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Biomedical subjects

S T Woolson

Publications and source records attributed to S T Woolson.

At least 19 recordsLinked to original sources
PubMed1992

Cementless total hip arthroplasty using a porous-coated prosthesis for bone ingrowth fixation. 3 1/2-year follow-up.

The clinical and radiologic results of a consecutive series of 59 patients (69 hips) who had primary total hip arthroplasty using cementless prostheses was studied. Harris-Galante acetabular and femoral prostheses, which have a porous fiber-metal mesh coating intended to encourage bone ingrowth fixation, were used in all cases. Two femoral components were revised during the follow-up period, one for aseptic loosening and the other for late septic loosening. In the remaining 67 hips, the average Harris hip score rose from a preoperative 52 to 94 at the last follow-up examination (average follow-up period, 44 months). Eighty-eight percent of these hips had an excellent result (Harris hip score of 90 or more). Radiologic analysis demonstrated that all the acetabular components were stable. Eighty-three percent of the femoral components appeared to have stable bone ingrowth fixation, five components (7%) had stable fibrous ingrowth, and seven (10%) were unstable. Parallel radiodense lines were seen around the smooth portion of the stem in 93% of hips, but this finding appeared to have no clinical importance. Significant stress shielding of the proximal femur was seen in 16% of hips. Endosteal lysis of the distal femur occurred in 22% of hips, including large lesions in two patients who will require future revision surgery because of femoral diaphysis weakening. Femoral lysis was not associated with hip or thigh pain and was most common in young, male patients who had high activity levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Piriformis tendon repair failure after total hip replacement.

Posterior hip dislocation is a common complication after total hip replacement. Some authors recommend repair of the short external rotator tendons to stabilize the hip joint postoperatively. We evaluated the efficacy of repair of the piriformis tendon in 10 consecutive total hip replacement cases. Eight of the 10 repairs failed during the early postoperative period, and one of the two repairs that did not fail was in the only patient to sustain a posterior dislocation. We believe that repair of the piriformis tendon is of no significant benefit to the stability of a total hip replacement joint.

Hip Dislocation↗
PubMed1991

Venous ultrasonography in the detection of proximal vein thrombosis after total knee arthroplasty.

A prospective study of the accuracy of real-time B-mode ultrasonography in detecting deep venous thrombosis in the proximal veins of the lower extremity was conducted in a consecutive series of total knee arthroplasty (TKA) patients. Ascending venography was used as the diagnostic standard. Ninety-six consecutive TKA procedures performed in 68 patients were considered. Eight extremities were excluded because paired ultrasonic and venographic studies were not performed. Eighty-eight extremities in 61 patients had paired studies (bilateral venous ultrasonography of the proximal veins and venography of the operated extremity), and were done at an average of eight days postoperatively. Both tests were done within 24 hours of each other (98% on the same day) and the radiologist and ultrasound technologist were blinded to the results of the others' study. Both tests were negative for proximal (common femoral through the popliteal vein) thrombosis in 72 extremities. Ten extremities had positive-paired tests for proximal thrombosis that correlated for thrombus size and location. There were five false-negative and one false-positive ultrasound studies for a sensitivity of 67%, a specificity of 99%, and an overall accuracy of 93%. Considering the 54 extremities that were examined after the vascular laboratory had gained considerable experience in venous imaging, the ultrasonic sensitivity, specificity, and overall accuracy rose to 83%, 100%, and 96% respectively. The authors believe that venous ultrasonography is accurate in the diagnosis of proximal vein thrombosis after TKA when the noninvasive vascular laboratory has experience with such studies.

Adult↗
PubMed1991

Use of autologous blood in total hip replacement. A comprehensive program.

We evaluated the effectiveness of a comprehensive program for the use of autologous blood in reduction of the need for transfusion of homologous blood in total hip replacement in a prospective study of a consecutive series of patients. Transfusion of homologous blood was minimized through transfusion of preoperatively deposited autologous blood, intraoperative and postoperative salvage of washed red blood cells, and use of the clinical condition of the patient as the sole criterion for transfusion of non-autologous blood, regardless of the hematocrit. The cases of 143 patients who had had 154 primary total hip replacements were studied. One hundred and forty-three procedures were done on patients who had not been prevented from donating blood for medical reasons, and 93 per cent of these 143 procedures were performed with the availability of one to five units of preoperatively deposited autologous blood. The patients predeposited an average of 2.6 units of blood for each procedure. Ninety-two per cent of the procedures for which autologous blood had been predeposited were performed without transfusion of homologous blood. In the entire group of patients, almost 90 per cent of the transfused blood was autologous blood. Intraoperative salvage of red blood cells was successful in 148 procedures, and salvage was continued in the recovery room for all of these patients. An average of 408 milliliters of red blood cells was saved and reinfused, and this was 28 per cent of the average total loss of blood (1435 milliliters) for this series of procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Intermittent pneumatic compression to prevent proximal deep venous thrombosis during and after total hip replacement. A prospective, randomized study of compression alone, compression and aspirin, and compression and low-dose warfarin.

A prospective, randomized study of the effectiveness of intraoperative and postoperative use of intermittent pneumatic compression, alone or in combination with oral administration of either aspirin or low-dose warfarin, was done of a consecutive series of patients who had a total hip replacement and were more than thirty-nine years old. All patients began walking by the third postoperative day. One hundred and ninety-six patients who had 217 total hip arthroplasties were included. Twenty-eight per cent of the procedures were revisions of a previous total hip replacement or of an endoprosthesis, and the remainder were primary arthroplasties. Patients were randomized as to the type of prophylaxis that they received: intermittent pneumatic compression alone, seventy-six hips; intermittent pneumatic compression and aspirin, seventy-two hips; or intermittent pneumatic compression and low-dose warfarin, sixty-nine hips. Before discharge from the hospital, and at an average of seven days after the operation, all patients were evaluated for the presence of proximal deep-vein thrombosis with either venography on the side of the operation or with bilateral venous ultrasonography. The relative frequency with which thrombosis occurred in a proximal vein was not significantly different in the three groups; the over-all relative frequency was 10 per cent. Intermittent compression during and after the operation effectively reduces the rate of proximal-vein thrombosis after total hip replacement. With the number of patients in our study, the effectiveness of this technique could not be shown to be augmented by oral administration of either aspirin or low-dose warfarin.

Adult↗
PubMed1990

Leg length equalization during total hip replacement.

A method of equalization of leg lengths during total hip replacement surgery was developed which utilizes the concept of equalizing the vertical dimensions of the resected femoral head and neck segment and the remaining hip joint cartilage space, which are removed during the procedure, with the vertical dimensions of the femoral and acetabular prostheses, which are implanted into that void. This was accomplished by determining the dimensions of the prostheses from careful preoperative templating technique and by using a simple arithmetic formula to determine the level of the femoral neck osteotomy. The level of the osteotomy was made by a measurement from the top of the dislocated head of the femur to the medial femoral neck calcar. The radiologic postoperative leg length differences of a consecutive series of 84 patients undergoing primary total hip replacement using this method were determined. The average discrepancy was 2.8 mm. Seventy-five patients (89%) were found to have a postoperative leg length discrepancy of 6 mm (1/4 inch) or less. Six patients (7%) had a discrepancy of 7 to 13 mm, and only three patients (4%) had more than 13 mm (1/2 inch) leg length difference. Using this technique only two patients (2.5%) with unilateral hip replacements had leg lengthening of more than 6 mm.

Anthropometry↗
PubMed1990

B-mode ultrasound scanning in the detection of proximal venous thrombosis after total hip replacement.

A prospective study of the accuracy of real-time B-mode ultrasonography in detecting deep venous thrombosis in the femoral and popliteal veins of the lower extremity was conducted on a consecutive series of patients who had had a total hip replacement. Ascending venography was used as a diagnostic standard. One hundred and forty-three patients had ultrasound studies of both lower extremities and a venographic study of the operatively treated lower extremity at an average of 7.6 days postoperatively. The two tests were done within twenty-four hours of each other. Both ultrasonography and venography were done on 152 extremities. Two paired studies were excluded from the analysis of results because the ultrasound scans could not be interpreted. In 131 extremities, both diagnostic tests were negative for proximal thrombosis. Eight extremities had isolated thrombosis of a vein in the calf that was detected only by venography. In nineteen extremities, old or fresh thrombosis was diagnosed by venography. In four extremities, an old thrombosis of the superficial femoral vein was detected by both studies. In four of the extremities that had a new thrombus in the common femoral vein and in nine that had a new thrombus in the superficial femoral vein, abnormal findings on ultrasound scans correlated with those on venograms. There were two false-negative ultrasound scans and one false-negative venogram. The sensitivity, specificity, and accuracy of ultrasonography were 89, 100, and 99 per cent for the diagnosis of thrombosis of the proximal veins of the lower limb and 63, 100, and 93 per cent for the diagnosis of thrombosis when the entire venous system of the limb was included.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Clinician-directed hospital cost management for total hip arthroplasty patients.

Can patients treated with total hip arthroplasty (THA) receive high-quality inpatient care at less cost? In 1984, a group of orthopedic surgeons and nurses examined the use of resources for THA patients and changed certain clinical practices to promote more cost-effective hospital care. At the end of the two-year project, orders for complete blood counts fell 72% and mean operating room time dropped 47 minutes for the participating orthopedists. For all orthopedists in the division, average length of stay (ALOS) decreased from 13 to 11 days. By the end of the following year, when clinicians received quarterly length-of-stay (LOS) data, ALOS dropped further to 9.8 days. This significant ALOS reduction was not accompanied by an increase in hospital readmissions or nursing home placements. The ALOS reduction was also not seen in elective coronary artery bypass graft patients whose ALOS did not substantially change over the same period. Two years after the project, ALOS for THA patients remained at ten days or below. This reduction in LOS and in the use of other hospital services translated into a mean total hospital charge decrease of $2045 per THA patient.

Cost Control↗
PubMed1989

External iliac arteriovenous fistula following total hip arthroplasty. A case report.

An external iliac arteriovenous fistula developed 3 years after revision of the acetabular component of a total hip arthroplasty in a patient with rheumatoid arthritis. The mechanism of this complication, which also produced disseminated intravascular coagulopathy, was chronic erosion of the iliac artery from a large bolus of bone cement and/or the protrusio shell that were used to reconstruct a severe acetabular protrusio. Care must be taken to avoid intrapelvic intrusion of hardware or cement during acetabular reconstruction to avoid immediate and late injury to the iliac vessels.

Adult↗
PubMed1989

A clinical-pathologic-biochemical study of the membrane surrounding loosened and nonloosened total hip arthroplasties.

The clinical and roentgenologic data from 31 excised components from 19 revision arthroplasty cases were correlated with the histology and biochemistry of the membrane at the bone-cement or bone-prosthesis interface. Twenty-seven components were cemented and four were uncemented. Twenty-four implants were clinically and roentgenologically loose, one was possibly loose, and six were well fixed. Loose components, whether cemented or not, demonstrated statistically higher prostaglandin E2 levels in the surrounding membrane compared to the nonloose group. Collagenase and M-collagenase levels were absent or insignificantly low in all specimens; no detectable interleukin 1 beta was found. This suggests that prostaglandin E2 may be associated with the bone lysis associated with prosthesis loosening.

Bone Cements↗
PubMed1989

Postoperative blood salvage using the Cell Saver after total joint arthroplasty.

The purpose of this study was to investigate whether the salvage in the recovery room of blood from the drainage tubes of patients who had total joint arthroplasty was both feasible and efficacious. The cases of seventy-four patients who had seventy-six consecutive total hip or knee arthroplasties were studied prospectively. Intraoperative salvage of blood was performed using the Cell Saver. After closure of the fascial layer or joint capsule, the drainage tubes were connected to the Cell Saver in the operating room and remained connected in the recovery room for a mean of 2.9 hours. Blood that was collected in the recovery room was then processed and transfused back to the patient. The average amount of blood that was salvaged after different types of arthroplasty varied. The addition of bone cement to the acetabular side during primary total hip replacement decreased the amount of postoperative bleeding and of salvaged blood (p = 0.018), whereas cementing the femoral component had no statistically significant effect. Revision total hip replacement also resulted in more bleeding and in the collection of more blood in the recovery room than did primary total hip replacement (p = 0.03), especially if cement was not used (p less than 0.001). There were no statistical differences in the amount of blood that was collected in the recovery room after unilateral, bilateral, primary, or revision total knee replacement.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Transfusion, Autologous↗
PubMed1987

Total joint arthroplasty for steroid-induced osteonecrosis in cardiac transplant patients.

Ten cardiac transplant patients have had bilateral total hip or knee surgery for treatment of osteonecrosis secondary to corticosteroid immunosuppression. Nine had bilateral total hip arthroplasty and one had bilateral total knee arthroplasty for osteonecrosis of the tibial plateaus. The only immediate postoperative complication was in a single hip patient who had a nonfatal pulmonary embolism. Two patients died from cardiovascular causes; the remaining eight had excellent results from arthroplasty, with an average Harris hip rating of 95 at a mean follow-up period of 34 months. No patient had required revision surgery and radiographic follow-up examination has revealed no evidence of loosening of any of these cemented arthroplasties. One patient developed a late hematogeneous sepsis of one hip seven years after replacement from atypical mycobacterium three months following renal transplantation, which was done 11 years after cardiac transplantation. Total joint arthroplasty has resulted in excellent clinical and radiologic results in this patient population. Despite the increased risks of major surgery in these immunocompromised transplant recipients, total joint arthroplasty appears to be a safe and effective method of treatment of osteonecrosis of the hip.

Adrenal Cortex Hormones↗
PubMed1987

Transfusion of previously deposited autologous blood for patients undergoing hip-replacement surgery.

The efficacy of a program of transfusion of previously deposited autologous blood for patients undergoing total hip-replacement surgery was studied by comparing five different parameters for a group of fifty consecutive patients who deposited blood for autologous transfusion and a randomly chosen, closely matched control group of fifty patients who received only homologous blood. Sixty-two per cent of the patients in the group that deposited autologous blood did not receive additional homologous blood while in the hospital. The patients who deposited autologous blood had a mean preoperative hematocrit of 36 per cent, compared with 39 per cent for the control group, but the average postoperative hematocrits of the two groups did not differ (33 per cent). There was no significant difference in the average total loss of blood or need for replacement of blood between the groups. Transfusion-related complications developed in two patients in the control group. We concluded that previous deposit of autologous blood for transfusion is an effective method for reducing the need for transfusion of homologous blood and for avoiding the attendant complications of transfusion of homologous blood. This method of the replacement of blood should be considered for patients who are to undergo a major orthopaedic procedure on the hip.

Aged↗
PubMed1986

Three-dimensional imaging of bone from computerized tomography.

An automatic computer technique was designed to produce three-dimensional (3D) images of bony anatomy on a cathode ray tube (CRT) from computerized tomography (CT) data. The authors transferred CT scan data of a cadaver and 11 patients to a computer system via magnetic tape. An automatic edge extraction algorithm generated an outline of bone specified by a range of CT numbers for each scan slice. These outlines were stacked in the computer and various graphics options used to represent the 3D anatomy of bone on a high-resolution CRT screen. The 3D image data were interfaced with a three-axis computer numerically controlled milling device to produce solid models of these bone images. Comparison of the dimensions of the solid models of the femur, hemipelvis, and femoral medullary canal to the actual cadaver specimen demonstrated that the models were accurate in size to within 1-3 mm. These 3D images and solid models will be helpful for preoperative diagnosis, surgical planning, and customized prosthesis manufacture in complex orthopaedic cases.

Bone and Bones↗
PubMed1986

Greenfield vena caval filter for management of selected cases of venous thromboembolic disease following hip surgery. A report of five cases.

The use of the Greenfield vena caval filter for thromboembolic disease following major hip surgery is an important part of the orthopedist's armamentarium for treatment of complications or contraindications to standard anticoagulation therapy. The authors report five cases in which a Greenfield vena caval filter was employed for treatment of a femoral thrombus or pulmonary embolism in postoperative hip patients who developed bleeding complications from heparin, had a recurrent embolism while on heparin, or who had had a contraindication to anticoagulation therapy.

Aged↗
PubMed1985

Three-dimensional imaging of the ankle joint from computerized tomography.

A computer system was developed to rapidly reconstruct three-dimensional (3D) images of bone from computerized tomography scans of the ankle joint. Solid models of the bones were produced from the 3D image data through the use of a computer numerically controlled milling machine. A cadaver ankle joint was scanned, and models of the distal tibia and fibula and dome of the talus were made and compared to the actual bone specimens. The measurements of the models were within 3 mm or less of the bones in all three planes (average, 1.2 mm or 5.5%). These 3D images and models of bone should allow better visualization of joint pathology and a system for preoperative planning on exact bone models to optimize the results of surgery.

Ankle Joint↗