Perceptions of allograft safety and efficacy among spinal deformity surgeons.

Since current bone procurement and processing standards have been adopted, published studies have consistently shown that the risk of disease transmission from allograft is small. The purpose of this study was to evaluate allograft use and opinions regarding allograft safety during spinal deformity surgery. A postal survey was sent to 151 pediatric orthopaedists chosen from a cross-referenced listing of active members of both the Scoliosis Research Society and the Pediatric Orthopaedic Society of North America. The survey consisted of six questions covering allograft use during idiopathic and neuromuscular scoliosis cases, concerns about disease transmission, preoperative counseling, concerns about providers, and evaluation of clinical results. The response rate was 80%. Allograft bone use was reported by 96% of those responding for neuromuscular cases and by 62% for idiopathic cases. Infection (68%) and pseudoarthrosis (26%) were the most common topics mentioned among the 41% who addressed potential risks. Variation was found in surgeons' perceptions regarding the safety and efficacy of allograft for scoliosis surgery.

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

The purpose of this study was to assess the dynamic in vitro and in vivo characteristics of two different bioabsorbable copolymer soft-tissue fixation devices and to determine their efficacy in reattaching soft tissue to bone. Suretac fixators (Smith & Nephew/Acufex MicroSurgical Inc., Northwood, MA), made of polyglyconate (2:1 glycolic acid:trimethylene carbonate), and Pop Rivets (Arthrotek, Warsaw, IN), made of LactoSorb (82% poly L-lactic acid, 18% polyglycolic acid), were anchored into synthetic bone, and their pull-out strengths were evaluated. The devices were also evaluated with the use of an in vivo goat model in which the medial collateral ligament (MCL) was elevated from the tibia and directly reattached. In the in vitro biomechanical study, the Suretac fixators had negligible strength remaining by four weeks, whereas the Pop Rivets retained 50% of their strength at 4 weeks, 20% at 8 weeks, and negligible strength at 12 weeks. The in vivo strength of MCL repairs affected by each implant was not statistically different at any of the time points. Histologically, both implants were absorbed by 52 weeks, and there was no appreciable adverse tissue response. In conclusion, both copolymer fixators were found to be biocompatible. The Pop Rivet fixators demonstrated in vivo performance comparable to the Suretac fixators, although the Pop Rivets retained strength longer in vitro. Our results suggest that both devices provide adequate strength of fixation before degrading to allow the healing soft tissues to reach or surpass their native strength.

Pre-clinical in vivo evaluation of orthopaedic bioabsorbable devices.

The presence of bioabsorbable materials in orthopaedics has grown significantly over the past two decades with applications in fracture fixation, bone replacement, cartilage repair, meniscal repair, fixation of ligaments, and drug delivery. Numerous biocompatible, biodegradable polymers are now available for both experimental and clinical use. Not surprisingly, there have been a wealth of studies investigating the biomechanical properties, biocompatibility, degradation characteristics, osteoconductivity, potential toxicity, and histologic effects of various materials. Promising results have been reported in the areas of fracture fixation, ligament repair, and drug delivery. In this article we review the pre-clinical in vivo testing of bioabsorbable devices with particular emphasis on implants used for these applications.