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Biomedical subjects

R H Fitzgerald

Publications and source records attributed to R H Fitzgerald.

At least 19 recordsLinked to original sources
PubMed1992

Total hip arthroplasty sepsis. Prevention and diagnosis.

Postoperative deep wound infection following total hip arthroplasty remains a serious and all too frequent complication. Although diagnostic capabilities have improved with the evolution of new imaging and immunologic techniques, the devastating consequences for patients with an early diagnosis cannot yet be aborted. Thus, further emphasis must be placed on prevention of this complication. Although major referral centers have managed to achieve exceptionally low incidences of postoperative sepsis with the prophylactic administration of antimicrobial agents and discipline within the operating room, these advances have not translated into a similar reduction of the national experience. Thus, further investigation and the development of additional techniques must be sought.

Hip Prosthesis↗
PubMed1991

Bypassing femoral cortical defects with cemented intramedullary stems.

The objective of this investigation was to examine the effect of cemented intramedullary stem bypass on bone torsional property in the presence of femoral cortical defect. We intended to test two hypotheses; first, intramedullary fixation without bypass will accentuate the stress concentration effect and second, there will be an optimal length of stem bypass beyond the defect. Cemented intramedullary stems were used to bypass 50% diaphyseal diameter unicortical defects in paired, fresh-frozen canine femora. One member of each pair served as an unaltered control and all specimens were tested to failure in torsion. Both single-tailed paired t-test and analysis of variance were used for data analysis. Bones subjected to the cortical defect and no bypass were substantially weakened, exhibiting only 44 +/- 8% of control side maximum torque (p less than 0.001). Positioning of the intramedullary stem with its tip at the center of the defect provided a small degree of strength improvement, achieving 60 +/- 7% of control side maximum torque. One and two diaphyseal diameter bypass, however, significantly (p less than 0.01) improved bone torsional strength, resulting in 80 +/- 6% and 84 +/- 13% of control side maximum torque, respectively. Three diameter bypass achieved only 68 +/- 8% of control side maximum torque. This significant (p less than 0.05) decline in strength when compared to two diameter bypass appears to indicate that the length of stem bypass beyond the cortical defect does have an optimum, probably due to the geometric characteristics of the canine femora.

Animals↗
PubMed1991

Metachronous infections in patients who have had more than one total joint arthroplasty.

Sixty-eight patients who had had 159 replacement arthroplasties of more than one major joint between 1975 and 1984 and who had had an infection after at least one of these procedures were identified in a retrospective review. Subsequent infection in another total joint replacement was documented in ten of these patients. The risk of development of an infection about another total joint replacement after an infection had occurred about one total joint replacement in a patient who had had more than one arthroplasty was 18 per cent, according to the survivorship-analysis method of Kaplan and Meier. Many variables that were previously thought to increase the risk of infection, such as rheumatoid arthritis, older age of the patient, previous operations, and the use of corticosteroids or immunosuppressive agents, or both, were not found to increase the risk of a subsequent infection in patients who had had more than one arthroplasty with infection of one of the arthroplasties. The recent occurrence of a major systemic infection did increase the risk of infection about the other total joint replacements. Eight of the ten subsequent joint infections were due to the same causative organism as the index infection about a total joint replacement and occurred within the first year after the index infection. The initial treatment of the index infection included specific parenteral antimicrobial therapy combined with débridement and excisional arthroplasty in forty patients, removal of the components and arthrodesis in three patients, and débridement with retention of the prosthesis in twenty-five patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Limitations of indium leukocyte imaging for the diagnosis of spine infections.

The usefulness of indium-111 white blood cell (WBC) scintigraphy in the detection of spine sepsis was studied in 22 patients who had open or percutaneous biopsies for microbiologic diagnosis. The indium images in 18 patients with vertebral infection were falsely negative in 15 (83%) and truly positive in 3 (17%). All four patients with negative cultures and histology had true-negative scans. The indium-111 WBC imaging results yielded a sensitivity of 17%, a specificity of 100%, and an accuracy rate of 31%. Prior antibiotic therapy was correlated with a high incidence of false-negative scans and photon-deficient indium-111 WBC uptake. The usefulness of indium-111 WBC scintigraphy for the diagnosis of vertebral infection may be limited to those patients who have not been treated with antibiotics previously.

Anti-Bacterial Agents↗
PubMed1990

Results of treatment of tibial and femoral osteomyelitis in adults.

From January 1, 1971, to December 31, 1985, 425 patients with chronic osteomyelitis of the femur or tibia were seen at the authors' institution. The success rate in this recent experience was 84.4% compared with 50.9% in the authors' results published in 1970. A classification of chronic osteomyelitis is as follows: (1) hematogenous osteomyelitis; (2) osteomyelitis in united fractures (fracture with union); (3) osteomyelitis in nonunion (fracture with nonunion); and (4) postoperative or posttraumatic osteomyelitis in which bone was not fractured. For management of the scarring of surrounding soft tissue, there has been a change to excision of the scarred tissue and reliance on muscle flap, free-tissue transfer, or closure of soft tissues without irrigation with antibiotic solution. In recent years, free microvascular osseous grafts have permitted more aggressive resection of the involved osseous tissue. The predominance of gram-negative organisms and penicillin-resistant Staphylococcus aureus and the occurrence of methicillin-resistant S. aureus continue.

Adult↗
PubMed1989

Diagnosis and management of the infected total knee arthroplasty.

The infected total knee arthroplasty presents challenges for diagnosis and management. Infection develops in patients with compromised host defense mechanisms and in those in whom there is compromised wound healing or intraoperative wound contamination. A high index of suspicion of infection is necessary to diagnose infection in the patient without implant loosening. Eradication of the infection is the most important objective of management. The treatment option that offers the best possible function for the patient should be selected. Prevention of infection by correct patient selection and proper surgical technique should remain the goal of the attending surgeon.

Humans↗
PubMed1989

Infections of hip prostheses and artificial joints.

Infections following total joint arthroplasty have been dramatically lowered with the administration of prophylactic antibiotics. Anecdotal experience as well as prospective data suggests that ultra-clean operating rooms can further reduce the incidence of postoperative wound sepsis following total joint arthroplasty. Once a deep infection complicates a total joint arthroplasty, resection arthroplasty will usually be necessary. Staphylococci are the most common causal organisms. Four weeks of specific, parenteral therapy should be administered at the time of the resection arthroplasty. Reconstruction with another total joint can be performed in a "one-staged" or a delayed fashion. The decision as to which procedure should be performed is made based on the degree of virulence of the infection (microbiology) and the anatomic location. Successful reconstruction can be achieved in 95 per cent of carefully selected patients.

Bacterial Infections↗
PubMed1989

Two-stage reconstruction of a total hip arthroplasty because of infection.

From 1969 to 1985, eighty-one patients (eighty-two hips) who had an infection after a previous total hip arthroplasty were treated with a resection arthroplasty, followed by delayed reconstruction in the form of a repeat total hip arthroplasty. For all of the reconstructions, the femoral and acetabular components were fixed to bone with cement that did not contain antibiotics. An average of 5.5 years (range, 2.0 to 13.6 years) after reimplantation, infection had recurred in eleven hips (13 per cent). The presence of retained cement at the time of the resection arthroplasty appeared to be associated with recurrent sepsis, as three of seven patients who had retained cement had a recurrent infection, compared with only eight (11 per cent) of seventy-five patients from whom the cement had been completely removed (p less than 0.01). The twenty-six patients (twenty-six hips) who had the reimplantation less than one year after the resection arthroplasty had seven recurrent infections (27 per cent), while the fifty-six patients who had reimplantation more than one year after the resection arthroplasty had only four recurrences (7 per cent) (p less than 0.001). Three of the seven patients in whom the infection was caused by gram-negative bacilli and group-D streptococcal organisms (which are considered highly virulent) and who received systemic antimicrobial therapy for less than twenty-eight days had a recurrence. In contrast, only one of the thirteen patients in whom the infection was caused by a virulent organism and who were treated for longer than twenty-eight days had a recurrence (p = 0.055). The two-stage reconstruction is an effective, safe technique even when the infection is caused by a virulent organism.

Adult↗
PubMed1988

In-111-labeled leukocyte scintigraphy in suspected orthopedic prosthesis infection: comparison with other imaging modalities.

When infection of prosthetic orthopedic implants is suspected, optimal management requires accurate confirmation or exclusion of infection. The authors retrospectively studied 98 patients with possible infection who underwent scanning with indium-111-labeled white blood cells (WBCs) and subsequently underwent surgery within 14 days. At surgery, 50 patients had infections, as determined by means of culture or histologic results. The diagnostic accuracy of In-111 scanning was compared with that of plain radiography, arthrography, three-phase bone scanning, and various clinical and laboratory findings classically associated with infection. Positive findings on In-111 WBC scans and elevated erythrocyte sedimentation rates were found to be the most predictive variables in the diagnosis of septic prostheses (P less than or equal to .001 and P less than or equal to .002, respectively). Likelihood ratio analysis more clearly demonstrated the superiority of In-111 WBC scanning, with positive and negative scans yielding likelihood ratios of 5.0 and 0.16, respectively.

Adult↗
PubMed1988

A histological study of acute hematogenous osteomyelitis following physeal injuries in rabbits.

In young rabbits, the effects of an intravenous injection of Staphylococcus aureus alone, and in combination with a traumatic injury of the proximal tibial physis, were studied by light and electron microscopy. Metaphyseal osteomyelitis and radiographic changes were seen within forty-eight hours after the injury in all rabbits that had a growth-plate disruption and bacteremia. An intravenous injection of bacteria alone produced no morphological or microbiological evidence of infection. In the absence of trauma, normal tibiae were sterile after forty-eight hours. Foreign-body particles have been shown to accumulate in the fine vessels that are adjacent to the growth plate, but we found no similar deposition of bacteria or evidence of phagocytic removal in this area. Phagocytosis of bacteria by neutrophils did not appear to be impaired in the distal third of the metaphysis, but a delayed inflammatory response that allowed proliferation of bacteria and destruction of tissue was observed in the proximal two-thirds of the metaphysis after trauma.

Animals↗
PubMed1988

The enhancement of fixation of a porous-coated femoral component by autograft and allograft in the dog.

Revision total arthroplasty of the hip, without cement, was done in dogs to compare the abilities of autologous grafts and allografts of bone to enhance histological ingrowth of bone and biomechanical strength. Six weeks after primary total hip arthroplasty with cement, the femoral component was revised to a titanium fiber-metal prosthesis. On the basis of the type of graft that was impacted into the voids around the ingrowth surface at revision, three study groups were created: no graft (control), four dogs; fresh autograft, six dogs; and frozen allograft, six dogs. Twelve weeks after revision, histological analysis revealed the greatest amount of ingrowth proximally in the grafted specimens. A mean of 22.3 per cent ingrowth was observed in the dogs that had an autograft; this was not significantly different from the mean of 17.5 per cent in those that had an allograft. The non-grafted specimens showed little ingrowth, the values being significantly less than those for the grafted specimens. Push-out testing showed greater ultimate shear strength proximally than distally in the grafted specimens, and at the proximal level there was a significant difference between the group that had an autograft and the control group (mean, 4.03 and 1.22 megapascals, respectively). Ultimate strength correlated positively with ingrowth of bone (r = 0.82). Radiographically, subsidence of the components and lucent lines were observed more frequently in the nongrafted specimens, and if both were present, significantly less ingrowth of bone and strength were observed.

Animals↗
PubMed1988

Total hip arthroplasty in the ankylosed hip. A ten-year follow-up.

Eighty total hip arthroplasties in seventy-four patients who had had either a spontaneous or a surgical ankylosis (arthrodesis) of the hip were evaluated at nine to fifteen years (average, 10.4 years) after the total hip replacement. There was only one failure in the twenty hips of the fifteen patients who had had a spontaneous ankylosis. In contrast, twenty (33 per cent) of the sixty hips of the sixty patients who had had a surgical ankylosis had complications that were associated with the arthroplasty. Of these twenty hips, mechanical loosening developed in eleven; infection, in eight; and recurring dislocation, in one. Failure of the total hip arthroplasty was more common (p less than 0.05) in the patients who had had a previous surgical attempt at arthrodesis and in the patients who were fifty years old or less at the time of the arthroplasty. The risk of failure was not related to the length of time that the hip had been ankylosed.

Activities of Daily Living↗
PubMed1988

The uncemented total hip arthroplasty. Intraoperative femoral fractures.

Intraoperative fractures of the proximal femur occurred in 40 (38 patients) of 630 (6.3%) biological ingrowth total hip arthroplasties performed between January 1984 and July 1986. Twenty-three of these fractures occurred during 131 revision arthroplasties (17.6%) and 17 during 499 primary arthroplasties (3.5%). All but two of the fractures were recognized during surgery. Thirty-seven were treated with either Parham bands or cerclage wires. Bone graft was added to the fracture site in 31 fractures. All of the fractures healed. Three of the patients failed to achieve stable fixation and have required revision surgery. An additional patient has thigh pain with 2 mm of subsidence noted with serial roentgenographs. Femoral fractures can be prevented by preoperative templating of roentgenograms containing markers to measure magnification, routine overreaming of the femoral canal when implanting long-stemmed prostheses, and prophylactically applying wires or bands to femurs requiring the removal of screws.

Bone Cements↗
PubMed1987

Primary malignant mediastinal germ-cell tumors and the contribution of radiotherapy: a southeastern multi-institutional study.

A retrospective review was performed by a multi-institutional study group to determine the contribution of radiotherapy to the management of primary malignant mediastinal germ-cell tumors. Twenty-seven patients diagnosed with a primary mediastinal germ-cell tumor between January 1965 and July 1985 form the basis of this study. Twenty-five of the 27 patients were male. Thirteen patients' tumors were diagnosed as seminoma and the remaining 14 patients' tumors had other germ-cell histologies. The single most important prognostic factor was histology, with a 5-year actuarial survival of 100% for the seminomas and only 8.8% for the remaining germ-cell varieties. If total surgical extirpation is not possible, biopsy may be adequate. Of the patients with seminoma, 11 of 12 had local control, and 3 of the 12 patients were treated with doses between 3,000 and 3,100 cGy. High doses for this variety of mediastinal germ-cell tumor might not be required. For the germ-cell tumors other than seminoma, no patient had local control with doses over the range of 3,000-4,750 cGy.

Adolescent↗