports. Despite the improved outcomes and higher percentage of patients that had
already RTS, a side-to-side difference in anterior laxity of ≥3mm was observed in only 3 H-
AUG patients (4.7%) at 1 year post-surgery.
Conclusions: In a comparable group of patients, the H-AUG technique promoted an earlier
(and safe) return to sporting activities. The theoretical benefit in early graft protection and
acceleration in rehabilitation appears to provide improved strength and functional benefit
critical for reducing re-injury rates upon RTS.
Keywords: anterior cruciate ligament reconstruction, hybrid technique, augmented repair,
clinical outcomes, knee function, re-injury.