Intrawound Vancomycin Powder Reduces Early Prosthetic Joint Infections in Revision Hip and Knee Arthroplasty.

Intrawound vancomycin powder has shown efficacy and safety in decreasing postoperative spine infections, but its use in arthroplasty has not been well established. The purpose of this study was to compare the rate of early prosthetic joint infections (PJI) with and without the use of intrawound vancomycin powder during joint arthroplasty. A retrospective cohort of all patients who underwent primary or revision hip or knee arthroplasty by two surgeons over a two-year period at a single hospital system was evaluated. The control group received standard systemic prophylaxis only, whereas the treatment group received 1 g of vancomycin powder in the surgical wound in addition to systemic prophylaxis. A statistically significant decrease in the overall PJI rate was found in the treatment group (4/816=0.49%) compared to the control group (13/824=1.57%; p=0.0479). Subgroup analysis demonstrated a trend toward fewer PJIs in the vancomycin group, however, only the revision procedures showed a statistically significant reduction in early PJIs after the initiation of vancomycin (7/180=3.89% to 0/134=0%; p=0.0217). The use of intrawound vancomycin powder was associated with a significant reduction in the overall incidence of early PJIs following joint arthroplasty, however, only the revision procedures demonstrated a significant reduction in the rate of early PJIs.

Dexamethasone reduces length of hospitalization and improves postoperative pain and nausea after total joint arthroplasty: a prospective, randomized controlled trial.

Controlling postoperative pain and nausea after total joint arthroplasty remains an important challenge. We conducted a prospective, randomized controlled trial with 120 patients to determine if the addition of perioperative dexamethasone to a multimodal regimen improves antiemetic and analgesic control, enhances mobility, and shortens hospital length of stay after total hip and knee arthroplasty. Patients administered 10mg of intravenous dexamethasone intraoperatively consumed less daily rescue anti-emetic and analgesic medication, reported superior VAS nausea and pain scores, ambulated further distances, and had a significantly shorter length of stay compared to the control group (P<0.05). A second, 24-hour postoperative dose of 10mg intravenous dexamethasone provided significant additional pain and nausea control and further reduced length of stay (P<0.05). No adverse events were detected with the administration of the intraoperative and/or postoperative dexamethasone.

Platelet-mediated thrombolysis in patients with δ-storage pool deficiency: a thrombelastographic analysis.

We present the first thrombelastographic descriptions of three patients with δ-storage pool deficiency, a platelet disorder that involves a deficiency of dense granules and moderate bleeding. The patients demonstrated a 49-54% loss of platelet-mediated clot strength over a 1-2-h period after normal thrombus formation. This pattern persisted, with some attenuation of loss of strength following administration of epsilon aminocaproic acid, desmopressin and platelets for tonsillectomy. Assessment of platelet function in patients with platelet granule disorders can be accomplished with thrombelastographic methods in ambulatory and perioperative settings; however, the effects of therapy for this disorder cannot be monitored with thrombelastography without obtaining a blood sample prior to prophylactic hemostatic intervention.

Evaluation of postoperative fever and leukocytosis in patients after total hip and knee arthroplasty.

Fever and leukocytosis are common after joint arthroplasty, often resulting in additional studies. This study was conducted to determine the incidence of fever and leukocytosis after joint arthroplasty and the use of tests. We retrospectively reviewed records (n = 426) of patients who underwent knee or hip arthroplasty between February 2006 and April 2008 to determine the incidence of fever and leukocytosis, tests, and results. Sixty-four had fever, and 247 had postoperative leukocytosis. Sixty additional tests were performed; 6 (10%) of 60 tests were clinically relevant. After joint arthroplasty, more than half of patients developed leukocytosis, and nearly 15% developed fever. Diagnostic testing should be based on physical examination or symptomatic findings and not solely on laboratory values or vital signs, decreasing the patient discomfort and potentially lower costs.

Bacterial growth on articulating spacers: an in vitro study.

We fashioned cement disk-shaped spacer models using antibiotic-loaded Palacos and embedded polyethylene and titanium into the surface of half of the models and inoculated the models with methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant S aureus (MRSA), or Staphylococcus epidermidis, and placed them in nutrient broth. Vancomycin was loaded into the cement of the MRSA spacer models and tobramycin into the MSSA and Staphylococcus epidermidis models. In the MSSA and MRSA models, no organisms survived beyond 48 hours in the antibiotic bath regardless of the presence of additional materials. At 96 hours, 86.6% of models with only antibiotic cement had viable Staphylococcus epidermidis, while 80% of models with antibiotic cement, polyethylene, and titanium had viable Staphylococcus epidermidis. Adding polyethylene and titanium to antibiotic-loaded cement does not promote bacterial survival.

Hydroxyapatite-coated tapered cementless femoral components in total hip arthroplasty.

Tapered cementless femoral fixation provides a reliable option for routine primary total hip arthroplasty (THA). The use of hydroxyapatite (HA)-coated stems is increasing as a result of mounting evidence that HA may improve the reliability of bone osseointegration and improve overall THA outcomes. These trends are based on a growing body of literature that supports both the theoretical and clinical rationale of this approach. There is solid clinical evidence that the combination of tapered geometry with an HA coating increases the likelihood of reliable femoral fixation. A comprehensive review of this literature evaluating the clinical use of cementless femoral components that use an HA coating is presented, and reveals that HA-coated stems have significantly improved proximal femoral fixation with less stress shielding and superior osseous remodeling. Although these advantages have not been shown to significantly increase long-term durability, there is sufficient data to support the routine use of HA-coated, tapered cementless femoral stems in THA.

Use of X-ray absorption imaging to examine heterogeneous diffusion in fractured crystalline rocks.

Heterogeneous diffusion in different regions of a fractured granodiorite from Japan has been observed and measured through the use of X-ray absorption imaging. These regions include gouge-filled fractures, recrystallized fracture-filling material and hydrothermally altered matrix. With the X-ray absorption imaging technique, porosity, relative concentration, and relative mass of an iodine tracer were imaged in two dimensions with a sub-millimeter pixel size. Because portions of the samples analyzed have relatively low porosity values, imaging errors can potentially impact the results. For this reason, efforts were made to better understand and quantify this error. Based on the X-ray data, pore diffusion coefficients (Dp) for the different regions were estimated assuming a single diffusion rate and a lognormal multirate distribution of Dp. Results show Dp for the gouge-filled fractures are over an order of magnitude greater than those of the recrystallized fracture-filling material, which in turn is approximately two times greater than those for the altered matrix. The recrystallized fracture-filling material was found to exhibit the greatest degree of variability. The results of these experiments also provide evidence that diffusion from advective zones in fractures through the gouge-filled fractures and recrystallized fracture-filling material could increase the pore space available for matrix diffusion. This evidence is important for understanding the performance of potential nuclear waste repositories in crystalline rocks as diffusion is thought to be an important retardation mechanism for radionuclides.