The objective of this study was to determine if combining variations in mixing technique of antibiotic-impregnated polymethylmethacrylate (PMMA) cement with low frequency ultrasound (LFUS) improves antibiotic elution during the initial high phase (Phase I) and subsequent low phase (Phase II) while not diminishing mechanical strength. Three batches of vancomycin-loaded PMMA were prepared with different mixing techniques: a standard technique; a delayed technique; and a control without antibiotic. Daily elution samples were analysed using flow injection analysis (FIA). Beginning in Phase II, samples from each mix group were selected randomly to undergo either five, 15, 45, or 0 minutes of LFUS treatment. Elution amounts between LFUS treatments were analysed. Following Phase II, compression testing was done to quantify strength. Objectives
Methods
A porcine model using Yucatan minipigs was found to be very promising for the investigation of healing around transcutaneous osseointegrated implants. Pigs demonstrated surprising agility and adaptability including the ability to ambulate on three legs during the immediate postoperative period. Previous non weight-bearing and weight-bearing caprine, canine and ovine models have evaluated design, material, and biological coating variations in an attempt to improve the wound healing and skin-implant seal around transcutaneous osseointegrated implants. Although these models have primarily been used as a window into the application of transcutaneous osseointegrated implants in humans, some important model characteristics affecting wound healing and infection have been missing including: 1) replication of the physiological tissue response, and 2) availability of a transcutaneous site with sufficient soft tissue coverage. Pig skin, like human, is relatively hairless, tightly attached to the subcutaneous tissue, vascularised by a cutaneous blood supply, and healed by means of epithelialization. Swine have been extensively utilised for superficial and deep wound healing studies and can offer ample soft tissue coverage following a lower limb amputation. Development of a porcine model is important for continued understanding and improvement of weight-bearing transcutaneous osseointegration.Summary Statement
Introduction
