Mark S. Meyer

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

Derivation and characterization of an extra-axial chordoma cell line (EACH-1) from a scapular tumor.

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.

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

BACKGROUNDnExtra-axial chordomas are rare low-grade malignant tumors thought to arise from notochordal remnants in the extra-axial skeleton. Few studies have been done on this neoplasm because of its rarity. In addition, there is a lack of a good in vitro model on which to perform more characterization.nnnMETHODSnWe describe a twenty-eight-year-old man with a mass in the right scapula. Cytomorphology and immunohistochemistry, including brachyury staining, were used to formulate the final diagnosis. A fragment of the tumor was placed in culture, and cells obtained were injected subcutaneously in an immunocompromised mouse. From the tumor developed in mice, a cell line has been derived and characterized by fluorescence-activated cell-sorting analysis, karyotyping, clonogenicity, and cell and tumor growth curves.nnnRESULTSnCytomorphology on the tumor showed nests of round cells with vacuoles and also physaliferous-like cells with uniform nuclei. Immunochemistry revealed a tumor positive for vimentin, moderately positive for S-100 and cytokeratin AE1/AE3, weakly positive for epithelial membrane antigen, and negative for p63 and cytokeratin (CK)-7. Further analysis revealed the tumor was diffusely and strongly positive for brachyury. The cell line derived from the tumor showed rapid doubling-time, a strong expression of mesenchymal cell surface markers, a karyotype of diploid or hypotetraploid clones with numerous chromosomal aberrations, and the ability to form colonies without attachment and to form tumors in immunocompromised mice.nnnCONCLUSIONSnThe diagnosis of the extra-axial chordoma is difficult but can be resolved by the detection of a strong brachyury expression. In addition, the derivation of a human extra-axial chordoma cell line could be a useful tool for the basic research of this rare neoplasm.

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.

Interscapulothoracic (forequarter) amputation for malignant tumors involving the upper extremity: surgical technique and case series

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.

Risk Stratified Usage of Antibiotic-Loaded Bone Cement for Primary Total Knee Arthroplasty: Short Term Infection Outcomes With a Standardized Cement Protocol

BACKGROUNDnForequarter amputation (FQA) is reserved for large, multifocal, or recurrent tumors affecting the shoulder and upper extremity. Although it is performed less frequently with the advancement of limb salvage surgery, FQA remains an important treatment in select patients. The purpose of this study is to illustrate the surgical technique in a case series of 4 patients.nnnMETHODSnBetween 2010 and 2012, 4 patients (mean age, 61 years; range, 36-78 years) presented with malignant disease of the upper extremity that was not amenable to or had failed limb salvage. All patients had FQA by the illustrated anterior clavicular osteotomy technique. Patient data were retrospectively reviewed from preoperative workup until last follow-up or death.nnnRESULTSnAll patients had tumors that involved major neurovascular structures of the upper extremity and shoulder girdle. One presented with neuroendocrine carcinoma and has achieved local control after FQA. Three presented with high-grade sarcoma. One of these had recurrence after prior limb salvage and neoadjuvant radiation and unfortunately succumbed to metastatic disease 6 months after FQA. An additional sarcoma patient who presented after shoulder arthroscopy for a labral cyst with recurrent and fulminant synovial sarcoma succumbed to her disease. The remaining sarcoma patient has had no recurrence and minimal phantom pain at last follow-up.nnnDISCUSSIONnObtaining vascular control early in the procedure is crucial to minimize blood loss. When it is indicated, FQA is a relatively safe and reliable procedure for dealing with otherwise challenging tumors of the shoulder girdle and upper extremity.nnnLEVEL OF EVIDENCEnLevel IV, case series, treatment study.

High CD49f expression is associated with osteosarcoma tumor progression: a study using patient-derived primary cell cultures.

Efficacy of antibiotic cement (ALBC) in primary knee arthroplasty (pTKA) has been debated. The studys purpose was to examine efficacy of ALBC versus plain cement (PBC) in preventing infection in high-risk patients undergoing pTKA. 3292 consecutive pTKAs were divided into three cohorts: (1) patients receiving only PBC, (2) patients receiving only ALBC, and (3) only high-risk patients receiving ALBC. Cohorts infections were compared. The 30-day infection rates for cohorts 1, 2, 3 were 0.29%, 0.20%, and 0.13% respectively. 6-month rates were 0.39%, 0.54% and 0.38%. 1-year rates were 0.78%, 0.61%, and 0.64%. Differences in infection rates at all time intervals were not statistically significant. The study supports that even judicious risk-stratified usage of ALBC may not confer added benefit in decreasing infection at one year.

The Effects of a Hospitalist Comanagement Model for Joint Arthroplasty Patients in a Teaching Facility

Overall prognosis for osteosarcoma (OS) is poor despite aggressive treatment options. Limited access to primary tumors, technical challenges in processing OS tissues, and the lack of well‐characterized primary cell cultures has hindered our ability to fully understand the properties of OS tumor initiation and progression. In this study, we have isolated and characterized cell cultures derived from four central high‐grade human OS samples. Furthermore, we used the cell cultures to study the role of CD49f in OS progression. Recent studies have implicated CD49f in stemness and multipotency of both cancer stem cells and mesenchymal stem cells. Therefore, we investigated the role of CD49f in osteosarcomagenesis. First, single cell suspensions of tumor biopsies were subcultured and characterized for cell surface marker expression. Next, we characterized the growth and differentiation properties, sensitivity to chemotherapy drugs, and anchorage‐independent growth. Xenograft assays showed that cell populations expressing CD49fhi/CD90lo cell phenotype produced an aggressive tumor. Multiple lines of evidence demonstrated that inhibiting CD49f decreased the tumor‐forming ability. Furthermore, the CD49fhi/CD90lo cell population is generating more aggressive OS tumor growth and indicating this cell surface marker could be a potential candidate for the isolation of an aggressive cell type in OSs.

Financial Analysis of Treating Periprosthetic Joint Infections at a Tertiary Referral Center

BACKGROUNDnThe goal of this study was to compare postoperative medical comanagement of total hip arthroplasty and total knee arthroplasty patients using a hospitalist (H) and nonhospitalist (NH) model at a single teaching institution to determine the clinical and economic impact of the hospitalist comanagement.nnnMETHODSnWe retrospectively reviewed the records of 1656 patients who received hospitalist comanagement with 1319 patients who did not. The NH and H cohorts were compared at baseline via chi-square test for the American Society of Anesthesiologists classification, the t test for age, and the Wilcoxon test for the unadjusted Charlson Comorbidity Index score and the age-adjusted Charlson Comorbidity Index score. Chi-square test was used to compare the postoperative length of stay, readmission rate at 30 days after surgery, diagnoses present on admission, new diagnoses during admission, tests ordered postoperatively, total direct cost, and discharge location.nnnRESULTSnThe H cohort gained more new diagnoses (P < .001), had more studies ordered (P < .001), had a higher cost of hospitalization (P = .002), and were more likely to be discharged to a skilled nursing facility (P < .001). The H cohort also had a lower length of stay (P < .001), but we believe evolving techniques in both pain control and blood management likely influenced this. There was no significant difference in readmissions.nnnCONCLUSIONnAny potential benefit of a hospitalist comanagement model for this patient population may be outweighed by increased cost.

Topical Tranexamic Acid Use in Knee Periprosthetic Joint Infection Is Safe and Effective.

BACKGROUNDnPeriprosthetic joint infection (PJI) is a significant challenge to the orthopedic surgeon, patient, hospital, and insurance provider. Our study compares the financial information of self-originating and referral 2-stage revision hip and knee surgeries at our tertiary referral center for hip or knee PJI over the last 4 years.nnnMETHODSnWe performed an in-house retrospective financial review of all patients who underwent 2-stage revision hip or knee arthroplasty for infection between January 2008 and August 2013, comparing self-originating and referral cases.nnnRESULTSnWe found an increasing number of referrals over the study period. There was an increased cost of treating hips over knees. All scenarios generated a positive net income; however, referral hip PJIs offered lower reimbursement and net income per case (although not statistically significant), whereas knee PJIs offered higher reimbursement and net income per case (although not statistically significant).nnnCONCLUSIONnWith referral centers treating increased numbers of infected joints performed elsewhere, we show continued financial incentive in accepting referrals, although with less financial gain than when treating ones own hip PJI and an increased financial gain when treating referral knee PJIs.