gms | German Medical Science

Objectives: Saving the meniscus is important, but the optimal suture spacing in meniscus repair is not yet defined. This study aimed to determine the optimal suture spacing of meniscal sutures in meniscal repair. It was hypothesized that there is a spacing limit beyond which the biomechanical performance decreases significantly.

Methods: 25 bovine medial and lateral menisci were obtained and divided into an anterior and posterior samples. A complete vertical meniscal tear was created 5mm from the peripheral meniscal rim. All lesions were repaired using two 2–0 braided sutures (Ultrabraid, Smith&Nephew) with vertical mattress sutures placed 3mm from the torn edges. The sutures were tensioned to 30 N using a tensiometer and securely tied to the meniscus base with sliding knots. Five different suture spacings (3, 5, 7, 9, and 11 mm) with ten samples each were tested. A custom-designed testing device was developed to simulate radial loading of the repair. Three #5 braided polyester loading sutures were placed at the peripheral meniscal rim, spaced equally at intervals of 10 mm and preloaded with 2 N, using small weights. Each sample underwent 1,000 loading cycles between 5–20 N (combined suture load) at a crosshead speed of 75 mm/min. The tear opening gap between the two meniscal sutures was measured using a Digital Image Correlation system (DIC) with two high-speed cameras after 1, 10, 100, 500 and 1,000 cycles. An ANOVA test with a Bonferroni correction was performed to determine differences in gap-opening displacement between groups at the 1,000th cycle. Data is presented in mean ± standard deviation.

Results and conclusion: Meniscus repairs with suture distances of 3 mm, 5 mm, and 7 mm demonstrated statistically significantly smaller (on average 36%) opening gaps (1.6 ± 0.3 mm, 1.7 ± 0.5 mm and 1.7 ± 0.5 mm, resp.) compared to those with suture distances of 9 mm and 11 mm (2.5 ± 0.3 mm and 2.7 ± 0.6 mm; all p < .05; Figure1 [Fig. 1]), respectively. Displacement among suture distances of 3 mm, 5 mm, and 7 mm exhibited no significant differences. Similarly, no statistically significant difference in displacement was observed between 9 mm and 11 mm. Failure mode did not correlate with suture distance. Sutures broke in 76% (38/50) and cut through the meniscus tissue in 22% (11/50), while a combination of one suture breakage and one tissue transection was observed in 2% (1/50).

Meniscal repair with a suture distance greater than 9mm demonstrates statistically significant higher gapping than suture distances of 7 mm and below. A larger gapping may potentially hinder the healing of a meniscus tear. Based on this biomechanical data, a suture distance of 7 mm or less is recommended when performing meniscal repair.