Mary E. Hardwick

Comparison of Enoxaparin and Warfarin for the Prevention of Venous Thromboembolic Disease After Total Hip Arthroplasty. Evaluation During Hospitalization and Three Months After Discharge

BACKGROUND Venous thromboembolic disease in the form of deep venous thrombosis and pulmonary embolism is a major risk after a total hip arthroplasty. Enoxaparin, a low-molecular-weight heparin, has been shown to reduce the prevalence of deep venous thrombosis after total hip arthroplasty. Warfarin, an orally administered anticoagulant, has been used historically to reduce the risk of deep venous thrombosis after total hip arthroplasty. METHODS We compared enoxaparin and adjusted-dose warfarin with respect to their safety and their efficacy in the prevention of clinically important venous thromboembolic disease, defined as distal or proximal deep venous thrombosis or pulmonary embolism, or both, during hospitalization after total hip arthroplasty. We also evaluated the prevalence of complications and mortality from venous thromboembolic disease within three months after discharge. RESULTS Three thousand and eleven patients at 156 centers were randomly assigned to prophylactic treatment with injection of enoxaparin or oral administration of adjusted-dose warfarin during hospitalization. During the study, fifty-five (3.6 percent) of the 1516 patients who were managed with enoxaparin and fifty-six (3.7 percent) of the 1495 patients who were managed with warfarin had venous thromboembolic disease. Twenty-one patients (0.7 percent), which included four (0.3 percent) of those managed with enoxaparin and seventeen (1.1 percent) of those managed with warfarin (p = 0.0083), had venous thromboembolic disease during hospitalization. After discharge from the hospital, venous thromboembolic disease developed in ninety patients (3.0 percent): fifty-one (3.4 percent) of those managed with enoxaparin and thirty-nine (2.6 percent) of those managed with warfarin. One patient who had been managed with enoxaparin died because of a pulmonary embolism, which was confirmed at autopsy. Three additional patients (one who had been managed with enoxaparin and two who had been managed with warfarin) died, and the deaths were attributed to venous thromboembolic disease; however, no autopsies were performed. Twenty-six patients (0.9 percent) (eighteen managed with enoxaparin and eight managed with warfarin) had clinically important bleeding. CONCLUSIONS Inpatient programs providing treatment with either enoxaparin (thirty milligrams every twelve hours) or adjusted-dose warfarin for a mean of 7.3 days afforded protection against venous thromboembolic disease, with overall rates of morbidity and mortality of 3.7 and 0.6 percent, respectively, and a very low rate of major bleeding complications (0.9 percent) for three months after total hip arthroplasty. During hospitalization, the patients managed with enoxaparin had a lower rate of venous thromboembolic disease than those managed with adjusted-dose warfarin (p = 0.0083). This benefit was lost after the medication was discontinued, with no difference in the prevalences of venous thromboembolic disease between the two groups at three months after discharge from the hospital.

The effect of preoperative exercise on total knee replacement outcomes.

This study compared the effects of preoperative physical therapy or general cardiovascular conditioning exercises with the routine procedure of no preoperative physical therapy on patients undergoing primary total knee replacement. Thirty patients were randomly assigned to 1 of 3 groups. Group 1 was the control group. Group 2 participated in a physical therapy program designed to strengthen the upper and lower limbs and improve knee range of motion. Group 3 participated in a cardiovascular conditioning program, consisting of arm ergometry, cycle ergometry, aquatic exercises, and aerobic activity. All patients were evaluated preoperatively and postoperatively using the Hospital for Special Surgery Knee Rating, the Arthritis Impact Measurement Scale, and the Quality of Well Being instrument. Both experimental groups tolerated their respective exercise protocols extremely well. All 3 groups showed significant improvement postoperatively as measured by the Hospital for Special Surgery Knee Rating, the Arthritis Impact Measurement Scale and the Quality of Well Being measurement scales. However, neither type of preoperative exercise added to the degree of improvement after surgery at any of the postoperative evaluations.

Hemodilution with other blood reinfusion techniques in total hip arthroplasty

Acute normovolemic hemodilution has been reported to result in blood savings varying from 18% to 90%. Very few of these are randomized prospective studies. This study attempts to determine the blood transfusion savings if acute normovolemic hemodilution is used in combination with autologous predonated blood and cell saver. Thirty-three patients undergoing total hip arthroplasty were assigned randomly to one of two groups (control, n = 16; hemodilution, n = 17). Patients in both groups entered an autologous predonation program if cleared medically and were placed on Cell Saver intraoperatively and in the postanesthesia care unit. In addition, the hemodilution group underwent acute normovolemic hemodilution preoperatively. Only 41% of the patients in the hemodilution group required any autologous blood transfusion as compared with 75% of the control group. In addition, the hemodilution group required a mean lower quantity of autologous blood transfusion (41% of the estimated blood loss) as compared with the control group (71%). The net anesthesia time increased by an average of 11.4 minutes in the hemodilution group. Acute normovolemic hemodilution is a safe procedure even in an older patient population. Hemodilution resulted in fewer patients needing autologous predonated blood transfusions. The major benefit of hemodilution was seen when predonation was not possible.

Two-dose epoetin alfa reduces blood transfusions compared with autologous donation.

This study evaluated whether patients receiving a two-dose regime of epoetin alfa received less allogeneic blood than patients donating autologous blood before primary hip arthroplasty. Consenting patients with a hemoglobin level between 12 and 15 g/dL were randomly assigned to a two-dose administration of epoetin alfa (19 patients) or autologous donation (21 patients). Sixteen percent of the patients in the epoetin alfa group and 52% of the patients in the autologous donation group received transfusions, with a mean volume of 90 cc per patient in the epoetin alfa group and 340 cc in the autologous donation group. Hemoglobin was similar at screening; however, the epoetin alfa group achieved a higher hemoglobin (14.6 g/dL) than the autologous donation group (12.6 g/dL) before surgery. Hemoglobin remained significantly higher in the epoetin alfa group for 3 days after surgery. Administration of two doses of epoetin alfa provided patients with effective and safe reduction of allogeneic blood transfusions and decreased the necessity and difficulty of autologous donation before total hip arthroplasty.

The use of handheld technology in nursing research and practice.

Use of handheld devices with electronic patient diaries (EPDs) can improve the quality of patient-reported information collected in clinical and research settings. EPDs have advantages compared with traditional paper-based instruments that include decreased data entry error and decreased time spent on data management. Orthopaedic pain management, which is often dependent on patient-reported pain levels, can benefit from the use of EPDs. A pilot survey was conducted to compare two self-report pain diary methods in shoulder surgery patients: (a) EPD or (b) paper entry. Compliance was lower in the EPD group, which was attributed to insufficient ease of use. Handheld technology can be used by nurses to improve and streamline patient care by capturing clinical data, by organizing and reporting home health services, and by providing references for evidence-based practice. Handheld technology can facilitate the transformation of clinical documentation of assessments, interventions, and outcomes into evidence-based decision making in orthopaedic nursing.

Early Dislocation Rate in Ceramic-on-Ceramic Total Hip Arthroplasty

Wear debris from metal-on-polyethylene articulation in conventional total hip arthroplasty (THA) may limit THA longevity. Bearing surfaces made of modern ceramic material, with high wear resistance and low fracture risk, have the potential to extend the longevity of THA and make the procedure more suitable for young, active patients. Concerns regarding a ceramic-on-ceramic bearing surface have included potential for a higher incidence of dislocation caused by limited modular neck length and liner options. This prospective study assessed the early dislocation incidence for a ceramic-on-ceramic THA system. Out of the 336 consecutive ceramic-on-ceramic THA performed at our institution over an 8-year (1997–2005) period, 2 (0.6%) sustained dislocation during, and none after, the first postoperative year. Both dislocations were treated with closed reduction. No component fracture or revision for any reason has occurred in this series.

Thrombosis Incidence in Unilateral vs. Simultaneous Bilateral Total Knee Arthroplasty with Compression Device Prophylaxis

This study compares the incidence of venous thromboembolic event (VTE) in 55 patients (110 knees) undergoing simultaneous bilateral TKA with 287 patients (287 knees) undergoing unilateral TKA using a mobile compression device as monotherapy prophylaxis in both groups. All patients were clinically evaluated 3months after surgery with symptomatic confirmed VTE as an endpoint. Deep venous thrombosis (DVT) was documented by duplex ultrasound and pulmonary embolism (PE) was documented by spiral CT. The simultaneous bilateral TKA group had 6 VTEs (10.9%) with 2 PEs (3.6%). The unilateral TKA group had 9 VTEs (3.1%), and 0 PE. Patients undergoing simultaneous bilateral TKA yielded more than twice the rate of VTE compared with patients undergoing unilateral TKA using a mobile compression device as sole thromboprophylactic modality.

Erythrocyte viability in blood salvaged during total joint arthroplasty with cement.

Background: Erythrocyte salvage, the collection of a patient’s blood shed from the surgical wound, is one aspect of blood management. Previous investigators have examined salvaged blood for content; however, to our knowledge, none have examined the viability of erythrocytes after exposure to the chemical and thermal reactions produced by motorized instruments and polymethylmethacrylate during surgery. The purpose of this study was to determine the viability of salvaged erythrocytes from patients undergoing primary total joint arthroplasty with cement. Methods: Erythrocyte viability studies were performed on specimens from three subjects with use of a double isotope-labeling technique employing chromium-51 and technetium-99m. With use of a fresh blood specimen obtained prior to surgery and a specimen of salvaged blood that had been recycled, washed, and filtered with use of the Cell Saver, the viability of the Cell-Saver-processed erythrocytes, labeled with chromium-51, was calculated on the basis of the technetium-99m-labeled red blood-cell mass. Results: The mean erythrocyte viability (and standard deviation) in blood salvaged with use of the Cell Saver was 88.0% ± 3.8%. The standard of the American Association of Blood Banks for minimum erythrocyte viability in adequately cross-matched allogeneic blood or predeposited autologous blood is 70%. Conclusions: The high rate of viability of the erythrocytes in this study shows that the Cell Saver is a valuable adjunct to other blood management techniques for patients having total joint arthroplasty. We believe that the very high mean rate of erythrocyte viability and the extremely small standard deviation in our three subjects, as compared with the standards of the American Association of Blood Banks, made additional study subjects unnecessary.

A mobile compression device compared with low-molecular-weight heparin for prevention of venous thromboembolism in total hip arthroplasty.

INTRODUCTION: Prevention of venous thromboembolism (VTE), including deep venous thrombosis (DVT) and pulmonary embolism (PE), has been at the forefront of orthopaedic care for many years for lower extremity arthroplasty, which is at high risk for VTE. Risk of bleeding increases in total hip arthroplasty (THA) with low-molecular-weight heparin (LMWH) prophylaxis. A mobile compression device (MCD) that allows patients to move freely in hospital and at home may be safer. HYPOTHESIS: The study hypothesized that patients using MCD would have less major bleeding than patients using LMWH without affecting the efficacy of thrombosis prevention in THA. SAMPLE: Following THA, 395 patients at 9 healthcare sites in the United States were randomized to receive either MCD or LMWH for VTE prophylaxis. METHODS: A mobile compression device was applied in the operating room and continued for 10 days with or without aspirin 81 mg daily. Low-molecular-weight heparin was started the morning after surgery and continued for 10 days. Days 10–12 following surgery, bilateral duplex ultrasound was performed on all patients. Bleeding events were recorded during treatment and VTE events were recorded for 3 months. Number of hours of device use was recorded. FINDINGS: Major bleeding events occurred in 11 patients, all in the LMWH group (6%). Venous thromboembolism occurrence was similar, 5.1% in the MCD group and 5.3% in the LMWH group. The MCD group used the device 83% of possible usable time. DISCUSSION: Findings of significantly less major bleeding in the MCD group than the LMWH group supported our hypothesis with no significant difference in VTE.

Unicompartmental knee arthroplasty (alias uni-knee). An overview with nursing implications.

During the past 30 years, the unicompartmental knee arthroplasty has undergone growing pains with various implant designs, refining indications, and improving surgical techniques and instrumentation. Today, studies show survivorship results comparable to the tricompartmental total knee arthroplasty and a renewed interest has emerged. Even though the unicompartmental knee arthroplasty is recommended for only a select 10-15% who have osteoarthritis of the knee, it has many advantages over the total knee arthroplasty. Although the nursing care and rehabilitation are similar to the total knee arthroplasty, including wound care, prophylactic antibiotics, and venous thromboembolism prophylaxis, the patient frequently has less pain, increased range of motion, shorter hospitalization, and fewer complications, resulting in a quicker rehabilitation.