An increasing number of hip prostheses are inserted without bone cement. Experimental research has shown that hydroxyapatite (HA) coated implants are strongly fixated in the bone, which is believed to reduce the likelihood of prosthetic loosening. However, in recent years, there has been much debate about the role of HA particles in third-body polyethylene (PE) wear and formerly we have shown the revision rate to be high among older-design HA coated cups. We hypothesized increased PE wear-rate using HA coated acetabular components in comparison with non-HA coated components (control group).Background
Purpose
Randomized, controlled trials (RCTs) are generally accepted as the “gold standard” for the provision of the most unbiased measures of the efficacy of interventions but are often criticized for the lack of external validity. We assessed the external validity of a RCT examining the efficacy of local infiltration analgesia (LIA) compared with continuous epidural infusion after total knee arthroplasty (TKA) During a one-year period, all patients consecutively admitted for elective, unilateral, primary TKA were identified as potential participants. All underwent eligibility screening to determine who were eligible for participation in a randomized controlled trial. We investigated the distribution of preoperative characteristics and postoperative variables among excluded patients, non-consenters, and enrolled and randomized participants.Background
Methods
Hip and knee arthroplasty present surgeons with difficult bone loss. In these cases the use of morselized allograft is a well established way of optimizing early implant fixation. In revisions, the surgical field is potentially infected. The use of allograft bone creates a “dead space” in which the immune system has impaired access, and even a small amount of bacteria may therefore theoretically increase the risk of infection. In vivo studies have shown that allograft bone is suitable as a vehicle of local antibiotic delivery. We hypothesized that the allograft bone could be used as a local antibiotic delivery vehicle without impairing the implant fixation, tested by mechanical push-out. Following approval of the Institutional Animal Care and use Committee we implanted a cylindrical (10×6 mm) porous-coated Ti implant in each distal femur of 12 dogs observed for 4 weeks. The implants were surrounded by a circumferential gap of 2.5 mm impacted with a standardized volume of morselized allograft. In the two intervention groups, 0.2ml tobramycin solution of high (800mg/ml) and low (200mg/ml) concentration was added to the allograft, respectively. In the control group 0.2ml saline was added to the allograft. ANOVA-test was applied followed by paired t-test where appropriate. A p-value < 0,05 was considered statistically significant.Introduction
Material and Methods
