Suture Interval Spacing in Meniscal Repair—Aim for ≤7 mm: A Biomechanical Study: ISAKOS Albert Trillat Award 2025

Abstract

Background:

The resistance to gap development under repetitive loading influences the probability of meniscal healing after meniscal repair. The optimal meniscal suture interval spacing for repairing longitudinal meniscal tears is poorly understood. This study aimed to investigate the effect of varying suture interval spacings on the biomechanical properties of vertical meniscal repairs.

Hypothesis:

There is a critical meniscal suture interval spacing beyond which the gap development during cycling loading increases and the stiffness of the construct decreases.

Study Design:

Controlled laboratory study.

Methods:

In 50 bovine menisci, complete vertical circumferential meniscal tears were created. All lesions were repaired using two 2-0 braided sutures with the vertical mattress inside-out technique. Five suture spacings (3, 5, 7, 9, and 11 mm) with 10 samples each were tested. Each sample underwent 1000 loading cycles between 5 and 20 N (combined load) at a 75-mm/min crosshead speed and subsequent load-to-failure testing. The tear opening gap between the 2 meniscal sutures was measured using the Digital Image Correlation system with 2 high-speed cameras after 10, 100, 500, and 1000 cycles. Gap formation, cyclic stiffness, and failure modes were measured. A 1-way analysis of variance with post hoc t testing with Bonferroni correction for significant pairwise analysis of all outcome variables was performed. Statistical significance was set at a P value <.05.

Results:

Meniscal repairs with suture interval spacings of 3 mm, 5 mm, and 7 mm demonstrated statistically significantly smaller gap formation—a mean of 36% less—compared with spacings of 9 mm and 11 mm. There were no significant differences in gap formation between the suture interval spacings of 3 mm, 5 mm, and 7 mm. Construct stiffness was significantly higher with a suture interval spacing of 7 mm and less compared with ≥9 mm (all P < .05). No significant differences in construct stiffness were observed among the 3-mm, 5-mm, and 7-mm suture intervals. Suture breakage occurred in 76% of cases (38/50), suture cut-through in 22% (11/50), and a combination of both in 2% (1/50). Failure mode did not correlate with suture distance.

Conclusion:

Meniscal repair with a suture interval spacing of ≤7 mm demonstrates significantly lower gap formation and higher construct stiffness during cyclic loading than interval spacings of >7 mm. Based on these biomechanical data, surgeons should consider a ≤7-mm suture interval spacing for vertical mattress meniscal repair of longitudinal tears.

Clinical Relevance:

On the basis of this biomechanical data, surgeons should consider a ≤7-mm suture interval spacing for vertical mattress meniscal repair of longitudinal tears.