George F. Chimento

GRAM STAIN DETECTION OF INFECTION DURING REVISION ARTHROPLASTY

We reviewed 194 revision arthroplasties of the hip and knee performed over a ten-year period. The results of intraoperative Gram staining were available in 169 (87%). Thirty-two were found to be infected (11 hips and 21 knees) and 137 had no evidence of infection. Intraoperative Gram staining was negative in all 169 cases. The method therefore had a sensitivity of 0% for detecting infection. We conclude that the absence of organisms on intraoperative Gram staining during revision arthroplasty does not confirm the absence of infection.

An evaluation of the use of topical tranexamic acid in total knee arthroplasty.

The purpose of this study was to evaluate the effectiveness of topical tranexamic acid in primary TKA from a clinical and economic standpoint. We retrospectively reviewed 683 primary total knee arthroplasties performed at a single institution over a 2-year period. We compared 373 cases performed in 2010 without tranexamic acid to 310 cases performed in 2011 with tranexamic acid. Demographic data, hemoglobin levels, transfusion rates, hospital length of stay, cost, and perioperative complications during the first 3 months were collected. Statistical analysis was performed using two sample t-tests and Fishers exact tests. There was no difference in age, sex, height, or pre-operative hemoglobin between the two groups. The tranexamic acid group had significantly higher post-operative hemoglobin (P<0.0001), lower transfusion rate (P<0.0001), decreased length of stay (P<0.0001), decreased blood bank costs (P<0.0001), increased pharmacy cost (P<0.0001), and decreased total direct cost to the hospital (P<0.0001). The average savings was approximately

Minimally invasive total hip arthroplasty

1500 per patient. There were no differences in thromboembolic events or infection. The use topical tranexamic acid in primary TKA is safe, effective, and results in significant cost savings.

An analysis of food and drug administration medical device reports relating to total joint components

Total hip arthroplasty (THA) is commonly performed by using a posterior approach through an incision of 15 to 20 cm in length. A modified posterior approach allows for THA to be performed through an incision of 5 to 10 cm in length. Most patients with a Body Mass Index less than 30 who have not had a previous hip surgery are candidates for this approach; hypotensive epidural anesthesia is recommended. The incision is based over the posterior aspect of the greater trochanter, and specially designed retractors are used. The femoral component may be cemented or press fit, and a press fit monoblock acetabular component is generally used. The wound is closed over suction drainage. Patients receive mechanical and pharmacologic antithrombolytic prophylaxis and follow a standard postoperative rehabilitation protocol. A review of the first 1,000 patients operated on with this approach shows results comparable with THA performed through a standard length incision. There has been 1 deep infection (0.1%), 2 patients with sciatic neuropraxia (0.2%), 12 dislocations (1.2%), and 1 patient revised for recurrent instability (0.1%).

Possible bupivacaine toxicity after intraarticular injection for postarthroscopic analgesia of the knee: implications of the surgical procedure.

A total of 1,717 total hip and 2,769 total knee medical device reports submitted to the U.S. Food and Drug Administration (FDA) from 1984 through 1993 were reviewed. A large percentage of total hip complications could be attributed to some aspect of component modularity. Cementless modular acetabular components were the single largest source of device-related complications. Fifty-six percent of total knee medical device reports (MDRs) were associated with accelerated polyethylene wear. By location, MDRs identified patellar (46%), tibial (33%), and femoral (5%) component complications. It was estimated that less than 5% of device-related complications were reported to the FDA. Based on the reports received, it was apparent that mechanical failure of components was a common and increasing cause of total joint revision.

Intraspinal extradural ganglion cyst.

IMPLICATIONS We report a case of possible bupivacaine toxicity after intraarticular injection during knee arthroscopy. The importance of the specific type of surgical procedure performed during arthroscopy and its relationship to potential local anesthetic toxicity are highlighted.

Establishing a Role for Vancomycin Powder Application for Prosthetic Joint Infection Prevention—Results of a Wear Simulation Study

Occurrence of ganglion cysts in the spine is extremely rare. Common symptoms include intermittent lumbar pain and pain at night. Neurological examination to distinguish from other etiologies of radicular pain may be difficult. The L4-L5 level is the most common sight of occurrence. Radiographically, degenerative changes, particularly spondylolisthesis, are a common finding. MRI appearance of the cysts is variable, according to the composition of the cyst. A ganglion cyst should be considered in the differential of radicular pain in the presence of degenerative changes of the lumbar spine.

The Financial Impact of a Multidisciplinary Preoperative Risk Stratification Program for Joint Arthroplasty

Topical vancomycin powder (VP) has shown efficacy and safety in decreasing post-operative spine infections. VP use in arthroplasty has not been established. Concerns remain for third-body wear with the addition of crystalline substrate at the implant interface. The studys purpose was to compare wear behavior of CoCr on UHMWPE to identical wear couples with VP. A six-station wear simulator was utilized and cyclic articulations were run for 10 million cycles (Mc). UHMWPE wear was measured using photography, stereomicroscopy, and gravimetric measurement. There were no differences in wear mark length (P = 0.43), width (P = 0.49), or gravimetric wear at 10 Mc (P = 0.98). VP and control groups lost 0.32 and 0.33 mg, respectively. VP may have a role in PJI prevention. A well-designed clinical study is needed.

Accuracy and Clinical Utility of a Peri-Operative Risk Calculator for Total Knee Arthroplasty

This studys purpose was to assess the impact of a preoperative risk stratification program on joint arthroplasty outcomes at a single institution. We hypothesized that by using a standardized preoperative risk stratification center we would see better outcomes and decreased costs. The triage cohort (T) included 1498 patients assessed at a standardized risk stratification center, and the non-triage cohort (NT) included 1100 patients who did not utilize the center. The T cohort had significantly higher ASA classification (P<0.0001) and ACCI scores (P=0.028). We found no significant difference in complication rates. The T cohort showed a significant decrease in LOS (P<0.0001) and an increase in average reimbursement (P=0.009). A standardized preoperative risk stratification center can contribute to decreased LOS, increased reimbursement and help prevent complications.

Angiotensin-converting Enzyme Activity: A Novel Way of Assessing Pulmonary Changes During Total Knee Arthroplasty

Utilizing the Medicare Provider Analysis and Review dataset, a, peri-operative total knee arthroplasty (TKA) risk calculator was created based on select preoperative comorbidities. We retrospectively identified and reviewed 2284 primary TKAs at a single institution from 2000-2008. A numerical, predicted complication risk was established for each patient. Actual complications occurring within the first 14 post-operative days were recorded. Statistical analysis was performed using the C-statistic and ANOVA test. Patients with higher predicted probability of a complication did show higher complication rates. The corresponding C-statistic was 0.609. (95% Confidence Interval: 0.542-0.677). When the patients were divided into 4 groups based on their calculated complication risk (0-5%, 5-10%, 10-25%, >25%) the statistical significance of the associated ANOVA was P < .001, showing that patients with higher predicted risk experienced more complications, and those with lower predicted risk experienced fewer complications. Based on our results, the calculator has predictive value and is clinically relevant.