OBJECTIVE To investigate microbiological biofilm contamination of retrieved bone-anchored hearing aids. MATERIALS AND METHODS Nine failed, retrieved bone-anchored hearing aids and 16 internal screws were examined by scanning electron microscopy. A fixture from a failing implant, which had been removed and disassembled under aseptic conditions, was cultured. Finally, an internal screw from a n...

INTRODUCTION Achieving solid implant fixation to osteoporotic bone presents a challenge to both spinal surgeons and hardware designers. Loss of surgical construct stability as a result of screw loosening is a well-known complication [1,2], particularly in patients with poor bone quality [3,4]. Thus, the development of novel strategies to address the issue of obtaining enhanced bone-to-screw pur...

BACKGROUND In the literature, 'below and lateral to the superior S1 facet' is defined as the basic technique for screw introduction. Until a recently published modification, no analysis for alternative starting point has been proposed nor evaluated, although some surgeons claim to use some modifications. In this study, we analyse the data from anatomical and radiological studies for optimal sta...

BACKGROUND Rough-surface implants have become very popular during the last 10 years due to greater reported bone-implant-contact and bone volume between implant threads compared to machined-surface implants. PURPOSE The aim of this clinical report is to present the 26-year clinical outcomes of machined-surface implants supporting screw-retained fixed dental prostheses in a 77-year-old woman. ...

BACKGROUND Fixation of an anterior cruciate ligament graft at the joint line with an interference screw restores anterior laxity better than low-stiffness distal fixation with double staples and sutures tied to a post at implantation in porcine bone. HYPOTHESIS Fixation of an anterior cruciate ligament graft with a high-stiffness distal fixation device restores anterior laxity and knee stiffn...

INTRODUCTION Interference screws used in fixation of anterior cruciate ligament (ACL) hamstring grafts create mechanical hold by forcing the graft into frictional contact with the bone tunnel. We analyzed the resultant graft-tunnel contact pressure using an in vitro model of human cadaver 8mm hamstring grafts. METHODS Contact characteristics were assessed using both pressure sensitive films a...

BACKGROUND This study was designed to derive the theoretical formulae to predict the pullout strength of pedicle screws with an inconstant outer and/or inner diameter distribution (conical screws). For the transpedicular fixation, one of the failure modes is the screw loosening from the vertebral bone. Hence, various kinds of pedicle screws have been evaluated to measure the pullout strength us...

PURPOSE During the early postoperative period, the stability of the fixation of a hamstring graft to the bone tunnel is the primary factor in limiting rehabilitation. The aim of this study was to evaluate if the initial fixation strength of a new suspension screw is comparable to that of the biodegradable interference screw fixation technique in the hamstring reconstruction of the anterior cruc...

PURPOSE A 3-dimensional finite element analysis was performed to evaluate the influence of implant type and length, as well as that of bone quality, on the stress/strain in bone and implant. MATERIALS AND METHODS Two types (screw and cylinder) and 4 lengths (9.2, 10.8, 12.4, and 14.0 mm) of titanium implants were buried in 4 types of bone modeled by varying the elastic modulus for cancellous ...

BACKGROUND Lag screw cut-out failure following fixation of unstable intertrochanteric fractures in osteoporotic bone remains an unsolved challenge. This study tested if resistance to cut-out failure can be improved by using a dual lag screw implant in place of a single lag screw implant. Migration behavior and cut-out resistance of a single and a dual lag screw implant were comparatively evalua...