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Biomedical subjects

W H Harris

Publications and source records attributed to W H Harris.

At least 109 records · Page 6Linked to original sources
PubMed1995

Total hip arthroplasty with use of so-called second-generation cementing techniques. A fifteen-year-average follow-up study.

One hundred and forty-nine patients (162 hips) had a standard primary total hip arthroplasty with a grit-blasted femoral component and use of so-called second-generation cementing techniques. No patient was lost to follow up. Fifty-one patients (sixty hips) died within fourteen years after the index operation. The remaining ninety patients (102 hips) were followed for a minimum of fourteen years. Of the fifty-one patients (sixty hips) who died within fourteen years, three patients (three hips; 5 per cent) had had a revision: one, because of aseptic loosening of the acetabular component; one, because of aseptic loosening of the femoral component; and one because of aseptic loosening of both components. Of the ninety patients (102 hips) who were alive fourteen years or more (average duration of follow-up, fifteen years) after the arthroplasty, one patient (two hips; 2 per cent) had a revision because of bilateral aseptic loosening of the femoral component. In seven patients (seven hips; 7 per cent), the femoral component loose according to radiographic criteria but was not revised. For the entire group of 162 hips, four femoral components (2 per cent) were revised because of aseptic loosening. In contrast, the rate of aseptic loosening of the acetabular component was higher and continued to increase. Of the eighty-one hips with an all-polyethylene acetabular component in the patients who were alive at fourteen years or more, eight (10 per cent) had a revision because of aseptic loosening. In addition, twenty-eight (42 per cent) of the sixty-seven all-polyethylene acetabular components that were in place after fourteen years or more, and for which there were current radiographs, were loose. Femoral components implanted with the use of second-generation cementing techniques appear to have fared much better than acetabular components that were inserted with similar techniques in this series of patients. A thin (less than one-millimeter) mantle of cement around the femoral component and defects in the mantle of cement were associated with increased loosening of the femoral component.

Adult↗
PubMed1995

Total hip replacement for developmental dysplasia of the hip.

Total hip arthroplasty relieves pain and improves function for many patients with endstage arthritis secondary to developmental dysplasia of the hip. Acetabular dysplasia, however, presents a special problem for total hip reconstruction in these patients. Structural bone grafting with femoral head autografting to the dysplastic acetabulum and cementing acetabular components into the graft provides satisfactory short-term results, but longer-term followup data show high acetabular component failure rates. At a mean followup period of 7 years, 20% of components were loose, and at a mean followup period of 12 years, 46% were loose. Noncemented porous-coated hemispherical acetabular components have considerably expanded the success of total hip replacement without the need for structural bone grafting in such patients. At a mean followup period of almost 7 years, none of the acetabular components were reported to be loose in 1 series. For most patients, the acetabular dysplasia can be managed by techniques such as reaming deeper, using small-diameter porous-coated acetabular components, using screws to provide rigid initial stability for the components, increasing the height of the prosthetic hip center, and covering small portions of the components with bone graft chips if necessary.

Hip Dislocation↗
PubMed1995

The problem is osteolysis.

Recent studies have generated considerable information that reveals substantial support for major change in the understanding of total hip arthroplasty and its current state. Although some of these observations appear unrelated at first glance, they can be drawn together to support the thesis that osteolysis is the dominant problem in total hip arthroplasty. These observations are as follows: (1) Five-year followup data are required for a minimum assessment of a new concept in total hip design and material because osteolysis is uncommon before that time. (2) Excellent fixation can be achieved on the femoral side with good cementing and good cementless techniques. Thus, femoral component loosening is less of an issue currently. (3) Many acetabular components become loose because of the ingress of particulate debris that leads to linear bone loss at the interface with the pelvis, a process that is biologically akin to the more florid forms of osteolysis. Thus, much acetabular component loosening represents a form of osteolysis. (4) Many cementless femoral reconstructions have developed a high incidence of femoral osteolysis. (5) Many cementless sockets have developed a high incidence of pelvic osteolysis. Taken in conjunction, these observations suggest that periprosthetic osteolysis is the leading problem in contemporary total hip replacement.

Hip Prosthesis↗
PubMed1995

The femoral stent. Surgical technique for a new method of cementing the femoral component in the presence of a large cortical defect.

Modern cement technique consists of the use of porosity reduction of the cement, a femoral medullary canal plug, injection of the cement using a cement gun, centralization of the stem, and pressurization of the cement. The use of cement in femoral revision is increasing rapidly; however, when there is a major cortical defect, forming and pressurizing the cement column might appear impossible. We describe a surgical technique for sealing such defects with a custom-made, intraoperatively fashioned femoral stent that allows for temporary restoration of the cortical tube of the femur, and therefore full pressurization of the cement.

Bone Cements↗
PubMed1995

The case for cementing all femoral components in total hip replacement.

Two important new observations underlie the recommendation that it is advisable to cement all femoral components of total hip replacement (THR). First, it is now clear that improved cementing techniques have remarkably extended the durability of the cemented fermoral fixation and markedly reduced the incidence of lysis. Second, the incidence of femoral lysis around all noncemented femoral components that have been reported with minimum 5-year follow-up is high, increasing and alarming. With good cementing in primary THR, the incidence of femoral revision for aseptic loosening at 15 to 18 years after the initial operation is only 2% to 3%, even in those 50 years of age and younger. Moreover, lysis is rare. Similarly, with improved femoral cementing, femoral revision is also far more effective. The juxtaposition of the excellent results with improved cementing and the high and rising lysis rates around noncemented femoral components clearly mandate the use of contemporary cementing procedures for all femoral components, regardless of the age or sex of the patient, the diagnosis and whether the procedure is a primary or revision one.

Bone Cements↗
PubMed1995

A 69-year-old woman with thigh pain 21 years after total hip arthroplasty.

The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopedic surgeon. Initial history, physical findings, and roentgenographic examinations are found on the first page. The final clinical and roentgenographic differential diagnoses are presented on the following pages.

Aged↗
PubMed1994

Polyethylene wear debris and tissue reactions in knee as compared to hip replacement prostheses.

Differences in bearing surface conformity and wear mechanisms suggest that the polyethylene (PE) wear debris generated by total knee replacement (TKR) prostheses should be different than that in total hip replacement prostheses (THR). To address this issue, PE wear debris and the cellular response in periprosthetic tissues from 19 failed TKRs was compared to that from 24 failed THRs using polarized light microscopy and a semiquantitative grading system. The foreign-body inflammatory reaction in the THR case was characterized by plump macrophages with a diffuse cytoplasmic birefringence when examined under polarized light, indicating the presence of multiple submicron particles of PE. The majority of PE particles were less than 1 mum in size and only a small fraction of the total were greater than 10 mum. The foreign-body inflammatory reaction in the TKR cases was characterized by giant cells with fewer macrophages. In the TKR specimens, the size range of PE particles was broader than in the hips. PE particles between 2 and 20 mum were frequent in TKR specimens; particles less than 1 mum in length were less common than in the THR specimens. Diffuse cytoplasmic birefringence was not a characteristic of the TKR cases. These histologic differences were so consistently distinct that the source of the specimen (i.e., from a THR or TKR) could be blindly determined by light microscopy.(ABSTRACT TRUNCATED AT 250 WORDS)

Foreign-Body Reaction↗
PubMed1994

Fit of the uncemented femoral component and the use of cement influence the strain transfer the femoral cortex.

To determine whether the strain patterns produced in the femoral cortex after uncemented femoral arthroplasty are influenced by the fit of the component and whether these patterns are different from those of cemented components, cortical surface strains of cadaveric femurs subjected to loads simulating single-limb stance were measured before and after the insertion of uncemented, collared, straight-stemmed femoral components. The effects of press fit, loose fit, and precise fit of the components were evaluated and were contrasted to the strain patterns occurring after insertion of cemented femoral components. Strains varied markedly, depending on the fit of the stem of the uncemented femoral component within the isthmus. Nearly normal patterns of femoral strain were produced when the femoral stem was fit precisely at the isthmus, and the proximal femoral strains were similar to those of the intact state. In contrast, press fit and loose fit at the isthmus altered the strain patterns. The proximal medial axial strains were significantly reduced with press fit, to a mean of 39% of normal (p < 0.05), and increased with loose fit, to a mean of 141% of normal (p < 0.05). The prostheses fixed with cement showed a mean reduction in proximal medial axial strains to 33% of normal, which was comparable with press fit uncemented components even though the collar was well seated. Thus, our findings indicated that, in the immediate postoperative period, femoral strain patterns can be influenced by the fit of an uncemented component within the isthmus and by the use of cement.

Aged↗
PubMed1994

The value of contrast arthrography in assessing loosening of symptomatic uncemented total hip components.

Twenty-five patients with symptomatic uncemented total hip components were studied with contrast arthrography prior to surgical exploration. All but one had uncemented femoral stems and 16 had an uncemented acetabular component. As judged by the findings at surgery, on the femoral side the sensitivity, specificity, and accuracy of arthrography were 57%, 60%, and 58% respectively. There was a relatively high incidence of both false positives (17%) and false negatives (25%). On the acetabular side sensitivity, specificity, and accuracy were 29%, 89%, and 62.5%. False negatives were common (31%), while there was only one false positive. The results in this small series show that arthrography has distinct limitations in identifying the fixation status of uncemented total hip components.

Adult↗
PubMed1994

High placement of porous-coated acetabular components in complex total hip arthroplasty.

The authors retrospectively evaluated the results of 56 hips in 51 patients with an acetabular deficiency who had a total hip arthroplasty with a porous-coated, cementless acetabular component implanted at a high hip center. Forty-nine cases were revisions and seven were primary operations. The mean height of the hip center was 43 mm above the interteardrop line compared to 14 mm for the anatomic center, threefold higher than normal. In contrast, the mean horizontal locus was reduced compared to normal (33 vs 37 mm for the anatomic center). Sixteen acetabular components were small (46-48 mm o.d.) and eight were miniature (40-44 mm o.d.). Despite superior placement of the acetabular component, 32 limbs were lengthened by the procedure. The mean preoperative Harris hip score was 51 (range, 28-93). At a mean follow-up period of 40 months (range, 24-64 months), the mean Harris hip score was 86 (range, 36-100). In 23 hips no radiolucent lines were present at the interface of the bone to the porous mesh, and 33 hips had a thin (0.5 mm), nonprogressive radiolucent line in one or more zones. No acetabular component had migrated and no problems occurred with the screws. Four hips (3 revisions and 1 primary operation) had a complete radiolucent line on one oblique view of the acetabulum. No acetabular component has been revised for loosening.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetabulum↗
PubMed1994

A quantitative in vitro assessment of fit and screw fixation on the stability of a cementless hemispherical acetabular component.

This investigation quantifies in vitro the effect of component fit, as well as the effect of adjuvant screw fixation, on the initial stability of cementless hemispherical titanium acetabular total hip arthroplasty components and assesses apposition of the acetabular components to bone. Six, fresh human hemipelvi (3 matched pairs) were harvested at autopsy. Titanium alloy acetabular components with a porous surface of commercially pure titanium fiber mesh (Harris Galante Porous acetabular components, Zimmer, Warsaw, IN) were used for implantation. Initially, each acetabulum was underreamed to achieve a 2 mm press-fit with the acetabular component. Pressure-sensitive film had been placed along the dome and medial wall at the bone-implant interface to assess the completeness of seating. After the implant was impacted into the acetabular cavity, relative motion between the implant and bone was measured during simulated single leg stance. Adjuvant fixation of the implant was then obtained with the insertion of four 6.5 mm cancellous screws. High-contrast roentgenograms of the specimens in multiple views were obtained after initial cup insertion and again after screw insertion. The stability of each implant under load was measured with four, three, two, one, and no screws in place. Further reaming of the bone was done to create a 1 mm press-fit. The sequence was then repeated. Further reaming was done to create an exact-fit and the sequence was repeated again. Under these conditions, 1 mm press-fit with or without screws provided the optimum combination of fit stability.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

The Harris-Galante porous acetabular component press-fit without screw fixation. Five-year radiographic analysis of primary cases.

One hundred twenty-two primary total hip arthroplasties were followed for an average of 56 months (range, 48-66 months) in which the Harris-Galante (Zimmer, Warsaw, IN) porous ingrowth acetabular component had been press-fit into the innominate bone without screw fixation. There were no acetabular fractures. No socket was revised for loosening and none were radiographically loose. There was no evidence of disruption of the titanium porous mesh. There was no acetabular osteolysis. Compared to the authors' series of primary hip reconstructions using this same prosthesis inserted with line-to-line reaming and screw fixation, the data indicate that the tight peripheral fit associated with the press-fit technique is effective in reducing both the incidence and extent of bone-implant radiolucencies. However, the increased incidence of radiolucencies near the apex of the acetabulum also suggest that initial contact of the porous surface with live acetabular bone at this location is desirable in order to obtain and maintain an optimal bone-implant interface. Additional studies are necessary to further establish the relationship between the initial fit and long-term fixation of cementless acetabular components. Based on the data and other considerations for eliminating both vascular risk and the potential for fretting wear between the screws and shell, the authors recommend press-fitting without screw fixation for this acetabular component in primary cases when anatomy and bone stock permit. Full seating of the component is recommended in order to obtain dome contact.

Acetabulum↗
PubMed1994

The prevalence of femoral osteolysis associated with components inserted with or without cement in total hip replacements. A retrospective matched-pair series.

The prevalence of femoral osteolysis in hips in which a femoral component had been inserted without cement was compared with that in hips with a cemented component, in a retrospective matched-pair study of the results of primary total hip arthroplasties; all patients had received the same type of acetabular component. Forty-one hips in thirty-nine patients who had a Harris-Galante porous-coated total hip prosthesis without cement were matched by age, sex, weight, duration of follow-up, and diagnosis with forty-one hips in thirty-eight patients who had a hybrid total hip reconstruction; the hybrid reconstruction consisted of the same acetabular component and a Precoat femoral component inserted with a so-called third-generation cementing technique. All of the operations were done by the same surgeon, who used the same operative approach and the same course of postoperative rehabilitation. All of the patients were followed for at least four years (mean, six years). Osteolysis developed in twelve (29 percent) of the hips that had a femoral component without cement compared with none of the hips that had a cemented component (p < 0.0002). At the latest follow-up examination, none of the femoral components that had been inserted with cement were loose and none had been revised, while eight (20 percent) of the femoral components that had been inserted without cement were loose and five (12 per cent) had been revised. This retrospective matched-pair study controlled for many of the variables associated with a comparison of the rates of femoral osteolysis in separate series of femoral components fixed with and without cement.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗