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Biomedical subjects

W H Harris

Publications and source records attributed to W H Harris.

At least 55 records · Page 3Linked to original sources
PubMed1999

Mast cells of the bovine trachea: staining characteristics, dispersion techniques and response to secretagogues.

Sections of the lower trachea of cattle, fixed in either Carnoy's or formalin, were stained with toluidine blue, alcian blue, or alcian blue and safranin O to study the mast cell population. After toluidine blue staining, about twice as many cells in tissue fixed in Carnoy's contained dark blue granules compared with tissue fixed in formalin. In addition, for the first time in cattle, a population of cells containing red granules was identified after staining with alcian blue and safranin O. Most of these red granules were formalin sensitive. An enzymatic dispersal technique for mast cells is described that yielded 9.4+/-0.4% mast cells (percentage of nucleated cells) with a viability of 92.3+/-0.6%. Spontaneous histamine release was 3.3+/-0.8%. Dispersed mast cells were challenged with various immunological and nonimmunological secretagogues. The calcium ionophores, A23187, ionomyocin, and BrX537A, were effective in releasing up to 94% of histamine in mast cells in a dose-response relationship. Pasteurella haemolytica culture supernate caused about 10% histamine release at a dose of 0.5 mg/mL after correction for spontaneous release. The average histamine content of the mast cells was 6.6+/-1.0 pg/cell. Cytospins of dispersed cells fixed in Carnoy's and stained with alcian blue and safranin O contained mast cells with blue and red granules, and a few cells with a mixture of both granule types. Based on the effects of type of fixation, staining characteristics and histamine content, a mix of subtypes of mast cells is present in the bovine trachea. However, functionally they respond to secretagogues differently than rodent mast cells. Without an immunological secretagogue, studies to determine compounds that will be effective in blocking mast cell degranulation will be limited.

Animals↗
PubMed1998

Analysis of the kinematics of different hip simulators used to study wear of candidate materials for the articulation of total hip arthroplasties.

We developed an analytical technique to determine the paths traced by specific points on the femoral head against the acetabulum in the human hip joint during gait. The purpose of the study was to apply this technique to the mechanical hip simulators chosen to conduct wear tests on polymeric acetabular liners used in total hip replacements. These simulators differ from one another in the type of motion produced, apart from other variables such as type of lubricant and head position. Due to the variation in the kinematics between the machines, the paths traced by the points on the femoral head against the acetabular liner ranged from simple linear traces to figure-8 loops and quasi-elliptical paths during a single simulator cycle. The distances traveled by these points during the same period also varied appreciably among the different hip simulator designs. These results are important when combined with other studies that have shown that kinematics can play an important role in the outcome of in vitro wear experiments. The kinematic differences quantified in this study can partially explain the substantial differences in wear data reported from different simulator designs and also underscore the usefulness of the technique described in this study in judging the results from different hip simulator experiments.

Acetabulum↗
PubMed1998

Polyethylene wear in cases using femoral stems of similar geometry, but different metals, porous layer, and modularity.

In this report, 83 total hip arthroplasties in 75 patients with femoral stems of similar geometry but different metals, porous surfaces, and femoral head-neck design were compared at a mean follow-up of 66 months (range, 40-104 months). One type of acetabular component and polyethylene were implanted in all hips. The femoral stem was monoblock in 25 hips, and in 58 it had a modular head-neck piece; 70 stems had chrome-cobalt heads, and 13 heads were titanium. Equally satisfactory clinical results were obtained with either type of femoral implant (i.e., modular and monoblock). The calculated average annual linear polyethylene wear was significantly higher for the titanium stems with a plasma-spray porous surface and chrome-cobalt head on a Morse taper than the chrome-cobalt, beaded, monoblock stems (0.22 mm/year vs 0.07 mm/year, P < .0001). The prevalence of periprosthetic osteolysis was higher for these modular stems ( 15.7% vs 0%), but this difference was not statistically significant (P = .09). Gross corrosion was present on the taper surfaces of an autopsy-retrieved femoral implant with a modular cobalt-chrome head on a titanium stem. Particles of chromium 3-orthophosphate were present at the taper rim and in the periarticular tissues.

Cementation↗
PubMed1998

Trochanteric union following revision total hip arthroplasty.

Ninety-nine patients (106 hips) with a trochanteric osteotomy during revision total hip arthroplasty were evaluated at a minimum of 5 years after surgery. Trochanteric reattachment was done with monofilament cobalt-chromium wires. The influence of the following variables on trochanteric union was examined: a prior trochanteric osteotomy, an existing trochanteric nonunion, trochanteric advancement to the lateral femur, use of vertical (in addition to horizontal) wires through the trochanter, and use of a trochanteric mesh. Overall, union occurred in 92 of the 106 trochanters (87%). Fifty-three of 61 trochanters (86.9%) healed after an initial osteotomy, whereas 34 of 38 (89.5%) healed after a repeat osteotomy. Five of the 7 trochanters with an existing nonunion healed, and 5 of 5 trochanters reattached to a bulk allograft healed. Twenty-nine of 36 trochanters (80.5%) reattached to cancellous bone healed, compared with 58 of 65 (89.2%) that were reattached to the lateral femoral cortex. Ninety percent (83/92) of the trochanters reattached in conjunction with use of a chrome-cobalt mesh healed, compared with 64.3% (9/14) of those without (P < .05). Of the variables studied, only the use of mesh was statistically significant. Osteotomy through a previously healed trochanter, advancement of the trochanter to cortical bone, existing trochanteric nonunion, trochanteric reattachment to a bulk allograft, and lack of vertical wires for fixation did not adversely affect the likelihood of obtaining trochanteric union.

Arthroplasty, Replacement, Hip↗
PubMed1998

Average 12-year outcome of a chrome-cobalt, beaded, bony ingrowth acetabular component.

Seventy-two hips (67 patients) were reconstructed with the Acetabular Reconstruction Component (ARC, Howmedica, Rutherford, NJ), a chrome-cobalt component with sintered ingrowth beads and peripheral flanges for screw fixation. All the materials used in the ARC (metal, porous layer, and polyethylene) are identical to those used in the Porous Coated Anatomic (PCA) acetabular component (Howmedica), but the design is different. To determine the importance of design features alone, clinical results obtained with the 2 different designs made of identical materials were compared. The average follow-up period for patients with the ARC was 12 years (range, 10-13.3 years). Seven patients (7 hips) with the ARC died prior to the minimum 10-year follow-up period, none having undergone revision procedures. Overall, 3 acetabular components (4%) in 3 patients were revised, at an average of 8.5 years (range, 7.6-9.3 years) from the index operation. The reasons for revision were aseptic loosening, third-body polyethylene wear observed during a revision for femoral lysis, and acetabular component malposition and recurrent dislocation. The total incidence of acetabular aseptic loosening was 4% (3 of 72 hips). Pelvic osteolysis occurred in 3 cases (4%). In contrast, the incidence of acetabular revision of the PCA acetabular component at follow-up periods of 2-10 years is reported to be as high as 11% (range, 3-11%). Rates of aseptic loosening are as high as 30% (range, 3-30%) at substantially shorter follow-up periods, and the incidence of pelvic osteolysis associated with the PCA component is also as high as 30% (range, 5-30%). These differences may reflect differences in design between the 2 acetabular components, as the materials used were identical. In this, the longest reported average follow-up study of a successful cementless acetabular component, the aseptic loosening rate of 4% contrasts with the 42% rate at similar follow-up duration for cemented acetabular components placed by the same surgeon in patients of similar age.

Acetabulum↗
PubMed1998

Cemented total hip arthroplasty following previous femoral osteotomy: an average 16-year follow-up study.

The indications for proximal femoral osteotomy would be substantially limited if it significantly compromised the outcome of a subsequent hip arthroplasty. Previous reports have followed only early cementing techniques over intermediate duration. This study comprised 22 primary cemented total hip arthroplasties performed by a single surgeon following failed proximal femoral osteotomies at an average follow-up period of 15.8 years. Three patients who died prior to the 11-year minimum follow-up period are not included, leaving 19 hips for long-term review. All stems were cemented with second-generation techniques. Stem placement and collar-calcar contact, however, were substantially worse compared with historical control subjects. Eight reconstructions required custom miniature or calcar replacement components, and in 6 hips, the stems were inserted only in the diaphysis. Two of 19 femoral components (10.5%) were revised for aseptic loosening and 2 additional femoral components were loose. The average Harris hip score of those not revised was 80.4. Five acetabular components (26.3%) required revision. Four additional cups were loose, yielding a total acetabular loosening rate of 47.4% at 15.5 years. Intertrochanteric osteotomy in general did not affect the expected excellent results of the femoral component using modern cementing techniques. Severe deformity following subtrochanteric osteotomy, however, did adversely affect the outcome.

Adolescent↗
PubMed1998

Importance of a thin cement mantle. Autopsy studies of eight hips.

The question whether thin cement mantles around cemented femoral components led to an increased frequency of cracks in the cement was asked. Microscopically, multiple cross sections of eight femurs retrieved at autopsy from clinically successful total hip replacements after prolonged in vivo service containing well fixed Harris Design 2 cemented femoral components were studied. None of the components were loose by radiographic criteria. All were fixed solidly when loaded in vitro in simulated stair climbing and gait, as assessed by high resolution micromotion sensors. The specimens were sectioned transversely at 5-mm increments. The cross sections were examined under a dissecting microscope at x 100. A thin mantle arbitrarily was defined as a mantle of less than 1 mm in thickness. The analysis of the contact radiographs showed that the routine anteroposterior and lateral radiographs underestimated the prevalence of thin cement mantles and mantle defects. Although overall on all the cross sections 9% of the aggregated cement mantles was classified as having thin cement, 92 of the 101 cement cracks occurred in areas of the mantles that were less than 1 mm thick.

Activities of Daily Living↗
PubMed1998

Long-term results of cemented femoral stems with roughened precoated surfaces.

Several recent articles have raised the question that rough surfaces with or without precoating may contribute to the loosening of cemented femoral stems. In this article the author collates selected reports of several different cemented femoral stem designs that have rough surfaces which have shown excellent long term results. Femoral stem loosening is generally multifactorial. It often is difficult to separate the effect of stem design or other changes from the effect of surface finish. Many rough surfaced cemented femoral stems have served well for decades. It is important to analyze all the pertinent factors in cases of early loosening.

Aged↗
PubMed1998

Postoperative mortality after total hip arthroplasty. An analysis of deaths after two thousand seven hundred and thirty-six procedures.

We retrospectively determined the prevalence and nature of mortality as many as ninety days after 2736 primary and revision total hip arthroplasties performed in 2002 patients by one surgeon at a teaching hospital between January 1969 and December 1996. All but seventy-one of the patients had received prophylaxis against venous thromboembolic disease. There were no intraoperative deaths, and no events during the operation could be linked directly to postoperative mortality. Eight deaths (mortality rate, 0.3 per cent) occurred within ninety days after the 2736 procedures. Four deaths (mortality rate, 0.15 per cent) occurred during the initial hospitalization. The cause of seven of the deaths was determined. Three patients died as a result of preexisting disease (severe hepatorenal disease, metastatic esophageal cancer, or severe cardiac disease), and one patient died from sepsis with a gram-negative organism during a thoracotomy eight days postoperatively. A bleeding complication that occurred while the patient was receiving warfarin therapy led to the death of two other patients; one of these deaths occurred in 1974 and the other, in 1982. At the time that these patients were managed, the desired prothrombin time was considered to be twice the control value. The remaining patient, who had had a clip placed on the inferior vena cava after a pulmonary embolus occurred in 1970, died secondary to acute, severe thrombosis of this vessel after a total hip arthroplasty in 1971. The patient for whom the cause of death was not determined had had an artificial aortic valve and had been receiving chronic warfarin therapy. She died suddenly eighty-nine days postoperatively; no autopsy was performed. No patient died as the direct result of a known pulmonary embolus. No deaths related to venous thromboembolic disease or its prophylaxis or treatment occurred after 1982 (1458 operations). We attribute this, in part, to reduced levels of warfarin prophylaxis and improved management with warfarin. The ninety-day postoperative mortality rate after 2736 procedures performed over nearly three decades was low (0.3 per cent). This span of time included the period before the introduction of many current improvements in perioperative care, such as routine intubation of patients under general anesthesia, continuous monitoring of the electrocardiogram intraoperatively, and blood-gas determinations. When the patients who died as a result of known, severe preexisting disease were excluded, the mortality rate was 0.18 per cent (five of 2733).

Adolescent↗
PubMed1998

Total hip arthroplasty with use of second-generation cementing techniques. An eighteen-year-average follow-up study.

In this report, we present the results of a further follow-up of a series of 140 consecutive patients (161 hips) who had had a primary total hip arthroplasty with insertion of a bead-blasted monoblock femoral component with use of so-called second-generation cementing techniques. The average age of the patients at the time of the arthroplasty was sixty-one years (range, twenty-one to eighty-five years). Sixty-seven patients (seventy-seven hips) died less than seventeen years after the index operation. The remaining seventy-three patients (eighty-four hips) were followed for an average of eighteen years (range, seventeen to twenty years). No patient was lost to follow-up. In the entire group of 161 hips, over the twenty-year span of the study, eight femoral components (5 percent) and twenty-eight acetabular components (17 percent) had been revised because of aseptic loosening. Of the seventy-seven hips in the sixty-seven patients who died, four had been revised because of aseptic loosening of the acetabular component only; one, because of aseptic loosening of the femoral component only; and one, because of aseptic loosening of both components. Of the eighty-four hips in the seventy-three patients who were alive at least seventeen years after the index arthroplasty, twenty-four hips (29 percent) in twenty-one patients had had revision of one or both components for any reason. Twenty-three acetabular components (27 percent) and six femoral components (7 percent) had been revised because of aseptic loosening. An additional two hips (2 percent) in two patients were loose according to radiographic criteria but had not been revised. Of the sixty-five all-polyethylene acetabular components that had been inserted with cement and were in patients who were alive at least seventeen years postoperatively, fifteen (23 percent) had been revised because of aseptic loosening. An additional seventeen cups (26 percent) were loose according to radiographic criteria. Thus, a total of thirty-two cups (49 percent) had been revised because of loosening or were loose but had not been revised at the time of the latest follow-up. The femoral components that had been inserted with use of second-generation cementing techniques fared better than did the acetabular components that had been inserted with these techniques during the same time-period. We found that assessment of all postoperative radiographs rather than only those that had been made immediately postoperatively increased the accuracy of the grading of the cement around the femoral component. Subsequent radiographs frequently had been made at different projections, which revealed new findings, consisting primarily of previously undetected voids, areas of thin cement, and defects in the cement mantle. Thus, we now use all available radiographs to determine the grade of the cement.

Adult↗
PubMed1998

Follow-up of intertrochanteric osteotomy of the hip during a 25-year period.

In 1984, in reporting follow-up on 67 hips in 61 patients who underwent intertrochanteric osteotomies for osteoarthritis of the hip, we found that between 12 and 15 years after osteotomy, 34% (23) of the 67 hips remained functional and the remainder had been converted to an arthroplasty. We now report on the fate of those osteotomies over a 25-year period. Ten patients with 10 osteotomies did not require an arthroplasty, having died without requiring conversion to total hip arthroplasty at an average of 18.3 years after osteotomy (range: 11 to 24.1 years). Two others were living at an average of 25.2 years after osteotomy without requiring conversion. Thus, for 18% of the hips, no further hip surgery was performed. For the remaining 55 hips in 49 patients, the osteotomy had served for an average of 9.8 years (range: 1.3 to 26.1 years) before requiring arthroplasty. The cumulative probability of osteotomy survival was 57.8% (standard error: 6.0%) at 10 years, 20.0% (standard error: 4.9%) at 20 years, and 5.7% (standard error: 2.9%) at 25 years by Kaplan-Meier survivorship analysis.

Adult↗
PubMed1997

Factors influencing stability at the interface between a porous surface and cancellous bone: a finite element analysis of a canine in vivo micromotion experiment.

Several factors contribute to the success of stable bony ingrowth into the porous coated surfaces of orthopaedic implants used in hip arthroplasty. Despite having good bony apposition, bony ingrowth might not occur if the relative motion between bone and implant is large. Therefore, determining the limiting micromotion value that inhibits stable bony ingrowth is important. From a previous canine in vivo micromotion study performed at our laboratory, this limiting value was found to be 20 microns. Initially, cementless orthopaedic implants are stabilized only by frictional forces at the bone-implant interface. Therefore, other parameters such as the coefficient of friction and the compressive force normal to the interface should be considered as important factors which stabilize the interface along with micromotion. The purpose of this analytical study was to elucidate how the stability at the bone-implant interface is influenced by various factors, namely, motion of the implant, the coefficient of friction, the degree of pres fit, and the modulus of the surrounding cancellous bone in determining the stability of the bone-implant interface. Nonlinear and linear finite element models which simulated the immediate postsurgical condition and the end point of the canine in vivo micromotion experiment, respectively, were used to this end. From the results of the finite element models it was possible to identify the displacement magnitude for which the implant slipped relative to the bone as the motion of the implant was increased incrementally. This was done for combinations of the coefficient of friction, press fit, and Young's modulus of cancellous bone. This was used as an indicator of the limiting implant motion value beyond which bony ingrowth will be inhibited. The stress distribution in the surrounding cancellous bone bed was also obtained from the results of the finite element analyses for different press-fit conditions. The results of the study indicated that under slight press-fit conditions, the implant slipped relative to bone for implant motions as low as 20 microns. For higher degrees of press fit and reasonable values for the coefficient of friction, no slip occurred for implant motions as much as 100 microns. Although higher degrees of press fit were theoretically conducive to better implant stability, the concomitant high stresses in the adjacent cancellous bone will tend to compromise the integrity of the press fit. This was also evident when the results of an analytical model with a lower degree of press fit correlated well with those of the canine in vivo experiment in which a higher press fit was used, suggesting a possibility of achieving a less than desired press fit during the process of implantation. Through this study the importance of factors other than implant motion was emphasized. The results of the study suggest that the limiting value of implant motion that inhibits bone ingrowth might vary with the degree of press fit for reasonable coefficients of friction.

Animals↗
PubMed1997

Comparison of cerclage techniques using a hose clamp versus monofilament cerclage wire or cable.

To assess the compressive force generated by different techniques of cerclage wiring, the compression produced by 6 different cerclage techniques, including monofilament wires, Dall-Miles cables (Howmedica, Rutherford, NJ), and hose clamps, was measured. Tests were performed on both a polysulfone cylinder model and a cadaver bone model. The hose clamp generated significantly higher compression force than any other cerclage device tested. Doubled wires produced similar compressive force as the cables. As the hose clamp is the least expensive and produces the maximum compression, it may be advantageous in instances in which maximum compression is desirable as a temporary device, but because it is not implantable, it must be replaced by other techniques prior to wound closure. The Dall-Miles cable is expensive and its compressive force can be equaled at lower cost by a doubled wire. The use of a single strand of monofilament wire was the least effective.

Bone Wires↗
PubMed1997

Enhancement of the value of hip questionnaires by telephone follow-up evaluation.

Errors, omissions, false understanding, and contradictory answers can compromise the use of questionnaires to generate follow-up data. To assess the utility of and effort involved in adding routinely a telephone interview to clarify the questionnaire, a study of total hip arthroplasty patients was carried out. Thirty-six patients with 37 primary and 13 revision total hip arthroplasties filled out a standardized questionnaire (which asks a number of demographic questions as well as questions that allow calculation of the Medical Outcome Studies [MOS] 36-Item Short-form Health Survey [SF-36], Western Ontario MacMaster Arthritis Center [WOMAC] osteoarthritis index, and Harris hip score) prior to returning for routine follow-up evaluation a minimum of 1 year after surgery. Two hundred thirty-two of a possible 4,350 responses (5.3%) were missing, contradictory, or answered with two or more answers on the questionnaire. Only eight such defects occurred following the telephone interview by a skilled orthopaedic surgeon, representing a significant reduction in these defects (P < .005). The average time of the telephone call was 2.8 minutes (range, 1-12 minutes), and the average number of attempts to contact the patient was 1.4 (range, 1-6). All questionnaire data and questionnaire data plus telephone data were compared with data obtained from a subsequent face-to-face interview by a different skilled orthopaedic surgeon who was blinded to the data from both the questionnaire and the telephone interview. It is demonstrated that a telephone call to follow up a standardized, self-administered questionnaire is a very effective way to augment the quality and quantity of questionnaire responses.

Adult↗
PubMed1997

Periprosthetic femoral osteolysis around an uncemented nonmodular Moore prosthesis.

Periprosthetic osteolysis is a major problem in total joint arthroplasty surgery today. The particulate debris from ultrahigh-molecular-weight polyethylene, polymethyl methacrylate, and corrosion products from modular connections have been implicated in this process. A case of femoral osteolysis at the tip of a nonmodular Moore prosthesis, in the absence of polyethylene, polymethyl methacrylate, and modular connections, is reported. In the area of osteolysis, histochemical and in situ hybridization techniques established the expression of messenger ribonucleic acid encoding for certain cytokines implicated in bone resorption, preferentially in the area of osteolysis. This case illustrates that the etiology of periprosthetic osteolysis is multifactorial and can occur in the absence of polyethylene, methacrylate, or modular components. All joint implants should be monitored for the development of this complication.

Aged↗