The Effect of Absorbable Calcium Sulfate on Wear Rates in Ultra-high-Molecular-weight Polyethylene: Potential Implications for Its Use in Treating Arthroplasty Infections.

INTRODUCTION: Patients, hospitals, and healthcare systems incur substantial burdens when infections result in total joint revisions. One potential solution to mitigate some of these burdens may be to transition from a two-stage infection treatment to a single-stage procedure. Off-label use of an absorbable calcium sulfate antibiotic carrier has been implemented in single-stage and two-stage procedures globally, with the goal of moving toward more single-stage revisions in the United States. Adverse effects of calcium sulfate on the joint space during articulation are currently unknown. METHODS: This study aims to determine the impact of calcium sulfate beads on wear of polyethylene during and following exposure. Two phases of in vitro pin-on-disk testing were conducted. The first phase exposed polyethylene pins to calcium sulfate for 500,000 cycles of a 2-million cycle test. The second phase examined the wear of pins that were created from retrieved components exposed to calcium sulfate in vivo. RESULTS: No clinically significant difference was observed between the wear rates of the calcium sulfate-exposed polyethylene pins and the control polyethylene pins. DISCUSSION: Preliminary results suggest that a substantial increase in the wear rate of polyethylene is not expected with the addition of calcium sulfate beads during treatment of infection.

Use of the spider limb positioner in oncologic lower extremity surgery.

Orthopedic extremity surgery presents a unique set of restraints and difficulties relative to other surgical specialties. Among these is the positioning of heavy limbs in sometimes awkward positions for long periods of time. Ideal positioning of an extremity allows accurate and precise surgery to occur at otherwise difficult to access joints and proximal bones and soft tissues. Numerous solutions to this problem have been proposed, one such solution is the Smith and Nephew Spider Limb Positioning System. The table-mounted pneumatic arm features three fully articulating joints and a simple repositioning mechanism. Classic uses of the Spider Limb Positioner System include shoulder and elbow surgery, total knee replacement and ankle procedures. In our institution, the Spider Limb Positioner is used primarily for shoulder arthroscopy and total shoulder arthroplasty. In addition, we have had success using the system for orthopedic oncology cases. This manuscript addresses the conventional as well as unconventional uses implemented at our institution. Limb positioning in orthopedics provides a unique challenge for prepping, draping and surgery. The use of positioning aids can improve exposure, decrease contamination and reduce the risk of surgeon strain. Our institution has developed a solution to positioning of heavy lower limbs for hip disarticulation via the Smith and Nephew 'Spider'. This pneumatic, full articulating device used primarily for shoulder surgery can be modified to allow lower extremity use in the setting of hip disarticulation. This paper describes the standard and novel use of this device.

A computer support program that helps clinicians provide patients with metabolic syndrome tailored counseling to promote weight loss.

BACKGROUND: Physician counseling can help patients make substantial changes in diet and physical activity behaviors that can result in weight loss and a reduction in metabolic risk factors. Unfortunately, time constraints and a lack of training often make it difficult for physicians to provide effective counseling. The objective in this study was to test the effect of a computerized support tool to enhance brief physician-delivered health lifestyle counseling to patients with increased metabolic risk factors during two usual care visits. DESIGN/SETTING/PARTICIPANTS: This is a prospective controlled trial of a 12-month intervention conducted at two large community health centers serving mostly Hispanic patients. Participants (n = 279) had a body mass index (calculated as kg/m²) ≥ 25 and at least two components of the metabolic syndrome. INTERVENTION: In the intervention group, a computer program was used to help patients set tailored self-management goals for weight loss, nutrition, and physical activity. Goals were then reviewed and reinforced at clinic visits with participants' physicians at baseline and again at 6 months. The control group received care as usual. Data were collected between July 2007 and August 2008. MAIN OUTCOME MEASURES: Change in body weight was the primary outcome. Secondary measures included changes in blood glucose, blood cholesterol, blood pressure, physical activity, and energy intake. RESULTS: Significantly more patients in the intervention group lost ≥ 5% of their body weight at 12 months than controls (26.3% vs 8.5%; odds ratio = 3.86; P < 0.01). Loss of > 5% of total body weight was associated with improvements in cardiovascular risk factors, including low-density lipoprotein cholesterol (-14.0 vs -4.1 mg/dL; P = 0.04). CONCLUSIONS: A brief computer-based intervention designed to increase the dialogue between patients and clinicians about behavioral goals can lead to increased 12-month weight loss.