Strength of Arthroscopic Meniscal Root Repair Constructs

Abstract

Clinical study has illustrated the prevalence of meniscal root injury and potential for degenerative sequel without repair. Repair constructs have been presented by authors, and repair strengths determined. However, prior studies have evaluated constructs placed ex vivo without method to place the strongest construct in an arthroscopic fashion nor strength evaluation of constructs placed arthroscopically. We present two new meniscal root repair constructs with arthroscopic technique and strength evaluation of arthroscopically placed repair constructs. Pullout strength, stiffness, and time of suture construct for the different meniscal repair patterns was evaluated. This will aid the clinician in determining the best method for arthroscopic meniscal root repair and aid in the development of appropriate postoperative rehabilitation plans. The hypothesis of this study is that maximum failure load, stiffness, and repair execution time will vary based upon suture construct, with higher strengths and execution times with increased repair technique complexity. Twenty cadaveric knees were mounted in a simulated surgical position, and sutures were placed arthroscopically at the root of the medial and lateral menisci. Four repair constructs were tested including 2 novel repair constructs: 2 simple stitches, 1 inverted mattress stitch, 1 double locking loop stitch, and 2 double locking loop stitches. Arthroscopic placement of suture repair construct was timed. In total 40 posterior meniscal roots, both lateral and medial from 21 cadaveric specimens were tested, with 10 trials for each construct. Specimens were dissected, and the medial and lateral menisci harvested. Individual meniscus specimens were cycled and then tested to failure on an Instron machine with a custom baseplate mimicking the transosseous suture tunnel utilized in meniscal root repair. The Kruskal-Wallis Test was used to evaluate for statistical significance between groups. The mean maximum failure loads were: 2 simple stitches (2SS) 137±49 N, 1 inverted mattress stitch (1MS) 126±44 N, 1 double loop locking stitch (1DLS) 201±44 N, 2 double loop locking stitches (2DLS) 396±69 N. Inter-construct comparison revealed statistical difference between 2DLS (p < 0.01) and all three remaining constructs (< 0.01), and 1DLS when compared to 2SS and 1MS (p <0.01, <0.01). Statistical significance was not found between 2SS and 1MS (p=0.8). The average time for repair of the 4 fixation techniques were: 2SS 1.78 ± 0.87 minutes, 1MS 2.40 ± 1.90 minutes, 1DLS 4.67 ± 2.01minutes, 2DLS 5.38 ± 0.62 minutes. Constructs with four suture limbs within the simulated repair tunnel illustrated stiffer constructs. Arthroscopically placed locking loop repair constructs are stronger than current arthroscopic techniques with increase in time of repair. As complexity of the repair construct increases so does time for fixation and pullout strength. With this study, an arthroscopic technique is presented to produce stronger meniscal root repair constructs with little increase in surgical time.