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Biomedical subjects

D C Hardy

Publications and source records attributed to D C Hardy.

At least 19 recordsLinked to original sources
PubMed2000

The chronic ventilator-dependent unit: a lower-cost alternative to intensive care.

OBJECTIVE: To evaluate the fixed costs and patient outcomes of a specialty hospital unit for medically stable ventilator-dependent patients. The chronic ventilator-dependent unit (CVDU) was established to facilitate early dismissal from costly intensive care unit (ICU) hospitalization for patients requiring continued specialized care. PATIENTS AND METHODS: We carried out a cost analysis of the various ICUs that transferred patients to the CVDU by year from 1993 through 1998. In addition, direct and indirect costs for the CVDU were established by year for the same period. We then calculated the cost effect of transferring these patients for care from each high-cost ICU to the lower-cost CVDU. Ventilator weaning and mortality rates were also determined. RESULTS: During the 6 years of this study, $4,832,551 in patient care costs were saved by transferring care for 964 patients from ICUs to the CVDU. Ventilator weaning was successful in 64% of 549 patients, and mortality was 7% in the same patient group. CONCLUSIONS: Care in the CVDU yielded lower fixed costs per patient-day, and CVDU care was comparable to ICU hospitalization.

Cost Savings↗
PubMed1999

Histopathology of a well-functioning hydroxyapatite-coated femoral prosthesis after 52 months.

A fully hydroxyapatite-coated femoral implant was retrieved during autopsy. This component, provided with a bipolar femoral head, had been inserted for a displaced fracture of the femoral neck 52 months before. Osseointegration of the implant was evident, without any formation of fibrous tissue :39.9% of the perimeter of the prosthesis at the level of its proximal third was interfaced with bone (62.8% at the mid-third and 65.2% at the distal third). Remodeling of bone had ensued. Deposition of bone was most prominent in the calcar zone, along the medial and lateral aspects and around the tip. Proximally, cortical porosity was found to be increased by 73%, whereas medullary bone porosity was increased by a factor of 2. Cell-mediated resorption of the coating was systematically present in these bone remodeling areas. The average thickness of the coating was respectively 10.8, 50.2 and 151.2 microns in the proximal, mid- and distal thirds of the implant. Formation of new bone was often coupled with resorption. No debris from the coating was found in the joint tissues or in the articulating surface of the polyethylene insert. These overall histopathological features support mechanical stability of the implant and active remodelling of bone along with focal removal of HA coating associated with osteoclastic activity. No side effects from coating degradation could be demonstrated.

Aged↗
PubMed1998

Use of an intramedullary hip-screw compared with a compression hip-screw with a plate for intertrochanteric femoral fractures. A prospective, randomized study of one hundred patients.

One hundred elderly patients who had an intertrochanteric femoral fracture were randomized to treatment with a compression hip-screw with a plate (fifty patients) or a new intramedullary device, the intramedullary hip-screw (fifty patients). All patients were followed prospectively for one year or until death. A detailed assessment of the functional status and the plain radiographs of the hip was performed one, three, six, and twelve months postoperatively. The two treatment groups were strictly comparable. The operative time needed to insert the intramedullary hip-screw was significantly greater than that needed to insert the compression hip-screw with the plate (p = 0.02), but use of the intramedullary hip-screw was associated with less estimated intraoperative blood loss (p = 0.011). The prevalence of perioperative complications, such as bronchopneumonia, cardiac failure, and urinary tract infection, was comparable in the two treatment groups. There were one intraoperative fracture of the femoral shaft and two intraoperative fractures of the greater trochanter in the group managed with the intramedullary hip-screw. One patient had pulling-out of the compression hip-screw on the seventh postoperative day. Four patients had a trochanteric wound hematoma, without infection, after insertion of an intramedullary hip-screw. All but one of the fractures healed. The one non-union, which was in a patient who had a compression hip-screw, was treated with a hemiarthroplasty. The mortality rate was similar in the two treatment groups. The patients who had an intramedullary hip-screw had, on the average, significantly better mobility at one (p < 0.0001) and three months (p = 0.0013) postoperatively. This difference was no longer seen at six and twelve months, although the patients who had an intramedullary hip-screw still had significantly better walking ability outside the home at those time-periods (p = 0.05). The compression hip-screw was removed from two patients because of pain in the mid-portion of the thigh, which had begun after consolidation of the fracture. Fourteen patients who had an intramedullary hip-screw had cortical hypertrophy at the level of the tip of the nail at twelve months postoperatively. Cortical hypertrophy was significantly related to the use of two interlocking screws (p = 0.02). Six of these patients also had pain in the mid-portion of the thigh, and the nail had been locked with two screws in five of them. Three of the six patients had the hardware removed because of the pain, and the symptoms resolved. A seventh patient had pain without cortical hypertrophy. The intramedullary hip-screw device was associated with significantly less sliding of the lag-screw and subsequent shortening of the limb in the region of the thigh (p = 0.012 and 0.019, respectively); these differences were more pronounced when the unstable fractures in the two treatment groups were compared (p < 0.001).

Aged↗
PubMed1997

The Mayo Ventilator-Dependent Rehabilitation Unit: a 5-year experience.

OBJECTIVE: To describe the outcomes of 206 patients admitted to the Mayo Ventilator-Dependent Rehabilitation Unit (VDRU) during a 5-year study period. DESIGN: We analyze the patient data for 1990 through 1994, which had been prospectively entered into a computer database for a cohort of 206 patients who had become ventilator dependent during their current hospitalization. MATERIAL AND METHODS: Patients in the VDRU were classified into one of six categories that reflected the reasons for ventilator dependence. Ability to be weaned from mechanical ventilation, duration of hospital stay and ventilator dependence, outcome, disposition, demographics, and long-term survival were analyzed. The VDRU patient group was compared for hospital and follow-up outcomes with a group of historical control patients previously described by us. RESULTS: The Mayo VDRU was established in January 1990. During the first 5 years of its operation, 206 newly ventilator-dependent patients were admitted to the VDRU, 190 (92%) of whom survived to be dismissed; 16 patients (8%) died in the hospital. Of the 190 patients dismissed, 77% were able to return to their homes. Overall, 153 patients were liberated from mechanical ventilation, whereas 37 remained either completely or partially ventilator dependent. Of these 37 patients, 27 (73%) were receiving nocturnal mechanical ventilation only. The 4-year survival was 53%. CONCLUSION: The Mayo VDRU has been highly successful in liberating newly ventilator-dependent patients from mechanical ventilation. The long-term survival after management in the VDRU has been excellent. In addition, the medical charges for care in the VDRU are less than intensive-care unit charges.

Adolescent↗
PubMed1994

Two-year outcome of hydroxyapatite-coated prostheses. Two femoral prostheses retrieved at autopsy.

We performed a histological study of the bone-implant interface on 2 human femurs implanted with a hydroxyapatite-coated self-locking stem for 2 years. Extensive bone formation with no intervening fibrous tissue was noted around the entire circumference of the 2 prostheses. The newly-formed bone had 2 morphotypes: an alveolar disposition with a continuous contact between bone and hydroxyapatite, and a digitiform one where distinct bony trabeculae were in contact with the ceramic coating or with the bone marrow. Partial or even total resorption of the hydroxyapatite coating was clearly identified, these areas showing bone in contact with the metal.

Aged↗
PubMed1992

Stress fracture of the hip. An unusual complication of total knee arthroplasty.

Stress fracture of the hip is a rare complication of total knee arthroplasty (TKA). Only eight cases seem to have been reported in the literature. A ninth case is reported in the present study. A 76-year-old obese woman was treated by right TKA for osteoarthrosis with cementing of the tibial component because of insufficient primary fixation. One year after TKA, she complained of tenderness above the right adductor tendons. There was no history of trauma. One month later, bone scintigrams and roentgenograms demonstrated a stress fracture of the femoral neck. Conservative management was successful. Etiologic factors such as rheumatoid arthritis, osteoporosis, steroid medication, or changes in static or dynamic forces of the hip secondary to knee arthroplasty could not be demonstrated in this patient. The increase in activity after TKA may be a factor in the incidence of these stress fractures of the hip. Radionuclear-type bone scan is helpful in diagnosis. The foci of increased isotope uptake are not always seen at the site of the stress fracture and only later visualized by roentgenograms.

Aged↗
PubMed1991

X-linked hypophosphatemia: skeletal mass in adults assessed by histomorphometry, computed tomography, and absorptiometry.

PURPOSE AND PATIENTS AND METHODS: X-linked hypophosphatemia (XLH) is the most common inherited form of rickets, yet its influence on skeletal mass in adulthood is controversial and incompletely characterized. Accordingly, we measured bone mass at several skeletal sites using histomorphometric and radiographic techniques in 19 adults (four men) with XLH (age range 20 to 66 years). Most subjects had not received medical therapy for XLH since puberty. RESULTS: Eight of 14 subjects who underwent transiliac bone biopsy had an elevated cancellous bone volume (osteoid and calcified bone), and the group's mean value was supranormal (p less than 0.01). Mineralized bone volume, however, was above normal in only three subjects (NS). Another measure of trabecular bone density, vertebral mineral density by computed tomography, was elevated in three of 13 subjects, and the mean value of the group was increased (p = 0.05). Integral spine bone mineral density (BMD) assessed by dual photon absorptiometry (DPA) was elevated in six of 16 subjects, and the mean was also above normal (p less than 0.01). However, total body calcium, total body BMD (both by DPA), and forearm bone mineral content assessed by single photon absorptiometry (predominantly cortical bone) were normal in almost all subjects, as were the group means for these parameters. Mean regional BMD (by DPA) was below normal in the upper and lower limbs (p less than 0.001) and above normal in the spine (p less than 0.005) and ribs (p less than 0.01). There was no relationship between these indices of bone mass and either biochemical or clinical parameters of disease severity, although men tended to have higher z-scores for axial bone density than premenopausal women whose values, in turn, tended to be higher than those in postmenopausal women (NS). CONCLUSION: We conclude that axial bone mass tends to be increased in adults with XLH, sometimes dramatically so, and this is only partially attributable to hyperosteoidosis. Peripheral bone mass, however, tends to be diminished. Despite these group trends, most adults with untreated XLH have normal indices of bone mass as assessed by a variety of techniques at the commonly used measurement sites. These findings suggest that "osteoporotic" fractures are unlikely to develop as a late complication of XLH in adults.

Absorptiometry, Photon↗
PubMed1991

Bonding of hydroxyapatite-coated femoral prostheses. Histopathology of specimens from four cases.

We examined specimens of hydroxyapatite-coated femoral prostheses from four patients who had died within nine months of implantation for fractured neck of femur. Histology showed newly formed immature bone overlying the hydroxyapatite coating with new trabeculae bridging to the endosteal bone layer. In the diaphysis, where there had been contact between the hydroxyapatite and the cortex, there was dense, firmly anchored bone with an haversian architecture. In other places the newly formed bone had a trabecular structure, containing bone marrow tissue with normal cellularity. It appeared that biological osseointegration had taken place.

Aged↗
PubMed1989

X-linked hypophosphatemia in adults: prevalence of skeletal radiographic and scintigraphic features.

The radiologic studies of 38 essentially untreated adults with X-linked hypophosphatemia (XLH) were reviewed to determine the prevalence of radiologic features, to compare the findings in men and in women, and to elucidate the natural history of the disease by comparing the findings in young, intermediate-age, and older patients. Bone-reinforcement lines were common, but no characteristic mineral mass alteration was established. Looser zones were more prevalent in older subjects. Osteoarthritis was common, occurring in the ankles, knees, feet, sacroiliac joints, and wrists. Enthesopathy was infrequent in the younger group but was present in every member of the intermediate and older groups and was often accompanied by extra ossicles. Curvatures of the lower-extremity long bones were common in all age groups. Three new skeletal alterations in XLH were found to be common: flaring of the iliac wings, trapezoidal distal femoral condyles, and alterations in talar morphology, including shortening of the talar neck and flattening of the talar dome. Technetium-99m methylene diphosphonate scintigrams of 17 subjects were often abnormal, depicting bowing deformity and focal tracer accumulation in diaphyseal cortices and in periarticular and extraarticular regions. The mean metabolic index was moderately elevated (4.0). Both radiographic and scintigraphic findings were more severe in men, consistent with hemizygosity. The natural history of untreated XLH in both sexes is characterized by the development of a variety of age-related skeletal abnormalities during adulthood.

Adult↗
PubMed1989

Shoulder joint: arthrographic CT and long-term follow-up, with surgical correlation.

One hundred two computed tomographic (CT) arthrograms of the shoulder were retrospectively reviewed and compared with conventional double-contrast arthrograms from 101 patients (24 females and 77 males aged 9-70 years). One- to 4-year follow-up was obtained in 84 patients, 40 of whom underwent open-shoulder surgery or arthroscopy. Morphology of the normal portions of each labrum was categorized according to length, width, and tip shape. Correlation between morphology and age was weak, but abnormal labra were more common in younger patients. Conventional radiography was more accurate for detecting bony glenoid margin fractures, but CT was more accurate for detecting Hill-Sach fractures. CT was also more reliable than conventional arthrography in the detection of rotator cuff tears. Hence, few if any conventional radiographs are necessary between contrast material injection and CT imaging. A reduction in the number of images obtained will result in decreased radiation dose, less cost, and shorter examination time without loss of diagnostic accuracy.

Adolescent↗
PubMed1989

A unified approach to symptomatic juxtasternal arthritis and enthesitis.

Symptomatic arthritic and enthesopathic conditions of the sternum and its articulations have not been studied well as a group, despite previous reports of individual diseases and radiographic abnormalities that affect these structures. The lack of a unified clinical approach has been partly due to the absence of a name for the clinical condition, which we propose to call juxtasternal arthro-osteitis. Although juxtasternal arthro-osteitis may be caused by septic arthritis, this study was based on 24 adult patients with noninfectious juxtasternal arthro-osteitis, collected retrospectively from records of patients who had sternal tomography and from rheumatology clinic populations. Twelve of the patients had an underlying systemic arthropathy that met standard diagnostic criteria; three patients had an unclassifiable systemic arthropathy; and nine patients had the idiopathic localized disease, which has been termed sternocostoclavicular hyperostosis. Radiographic findings in the various diseases followed definite trends, but were not sufficiently distinct to provide the sole basis for diagnosis. Initial failure to correlate dermatologic, rheumatologic, radiographic, and laboratory findings led to prolonged delays in diagnosis in many cases. When juxtasternal arthro-osteitis is encountered, a thorough evaluation should be made for systemic disease. Idiopathic sternocostoclavicular hyperostosis can be diagnosed only after systemic arthropathy or enthesopathy has been excluded.

Adult↗
PubMed1989

Ascending lower limb phlebography: comparison of ioversol and iothalamate meglumine.

Fifty patients undergoing ascending phlebography of a lower limb were evaluated, in a randomized double-blind fashion, to compare the efficacy, patient tolerance, and safety of two different contrast agents. Ioversol-240 (MP-238), a new nonionic agent, and iothalamate-202 (Conray 43), an established ionic agent, were the contrast agents used. Twenty-five patients were injected with iothalamate and 25 with ioversol. The phlebograms were evaluated for diagnostic quality and the patients for symptoms, with special reference to complaints of heat and pain. No significant difference was demonstrated between the two agents in either examination quality or patient tolerance. No major contrast-related reactions were recorded. We conclude that ioversol-240 appears to be a safe and acceptable alternative to iothalamate-202.

Adult↗
PubMed1989

X-linked hypophosphatemia: a clinical, biochemical, and histopathologic assessment of morbidity in adults.

Research and management of XLH have concentrated on the disease in childhood, and the natural history and morbidity of XLH in adult life are thus poorly understood. We have studied 22 adults (6 men) with XLH to clarify these aspects of this most common inherited form of rickets and osteomalacia. Most study participants had presented with rickets in early childhood and had undergone tibial osteotomies on at least 1 occasion. Seventeen individuals had genu varum, 1 had genu valgum, and 4 had straight legs, attributable to successful osteotomies in 2. Five subjects reported increasing lower limb deformity in the late teens or subsequently. Eight subjects complained of bone pain, 6 of whom had radiologic evidence of pseudofractures; pseudofractures were found in 4 additional asymptomatic individuals. None of 16 subjects who underwent transiliac bone biopsy had normal double tetracycline labeling; accordingly, all were considered to have osteomalacia. Bone pain was associated with a relative osteoid volume in excess of 25%. Relative osteoid volume was inversely related to serum 1,25(OH)2D concentration (r = -0.74, p less than 0.02), but unrelated to serum concentrations of calcium and phosphate or their product. Eighteen participants complained of joint pain, predominantly in the knees and ankles. The severity of joint pain correlated with the degree of lower limb deformity (p = 0.011) which, in turn, was related to fasting serum phosphate concentration (r = -0.56, p less than 0.025) and TmP/GFR (r = -0.70, p less than 0.005). Enthesopathy affected 33% of those younger than 30 years, and all those above this age. Nineteen individuals had experienced significant dental problems, most commonly abscess formation. Eight had required complete dental clearance. Twelve women from the group had a total of 22 live births. Fifteen of these were by cesarean section, although radiologic evidence of pelvic narrowing was not found in any subject. Serum ALP was elevated in all but 3 of the 18 untreated subjects. Levels correlated with those of other indices of bone turnover (BGP r = 0.82, p less than 0.005; urine total HP r = 0.60, p less than 0.025; urine free HPr = 0.78, p less than 0.005), but were not related to the degree of osteomalacia found on bone biopsy. Serum levels of iPTH, 25(OH)D, 1,25(OH)2D, and thyroid hormones were generally normal in the untreated patients. We conclude that adults with untreated XLH have osteomalacia that is frequently symptomatic. Even greater morbidity is caused by degenerative joint disease arising from lower limb deformities.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1988

Arthrography after total hip arthroplasty: utility of postambulation radiographs.

We compare pre- and postambulation arthrograms in 24 patients with total hip arthroplasty. In nearly half (42%) of these cases, the arthrographic evidence of a loosened prosthesis was more obvious after ambulation. Three patients (12.5%) had components which were normal by arthrographic criteria before walking, but were abnormal afterwards. We conclude that postambulation radiographs are valuable in patients who are examined for suspected loosening of prosthetic components.

Adult↗
PubMed1988

Arthrographic surface anatomy of the carpal triangular fibrocartilage complex.

In a review of 364 radiocarpal and 123 distal radioulnar joint arthrograms we identified 44 (12%) patients with contrast defects at either the proximal or distal surface of the carpal triangular fibrocartilage complex (TFCC). Differences in their arthrographic characteristics distinguished two separate groups of patients; one with similar and another with dissimilar appearing TFCC surface contrast collections. Thirty-one of our 44 patients had similar appearing, isolated radial-sided collections at either the proximal or distal TFCC surfaces. Our arthrographic, demographic, and historical study of these patients suggests that the collections are not caused by traumatic partial TFCC tears but represent a normal anatomic variant, probably a synovial recess at the radial TFCC attachment. Arthrography and dissection of a limited number of cadaveric specimens confirmed this conclusion. The second group included the remaining 13 patients. This group had contrast collections at either the proximal or distal TFCC surface, which varied in location and appearance. This smaller group is more likely to represent those uncommon patients with partial TFCC defects caused by tears.

Adolescent↗