Meniscal fixation with an absorbable staple

Abstract

An absorbable staple for meniscal fixation was developed and evaluated in an in vivo canine study. The staple consisted of two rigid barbed legs, made of a copolymer of polyglycolic acid and polylactic acid, connected by a flexible suture made of the same absorbable material. The staple was developed for arthroscopic use, eliminating the risk of nerve or vascular injuries associated with suture fixation. Eighty-two mongrel dogs underwent meniscal repair in this study, which was performed in two sequential parts. An incision was made in the medial meniscus at the peripheral third and was fixed with either the staple or with a single 3-0 PDS suture. The animals from the first part of the study, in which the biocompatibility of a prototype staple design, was evaluated were sacrificed at 3 days, 2 weeks, 6 weeks, 3 months, and 9 months. Those from the second part of the study, in which an improved staple design of the same material, was evaluated were sacrificed at 6 weeks, 4 months, and 1 year. The operated menisci were either examined histologically or were mechanically tested for tensile strength. Absorption of the staple began by 3 months and was almost complete by 1 year. Mechanically, the staple provided greater tensile strength augmentation of the meniscus than suture fixation for up to 4 months. In the long term, there was no difference between the staple and suture in enhancement of healing.

Initial Fixation Strength of Flexible All-Inside Meniscus Suture Anchors in Comparison to Conventional Suture Technique and Rigid Anchors

“…Since the tissue is functionally adapted to its strain, 31 it seems likely that under in vivo conditions only low forces occur in the radial direction. Kirsch et al 25 investigated the forces occurring in meniscus sutures in a cadaveric model and found low forces that were never higher than 10 N. Koukoubis et al 27 showed in a canine model that the repair tissue after meniscus suture failed at 46 N. In addition, as in this study, most biomechanical research studies test a worst-case scenario, in which the load is applied parallel to the axis of the tested fixation device. Although the exact forces to which a meniscus repair is subjected in vivo are unknown, this setup may not reflect the in vivo situation.…”

Comparison of the biomechanics and histology of two soft‐tissue fixators composed of bioabsorbable copolymers

“…There are many published reports on the in vitro 30 -33 or in vivo 16,19,20,23 behavior of bioabsorbable fixation implants. This research attempted to study and compare, both in vitro and in vivo, similar implants made of two different bioabsorbable copolymers.…”

“…25,28,29 Factors influencing the degradation rate include the chemical identity of the monomeric constituents, the molecular weight distribution, crystallinity, size and shape of the implant, the implant site environment (intraosseous vs. soft tissue and degree of vascularity), and the metabolic condition of the recipient. 24,28,29 Many experimental studies of the degradation characteristics of bioabsorbable fixation implants are performed under in vitro 30 -33 or in vivo 16,19,20,23 conditions, but it is less common for the two methods to be employed simultaneously. 34,35 The devices investigated in this study were the Pop Rivet (Arthrotek, Inc., Warsaw, IN), made of a PGA/PLLA copolymer called LactoSorb (Biomet, Inc., Warsaw, IN), and the Suretac (Smith ϩ Nephew/Acufex Microsurgical, Inc., Northwood, MA), made of a glycolic acid/trimethylene carbonate copolymer called polyglyconate.…”

“…9 -11 Bioabsorbable fixation technology, while still relatively new, has been around long enough to now be an integral part of the surgeon's armamentarium. Over the past two decades, bioabsorbable fixation devices in the forms of screws, 3,4,[12][13][14] pins, 12,15,16 tacks, 5,9 -11,17 staples, 5,18,19 plates, 20 -22 , and suture anchors 7,23 have been experimented with and employed clinically in many aspects of orthopedic surgery, including fixation of fractures, meniscal repair, and fixation of ligaments. The oldest and most frequently used bioabsorbable materials are polyglycolic acid (PGA), poly-L-lactic acid (PLLA), and PGA/PLLA copolymers.…”

Der Einfluss verschiedener Nahtstärken auf das Verhalten von Meniskusnähten unter zyklischer Zugbelastung

“…Allerdings wurden die Untersuchungen an Leichenknien ohne Belastung durchgeführt, sodass die In-vivo-Bedingungen nur teilweise erfüllt werden konnten. Koukoubis et al [19] zeigten am Hundemodell, dass das Narbengewebe eines verheilten Meniskusrisses nach einer Meniskusnaht bei durschnittlich 46 N wieder reißt. Den Ergebnissen dieser Arbeiten entsprechend wurde der obere Grenzwert der zyklischen Belastung bestimmt.…”