Suture Purchase Length: A Biomechanical Study of Flexor Tendon Repair in Newborn Lambs

PurposeWe aimed to determine the effect of core suture purchase on repair strength of flexor tendon lacerations in newborn lambs as a model for pediatric tendon repairs. The dimensions of flexor tendons in these lambs are similar to those of children younger than 2 years.MethodsThirty-six flexor tendons were harvested from newborn lambs. The tendons were cut transversely and repaired using a single figure-of-eight core suture using 5-0 polypropylene. The 36 tendons were divided into 9 groups (n = 4 tendons in each group) according to the length of the core suture purchase: 2, 3, 4, 5, 6, 7, 8, 9, or 10 mm. The initial gap force and ultimate strength of the repairs were studied using a computerized tensometer.ResultsThere were no significant differences between core suture purchase lengths 2, 3, 4, and 5 mm for both initial gap and ultimate strength. Similarly, there were no significant differences between purchase lengths 6, 7, 8, 9, and 10 mm for both initial gap and ultimate strength. However, there was a significant difference between the former and the latter groups.ConclusionsThe optimal core suture purchase length in flexor tendon repair of newborn lambs was 6 mm. However, this length may be too much of a purchase when applied clinically in children younger than 2 years.