Effects of anticoagulation on markers of activation of clotting following major orthopedic surgery.

INTRODUCTION: This study examines makers of activation of clotting following three chemoprophylactic regimens used for prevention of postoperative venous thromboembolic disease (TED) following high-risk surgery for TED. METHODS: Patients having elective primary knee or hip replacement surgery received variable dose warfarin (target international normalized ratios 2.0-2.5), 1 mg warfarin daily starting 7 days preoperatively or aspirin 325 mg daily starting on the day of surgery. Twelve patients in each group were treated for 28 ± 2 days. Thrombin-antithrombin (T-AT) and prothrombin fragment F1 + 2 were measured at baseline and postoperative days 3 and 28 ± 2. RESULTS: Thrombin-antithrombin and F1 + 2 on postoperative day 3 were equal for the study groups. By days 28 ± 2, variable dose warfarin therapy group suppressed production of F1 + 2 (P = 0.002) with no difference in the T-AT accumulation. F1 + 2 for other patients overlapped the normal range. CONCLUSION: The signals of activated clotting following surgery did not differentiate the three regimens on postoperative day 3. Variable dose warfarin was associated with suppression of F1 + 2 after 1 month of therapy, with no effect on accumulation of T-AT. Fixed low-dose warfarin started 7 days prior to surgery and aspirin are not inferior on postoperative day 3, but appear to be inferior over a longer treatment.

Clinical effectiveness and cost-effectiveness of 2 management strategies for infected total hip arthroplasty in the elderly.

Optimal management of infected total hip arthroplasty poses a major challenge to clinicians. Exchange arthroplasty is usually advocated but has high rates of surgical morbidity and is expensive. Debridement with prosthesis retention is associated with less morbidity, but high rates of relapsed infection have been described. To estimate the effectiveness and cost-effectiveness of these 2 strategies among older patients, we used a Markov model to simulate patients' projected lifetime clinical course in hypothetical cohorts of 65-year-old and frail 80-year-old men and women. Initial debridement and retention increased life expectancy 2.2-2.6 quality-adjusted life months and had a favorable cost-effectiveness ratio in all cohorts. Results were most sensitive to the annual rate of relapse after debridement and age at initial diagnosis of infection. In the absence of prospective clinical trials, debridement and retention is a reasonable strategy for treatment of older persons with staphylococcal or streptococcal infection and a nonloosened prosthesis.

Transesophageal echocardiographic monitored events during total knee arthroplasty.

Although the risk of pulmonary embolism or other embolic events associated with total joint arthroplasty have been recorded for some time, to date no direct means of monitoring these events in human arthroplasty have been reported. The authors used transesophageal echocardiography to monitor directly the release of embolic particles into the circulatory system during the course of total knee arthroplasty. The transesophageal echocardiography, in conjunction with intramedullary instrumentation, revealed that showers of embolic particles entered the heart in repeated and unpredictable patterns during the course of conventional intramedullary instrumented total knee procedures. In response to the presence of these embolic showers in the heart, an extramedullary pneumatically positioned system of instrumentation permitting automatic and accurate alignment of the knee with the mechanical axis of the femur has been developed. This new instrumentation establishes proper knee kinematics by semiautomatically determining and maintaining accurate positioning of the femoral component along the mechanical axis of the knee. Qualitative and quantitative monitoring of embolic events using transesophageal echocardiography in conjunction with conventional intramedullary and the new instrumentation suggests that the embolic risk is substantially reduced using the new procedure. Furthermore, the new extramedullary instrumentation was able to align the femoral knee component to within 1 degree of the mechanical axis in an initial series of 25 procedures. Excellent component alignment in conjunction with a substantially reduced quantity of embolic particles in the right heart as seen using transesophageal echocardiography was achieved using the newly developed extramedullary positioning and alignment arm.

Occlusion of the external iliac vein by cement.

The case of an 80-year-old woman who sustained occlusion of the external iliac vein by methyl methacrylate cement following total hip arthroplasty is presented. The cement was removed via a pelvic approach without the need for revision of the acetabular cup and led to resolution of her symptoms.

Using patient reports to assess health-related quality of life after total hip replacement.

Data on disease severity, co-morbidity, and process of care were obtained from the medical records of 356 patients without rheumatoid arthritis undergoing a first unilateral total hip replacement at four teaching hospitals in California and Massachusetts. Socio-demographic characteristics, functional status prior and subsequent to hospitalization, and improvement in health status were measured with a patient questionnaire 12 months after discharge. Completed questionnaires were received from 284 patients, a response rate of 79.8%. The questionnaire was acceptable to patients, reliable, and had good construct validity. The data indicate substantial benefits from hip arthroplasty. As expected, pre-surgical functioning was a strong predictor of outcomes 1 year after surgery. Controlling for pre-surgical functioning, age was not related to outcomes.

The use of bone allografts in two-stage reconstruction after failure of hip replacements due to infection.

Bone allografts were used to reconstruct deficient acetabular and femoral bone in eighteen patients during two-stage revision of a hip arthroplasty that had failed due to infection. At a mean of 4.2 years after reimplantation, only two patients had had recurrence of the infection. Four patients needed another revision arthroplasty for reasons other than infection. These results suggest that allografts of bone are useful for the reconstruction of osseous deficiencies in carefully selected patients who have a hip arthroplasty after infection. The results do not support the concern that allografts that are used under these circumstances necessarily lead to a high rate of recurrence of infection. However, the long-term results of the use of allografts in hip arthroplasty after infection remain unknown.

Prospective comparative study of cefotetan with piperacillin for prophylaxis against infection in elective colorectal surgery.

This study compared one dose of cefotetan with three doses of piperacillin as prophylaxis against wound infection in 153 patients undergoing elective colorectal surgery. The patients were randomized into two groups: the first received 2 g cefotetan intravenously with induction of anaesthesia (n = 75), and the second received three doses of 2 g piperacillin (n = 78). Wound infection was defined as the presence of an abscess or discharging pus from the wound. In the cefotetan group there were 14 (19%) wound infections and 13 (17%) in the piperacillin group. There were three septic deaths, one in the cefotetan group and two in the piperacillin group. Both groups were comparable with regard to age, sex, nature of pathology and pre- and perioperative risk factors. No significant haematological or biochemical abnormalities were detected. The only adverse reaction was one patient who had an allergic reaction (rash) to piperacillin. These data suggest that single-dose cefotetan is as effective as triple-dose piperacillin in prophylaxis against infection in elective colorectal surgery.

Intraperitoneal placement of gentamicin beads in the management of prosthetic graft sepsis.

A simple and non-hazardous technique for intraperitoneal placement of gentamicin beads after excision of an infected prosthetic aortic graft is presented. It has been used successfully in six cases of aortic graft sepsis.

Vascular graft infection: the role of indium scanning.

Infection of a prosthetic graft is one of the most feared complications of vascular surgery. The difficulties of accurate, objective diagnosis are well recognised. We have used III Indium labelled white blood cell scans (InWBC) in two groups: 9 control patients who underwent uncomplicated aortic aneurysm surgery, and 23 patients with suspected graft sepsis. In the control group there was one positive scan in a patient with an inflammatory aneurysm. In the suspected sepsis group, 11 patients subsequently has proven graft sepsis. Nine were correctly predicted by Indium scanning. Ten of 12 patients who did not have proven graft sepsis had negative scans. There was a total of 5 inflammatory aneurysms in the control and suspected sepsis groups, of whom two had positive scans. False positive scans were not present in the early postoperative period i patients without inflammatory aneurysms. In our experience Indium labelled WBC scanning for suspected graft sepsis has a accuracy of 83% a negative predictive value of 83% and a positive predictive value of 82%. These results suggest that Indium white cell labelling techniques which do not involve substantial cross-labelling of platelets are the best objective methods of establishing the presence or absence of graft sepsis.

Diagnostic imaging evaluation of the postoperative patient following musculoskeletal trauma.

Diagnostic imaging is often used to document the progression of healing and diagnose complications in the patient with musculoskeletal trauma. Common types of fixation devices and their complications are discussed. Guidelines for acceptable positioning and alignment are described.

Prophylactic methods against thromboembolism.

Deep vein thrombosis and pulmonary embolism are significant hazards of surgery, especially in orthopedic procedures. However, the true incidence of these complications is unknown. Many surgeons are now using prophylactic methods to prevent the postoperative occurrence of thromboembolic disease. Pneumatic compression devices are recommended in some instances, especially in cases where increased bleeding could be devastating. Several pharmacologic agents are also used, alone or in combination with pneumatic devices. These include subcutaneous heparin, warfarin, dextran, and aspirin. Each agent has advantages and disadvantages. The US National Institutes of Health (NIH) and numerous ongoing clinical trials are attempting to establish recommendations and guidelines for the use of prophylaxis against postoperative deep vein thrombosis and pulmonary embolism.