Background

Presentations at national meetings provide an important forum to relay research findings in all areas of Orthopaedic surgery. Orthopaedic surgical trainees are encouraged throughout the training process to participate, present and ultimately publish their research. Indeed the well known mantra ‘Publish or Perish’ signifies the pressure trainees are sometimes placed under in order to achieve professional success. The number of original published papers is often the yardstick by which professional appointments are made. We aimed to determine the overall publication rates of presentations from the 2001 and 2002 Irish Orthopaedic Association meetings and to determine whether publication rates differed among other national Orthopaedic meetings and amongst the subspecialties.

Background

Meticillin-resistant Staphylococcus aureus (MRSA) are endemic in hospitals throughout Ireland and present a major concern in hospital hygiene causing significant morbidity, mortality and imposing a significant financial burden. This is particularly true in the field of orthopaedic surgery where a nosocomial MRSA infection can prove catastrophic to a patient's recovery from surgery. Much has been made of the possibility of healthcare workers acting as vectors for the transmission of MRSA and other pathogenic bacteria in the hospital setting. This focus has led to the implementation of strict hand decontamination policies in hospitals in order to counter the possibility of staff - patient transmission of such bacteria. Investigations have also attempted to assess the bacterial contamination of work uniforms such as white coats, ties and scrubs. An area that has been generally overlooked however, is the assessment of the bacterial contamination some of the most commonly handled items of many healthcare workers, namely pagers and mobile phones. In this study we aimed to assess the potential for these items to act as reservoirs for MRSA contamination and thus propagate its transmission in the hospital setting.

Aims Cemented acetabular components remain the standard for many surgeons around the world, however the main draw back of this technology is that of aseptic loosening. It has been suggested that loosening is initiated when mechanical failure occurs at the cement/bone interface. Successive generations of cementation techniques have evolved over the years in order to address this problem by improving the mechanical integrity of the cement bone construct. Negative pressure intrusion cementation techniques (NPI) represent a more recent phase of this evolution. These techniques involve the introduction of vacuum into the peri-acetabular bone immediately prior to cement application with the aims of decreasing the deleterious effects of the systemic bleeding pressure, removing fat and debris from the path of the advancing cement and causing deeper cement ingress through the direct effects of negative pressure. There exists in the literature very little scientific information relating to this technique; therefore our aim is to assess the quality of the cement bone interface in constructs created using a specially constructed rig.

Methods: Samples of screened, fresh frozen, human femoral head are machined to create a cylindrical core of cancellous bone measuring 24 x 40 mm. These samples are carefully stratified for porosity using a method of combing DEXA scan bone mineral density findings with microCT (Scanco 40, Bassendorf, Switzerland) histomorphological parameters. These cores are then introduced into the vacuum chamber of the rig and are subjected to a negative pressure of −30 kPa using a clinical suction machine (Cherion, Czech Rep). Simplex P (Stryker, Mahwah, US) polymethylmethacrylate cement is applied to the exposed cancellous bone within the rig and subjected to a constant positive external pressure via the vertical actuator of a servohydraulic materials testing machine (Instron 8873, Mass. US). The cement is allowed to set and the constructs are removed en bloc and frozen. The constructs produced are cylindrical and consist of three distinct zones; cement, bone and that of the cement bone interface. The quality of the cement bone interface is assessed in two distinct ways:

MicroCT is used to produce both quantitative and qualitative data relating to the cement bone interface. This data is processed using the 3D reconstruction software (Scanco, Bassendorf, Switzerland) to give values for intrusion depth and the integrity of cement bone interlock indicated using a previously published method of recording incidence and size of vacuolation within the cement bone interface.

Results: Early results indicate a tendency toward deeper and ‘tighter’ cement interdigitation within the cement bone interface in the samples created using the NPI method. These samples also tend to be mechanically stronger than controls.

Discussion This series of in-vitro experiments provides important information about this accepted but poorly understood technique. The model accurately mimics the operative technique and the use of microCT in this way is a novel application, allowi ng the digital assessment of cement intrusion depth and quality without having to physically section the constructs. It also attempts to relate these properties to mechanical strength.

Introduction: The National Bone Bank of Ireland was established in June 1996 at Cappagh National Orthopaedic Hospital, Dublin in response to the increased demand of allogenic bone grafts in Ireland. We reviewed the Bone Bank performance since it started with special emphasis on Microbiological monitoring of bone allograft as infection is the main complication of bone allograft (Chapman and Villar 1992).

Material and Methods: The femoral head allograft is harvested from living volunteer donors who are undergoing primary total hip replacement at Cappagh Hospital and have been assessed by the Bone Bank Co-Ordinator.

Harvesting: The bone is retrieved and harvested at the time of total hip replacement according to a strict protocol.

Storage: The bone is stored in the “Quarantine” freezer at −80 degrees C for a minimum period of 180 days. Each specimen is subjected to a full technical review by the Bone Bank Co-Ordinator and Medical Director and only when results of screening confirmed negative, the bone designated suitable for “Issue Stock” freezer.

Issue of Allografts: Bone is supplied for use, only after receiving full details of recipient to allow tracking. The results of the culture swab taken at the time of implantation and details of any post operative infection in recipients are forwarded to the bone bank.

Results: From June 1996 to December 2003, 5089 Primary Total Hip Replacements done at Cappagh Hospital and 1921 (38%) femoral heads were harvested. 109 (5.7%) of grafts had initial positive swabs/chips and 22 of these were discarded because of second positive chips. 1457 femoral head grafts supplied to 876 recipients and were used in Revision Total Hip Replacement (60%), Spine Surgeries (15%), Revision Total Knee (12%), Fractures, Tumours, Foot and Ankle (12%). 6 swabs at the time of grafting in recipients grew Staphylococcus Epidermidis but no clinical infection reported in our follow-up system. To double check, we posted a questioner to all consultants with list and details of their recipient patients and only 2 cases of suspected grafts related infection reported.

Discussion and Conclusion: Microbiological surveillance of bone grafts protect recipients from infection and is useful as a quality control of the process of bone banking (Farrington et al 1998). Our study showed contamination rate of 5.7%. Minimum infection rate post Revision Hip Replacement has been reported by Tomford in 1990, but after massive femoral allograft, infection has been reported 4% – 5% (Tomford 1990) and over 11% by Lord et al in 1988. Our experience showed only 2 cases in spite of strict follow-up protocol. We follow the policy of discarding the heavily contaminated grafts (Chapman 1992).

The quality performance of a Bone Bank depend on a full time bone bank co-ordinator, identification of donors, retrieval and harvesting of grafts, blood and microbiological assessment, medical supervision for decisions about contaminated grafts, a strict follow-up protocol and a regular audit of bone bank (Ivory and Thomas 1993). We also suggest that regular correspondence to the consultant using the bone grafts will improve the accuracy of follow-up.