2015 ISAKOS Biennial Congress ePoster #1249
Suture Anchor Versus Drill Tunnel Primary ACL Repair: An In Vitro Comparison of Gap Formation
Gregory S. Difelice, MD, New York, NY UNITED STATES
Jeffrey DeLong, BS, MD, Charleston, SC UNITED STATES
Christine Villegas, MBS, New York, NY UNITED STATES
Hospital for Special Surgery, New York, New York , USA
FDA Status Cleared
Summary: Biomechanical comparison of two different techniques of primary repair for proximal ACL tears after simulated active range of motion.
Primary anterior cruciate ligament (ACL) suture repair techniques fell out of favor several decades ago due to inconsistent results. However, traditional primary ligament repair approaches lacked inclusion criteria and attempted to repair all types of ACL tears regardless of tear pattern or tissue quality. Techniques were long, morbid, open procedures that utilized multiple suture constructs tied over proximal and/or distal bone bridges depending on tear pattern. Long post-operative immobilization in cylinder casts was the rehabilitation standard. Virtually all published outcomes of primary ACL repair are the reporting of these open techniques performed several decades ago. While the results interpreted in aggregate were discouraging, and lead to the abandonment of the procedure, cohort analysis suggests that focusing repair efforts on proximal avulsions with excellent tissue quality may have yielded more acceptable results. Revisiting and improving primary ACL repair by applying decades of amassed knowledge and improved diagnostic, surgical and rehabilitative technology may provide insight into the actual potential of primary repair in the restoration of knee stability and function. The purpose of the study was to evaluate in vitro gap formation of primary ACL repair on proximal avulsion type tears after simulated active motion via comparison between knotless suture anchor fixation and a more traditional bone-tunnel bone-bridge with suture-button fixation.
Primary ACL repair with knotless suture anchors versus primary ACL repair with bone-bridge and suture-button were compared utilizing matched-pairs. Six match-paired, fresh-frozen cadaveric knees with no evidence of previous injury or disease with an average age of 52.3 ± 3.3 years (range, 48-56 years) were utilized for the study. To test the null hypothesis, a one-way analysis of variance (ANOVA), was utilized to compare the gap formation between the two methods after simulated active range of motion by cycling the knee from 90° flexion to full extension by mechanically activating the quadriceps tendon. Gap formation was measured by high resolution digital photography comparing the gap at 0, 5, 50 and 100 cycles. A 14.1 megapixel digital camera was used. Pairwise multiple comparisons were performed using the Holm-Sidek method. A significant difference was determined to be present for P < 0.05 (a = 0.05).
There was no significant difference in gap formation between samples comparing primary ACL repair with knotless suture anchors versus primary ACL repair with bone-bridge and suture-button at 5, 50 or 100 cycles (p = 0.110, p = 0.835, p = 0.625, respectively). The average gap formation for the primary ACL repair with knotless suture anchors at 5, 50, and 100 cycles was 0.40 ± 0.22 mm, 0.72 ± 0.37 mm, and 1.11 ± 0.73 mm, respectively. The average gap formation for the primary ACL repair with bone-bridge and suture-button at 5, 50, and 100 cycles was 0.20 ± 0.21 mm, 0.81 ± 0.72 mm, and 0.83 ± 0.70 mm, respectively.
Gap formation with both fixation methods for primary ACL repair after 100 cycles of simulated active motion was approximately 1mm and is likely to be clinically insignificant in vivo. There was no significant difference in gap formation noted between groups. Equivalent gap formation existed among primary ACL repair utilizing knotless suture anchors versus primary ACL repair utilizing a bone-bridge and suture-button.