2015 ISAKOS Biennial Congress ePoster #1610

Cyclic Displacement after Meniscal Root Repair Fixation: A Human Biomechanical Evaluation

Robert F. LaPrade, MD, PhD, Edina, MN UNITED STATES
Christopher M. LaPrade, MD, Redwood City, CA UNITED STATES
Michael B. Ellman, MD, Chicago, IL UNITED STATES
Travis Lee Turnbull, PhD, Vail, CO UNITED STATES
Anthony J. Cerminara, MD, Vail, CO UNITED STATES
Coen Abel Wijdicks, PhD, Naples, Florida UNITED STATES
Steadman Philippon Research Institute, Vail, Colorado, USA

FDA Status Not Applicable

Summary: Optimization of surgical technique at the meniscus-suture interface may minimize displacement and improve the strength of meniscal root repairs; in this human meniscal tissue study, the two simple sutures technique proved its robustness as the current clinical standard by displacing the least after 1000 cycles of simulated post-operative rehabilitation loading.

Abstract:

Background

Recent biomechanical evidence suggests that the meniscus-suture interface contributes the most displacement to the transtibial pull-out repair for meniscal root tears. Therefore, optimization of surgical technique at the meniscus-suture interface may minimize displacement and improve the strength of meniscal root repairs.

Purpose

The purpose of this study was to investigate the cyclic displacement and ultimate failure loads of four different meniscus-suture fixation techniques for posterior medial meniscal root repairs in allograft quality human meniscal tissue. We hypothesized that there would be no significant difference between the two simple sutures (TSS) and three other techniques in cyclic displacement or ultimate failure load.

Methods

Thirty-two medial meniscal transplant specimens were randomly assigned to four meniscus-suture fixation techniques for the posterior medial meniscal root. The four suture techniques included: (i) two simple sutures (TSS), the current clinical standard; (ii) modified Mason-Allen (MMA); (iii) single double-locking loop (S-DLL); and (iv) double double-locking loop (D-DLL). The menisci were subjected to a cyclic tensioning protocol representative of post-operative rehabilitation (10-30 N for 1000 cycles) and pulled to failure at a rate of 0.5 mm/s.

Results

After 1000 cycles, the TSS displaced the least (mean ± SD, 1.78 ± 0.64 mm), followed by the MMA (2.14 ± 0.65 mm), D-DLL (2.97 ± 0.57 mm), and S-DLL (3.81 ± 0.78 mm). After 100, 500, and 1000 cycles, suture displacements using the TSS and MMA techniques were not significantly different (p > 0.130), while the TSS resulted in significantly less displacement than the S-DLL and D-DLL (p < 0.03). The ultimate failure loads of the MMA (325 ± 77 N) and D-DLL (320 ± 50 N) were significantly greater than those of the TSS (192 ± 52 N) and S-DLL (217 ± 51 N) techniques (p < 0.05).

Conclusion

The TSS and MMA fixation techniques were not significantly different while the TSS was significantly better at resisting displacement when compared to the S-DLL and D-DLL stitch configurations. The MMA and D-DLL techniques exhibited significantly greater failure loads than the TSS and S-DLL techniques; however, all techniques demonstrated ultimate failure loads above the currently accepted rehabilitation force threshold. The TSS fixation technique combines the lowest technical difficulty and ability to resist displacement at time zero. The MMA technique, although more technically challenging, may provide an alternative means to resist displacement while enhancing the failure load, although this increase in strength may not be of clinical relevance.

CLINICAL RELEVANCE
To the authors’ knowledge, this study was the first to evaluate different meniscus-suture fixation techniques for meniscal root repair under cyclic loading in a human menisci model. As such, the results of this study are more representative of a clinical scenario and did not underestimate displacement as a consequence of meniscal tissue properties (e.g., porcine compared to human). Correspondingly, the displacements observed in this study provide further evidence of the importance of a slow and careful post-operative rehabilitation program to prevent significant displacement at the root repair site.